God is dead and no one cares...

Cosmologists aim to reveal first moments of time
Feb. 16, 2009
Courtesy University of Chicago and World Science staff

With­in a dec­ade, a del­i­cate meas­ure­ment of pri­mor­di­al light might re­veal ev­i­dence for the pop­u­lar cos­mic infla­t­ion the­o­ry, which pro­poses that a ran­dom, mi­cro­scop­ic dens­ity fluctua­t­ions in the fab­ric of space and time spawned the uni­verse.

Such fluctua­t­ions would have led to a hot “Big Bang,” as as­tro­no­mers call the sort of ex­plo­sion be­lieved to have giv­en birth to the cos­mos some 13.7 bil­lion years ago.

Among cos­mol­o­gists search­ing for ev­i­dence of these events will be John Carl­strom, a Uni­ver­s­ity of Chica­go cos­mol­o­gists who op­er­ates the South Pole Tel­e­scope with sci­en­tists from nine in­sti­tu­tions.

They plan to put cos­mic infla­t­ion the­o­ry to its most strin­gent ob­serva­t­ional test so far by de­tect­ing faint “gra­vity waves”—an ex­ot­ic phe­nom­e­non that Ein­stein’s gen­er­al rel­a­ti­vity the­o­ry pre­dicts cos­mic infla­t­ion should pro­duce.

“If you de­tect gra­vity waves, it tells you a whole lot about infla­t­ion for our uni­verse,” Carl­strom said. It al­so would rule out var­i­ous com­pet­ing ideas for its or­i­gin. “There are few­er than there used to be, but they don’t pre­dict that you have such an ex­treme, hot big bang, this quan­tum fluctua­t­ion, to start with,” he said. Nor would they pro­duce gra­vity waves at de­tecta­ble lev­els.

Carl­strom and col­league Scott Do­del­son were on pan­el of cos­mol­o­gists dis­cussing these and re­lat­ed is­sues on Feb. 16 at the Amer­i­can As­socia­t­ion for the Ad­vance­ment of Sci­ence an­nu­al meet­ing in Chica­go. Fel­low pan­elists in­clud­ed Al­an Guth of the Mas­sa­chu­setts In­sti­tute of Tech­nol­o­gy. In 1979, Guth pro­posed the cos­mic infla­t­ion the­o­ry, which pre­dicts the ex­ist­ence of an in­fi­nite num­ber of uni­verses. Un­for­tu­nate­ly, cos­mol­o­gists have no way of test­ing this pre­diction.

“S­ince these are sep­a­rate uni­verses, by def­i­ni­tion that means we can nev­er have any con­tact with them. Noth­ing that hap­pens there has any im­pact on us,” said Do­del­son, a sci­ent­ist at Fer­mi Na­tional Ac­cel­er­a­tor Lab­o­r­a­to­ry and the Uni­ver­s­ity of Chica­go.

But there is a way to probe the val­id­ity of cos­mic infla­t­ion. The phe­nom­e­non would have pro­duced two clas­ses of per­turba­t­ions, cos­mol­o­gists say. The first, fluctua­t­ions in the dens­ity of sub­a­tom­ic par­t­i­cles, hap­pen con­tin­u­ously eve­ry­where; sci­en­tists have de­tected them. Infla­t­ion would have in­stan­ta­ne­ously stretched some of these per­turba­t­ions in­to cos­mic pro­por­tions. “We can cal­cu­late what those per­turba­t­ions should look like, and it turns out they are ex­actly right to pro­duce the ga­lax­ies we see,” Do­del­son said.

The sec­ond class of per­turba­t­ions would be gra­vity waves—E­in­steinian dis­tor­tions in space and time. Gra­vity waves al­so would get pro­mot­ed to cos­mic pro­por­tions, per­haps even strong enough for cos­mol­o­gists to de­tect them with sen­si­tive tele­scopes. “We should be able to see them if John’s in­stru­ments are sen­si­tive enough,” Do­del­son said.

Carl­strom and col­leagues are build­ing a spe­cial in­stru­ment, a po­lar­im­e­ter, as an at­tach­ment to the South Pole Tel­e­scope, to search for gra­vity waves. The tel­e­scope is built to de­tect light waves from the mi­cro­wave to the in­fra­red range.

Cos­mol­o­gists al­so use the tel­e­scope in their quest to solve the mys­tery of dark en­er­gy. A re­pul­sive force, dark en­er­gy is pro­posed to push the uni­verse apart and over­whelm gra­vity, the at­trac­tive force ex­erted by all mat­ter. Dark en­er­gy is in­vis­i­ble, but as­tro­no­mers see its ap­par­ent in­flu­ence on clus­ters of ga­lax­ies that formed with­in the last few bil­lion years.

The South Pole Tel­e­scope de­tects the cos­mic mi­cro­wave back­ground radia­t­ion, the af­ter­glow of the “Big Bang.” Cos­mol­o­gists have mined a for­tune of da­ta from the mi­cro­wave back­ground da­ta, which rep­re­sent the force­ful drums and horns of the cos­mic sym­pho­ny. But now the sci­en­tif­ic com­mun­ity has its ears cocked for the tones of a sub­tler in­stru­ment—gravita­t­ional waves—that un­der­lay the mi­cro­wave back­ground.

“We have these key com­po­nents to our pic­ture of the uni­verse, but we really don’t know what phys­ics pro­duces any of them,” said Do­del­son of infla­t­ion, dark en­er­gy and the equally mys­te­ri­ous dark mat­ter. “The goal of the next dec­ade is to iden­ti­fy the phys­ics.”

"Long before it's in the papers"
Nov. 13, 2008
World Science staff

The tech­nol­o­gy for pho­tograph­ing plan­ets in dis­tant so­lar sys­tems is mak­ing strides, as­tro­no­mers say, with new im­ages in­clud­ing one that shows three worlds around a young star.

As­t­ro­phys­i­cist Chris­tian Marois and col­leagues said they used the Keck and Gem­i­ni North tele­scopes on Mauna Kea in Ha­waii to find the plan­ets or­bit­ing the star HR 8799.

Mem­bers of Marois’ group said they de­vel­oped an ad­vanced com­put­er pro­cess­ing meth­od that helped dis­tin­guish the plan­ets from the star­light. Their find­ings ap­pear in the Nov. 13 is­sue of Sci­ence Ex­press, the ad­vance on­line edi­tion of the re­search jour­nal Sci­ence.

HR 8799 is just vis­i­ble to the un­aided eye and lies about 130 light-years from Earth in the di­rec­tion of the con­stella­t­ion Peg­a­sus, in the north­ern sky. A light-year is the dis­tance light trav­els in a year.

These plan­ets, about 60 mil­lion years old, are young enough that they are still glow­ing from heat left over from their forma­t­ion, said the re­search­ers, led by Marois, of the Na­tional Re­search Coun­cil of Can­a­da Herzberg In­sti­tute of As­t­ro­phys­ics in Vic­to­ria, Brit­ish Co­lum­bia.

The worlds seem to be around sev­en, ten, and ten times the weight of Ju­pi­ter and some­what wid­er, they added. But these es­ti­mates are rough, the group not­ed, be­cause the speed of the plan­ets’ or­bit, which would yield the best meas­ure of weight, is un­known.

“Com­par­i­son with the­o­ret­i­cal mod­el at­mo­spheres con­firms that all three plan­ets pos­sess com­plex at­mo­spheres with dusty clouds par­tially trap­ping and re-radiating the es­cap­ing heat,” said Travis Bar­man, an as­tron­o­mer at Low­ell Ob­serv­a­to­ry at the Uni­ver­s­ity of Cal­i­for­nia Los An­ge­les, a co-author of the stu­dy.

Fur­ther stud­ies of the light emis­sions from the plan­ets will let re­search­ers study their make­up in de­tail, he added. The plan­ets are meas­ured to lie up to 70 times furth­er from their sun than the Earth does from ours.

Sep­a­rate­ly, anoth­er re­search team im­aged a plan­et or­bit­ing the star Fo­mal­haut, one of the bright­est in the sky and just 25 light years from Earth. These are the first snap­shots of a plan­et out­side our so­lar sys­tem tak­en in vis­i­ble light rath­er than in oth­er forms of light not vis­i­ble to hu­man eyes, said Uni­ver­s­ity of Cal­i­for­nia, Berke­ley, as­tron­o­mer Paul Kalas, co-author of a pa­per on the find­ings. That re­port al­so ap­pears in the Nov. 13 Sci­ence Ex­press.

* * *

A star explodes in the sky, but nobody sees it ...
Orbiting X-ray observatory discovers an exploding star in the Milky Way
updated 9:42 a.m. PT, Tues., July. 22, 2008

An orbiting X-ray observatory has discovered an exploding star in the Milky Way which somehow escaped notice by the usual crowd of star gazers.

Calculations show that the star’s sudden brightness was clearly visible to the naked eye, but no one reported anything until the European Space Agency’s XMM-Newton telescope spotted an unexpected burst of cosmic X-rays.

On Oct. 9, 2007, XMM-Newton was turning from one target to another when it passed across a bright source of X-rays that no one was expecting. The source was not listed in any previous X-ray catalog, yet the mysterious object was lighting up XMM-Newton’s view of the cosmos.

The XMM-Newton team looked up three possible celestial candidates as at this location, including a normally faint star known only by its catalog number USNO-A2.0 0450-03360039. Acting quickly, Andy Read of the University of Leicester and Richard Saxton of ESA's European Space Astronomy Centre (ESAC), Spain, e-mailed other astronomers about the newly-discovered X-ray source.

More sleuthing
Astronomers turned to the 6.5-meter Magellan-Clay telescope at Las Campanas Observatory in Chile, and found that USNO-A2.0 0450-03360039 had become 600 times brighter than normal. Analyzing the light from the source meant that they could classify the object as a nova.

Novae occur when a small, compact star, called a white dwarf, feeds off the gas of a nearby companion star. Gas builds up on the white dwarf until a nuclear reaction begins releasing large quantities of
energy, causing the white dwarf to explode in brightness.

That led to a puzzle. An explosion of this type does not immediately release X-rays, because the expanding cloud of debris created in the detonation temporarily masks them. That meant the explosion must have taken place many days before XMM-Newton spotted the X-ray burst, although no one reported seeing it.

Amateur and professional astronomers usually find novae by regularly sweeping the night sky for stars or other objects that suddenly brighten — but humans are not alone in watching the sky. Saxton contacted the robotic All Sky Automated Survey project and asked astronomers to check their data. They found the nova had taken place on June 5, 2007, and had been clearly visible, and that it would have been bright enough to see with the unaided eye.

"Anyone who went outside that night and looked towards the constellation of Puppis would have seen it," Saxton says.

Still tracking
The nova has now received the official name of V598 Puppis and has become one of the brightest for almost a decade, despite not getting spotted during its brilliant peak. As news of its existence spread, the global effort to track its fading light became intense.

"Suddenly there was all this data being collected about the star,” Read says. “For variable star work like this, the contribution of the amateur community can be at least as important as that from the professionals.”

This story has a happy ending thanks to XMM-Newton, which has covered 30 percent of the sky and documented 7,700 X-ray sources. However, the event does make astronomers wonder whether there are other discoveries going unnoticed.

NASA: Black holes have simple feeding habits

The biggest black holes may feed just like the smallest ones, according to data from NASA's Chandra X-ray Observatory and ground-based telescopes. This discovery supports the implication of Einstein's relativity theory that black holes of all sizes have similar properties, and will be useful for predicting the properties of a conjectured new class of black holes.

The conclusion comes from a large observing campaign of the spiral galaxy M81, which is about 12 million light years from Earth. In the center of M81 is a black hole that is about 70 million times more massive than the Sun, and generates energy and radiation as it pulls gas in the central region of the galaxy inwards at high speed.

In contrast, so-called stellar mass black holes, which have about 10 times more mass than the Sun, have a different source of food. These smaller black holes acquire new material by pulling gas from an orbiting companion star. Because the bigger and smaller black holes are found in different environments with different sources of material to feed from, a question has remained about whether they feed in the same way.

Using these new observations and a detailed theoretical model, a research team compared the properties of M81's black hole with those of stellar mass black holes. The results show that either big or little, black holes indeed appear to eat similarly to each other, and produce a similar distribution of X-rays, optical and radio light.

One of the implications of Einstein's theory of General Relativity is that black holes are simple objects and only their masses and spins determine their effect on space-time. The latest research indicates that this simplicity manifests itself in spite of complicated environmental effects.

"This confirms that the feeding patterns for black holes of different sizes can be very similar," said Sera Markoff of the Astronomical Institute, University of Amsterdam in the Netherlands, who led the study. "We thought this was the case, but up until now we haven't been able to nail it."

The model that Markoff and her colleagues used to study the black holes includes a faint disk of material spinning around the black hole. This structure would mainly produce X-rays and optical light. A region of hot gas around the black hole would be seen largely in ultraviolet and X-ray light. A large contribution to both the radio and X-ray light comes from jets generated by the black hole. Multi-wavelength data is needed to disentangle these overlapping sources of light.

"When we look at the data, it turns out that our model works just as well for the giant black hole in M81 as it does for the smaller guys," said Michael Nowak, a coauthor from the Massachusetts Institute of Technology. "Everything around this huge black hole looks just the same except it's almost 10 million times bigger."

Among actively feeding black holes the one in M81 is one of the dimmest, presumably because it is "underfed". It is, however, one of the brightest as seen from Earth because of its relative proximity, allowing high quality observations to be made.

"It seems like the underfed black holes are the simplest in practice, perhaps because we can see closer to the black hole," said Andrew Young of the University of Bristol in England. "They don't seem to care too much where they get their food from."

This work should be useful for predicting the properties of a third, unconfirmed class called intermediate mass black holes, with masses lying between those of stellar and supermassive black holes. Some possible members of this class have been identified, but the evidence is controversial, so specific predictions for the properties of these black holes should be very helpful.

In addition to Chandra, three radio arrays (the Giant Meterwave Radio Telescope, the Very Large Array and the Very Long Baseline Array), two millimeter telescopes (the Plateau de Bure Interferometer and the Submillimeter Array), and Lick Observatory in the optical were used to monitor M81. These observations were made simultaneously to ensure that brightness variations because of changes in feeding rates did not confuse the results. Chandra is the only X-ray satellite able to isolate the faint X-rays of the black hole from the emission of the rest of the galaxy.

This result confirms less detailed earlier work by Andrea Merloni from the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany and colleagues that suggested that the basic properties of larger black holes are similar to the smaller ones. Their study, however, was not based on simultaneous, multi-wavelength observations nor the application of a detailed physical model.

Hints of 'time before Big Bang'
By Dr Chris Lintott
Co-presenter, BBC Sky At Night, St Louis, US

A team of physicists has claimed that our view of the early Universe may contain the signature of a time before the Big Bang.

The discovery comes from studying the cosmic microwave background (CMB), light emitted when the Universe was just 400,000 years old.

Their model may help explain why we experience time moving in a straight line from yesterday into tomorrow.

Details of the work have been submitted to the journal Physical Review Letters.

The CMB is relic radiation that fills the entire Universe and is regarded as the most conclusive evidence for the Big Bang.

Although this microwave background is mostly smooth, the Cobe satellite in 1992 discovered small fluctuations that were believed to be the seeds from which the galaxy clusters we see in today's Universe grew.

Every time you break an egg or spill a glass of water you're learning about the Big Bang
Professor Sean Carroll,
California Institute for Technology

Dr Adrienne Erickcek, from the California Institute of Technology (Caltech), and colleagues now believe these fluctuations contain hints that our Universe "bubbled off" from a previous one.

Their data comes from Nasa's Wilkinson Microwave Anisotropy Probe (WMAP), which has been studying the CMB since its launch in 2001.

Their model suggests that new universes could be created spontaneously from apparently empty space. From inside the parent universe, the event would be surprisingly unspectacular.

Arrow of time

Describing the team's work at a meeting of the American Astronomical Society (AAS) in St Louis, Missouri, co-author Professor Sean Carroll explained that "a universe could form inside this room and we’d never know".

The inspiration for their theory isn't just an explanation for the Big Bang our Universe experienced 13.7 billion years ago, but lies in an attempt to explain one of the largest mysteries in physics - why time seems to move in one direction.
WMAP (Image: Nasa)

The laws that govern physics on a microscopic scale are completely reversible, and yet, as Professor Carroll commented, "no one gets confused about which is yesterday and which is tomorrow".

Physicists have long blamed this one-way movement, known as the "arrow of time", on a physical rule known as the second law of thermodynamics, which insists that systems move over time from order to disorder.

This rule is so fundamental to physics that pioneering astronomer Arthur Eddington insisted that "if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation".

The second law cannot be escaped, but Professor Carroll pointed out that it depends on a major assumption - that the Universe began its life in an ordered state.

This makes understanding the roots of this most fundamental of laws a job for cosmologists.

"Every time you break an egg or spill a glass of water, you're learning about the Big Bang," Professor Carroll explained.

Before the bang

In his presentation, the Caltech astronomer explained that by creating a Big Bang from the cold space of a previous universe, the new universe begins its life in just such an ordered state.

The apparent direction of time - and the fact that it's hard to put a broken egg back together - is the consequence.

Much work remains to be done on the theory: the researchers' first priority will be to calculate the odds of a new universe appearing from a previous one.

In the meantime, the team has turned to the results from WMAP.

Detailed measurements made by the satellite have shown that the fluctuations in the microwave background are about 10% stronger on one side of the sky than those on the other.

Sean Carroll conceded that this might just be a coincidence, but pointed out that a natural explanation for this discrepancy would be if it represented a structure inherited from our universe's parent.

Meanwhile, Professor Carroll urged cosmologists to broaden their horizons: "We're trained to say there was no time before the Big Bang, when we should say that we don't know whether there was anything - or if there was, what it was."

If the Caltech team's work is correct, we may already have the first information about what came before our own Universe.

From cracks to catastrophes, "singularity theory” could shed light
June 5, 2008
Courtesy European Science Foundation and World Science staff

The­re’s often more to everyday events than meets the eye. The folding of paper, or dripping of wa­ter from a tap, are two ex­am­ples: they both in­volve the crea­t­ion of points known as sin­gu­lar­i­ties.

Sin­gu­lar­i­ties oc­cur at places of cut­off or of sud­den change, as in forma­t­ion of cracks, light­ning strikes, crea­t­ion of ink drops in print­ers, and the break­ing of a cup when it drops. These points re­quire soph­is­t­icated math­e­mat­i­cal tech­niques to de­scribe, an­a­lyse and pre­dict.

Sci­en­tists say many sin­gu­lar­i­ties have much in com­mon at all size scales—from mi­cro­scop­ic in­ter­ac­tions to the forma­t­ion of the uni­ver­se it­self dur­ing the so-called Big Bang. But these seem­ingly dis­par­ate events are usu­ally stud­ied by dif­fer­ent sci­en­tists in re­la­tive isola­t­ion.

A work­shop or­gan­ised by the Eu­ro­pe­an Sci­ence Founda­t­ion in Par­is in Jan­u­ary was one of the first at­tempts to un­ify the field of sin­gu­lar­i­ties by bring­ing to­geth­er ex­perts in the dif­fer­ent fields from as­tron­o­my to nano­sci­ence—the study of atom­ic-scale struc­tures.

The meet­ing was aimed at de­vel­op­ing com­mon math­e­mat­i­cal ap­proaches to sin­gu­lar­i­ties. Im­proved un­der­stand­ing of the un­der­ly­ing math would have many ben­e­fits, for ex­am­ple in mak­ing ma­te­ri­als more re­sist­ant to break­ing, re­search­ers say.

The event was a suc­cess and and paved the way for fur­ther re­search with great­er cross-pollina­t­ion of ideas, said the con­ven­or, Jens Eg­gers of the founda­t­ion.

The work­shop con­firmed, sci­en­tists said, that most or all sin­gu­lar­i­ties, from mi­cro­scop­ic cracks to the Big Bang, share a key prop­er­ty known as self-si­m­i­lar­ity. This means that un­der mag­nif­ica­t­ion the event looks al­most the same. For ex­am­ple a crack in a piece of plas­tic ex­hibits the same jag­ged struc­ture when mag­ni­fied, say, 100 times. This means com­mon math­e­mat­i­cal ap­proaches can be ap­plied.

But the dev­il is in the de­tails when it comes to com­par­ing dif­fer­ent types of sin­gu­lar­i­ties, work­shop par­t­i­ci­pants cau­tioned. Dif­fer­ent sys­tems might have some com­mon fea­tures such as self-si­m­i­lar­ity, but al­so un­ique as­pects that re­quire spe­cial­ised stu­dy. One aim of the work­shop was to iden­ti­fy the com­mon meth­ods that could be ap­plied as a founda­t­ion for more de­tailed spe­cif­ic study.

Jay Fine­berg of He­brew Uni­ver­s­ity in Je­ru­sa­lem, for ex­am­ple, pre­sented in­ves­ti­ga­t­ions of cracks in struc­tures or rock forma­t­ions. Fine­berg dis­cussed new ex­pe­ri­ments in­volv­ing gels, al­low­ing the crack’s struc­ture to be de­ter­mined in great de­tail down to mi­cro­scop­ic di­men­sions, yield­ing some un­ex­pected find­ings.

Cracks are of­ten sur­pris­ingly com­plex, Eg­gers not­ed, with “many small side branches, which ap­pear to have com­pli­cat­ed, if not frac­tal, struc­ture.” Frac­tal struc­ture here means much the same as self-si­m­i­lar­ity, in­volv­ing a ge­o­met­ric pat­tern that looks un­changed un­der mag­nif­ica­t­ion or re­duc­tion.

Anoth­er ex­am­ple con­cerned the sin­gu­lar­i­ties of crum­pling in pa­per, pre­sented by Tom Wit­ten of the James Franck In­sti­tute in Chi­ca­go. Crum­pled pa­per com­prises many ridges and tips that de­fy sim­ple anal­y­sis. There are many un­an­swered ques­tions even in de­scrib­ing each in­di­vid­ual cone-shaped tip, Eg­gers said; fig­ur­ing out the un­der­ly­ing math would not just help un­der­stand what hap­pens when we crum­ple pa­per, but al­so oth­er phys­i­cal sys­tems in­volv­ing ridges and tips, such as the way bi­o­log­i­cal mo­le­cules fold in­to their char­ac­ter­is­tic forms.

One branch of sin­gu­lar­ity the­o­ry is “catas­tro­phe the­o­ry,” which rose to prom­i­nence in the 1970s, in­i­tially de­vel­oped by French math­e­ma­ti­c René Thom and ex­pand­ed by U.K. math­e­ma­ti­c Er­ik Zee­man. Ca­tas­tro­phe the­o­ry deals with events with space-and-time com­po­nents, such as col­li­sions be­tween wave fronts, Eg­gers said. “In that case, a prob­lem that takes place in all of space can be re­duced to a prob­lem that takes place along cer­tain lines,” known as caus­tics, “which can be clas­si­fied ac­cord­ing to ca­tas­tro­phe the­o­ry.” But not all sin­gu­lar­ity prob­lems are ame­na­ble to this sim­plifica­t­ion.

The sub­ject “cuts across dis­ci­plines and spe­cial­iz­a­tions, such as ex­pe­ri­men­tal phys­ics, the­o­ret­i­cal phys­ics, and rig­or­ous math­e­mat­i­cal proofs,” Eg­gers said. “This work­shop very much re­flected this fact, as we had speak­ers from very dif­fer­ent back­grounds.”

Old galaxies stick together in the young universe

UK astronomers have developed the most sensitive infrared map of the distant universe ever produced, revealing the origins of the most massive galaxies in the cosmos.

Using images obtained with the United Kingdom Infra-Red Telescope (UKIRT), astronomers combined data over a period of three years. This produced a map encompassing more than 100,000 galaxies over an area of sky four times the size of the full moon.

As light from the far reaches of the universe takes so long to reach observers on Earth, UKIRT allows astronomers to look back in time — more than ten billion years — producing images of the galaxies' infancy. The image is so large and so deep that thousands of galaxies can be studied at these early epochs for the first time.

By observing these galaxies at the infrared wavelength, astronomers can now peer even further back in time — as light is shifted towards the redder wavelength as it travels through the expanding universe.

Researchers at The University of Nottingham led the study, which also produced convincing evidence that galaxies which look old early in the history of the Universe reside in enormous clouds of invisible dark matter and will eventually evolve into the most massive galaxies that exist in the present day.

The distant galaxies identified are considered elderly because they are rich in old, red stars. But because the light from these systems has taken up to 10 billion years to reach Earth, they are seen as they appeared in the very early Universe, just four billion years after the Big Bang. The presence of such fully-evolved galaxies so early in the life of the cosmos is hard to explain and has been a major puzzle to astronomers studying how galaxies form and evolve.

The team used the deep UKIRT images to estimate the mass of the dark matter surrounding the old galaxies by measuring how strongly the galaxies cluster together. All galaxies are thought to form within massive halos of dark matter which collapse under their own gravity from a smooth distribution of matter after the Big Bang.

These halos are invisible to normal telescopes but their mass can be estimated through analysis of galaxy clustering.

“Luckily, even if we don't know what dark matter is, we can understand how gravity will affect it and make it clump together. We can see that the old, red galaxies clump together far more strongly than the young, blue galaxies, so we know that their invisible dark matter halos must be more massive,” said Will Hartley, PhD student at the University of Nottingham, who led the work into the clustering of old galaxies.

The halos surrounding the old galaxies in the early Universe are found to be extremely massive, containing material which is up to one hundred thousand billion times the mass of our Sun. In the nearby Universe, halos of this size are known to contain giant elliptical galaxies, the largest galaxies known.

“This provides a direct link to the present day Universe,” says Hartley, "and tells us that these distant old galaxies must evolve into the most massive but more familiar elliptical-shaped galaxies we see around us today. Understanding how these enormous elliptical galaxies formed is one of the biggest open questions in modern astronomy and this is an important step in comprehending their history.”

“I would compare these observations to the ice cores drilled deep into the Antarctic,” said Dr Sebastien Foucaud, who led the building of the new images into a map. “Just as they allow us to peer back in time, our ultra-deep image allows us to look back and observe galaxies evolving at different stages in cosmic history, all the way back to just one billion years after the big bang.

“We see galaxies ten times the mass of the Milky Way already in place at very early epochs. Now, for the first time, we are sampling a large enough volume of the distant universe to be able to see them in sufficient numbers and really pin down when they were formed.”

Will Hartley and Dr Foucaud presented their work at this week's National Astronomy Meeting held by the Royal Astronomical Society. They were joined by Dr Omar Almaini, Reader in Astronomy at the University and overall leader of the survey team.

Dr Almaini said: “We are leading the world with this project, and there is much more to come. We will continue taking data over the next few years, which will detect galaxies in the ever more distant Universe.”

The old galaxies were identified from images taken as part of the Ultra-Deep Survey (UDS), one element of a five-part project, the UKIRT Infrared Deep Sky Survey (UKIDSS), which commenced in 2005. UKIRT is the world's largest telescope dedicated solely to infrared astronomy, sited near the summit of Mauna Kea, Hawaii, at an altitude of 4194 metres (13760 feet) above sea level.

The Royal Astronomical Society National Astronomy Meeting is hosted by Queen's University Belfast. It is principally sponsored by the RAS and the Science and Technology Facilities Council.

More information is available from www.nottingham.ac.uk/astronomy/UDS/

Titan's Surface Organics Surpass Oil Reserves on Earth

Saturn's orange moon Titan has hundreds of times more liquid hydrocarbons than all the known oil and natural gas reserves on Earth, according to new data from NASA's Cassini spacecraft. The hydrocarbons rain from the sky, collecting in vast deposits that form lakes and dunes.

The new findings from the study led by Ralph Lorenz, Cassini radar team member from the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., are reported in the Jan. 29 issue of the Geophysical Research Letters.

"Titan is just covered in carbon-bearing material -- it's a giant factory of organic chemicals," said Lorenz. "This vast carbon inventory is an important window into the geology and climate history of Titan."

At a balmy minus 179 degrees Celsius (minus 290 degrees Fahrenheit), Titan is a far cry from Earth. Instead of water, liquid hydrocarbons in the form of methane and ethane are present on the moon's surface, and tholins probably make up its dunes. The term "tholins"was coined by Carl Sagan in 1979 to describe the complex organic molecules at the heart of prebiotic chemistry.

Cassini has mapped about 20 percent of Titan's surface with radar. Several hundred lakes and seas have been observed, with each of several dozen estimated to contain more hydrocarbon liquid than Earth's oil and gas reserves. The dark dunes that run along the equator contain a volume of organics several hundred times larger than Earth's coal reserves.

Proven reserves of natural gas on Earth total 130 billion tons, enough to provide 300 times the amount of energy the entire United States uses annually for residential heating, cooling and lighting. Dozens of Titan's lakes individually have the equivalent of at least this much energy in the form of methane and ethane.

"This global estimate is based mostly on views of the lakes in the northern polar regions. We have assumed the south might be similar, but we really don't yet know how much liquid is there," said Lorenz. Cassini's radar has observed the south polar region only once, and only two small lakes were visible. Future observations of that area are planned during Cassini's proposed extended mission.

Scientists estimated Titan's lake depth by making some general assumptions based on lakes on Earth. They took the average area and depth of lakes on Earth, taking into account the nearby surroundings, like mountains. On Earth, the lake depth is often 10 times less than the height of nearby terrain.

"We also know that some lakes are more than 10 meters or so deep because they appear literally pitch-black to the radar. If they were shallow we'd see the bottom, and we don't," said Lorenz.

The question of how much liquid is on the surface is an important one because methane is a strong greenhouse gas on Titan as well as on Earth, but there is much more of it on Titan. If all the observed liquid on Titan is methane, it would only last a few million years, because as methane escapes into Titan's atmosphere, it breaks down and escapes into space. If the methane were to run out, Titan could become much colder. Scientists believe that methane might be supplied to the atmosphere by venting from the interior in cryovolcanic eruptions. If so, the amount of methane, and the temperature on Titan, may have fluctuated dramatically in Titan's past.

"We are carbon-based life, and understanding how far along the chain of complexity towards life that chemistry can go in an environment like Titan will be important in understanding the origins of life throughout the universe," added Lorenz.

Cassini's next radar flyby of Titan is on Feb. 22, when the radar instrument will observe the Huygens probe landing site.

For images and more information visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

Where do they stand on the 2008/09 science budget?
Nearly all the remaining presidential candidates agree that the U.S. should continue to invest in energy and basic science research. Hillary Clinton provided the most detailed proposals, with Barack Obama a close second now that John Edwards is out of the race. The two main republican candidates, John McCain and Mike Huckabee, do not have specific proposals but they do support increased funding for energy research and education.

John McCain, Hillary Clinton and Barack Obama are still in the Senate and may vote on the 2009 science budget before the campaign is over.
The 2008 budget turned into a disaster for science, particularly for high energy physics for which funding of the international linear collider and the international thermonuclear experimental reactor were effectively zeroed out. In response, Fermilab and the Stanford Linear Accelerator Center had to curtail experiments early, cut staff and in some cases, ask their employees to take two days of unpaid furlough each month.
The cuts in the 2008 budget came about because Congress and the White House disagreed over how to pay for tax cuts and government services in an era of rising deficits.

In the 2009 budget the Office of Science at the Department of Energy, which funds Fermilab, would receive an 18% increase from $3.97 billion to $4.72 billion. The National Science Foundation would receive a 14 percent increase to $6.85 billion, and the National Institute of Standards and Technology would receive a 22 percent increase to $634 million.

Last year both Hillary Clinton and Barack Obama abstained from voting on the 2008 science budget. John McCain voted against it.
If the candidates want to support increased science funding, they can support the 2009 budget or, if Congress decides to delay passing the budget, call for supplemental spending bills that increase research funds above their 2008 level.

How important is the White House science adviser?
Presidents have had science advisers in one form or another since Franklin D. Roosevelt. The position gained new importance in 1976 when Congress established the White House Office of Science and Technology Policy (OSTP). The OSTP has a mandate to advise the President and others in the Executive Office of the President on the effects of science and technology on domestic and international affairs.

According to its website, the OSTP and science adviser, who until recently held the title "assistant to the president", has had some success in the past in pushing programs such as the Human Genome Project and getting support for doubling the budget of the National Institutes of Health.
As previous science advisers told Physics Today when current science adviser John Marburger was nominated in 2001, access to the president is critical. Through direct contact, the science adviser not only can discuss policy with the president, but he gains status as a true "insider," an invaluable asset when dealing with the federal bureaucracy.
Neal Lane, a former science adviser to the Clinton administration, told the New York Times for an article about the politicization of science, "Your influence depends on whether people around the president feel you have something to add."
Whether Marburger has had the access he would like in the Bush administration, remains in question, D. James Baker, the former head of the National Oceanic and Atmospheric Administration, has stated that "the administration has backed away from listening to the science adviser position."
In that regard, despite the experience and long list of eminent scientists providing advice to the Clinton, Obama, Romney, and McCain candidacies, only John Edwards and Hillary Clinton have explicitly stated that they will return the science adviser position to its previous rank of "assistant to the president."

Ron Paul on nuclear weapons
Ron Paul has stated that he is against military activity in almost every circumstance when war isn’t declared. He states that because the US went back and offered deals to the North Koreans after they exploded a nuclear weapon, while invading Iraq, a country that did not have an atomic bomb, the US is offering an “tremendous incentive” to non-nuclear states to develop nuclear weapons. He has no other statement on the future status of the U.S. nuclear weapons stockpile.

Ron Paul on science investment
From the 2007 GOP Values Voter Presidential Debate Sep 17, 2007
Ron Paul stated that the government should be very small and that the government should not be expected to fund everything..On April 27, 2007, Ron Paul voted against H.R. 362, the 10,000 Teachers, 10 Million Minds Science and Math Scholarship Act.
GOP Values Voter Presidential Debate Sep 17, 2007 Ron Paul stated that he would approve of tax credits for religious schools.


Hillary Clinton on science education
...I’ll improve math and science education, and open up science and engineering to more of our people. And I’ll end the assault on science waged by the Bush Administration.

Hillary Clinton on energy policy
Hillary has a bold and comprehensive plan to address America's energy and environmental challenges that will establish a green, efficient economy and create as many as five million new jobs.


Mike Huckabee on science investment
Huckabee has not outlined clear positions on the federal funding of science. He has pledge to simplify the immigration process for highly-skilled and highly-educated applicants.
Huckabee has also promised to increase funding for research into all avenues of alternative energy: nuclear, wind, solar, hydrogen, clean coal, biodiesel, and biomass.
Mike Huckabee on nuclear weapons

Mike Huckabee for President: ...There is no way Iran will acquire nuclear weapons on my watch. But before I look parents in the eye to explain why I had to put their son’s or daughter’s life at risk in military action against Iran, I want to know that I have done everything possible to avoid that conflict...
On June 5 at the CNN GOP debate in New Hampshire, Gov. Huckabee stated that he would consider a pre-emptive nuclear strike on Iran to stop their development of nuclear weapons.
Gov. Huckabee has made no statement on the role of the military or the funding of the nuclear weapon stockpile since running for office.


John McCain on science education
Although having a number of educators providing advice on education policy, such as Eileen Weiser of the National Assessment Governing Board and Phil Handy, former chairman of the Florida State Board of Education, McCain has yet to officially release an education policy.

During the 9 December 2007 republican primary debate on Univision McCain stated
"Choice and competition is the key to success in education in America. That means charter schools, that means home schooling, it means vouchers, it means rewarding good teachers and finding bad teachers another line of work. It means rewarding good performing schools, and it really means in some cases putting bad performing schools out of business. I want every American parent to have a choice, a choice as to how they want their child educated, and I guarantee you the competition will dramatically increase the level of education in America."
McCain has also suggested turning education policy back to individual states and offering federal money through unrestricted block grants. He will keep most aspects of No Child Left Behind legalization in place.

Moon systems, not planets, may be place to find life
Alien life might be both and ea­sier and more in­ter­est­ing to find through a new strategy, a study sug­gests
Feb. 19, 2008
Special to World Science

Many sci­en­tists in search of alien life pur­sue the ob­vi­ous strat­e­gy: look for po­ten­tially hab­it­a­ble plan­ets. But a new study suggests an­oth­er plan might work as well or bet­ter, and perhaps yield more in­tri­guing re­sults.

As­tro­no­mers should study gi­ant plan­ets that, while un­inhab­it­a­ble, lie in ar­eas suitably warm for life, the authors say. These may turn out to have moons—some of which might in­deed sup­port life.

One ad­van­tage of this tack, the re­search­ers argue, is that big worlds are far eas­i­er to find than the small, Earth-like ones on which most hab­it­a­ble-pla­net searches have fo­cused. Un­like the Earth-like breed, sev­er­al suitably warm gi­ants, dubbed “tem­per­ate Ju­pi­ters,” have been re­ported found al­ready.

Such bod­ies can “act as ‘sign-posts’ for fu­ture stud­ies look­ing for po­ten­tially hab­it­a­ble worlds,” said the Uni­ver­s­ity of Flor­i­da’s Scott Flem­ing, lead auth­or of the stu­dy.

If their moons do harbor life forms, these might even be more in­ter­est­ing in some ways than their plan­et-dwel­ling coun­ter­parts.

For in­stance, if one moon of a dis­tant “Ju­pi­ter” had life, so might oth­ers, as they would all lie in the same gen­er­al tem­per­a­ture zone. If ad­vanced enough, the in­hab­itants might even reg­u­larly ex­ploit the proxim­ity among moons to trav­el or com­mu­ni­cate among them. Or, bi­zarre ev­o­lu­tion­ary ex­pe­ri­ments might arise when me­te­ors ran­domly plop small or­gan­isms from one moon on­to an­oth­er.

On the oth­er hand, a large percentage of moons may be hos­tile to life, for in­stance be­cause they’re too small to hold at­mo­spheres. But giv­en ap­pro­pri­ate con­di­tions, life, trav­el and com­mu­nica­t­ion among a “tem­per­ate Ju­pi­ter’s” moons “would in­deed be very pos­si­ble,” said Flem­ing, a doctoral stu­dent. His re­search on de­tec­tion of “tem­per­ate Ju­pi­ters,” with col­leagues at the Space Te­le­s­cope Science In­sti­tute in Baltimore and at other ins­ti­tu­tions, is to ap­pear in a fu­ture is­sue of the jour­nal Monthly No­tices of the Roy­al As­tro­nom­i­cal So­ci­e­ty. The paper is also on­line here.

One “tem­per­ate Ju­pi­ter” re­ported found last year or­bits the star HD 75898, which is vis­i­ble with bin­oc­u­lars in the faint north­ern con­stella­t­ion Lynx. Tech­no­logy used to date has gen­erally been in­ca­pable of find­ing moons of such pla­nets. But Flem­ing said this could change next year with the launch of a NA­SA sa­tel­lite, Kep­ler: its instru­ments can de­tect both Earth-sized planets and moons, which would re­veal themselves through their gra­vi­ta­tional pulls on the planets. But there are con­cerns that Kep­ler’s mis­sion will be too short to find many moons, Flem­ing added.

Ju­pi­ter-like plan­ets, re­gard­less of tem­per­a­ture zone, are con­sid­ered un­inhab­it­a­ble them­selves, in part be­cause they’re made com­pletely of gas.

Yet if our So­lar Sys­tem is any guide, they’re rich in moons. Ju­pi­ter has 61 known moons. These range from the big­gest known—a­bout Mer­cury’s size, some 5,300 km (3,300 miles) wide—to chunks 2 km (1.2 miles) across, too small to even pull them­selves in­to round shapes with their gra­vity. Sat­urn, which is a bit like a some­what smaller Ju­pi­ter with rings, has 31 known moons, in a si­m­i­lar size range. In fact, most plan­ets in our sys­tem have moons, so as­tro­no­mers sup­pose the same would be true else­where.

Any residents of a Ju­pi­ter-like plan­et’s moon might find that trav­el to oth­er moons is rath­er easy com­pared to interplan­e­tary trav­el. The smaller size of moons greatly re­duces the en­er­gy re­quire­ments. For in­stance, it takes less than one-twentieth the en­er­gy to leave our moon as it does to leave Earth. As for com­mu­nica­t­ions among moons—it would take about three min­utes for ra­dio or light waves to trav­el be­tween the two furthest-apart of Ju­pi­ter’s moons. Res­i­dents of a multi-lu­nar sys­tem, Flem­ing said, could li­terally all tune in to the same ra­dio sta­tion.

Mystery world a merged planet?
Jan. 10, 2008
Courtesy Harvard-Smithsonian
Center for Astrophysics and World Science staff

A “mys­tery ob­ject” or­bit­ing a dis­tant star might have formed from the col­li­sion and merg­er of two de­vel­op­ing plan­ets, as­tro­no­mers say.

Re­search­ers have long puz­zled over what they call the ob­jec­t’s seem­ingly im­pos­si­ble com­bina­t­ion of tem­per­a­ture, bright­ness, age and loca­t­ion. “This is a strange enough ob­ject that it needs a strange ex­plana­t­ion,” said Er­ic Ma­ma­jek of the Har­vard-Smith­son­ian Cen­ter for As­t­ro­phys­ics in Cam­bridge, Mass., one of two re­search­ers who pro­poses the col­li­sion sce­nar­i­o based on new stud­ies.

The pro­pos­al was pre­sented Wednes­day at the an­nu­al meet­ing of the Amer­i­can As­tronomical So­ci­e­ty in Austin, Texas.

The ob­ject, known as 2M1207B, or­bits a brown dwarf star lying the di­rec­tion of the con­stella­t­ion Cen­tau­rus, 170 light-years from Earth. A light-year is the dis­tance light trav­els in a year. Com­put­er mod­els in­di­cate the star is eight mil­lion years old, very young for a star, as­tro­no­mers said; thus its com­pan­ion should al­so be no more than that old, since such ob­jects form around the same time.

At this age, the com­pan­ion should have cooled to less than 1300 de­grees Fahr­en­heit (1000 Kelv­in), said Ma­ma­jek and his col­league, Mi­chael Mey­er of the Un­ivers­ity of Ar­i­zo­na. But it’s meas­ured to have nearly twice that tem­per­a­ture. The re­search­ers say fric­tion from a re­cent col­li­sion might ex­plain the ex­tra heat.

“Most, if not all, plan­ets in our so­lar sys­tem were hit early in their his­to­ry. A col­li­sion cre­at­ed Earth’s moon and knocked Ura­nus on its side,” said Ma­ma­jek. “It’s quite likely that ma­jor col­li­sions hap­pen in oth­er young plan­e­tary sys­tems, too.”

The ap­par­ent merged world is al­so 10 times faint­er than ex­pected for its tem­per­a­ture, as­tro­no­mers said. In 2006, as­tro­no­mers sug­gested the faint­ness is due to a dusty cloud around the star. Ma­ma­jek and Mey­er pro­pose an al­ter­na­tive ex­plana­t­ion: that the ob­ject is smaller than pre­vi­ously es­ti­mat­ed, a bit smaller than Sat­urn. But the new es­ti­mate makes it even tougher to ex­plain how it re­tained its heat so long, un­less one pos­tu­lates a ti­tan­ic col­li­sion, they said.

Our so­lar sys­tem’s plan­ets are be­lieved to have as­sem­bled from dust, rock, and gas, grad­u­ally grow­ing over mil­lions of years. But some­times, two plan­et-sized ob­jects can crash. The Moon is thought to have formed when an ob­ject about half the size of Mars struck the young Earth. 2M1207B might be the prod­uct of a col­li­sion be­tween a Sat­urn-sized gas gi­ant and a plan­et about three times Earth’s size, Ma­ma­jek and Mey­er said. The two worlds would have smacked to­geth­er and stuck, form­ing a larg­er plan­et still boil­ing from the heat gen­er­at­ed in the col­li­sion.

The hy­poth­e­sis makes sev­er­al pre­dic­tions that as­tro­no­mers can test, the re­search­ers said. Chief among these is a low sur­face gra­vity, a quanti­ty that de­pends on a plan­et’s weight and width. To check this, as­tro­no­mers will need to bet­ter meas­ure the spec­trum of light from 2M1207B, Ma­ma­jek and Mey­ers said; more an­swers should be forth­com­ing with­in a year or two.

Even if a crash does­n’t turn out to be the right ex­plana­t­ion, oth­er ex­am­ples of col­lid­ing plan­ets are likely to turn up with the next genera­t­ion of ground-based tele­scopes, Ma­ma­jek said: “I would­n’t be sur­prised if some­one finds a clear-cut case in the next 10 years.”

Life’s building blocks formed on Mars: study
Dec. 11, 2007
Courtesy Carnegie Institution
and World Science staff

Sci­en­tists are re­port­ing that the mo­lec­u­lar build­ing blocks of life formed on Mars long ago—find­ings that sug­gest these mo­le­cules could form on any cold, rocky pla­net.

Or­gan­ic molecules, con­tain­ing car­bon and hy­dro­gen, are the ma­jor com­po­nents of all Earthly life. In a new stu­dy, re­search­ers with the Car­ne­gie In­sti­tu­tion in Wash­ing­ton, D.C. an­a­lyzed or­gan­ic com­pounds in a Mar­tian me­te­or­ite. Sci­en­tists had pre­vi­ously spec­u­lat­ed that these might have land­ed on the red plan­et thanks to me­te­or­ite im­pacts there. The new study in­stead con­clud­ed that the ma­te­ri­als probably formed on Mars it­self, pos­sibly as a re­sult of vol­can­ic erup­tions.

The find­ings “show that vol­can­ic ac­ti­vity in a freez­ing cli­mate can pro­duce or­gan­ic com­pounds,” said the in­sti­tu­tion’s Hans Amund­sen, one of the re­search­ers. “This im­plies that build­ing blocks of life can form on cold rocky plan­ets through­out the Un­iverse.”

The in­ves­ti­ga­tors com­pared the me­te­or­ite, called Al­lan Hills 84001, with rocks from Sval­bard, Nor­way. These oc­cur in vol­ca­noes that erupted in a freez­ing Arc­tic cli­mate about a mil­lion years ago, pos­sibly mim­ick­ing con­di­tions on early Mars, the sci­en­tists said.

“Or­gan­ic ma­te­ri­al oc­curs with­in ti­ny spheres of car­bonate min­er­als in both the Mar­tian and Earth rocks,” said An­drew Steele, lead au­thor of the stu­dy. The sci­en­tists, he added, found the or­gan­ic ma­te­ri­al in close as­so­ci­a­tion with a min­er­al called mag­netite—“the key to un­der­stand­ing how these com­pounds formed.”

When ma­te­ri­al blast­ed from Sval­bard vol­ca­noes cooled off, mag­net­ite acted as a cat­a­lyst, or chem­i­cal in­stiga­tor, for the forma­t­ion of or­gan­ic com­pounds from flu­ids rich in car­bon di­ox­ide and wa­ter, said the re­search­ers. “The si­m­i­lar as­socia­t­ion of car­bonate, mag­net­ite and or­gan­ic ma­te­ri­al in the Mar­tian me­te­or­ite... is very com­pelling,” they added in an an­nounce­ment of their find­ings Tues­day. “This is the first study to show that Mars is ca­pa­ble of form­ing or­gan­ic com­pounds at all.” The study is pub­lished in the Sep­tem­ber is­sue of the re­search jour­nal Me­te­or­it­ic & Plan­e­tary Sci­ence.

Steele said the work “sets the stage for the Mars Sci­ence Lab­o­r­a­to­ry mis­sion in 2009”—a NASA rov­er de­signed to help as­sess wheth­er Mars ev­er could, or can, sup­port mi­cro­bi­al life. One of its goals is to iden­ti­fy or­gan­ic com­pounds and their sources, said Steele, who is part of the mis­sion team. “We know that they are there. We just have to find them.”

“Clear signs” of water on foreign solar system
July 11, 2007
Courtesy Caltech
and World Science staff

Re­search­ers say they have found the best ev­i­dence to date that plan­ets out­side our so­lar sys­tem have wa­ter.

“Wa­ter is the quin­tes­sence of life as we know it,” said Yuk Yung, a pro­fes­sor of plan­e­tary sci­ence at the Cal­i­for­nia In­sti­tute of Tech­nol­o­gy in Pas­a­de­na, Ca­lif. It’s “ex­cit­ing to find that it is as abun­dant in an­oth­er so­lar sys­tem as it is in ours.” Yung is co-au­thor of a pa­per on the find­ing, ap­pear­ing in this week’s is­sue of the re­search jour­nal Na­ture.

As­tro­no­mers wrote that they found wa­ter’s chem­i­cal sig­na­ture in the at­mos­phere of a swel­t­er­ing plan­et called HD 189733b, sixty-three light-years away in the con­stella­t­ion Vul­pec­u­la. A light-year is the dis­tance light trav­els in a year.

The planet also re­cent­ly be­came the first to have its cli­mate mapped by hu­mans.

Re­search­ers had pre­dicted that plan­ets of its class, called “hot Jupiters,” would con­tain wa­ter va­por; re­cent ob­serva­t­ions had al­so sug­gested as much. The new re­search con­firmed this, us­ing the NASA Spitzer Space Tele­scope’s par­tic­u­larly keen abil­ity to study near­by stars and their plan­ets, sci­en­tists said.

They meas­ured changes in star­light as the plan­et slips in front of its star, fil­ter­ing star­light through its out­er at­mos­phere. The at­mos­phere was found to ab­sorb spe­cif­ic wave­lengths, or com­po­nents, of the light in a pat­tern char­ac­ter­is­tic of wa­ter con­tent.

“We’re thrilled to have iden­ti­fied clear signs of wa­ter on a plan­et that is tril­lions of miles away,” said Gio­van­na Ti­netti of the In­sti­tute d’As­tro­phy­sique de Par­is in France, lead au­thor of the Na­ture pa­per. “The dis­cov­ery of wa­ter is the key to the dis­cov­ery of al­ien life,” added co-au­thor Mao-Chang Liang of Cal­tech.

Al­though wa­ter is es­sen­tial to life as we know it, wet hot Ju­pi­ters probably don’t har­bor life. Temp­er­a­tures on HD 189733b are est­i­mated at a fiery 1,000 de­grees Kel­vin (1,340 de­grees Fahr­en­heit) on av­er­age. Ul­ti­mate­ly, as­tro­no­mers hope to use in­stru­ments like those on Spitzer to find wa­ter on rocky, hab­it­a­ble plan­ets like Earth.

“Find­ing wa­ter on this plan­et im­plies that oth­er plan­ets in the un­iverse, pos­sibly even rocky ones, could al­so have wa­ter,” said co-au­thor Sean Car­ey of the Spitzer Sci­ence Cen­ter at Cal­tech.

In a first, probe to focus on Martian ice
July 9, 2007
Courtesy NASA
and World Science staff

NASA’s next Mars mis­sion will be the first to spe­cif­ic­ally ze­ro in on fro­zen wa­ter—the cen­ter of sci­en­tists’ hopes for de­tect­ing the pos­si­bil­ity of past, pre­s­ent or fu­ture life on Mars.
--------------------------------------------------------------------------------
In­stead of rov­ing to hills or craters as past probes have done, NASA’s Phoe­nix Mars Lan­der is to claw in­to the icy soil of the Red Plan­et’s north­ern plains. The ro­bot would in­ves­t­i­gate wheth­er the ice might per­i­od­ic­ally melt enough to sus­tain mi­cro­bi­al life.

To ac­com­plish that and oth­er goals, Phoe­nix will car­ry in­stru­ments nev­er be­fore used on Mars. But first it must launch from Flor­i­da dur­ing a three-week pe­ri­od be­gin­ning Aug. 3, then sur­vive a risky de­scent and land­ing on Mars next spring.

“Our ‘fol­low the wa­ter’ strat­e­gy for ex­plor­ing Mars has yielded a string of dra­mat­ic dis­cov­er­ies in re­cent years about the his­to­ry of wa­ter on a plan­et where si­m­i­lar­i­ties with Earth were much great­er in the past than they are to­day,” said Doug Mc­Cuis­tion, di­rec­tor of the Mars Ex­plora­t­ion Pro­gram at NASA Head­quar­ters, Wash­ing­ton. “Phoe­nix will com­ple­ment our stra­te­gic ex­plora­t­ion of Mars by be­ing our first at­tempt to ac­tu­ally tou­ch and an­a­lyze Mar­tian wa­ter… in the form of bur­ied ice.”

NASA’s Mars Od­ys­sey or­biter found ev­i­dence in 2002 to sup­port the­o­ries that large ar­eas of Mars, in­clud­ing the arc­tic plains, have fro­zen wa­ter with­in an ar­m’s reach of the sur­face. Phoe­nix is to “ex­am­ine the his­to­ry of the ice by meas­ur­ing how liq­uid wa­ter has mod­i­fied the chem­is­try and min­er­al­o­gy of the soil,” said Pe­ter Smith, the Phoe­nix prin­ci­pal in­ves­ti­ga­tor at the Un­ivers­ity of Ar­i­zo­na, Tuc­son.

“In ad­di­tion, our in­stru­ments can as­sess wheth­er this po­lar en­vi­ron­ment is a hab­it­a­ble zone for prim­i­tive mi­crobes. To com­plete the sci­en­tif­ic char­ac­ter­iz­a­tion of the site, Phoe­nix will mon­i­tor po­lar weath­er and the in­ter­ac­tion of the at­mos­phere with the sur­face.”

With its so­lar pan­els un­furled, the lan­der is about 18 feet (5.5 me­ters) wide and 5 feet (1.5 me­ters) long. A ro­botic arm 7.7 feet long will dig to the icy lay­er, thought to lie a few inches down. A cam­era and probe on the arm will ex­am­ine soil and any ice. The arm would lift sam­ples to two in­stru­ments on the lan­der’s deck. One will use heat­ing to check for sub­stances such as wa­ter and carbon-based chem­i­cals that are build­ing blocks for life. The oth­er would an­a­lyze soil chem­is­try.

“Land­ing safely on Mars is dif­fi­cult no mat­ter what meth­od you use,” said Barry Gold­stein, proj­ect man­ag­er for Phoe­nix at NASA’s Je­t Pro­pul­sion Lab­o­r­a­to­ry in Pas­a­de­na, Ca­lif. “Our team has been test­ing the sys­tem re­lent­lessly since 2003” to iden­ti­fy and ad­dress vul­ner­a­bil­i­ties. Re­search­ers eval­u­at­ing land­ing sites have used ob­serva­t­ions from Mars or­biters to find the safest places where the mis­sion’s goals can be met, they said; the lead­ing can­di­date is a broad val­ley with few boul­ders at a lat­i­tude equiv­a­lent to north­ern Alas­ka.

Universe “forgets” its past
July 1, 2007
Courtesy PSU
and World Science staff

The cosmos may undergo ep­ic cy­cles of col­lapse and re-crea­t­ion—but some prop­er­ties of our pre­vi­ous un­iverse have left no mark on our own, a team of phys­i­cists has con­clud­ed. Two con­se­quences of this, they say, are that we can’t know our past un­iverse ex­actly, and suc­ces­sive un­iverses probably aren’t alike.

“An in­trin­sic cos­mic for­get­ful­ness” seems to pre­vent “the eter­nal re­cur­rence of ab­so­lutely iden­ti­cal un­ivers­es,” said team mem­ber Mar­tin Bo­jowald of Penn State Un­ivers­ity in Un­ivers­ity Park, Penn.

For dec­ades, most phys­i­cists have agreed that our un­iverse was born in a “Big Bang,” an ex­plo­sion of what pre­vi­ously had been an in­fi­nitely com­pact point of ma­te­ri­al. One sign of this is the cos­mos is still found to be ex­pand­ing. But what caused the Big Bang, and what might have pre­ced­ed it? These ques­tions have posed stum­bling blocks, be­cause as tra­di­tion­ally de­scribed by Ein­stein’s The­o­ry of Gen­er­al Rel­a­ti­vity, the Big Bang is a non­sen­si­cal state: a vast amount of en­er­gy packed in­to a point of ze­ro size.

A grow­ing num­ber of sci­en­tists, though, are in­terest­ed in the idea that the un­iverse goes through end­less cy­cles in which the ex­pan­sion re­verses; then space col­lapses back to a point, and re-explodes. Thus the Big Bang would really be a “Big Bounce.”

Bo­jowald and col­leagues at Penn State are ex­plor­ing this no­tion us­ing a the­o­ry called Loop Quan­tum Gra­vity, which they say serves as sort of math­e­mat­i­cal time ma­chine. Their find­ings are to ap­pear in the July 1 early on­line issue of the re­search jour­nal Na­ture Phys­ics, and the Au­gust print edi­tion.

Ein­stein’s the­o­ries did­n’t in­clude the quan­tum physic­s—the mod­ern sci­ence of the fun­da­men­tal build­ing blocks of mat­ter—needed to de­scribe the ex­tremely high en­er­gies of the early cos­mos, Bo­jowald said. Loop Quan­tum Gra­vity, pi­o­neered at Penn State, does, he added.

Loop Quan­tum Gra­vity is one of the more pop­u­lar the­o­ries that phys­i­cists have de­vised in at­tempts to un­ite na­ture’s var­i­ous forc­es, to de­scribe them as man­i­festa­t­ions of only one, un­der­ly­ing force.

Loop Quan­tum Gra­vity can al­so pro­duce cal­cula­t­ions that trace cos­mic his­to­ry, ac­cord­ing to Bo­jowald. Such work, he said, has found that the be­gin­ning was not in­fi­nitely small or dense after all; this in turn means the equa­t­ions can yield val­id re­sults for the pre-Big Bang era. The num­bers point to a pre­vi­ous un­iverse in which the ge­om­e­try of space and time was si­m­i­lar to that of ours, but with cer­tain prop­er­ties un­know­a­ble, the re­search­ers said.

Bo­jowald said his team re­vised pre­vi­ous equa­t­ions of Loop Quan­tum Gra­vity to create a sim­pler mod­el with more pre­cise re­sults. What tipped off re­search­ers that a sim­plifica­t­ion might ex­ist, he said, was that ear­li­er model was very com­pli­cat­ed, “but its so­lu­tions looked very clean.”

The new equa­t­ions, though, con­tain some “free” param­e­ters that aren’t pre­cisely known, but which are needed to de­scribe cer­tain prop­er­ties.

Bo­jowald and col­leagues found that two of these param­e­ters are com­ple­men­ta­ry: one is rel­e­vant al­most ex­clu­sively af­ter the Big Bounce, the oth­er al­most ex­clu­sively be­fore. Be­cause the lat­ter has es­sen­tially no in­flu­ence on cal­cula­t­ions of our cur­rent un­iverse, Bo­jowald con­cudes that its val­ue can’t be back-cal­culated from the oth­er. The param­e­ters rep­re­sent un­cer­tainty in the size of the cos­mos.

“The pre­cise un­cer­tainty fac­tor for the vol­ume of the pre­vi­ous un­iverse nev­er will be de­ter­mined by... cal­culating back­wards from con­di­tions in our pre­s­ent un­iverse, even with most ac­cu­rate mea­sure­ments we ev­er will be able to make,” he said. The idea is “si­m­i­lar to the un­cer­tainty rela­t­ions in quan­tum physics,” equa­tions that show it’s in­her­ently im­pos­si­ble to know both the po­si­tion and ve­locity of a par­t­i­cle ex­act­ly. The dis­con­nect be­tween one cos­mos and the next al­so im­plies that the un­iverses probably can’t be iden­ti­cal, he added.

Mars rover ready for descent into crater

NASA's Mars rover Opportunity is scheduled to begin a descent down a rock-paved slope into the Red Planet's massive Victoria Crater. This latest trek carries real risk for the long-lived robotic explorer, but NASA and the Mars Rover science team expect it to provide valuable science.

Opportunity already has been exploring layered rocks in cliffs around Victoria Crater. The team has planned the descent carefully to enable an eventual exit, but Opportunity could become trapped inside the crater or lose some capabilities. The rover has operated more than 12 times longer than its originally intended 90 days.

The scientific allure is the chance to examine and investigate the compositions and textures of exposed materials in the crater's depths for clues about ancient, wet environments. As the rover travels farther down the slope, it will be able to examine increasingly older rocks in the exposed walls of the crater.

"While we take seriously the uncertainty about whether Opportunity will climb back out, the potential value of investigations that appear possible inside the crater convinced me to authorize the team to move forward into Victoria Crater," said Alan Stern, NASA associate administrator, Science Mission Directorate, NASA Headquarters, Washington. "It is a calculated risk worth taking, particularly because this mission has far exceeded its original goals."

The robotic geologist will enter Victoria Crater through an alcove named Duck Bay. The eroding crater has a scalloped rim of cliff-like promontories, or capes, alternating with more gently sloped alcoves, or bays.

A meteor impact millions of years ago excavated Victoria, which lies approximately 4 miles (6 kilometers) south of where Opportunity landed in January 2004. The impact-created bowl is half a mile (800 meters) across and about five times as wide as Endurance Crater, where Opportunity spent more than six months exploring in 2004.

The rover began the journey to Victoria from Endurance 30 months ago. It reached the rim at Duck Bay nine months ago. Opportunity then drove approximately a quarter of the way clockwise around the rim, examining rock layers visible in the promontories and possible entry routes in the alcoves. Now, the rover has returned to the most favorable entry point.

"Duck Bay looks like the best candidate for entry," said John Callas, rover project manager, NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It has slopes of 15 to 20 degrees and exposed bedrock for safe driving."

If all of its six wheels continue working, engineers expect Opportunity to be able to climb back out of the crater. However, Opportunity's twin rover, Spirit, lost the use of one wheel more than a year ago, diminishing its climbing ability.

"These rovers are well past their design lifetimes, and another wheel could fail on either rover at any time," Callas said. "If Opportunity were to lose the use of a wheel inside Victoria Crater, it would make it very difficult, perhaps impossible, to climb back out."

"We don't want this to be a one-way trip," said Steve Squyres, principal investigator for the rovers' science instruments, Cornell University, Ithaca, N.Y. "We still have some excellent science targets out on the plains that we would like to visit after Victoria. But if Opportunity becomes trapped there, it will be worth the knowledge gained."

The Jet Propulsion Laboratory manages the Mars Exploration Rover project for NASA's Science Mission Directorate.

Scientists Ponder Plant Life on Extrasolar Earthlike Planets

When we think of extrasolar Earth-like planets, the first tendency is to imagine weird creatures like Jar Jar Binks, Chewbacca, and, if those are not bizarre enough, maybe even the pointy-eared Vulcan, Spock, of Star Trek fame.

But scientists seeking clues to life on extrasolar planets are studying various biosignatures found in the light spectrum leaking out to Earth to speculate on something more basic and essential than the musical expertise of Droopy McCool. They are speculating on what kind of photosynthesis might occur on such planets and what the extrasolar plants might look like.

Paint it black

It could be the plants are black, says Robert Blankenship, Ph.D., Lucille P. Markey Distinguished Professor in Arts & Sciences at Washington University in St. Louis. But it all depends on what size and light intensity of star — or sun — the planet feeds off, and the extrasolar planet's atmospheric chemistry.

Plants on Earth are green because of chlorophyll, which harnesses the energy of the sun to make sugars for metabolism. But our plants aren't completely efficient — they waste a little bit of light.

"Ideally, what you want is a black molecule that absorbs all of the light," Blankenship said. "There could be another system developed on an extrasolar planet where plants are completely black if the spectrum of light that's available to organisms is different from the light available to organisms on Earth.

"Then, for sure, the plants will have different types of pigments tuned to absorb those wavelengths of light available on the other world."

Blankenship is co-author of two papers recently published in the journal Astrobiology. The papers detail the kinds of clues that researchers are looking for and explore theories of what these other worlds might be like.

Blankenship is part of a NASA working group based at the Jet Propulsion Laboratory called the Virtual Plant Laboratory. He and his colleagues are studying light that comes from stars and extrasolar planets to infer their composition. They can see clues that suggest the presence of water vapor, oxygen or carbon dioxide, for instance. One key biosignature is the existence of disequilibrium — the simultaneous presence of things that should not coexist on a dead world. The presence of methane and oxygen together on an extrasolar planet, for instance, would be a strong smoking gun for the possible existence of life.

Life on the edge

They also are looking into the "red edge" effect. Seen at 700 nanometers out, beyond the limit of normal human vision, this reflectance spectrum is a signature of the fact that there is very intense chlorophyll absorption going on.

A third way to find extrasolar planets is to look for wobbly stars. As a planet — especially a massive planet — goes around the star it causes the star to wobble a bit. The Hubble Space Telescope has found wobbly stars.

NASA has two missions in the works designed to find possible evidence for life on extrasolar planets. One features a space-based instrument that will make measurements in the near infrared region; the other measures longer wavelengths to get good biosignatures for things like methane and oxygen.

Blankenship said that speculation about the natural world of extrasolar planets is at this point speculative, but that it is important to get a handle on what the possibilities are, how things might look, what measurements to make and what experiments to do to conclude whether there is life on another world.

"I think that everyone thinks that there are Earth-like ones out there, but very few have been detected so far," he said. "One of the things that I've learned is that you have to free your mind from the constraints of thinking that life elsewhere has to be like life here."

Energy on any world is critical, he said, and there has to be some system on an extrasolar planet that involves light capture and storage.

"When you consider another world you've got to find that life there depends on photosynthesis in the broad sense, but it's probably not identical to the way that photosynthesis works here," Blankenship said. "You'll need molecules that absorb light that are highly colored, but whether they have the same green colors we know on Earth is unlikely."

Similarly, on Earth life depends on DNA and proteins. But out there?

"I don't think that there is anything magical about DNA in that it has to be the same out there as here," he said. "But there has to be some sort of information-carrying molecule — again, highly unlikely the same as our DNA — that has information coded in a way that allows the ability to transfer information. We've got proteins that do all of the dirty work in the cell in terms of chemistry. You can imagine a different sort of molecule that would do that sort of chemistry. Maybe it would have the same protein backbone with peptide bonds and so forth. But there's no reason to think it would be comprised of the same 20 amino acids that we have on Earth. It's intriguing to speculate, and I think we'll know more when we get more clues."

Physicists discover 'triple scoop' baryon

Physicists of the DZero experiment at the Department of Energy's Fermi National Accelerator Laboratory have discovered a new heavy particle, the ?b (pronounced "zigh sub b") baryon, with a mass of 5.774±0.019 GeV/c2, approximately six times the proton mass. The newly discovered electrically charged ?b baryon, also known as the "cascade b," is made of a down, a strange and a bottom quark. It is the first observed baryon formed of quarks from all three families of matter. Its discovery and the measurement of its mass provide new understanding of how the strong nuclear force acts upon the quarks, the basic building blocks of matter.

The DZero experiment has reported the discovery of the cascade b baryon in a paper submitted to Physical Review Letters on June 12.

"Knowing the mass of the cascade b baryon gives scientists information they need in order to develop accurate models of how individual quarks are bound together into larger particles such as protons and neutrons," said physicist Robin Staffin, Associate Director for High Energy Physics for the Department of Energy's Office of Science.

The cascade b is produced in high-energy proton-antiproton collisions at Fermilab's Tevatron. A baryon is a particle of matter made of three fundamental building blocks called quarks. The most familiar baryons are the proton and neutron of the atomic nucleus, consisting of up and down quarks. Although protons and neutrons make up the majority of known matter today, baryons composed of heavier quarks, including the cascade b, were abundant soon after the Big Bang at the beginning of the universe.

The Standard Model elegantly summarizes the basic building blocks of matter, which come in three distinct families of quarks and their sister particles, the leptons. The first family contains the up and down quarks. Heavier charm and strange quarks form the second family, while the top and bottom, the heaviest quarks, make the third. The strong force binds the quarks together into larger particles, including the cascade b baryon. The cascade b fills a missing slot in the Standard Model.

Prior to this discovery, only indirect evidence for the cascade b had been reported by experiments at the Large Electron-Positron collider at the CERN Laboratory near Geneva, Switzerland. For the first time, the DZero experiment has positively identified the cascade b baryon from its decay daughter particles in a remarkably complex feat of detection. Most of the particles produced in high-energy collisions are short-lived and decay almost instantaneously into lighter stable particles. Particle detectors such as DZero measure these stable decay products to discover the new particles produced in the collision.

Once produced, the cascade b travels several millimeters at nearly the speed of light before the action of the weak nuclear force causes it to disintegrate into two well-known particles called J/? ("jay-sigh") and ?- ("zigh minus"). The J/? then promptly decays into a pair of muons, common particles that are cousins of electrons. The ?- baryon, on the other hand, travels several centimeters before decaying into yet another unstable particle called a ? ("lambda") baryon, along with another long-lived particle called a pion. The ? baryon too can travel several centimeters before ultimately decaying to a proton and a pion. Sifting through data from trillions of collisions produced over the last five years to identify these final decay products, DZero physicists have detected 19 cascade b candidate events. The odds of the observed signal being due to something other than the cascade b are estimated to be one in 30 million.

DZero is an international experiment of about 610 physicists from 88 institutions in 19 countries. It is supported by the Department of Energy, the National Science Foundation, and a number of international funding agencies. Fermilab is a national laboratory funded by the Office of Science of the U.S. Department of Energy, operated under contract by Fermi Research Alliance, LLC.

Telescope Gives Scientists Depth Perception

Astronomers now have a new "eye" for determining the distance to certain mysterious bodies in and around our Milky Way galaxy. By taking advantage of the unique position of NASA's Spitzer's Space Telescope millions of miles from Earth, and a depth-perceiving trick called parallax, they were able to pin down the most probable location of one such object. The findings will ultimately help astronomers better understand the different components of our galaxy.

"Forty years ago a visionary astronomer named Dr. Sjur Refsdal theorized that dark bodies could be located using parallax and a space telescope," said Andrew Gould of Ohio State University, Columbus, Ohio, who led the project. "It is truly remarkable that we have been able to prove him right with this Spitzer observation."

Spitzer is the only telescope that orbits the sun behind Earth, and is the farthest telescope from us with the ability to study distant stars. Currently, Spitzer is about 40 million miles (70 million kilometers) away from Earth. It will continue to drift farther and farther away at a rate of about 10 million miles (15 million kilometers) per year.

This great distance gives astronomers a great advantage. They can use Spitzer in the same way that a human brain uses two eyes to tell how far away objects are, a principle called parallax. With two eyes, we have two perspectives, which our brains combine to give us depth perception. In space, Spitzer acts as one eye, while a ground-based telescope acts as the other. With two very wide cosmic eyes, astronomers can determine the location of bodies within and just outside our galaxy.

Gould and his team are the first to use Spitzer to perform this astronomical feat. Their goal was to determine whether a previously identified dark matter candidate, called a massive compact halo object, or "Macho," is within our galaxy and contributing to its overall weight.

Our galaxy is heavier than it looks, with at least 80 percent of its mass consisting of mysterious, invisible dark matter. A large fraction of this dark matter is the exotic kind, different from the ordinary matter that makes up the familiar world around us. The rest might be so-called machos, which are ordinary-matter dark bodies that lurk in our galaxy's halo, the region that sits above and below its spiral disk. They are thought to be a combination of black holes, very faint stars and isolated planets.

Several suspected machos have been discovered in the past through a technique called microlensing, in which the dark bodies' gravity causes light from a passing background star to bend and brighten. But astronomers do not know whether these candidates are indeed machos in the galaxy halo, or other, non-macho objects just outside the Milky Way in small satellite galaxies. By pinpointing the location of the candidates, astronomers will learn whether they are in the halo and thus machos. This information, in turn, will help them figure out how much machos contribute to the total mass of our galaxy.

OGLE-2005-SMC-001 is one such macho candidate. It was first discovered by Andrzej Udalski, of the Optical Gravitational Lens Experiment (OGLE), and Warsaw University Observatory, Warszawa, Poland. Udalski and colleagues noticed that the dark object was causing a passing, background star to brighten. Gould and his team quickly sprang to action, following up with Spitzer observations of the short-lived event.

The data from both telescopes, or "eyes," were then combined and modeled through a series of complicated equations. The results indicate with 95 percent probability that OGLE-2005-SMC-001 is dark matter in our galaxy's halo and therefore a part of its overall mass.

In addition, the data show that OGLE-2005-SMC-001 consists of two bodies circling around each other. Gould and colleagues think the objects could be a pair of black holes, a very rare sighting in our universe. However, there is a small chance this feature is actually just a regular pair of orbiting stars in a neighboring, satellite galaxy.

"It will be very exciting to locate and measure the masses of more dark objects in the future by applying this technique. And we might finally be able to unravel the mystery of machos," said Subo Dong of Ohio State University, whose paper on OGLE-2005-SMC-001 has been accepted for publication in Astrophysical Journal. Dong presented the results today at a press conference, at the 210th meeting of the American Astronomical Society in Honolulu, Hawaii.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, please visit www.nasa.gov/spitzer or http://www.spitzer.caltech.edu/spitzer .

Monster black holes, quietly cruising the cosmos?
May 30, 2007
Courtesy American Physical Society
and World Science staff

Two merg­ing black holes can gen­er­ate a re­coil so pow­er­ful, the merged hole shoots out of its host gal­axy at up to 4,000 km (2,500 miles) per sec­ond, ac­cord­ing to a new com­put­er sim­ula­t­ion.

Its cre­ators said the work shows for the first time that these vi­o­lent events, which fol­low merg­ers of ga­lax­ies con­tain­ing black holes, can to­tally eject the black holes. So these ti­ta­nic ob­jects may be cruis­ing through the un­iverse, vir­tu­ally in­vis­i­ble un­less they should crash in­to some­thing.

But don’t wor­ry, as­tro­no­mers said. Most of the un­iverse by far is emp­ty space. The odds that a black hole will streak through our so­lar sys­tem are ti­ny.

Black holes are ex­tremely com­pact ob­jects that con­tain so much mat­ter crammed in­to so small a space that their gra­vity be­comes over­pow­ering and sucks in eve­ry­thing near­by, in­clud­ing light. De­spite their light-eating tal­ents, many black holes are as­sociat­ed with in­tense light emis­sions, be­cause the in­fall­ing ob­jects heat up and shine. But a black hole with noth­ing to feed on, called a “qui­es­cent” black hole, is dark.

Most lu­mi­nous ga­lax­ies are believed to con­tain a gi­ant, or supe­rmassive, black hole at their cen­ter. The sim­ula­t­ion, led by Manuela Cam­pan­elli at the Roch­es­ter In­sti­tute of Tech­nol­o­gy, N.Y., stud­ied the best con­di­tions for mer­gers to pro­duce re­coil speeds high enough to free a supe­rmassive black hole from its host gal­axy.

The re­coil would re­sult when, up­on crash­ing, the black holes cre­ate an ex­ot­ic type of radia­t­ion called gravita­t­ional waves. In Cam­pan­elli’s sce­nar­i­o, two black holes ap­proach and start to or­bit each oth­er. To pro­duce to­tal ejection, they should have equal mass­es and spin as fast as pos­si­ble. They must be tilted with their ax­es of rota­t­ion ly­ing in the plane of their or­bit, and must spin in op­po­site di­rec­tions.

They spir­al to­ward one anoth­er, and when they merge, the re­sulting ob­ject is kicked off pe­rpendicularly to the plane of or­bit. Some as­t­ro­phys­i­cists have ar­gued that such con­di­tions are rath­er un­like­ly; sci­en­tists said the prob­a­bil­ity of such a con­flu­ence of events re­mains a ques­tion for fu­ture re­search.

Past cal­cula­t­ions have found that black hole ejections may not be un­com­mon. But the ex­pelled black hole can easily fall back in­to the gal­axy due to con­tin­u­ing gravita­t­ional at­trac­tion be­tween the two, just as a can­non­ball shot to the sky re­turns to the ground.

A sec­ond new stu­dy, by Abra­ham Loeb of Har­vard Un­ivers­ity in Cam­bridge, Mass., ex­am­ined the pos­si­bil­ity of de­tect­ing a black hole if it is ex­pelled. If it’s sur­rounded by gas, he said, that gas will emit pow­er­ful light. Un­for­tu­nate­ly, by the time it leaves the gal­axy, it will likely ex­haust its gas supply and go dark.

None­the­less, one vis­i­ble ob­ject known as HE0450-2958, es­ti­mat­ed to lie more than three bil­lion light-years away, is the­o­rized by some to be an ejected supe­rmassive black hole. One of the re­search­ers who ad­vanced the pro­pos­al has said this black hole may be one of those that one day re­turns to its home gal­axy. It’s es­ti­mat­ed to have been mov­ing much more slowly on av­er­age than the fully-e­jected mono­liths that Cam­pan­elli stud­ied, en­hanc­ing the like­li­hood of an even­tu­al fall­back.

Loe­b’s and Cam­pan­elli’s stud­ies are to ap­pear in forth­com­ing is­sues of the re­search jour­nal Phys­i­cal Re­view Let­ters.

* * *

Spitzer nets thousands of galaxies in a giant cluster

In just a short amount of time, NASA's Spitzer Space Telescope has bagged more than a thousand previously unknown dwarf galaxies in a giant cluster of galaxies.

Despite their diminutive sizes, dwarf galaxies play a crucial role in cosmic evolution. Astronomers think they were the first galaxies to form, and they provided the building blocks for larger galaxies. They are by far the most numerous galaxies in our Universe, and are an important tracer of the large-scale structure of the cosmos. Computer simulations of cosmic evolution suggest that high-density regions of the Universe, such as giant clusters, should contain significantly more dwarf galaxies than astronomers have observed to date.

A team led by Leigh Jenkins and Ann Hornschemeier, both at NASA Goddard Space Flight Center in Greenbelt, Md., used Spitzer to study the Coma cluster, an enormous congregation of galaxies 320 million light-years away in the constellation Coma. The cluster contains hundreds of previously known galaxies that span a volume 20 million light-years across.

Jenkins, Hornschemeier, and their collaborators used data from Spitzer's Infrared Array Camera (IRAC) to study galaxies at the cluster's center. They also targeted an outlying region with the goal of comparing the galaxy populations in the different locations to see how environmental variations influence the evolution of galaxies. They stitched together 288 individual Spitzer exposures, each lasting 70 to 90 seconds, into a large mosaic covering 1.3 square degrees of sky.

The team found almost 30,000 objects, whose catalog will be made available to the astronomical community. Some of these are galaxies in the Coma cluster, but the team realized that a large fraction had to be background galaxies. Using data taken with the 4-meter (13 foot) William Herschel Telescope on the Canary island of La Palma, team member Bahram Mobasher of the Space Telescope Science Institute, in Baltimore, Md., measured distances to hundreds of galaxies in these fields to estimate what fraction are cluster members.

A surprising number turned out to be Coma galaxies. They appear to be comparable or even smaller in mass to the Small Magellanic Cloud, the Milky Way's second largest satellite galaxy. Jenkins estimates that about 1,200 of the 30,000 faint objects are dwarf galaxies in Coma, many more than have been identified in the past. Given that the observations only cover a portion of the cluster, the results imply a total dwarf galaxy population of at least 4,000.

Spitzer made these discoveries possible because it can survey large areas of sky very effectively. Even better, infrared observations in space can probe more deeply than ground-based near-infrared surveys because the sky background is up to 10,000 times darker.

"With Spitzer's superb capabilities, we have suddenly been able to detect thousands of faint galaxies that weren't seen before," says Jenkins. She is presenting these results on Monday at the American Astronomical Society meeting in Honolulu, Hawaii. The discovery paper will also appear in the Astrophysical Journal.

"We're blowing away previous infrared surveys of nearby clusters," adds Hornschemeier. "Thanks to Spitzer, we can observe nearby clusters such as Coma very deeply in a short amount of time. The total observing time is comparable to just a few nights at a ground-based observatory."

Additional Coma dwarf galaxies might be lurking in the Spitzer data, but more follow-up work is needed to determine how many. Hornschemeier and other astronomers are currently making deeper spectroscopic measurements with the 6.5-meter (21 foot) telescope of the MMT Observatory in Arizona, and the 10-meter (32 foot) Keck telescope in Hawaii, to find out how many of the faintest objects belong to the Coma cluster.
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28 more exoplanets discovered
Jeanna Bryner
Staff Writer
SPACE.com
Tue May 29, 7:01 AM ET

HONOLULU-Astronomers have discovered 28 new planets outside of our solar system, increasing to 236 the number of known exoplanets, revealing that planets can exist around a broad spectrum of stellar types-from tiny, dim stars to giants.

"We added 12 percent to the total in the last year, and we're very proud of that," said one of the study team members Jason Wright of the University of California at Berkeley. "This provides new planetary systems so that we can study their properties as an ensemble."

The planets are among 37 new objects spotted within the past year. Seven of the objects are failed stars called brown dwarfs, with masses that dwarf the largest, Jupiter-sized planets but too small to sustain the nuclear reactions necessary for stellar ignition.
( the rest )

Sun spewing fractal messages about its storm season

Plasma astrophysicists at the University of Warwick have found that key information about the Sun’s 'storm season’ is being broadcast across the solar system in a fractal snapshot imprinted in the solar wind. This research opens up new ways of looking at both space weather and the unstable behaviour that affects the operation of fusion powered power plants.

Fractals, mathematical shapes that retain a complex but similar patterns at different magnifications, are frequently found in nature from snowflakes to trees and coastlines. Now Plasma Astrophysicists in the University of Warwick’s Centre for Fusion, Space and Astrophysics have devised a new method to detect the same patterns in the solar wind.

The researchers, led by Professor Sandra Chapman, have also been able to directly tie these fractal patterns to the Sun’s ‘storm season’. The Sun goes through a solar cycle roughly 11 years long. The researchers found the fractal patterns in the solar wind occur when the Sun was at the peak of this cycle when the solar corona was at its most active, stormy and complex – sunspot activity, solar flares etc. When the corona was quieter no fractal patterns were found in the solar wind only general turbulence.

This means that fractal signature is coming from the complex magnetic field of the sun.

This new information will help astrophysicists understand how the solar corona heats the solar wind and the nature of the turbulence of the Solar Wind with its implications for cosmic ray flux and space weather.

These techniques used to find and understand the fractal patterns in the Solar Wind are also being used to assist the quest for fusion power. Researchers in the University of Warwick’s Centre for Fusion, Space and Astrophysics (CFSA) are collaborating with scientists from the EURATOM/UKAEA fusion research programme to measure and understand fluctuations in the world leading fusion experiment MAST (the Mega Amp Spherical Tokamak) at Culham. Controlling plasma fluctuations in tokamaks is important for getting the best performance out of future fusion power plants.

Static universe in 3 trillion years

When Dutch astronomer Willem de Sitter proposed a static model of the universe in the early 1900s, he was some 3 trillion years ahead of his time.

Now, physicists Lawrence Krauss from Case Western Reserve University and Robert J. Scherrer from Vanderbilt University predict that trillions of years into the future, the information that currently allows us to understand how the universe expands will have disappeared over the visible horizon. What remains will be "an island universe" made from the Milky Way and its nearby galactic Local Group neighbors in an overwhelmingly dark void.

The researchers’ article, "The Return of the Static Universe and the End of Cosmology," was awarded one of the top prizes for 2007 by the Gravity Research Foundation. It will be published in the October issue of the Journal of Relativity and Gravitation.

"While physicists of the future will be able to infer that their island universe has not been eternal, it is unlikely they will be able to infer that the beginning involved a Big Bang," report the researchers.

According to Krauss, since Edwin Hubble advanced his expanding universe observations in 1929, the "pillars of the modern Big Bang" have been built on measurements of the cosmic microwave background radiation from the afterglow of the early universe formation, movement of galaxies away from the Local Group and evidence of the abundance of elements produced in the primordial universe, as well as theoretical inferences based on Einstein’s General Relativity Theory.

What appears almost as a story from science fiction, the cosmologists began to envision a universe based on "what ifs." Long after the demise of the solar system, it will be up to future physicists that arise from planets in other solar systems to fathom and unravel the mysteries of the system’s origins from their isolated universes dominated by dark energy.

But the irony of the presence of that abundant dark energy, the researchers report, is that future physicists will have no way to measure its presence because of a void in the gravitational dynamics of moving galaxies.

"We live in a special time in the evolution of the universe," stated the researchers, somewhat humorously: "The only time at which we can observationally verify that we live in a very special time in the evolution of the universe."

The researchers describe that modern cosmology is built on Einstein’s theory of general relativity, which requires an expanding or collapsing universe for a uniform density of matter. However, an isolated region can exist inside of an otherwise seemingly static universe

They next discuss implications for the detection of the cosmic microwave background that provide evidence of the baby pictures of an early universe.

That radiation will ‘red shift" to longer and longer frequencies, eventually becoming undetectable within our galaxy. Krauss said, "We literally will have no way to detect this radiation."

The researchers followed up that discussion with one tracking early elements like helium and deuterium produced in the Big Bang. They predict systems that allow us to detect primordial deuterium will be dispersed throughout the universe to become undetectable, while helium in concentrations of approximately 25 percent at the Big Bang will become indiscernible as stars will produce far more helium in the course of their lives to cloud the origins of the early universe.

"Eventually, the universe will appear static," said Krauss. "All evidence of modern cosmology will have disappeared."

Krauss closed with a comment that he suggested is implicit in the paper’s conclusions. "We may feel smug in that we can detect a host of things future civilizations will not know about, but by the same token, this suggests we wonder about what important aspects of the universe we ourselves may be missing. Thus, our results suggest a kind of a ‘cosmic humility’".

Saturn rings found clumpier, heavier than thought
May 23, 2005
Courtesy NASA and World Science staff

Sat­urn’s larg­est, most compact ring con­sists of tightly packed clumps of par­t­i­cles sep­a­rat­ed by nearly emp­ty gaps, ac­cord­ing to new find­ings from NASA’s Cas­si­ni space­craft.

These clumps in Sat­urn’s B ring are neatly or­gan­ized and con­stantly col­lid­ing, which sur­prised sci­en­tists, they said.

“We orig­i­nally thought we would see a un­iform cloud of par­t­i­cles,” said Lar­ry Es­pos­ito, prin­ci­pal in­ves­ti­ga­tor for the Cas­si­ni ul­tra­vi­o­let im­ag­ing spec­tro­graph at the Un­ivers­ity of Col­o­rad­o, Boul­der.

“In­stead we find that the par­t­i­cles are clumped to­geth­er with emp­ty spaces in be­tween. If you were fly­ing un­der Sat­urn’s rings in an air­plane, you would see these flashes of sun­light come through the gaps, fol­lowed by dark and so forth. This is dif­fer­ent from fly­ing un­der a un­iform cloud of par­t­i­cles.”

Be­cause pre­vi­ous in­ter­preta­t­ions as­sumed the ring par­t­i­cles were dis­trib­ut­ed un­iformly, sci­en­tists un­der­es­ti­mated the to­tal mass of Sat­urn’s rings, re­search­ers said: the mass may ac­tu­ally be two or more times pre­vi­ous es­ti­mates.

“These re­sults will help us un­der­stand the over­all ques­tion of the age and hence the or­i­gin of Sat­urn’s rings,” said Josh Col­well of the Un­ivers­ity of Cen­tral Flor­i­da, Or­lan­do, and a team mem­ber of the Cas­si­ni ul­tra­vi­o­let im­ag­ing spec­tro­graph.

A pa­per de­tail­ing the re­sults ap­pears in the April 13 early on­line is­sue of the re­search jour­nal Ic­a­rus.

Breathtaking new views of mars

The High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has captured breathtaking images of the Deuteronilus Mensae region on Mars.

The images were taken on 14 March 2005 during orbit number 1483 of the Mars Express spacecraft with a ground resolution of approximately 29 metres per pixel.

They show the Deuteronilus Mensae region, located on the northern edge of Arabia Terra and bordering the southern highlands and the northern lowlands. Situated at approximately 39° North and 23° East, Deuteronilus Mensae are primarily characterised by glacial features. The scene is illuminated by the Sun from the south-west (from bottom left in the image).

The scene is dominated by a depression measuring approximately 2 000 metres in depth and 110 kilometres in diameter, north to south.

Visible in the centre of the first image, the interior of the depression is characterised by dark material, differing from the light-toned surrounding plains.

Deeply incised valleys of a depth ranging from 800 to 1 200 metres are clearly identifiable in the northern part of the scene. Deeply incised valleys with a depth ranging from 800 to 1 200 metres are clearly identifiable in the northern part of the scene.

It is believed that these valleys may have originated due to intense flooding by melted water ice. The water then froze rather quickly, flowing down the slopes of the depression like a glacier. Aeolian sediments (eroded by the action of wind) traced the flow pattern on the surface.

The northern part exhibits a finger - shaped elevation which was circumvented by the masses of water and ice.

To the west, the flow of water mixed with ice broke through another elevation and formed a drop - shaped feature while flowing into the depression.

Mars experienced numerous events of this kind in the past, when rising magma or impacts caused frozen groundwater to melt resulting in major flooding events.

One of the most striking features on Mars is the dichotomy between the southern highlands and the northern plains, lower by up to 3 kilometres. The boundary between these two regions is marked by a transition characterised by an intact highland zone and areas with remnant mesas and isolated eroded knobs.

The scene of Deuteronilus Mensae depicts different stages of highland degradation. Numerous flow patterns in wide valleys and along ridges and scarps indicate movement of debris mixed with ice towards the surrounding areas.

Since the discovery of these structures, scientists assume that the mixture of debris and ice resembles rock glaciers commonly found in cold-climate areas on the Earth.

As on Earth, these landscapes are climate indicators. Whether ice could be still present in the porous spaces in Martian features and how active these landforms may be today is still a subject of discussion.

The colour scenes have been derived from the three HRSC colour channels and the nadir channel. The perspective views have been calculated from the digital terrain model derived from the stereo channels.

The anaglyph image was calculated from the nadir and one stereo channel. The black and white high - resolution images were derived from the nadir channel which provides the highest detail of all channels. Image resolution has been decreased for easier downloading.

Baby stars hatching in Orion's head

A new image from NASA's Spitzer Space Telescope shows infant stars "hatching" in the head of Orion, the famous hunter constellation visible from northern hemispheres during winter nights. Astronomers suspect that shockwaves from a 3-million-year-old explosion of a massive star may have initiated this newfound birth.

The region featured in the Spitzer image is called Barnard 30. It is located approximately 1,300 light-years away and sits on the right side of Orion's head, just north of the massive star Lambda Orionis.

"When we decided to study this region, it was barely known, despite the fact that its properties made it a nice target. Our aim was to carry out a comprehensive study of the region's different properties," said David Barrado y Navascués, of the Laboratorio de Astrofísica Espacial y Física Fundamental in Madrid, Spain, who led the Spitzer observations.

"We now know, thanks to Spitzer, that there is a large population of low-mass stars and brown dwarfs [or failed stars]," he added.

A visibly dark and murky cosmic cloud is bright and clear in Spitzer's infrared image. Organic molecules called polycyclic aromatic hydrocarbons can be seen as wisps of green. These molecules are formed anytime carbon-based materials are burned incompletely. On Earth, they can be found in the sooty exhaust from automobile and airplane engines. They also coat the grills where charcoal-broiled meats are cooked.

Tints of orange-red seen in the cloud are dust particles warmed by the newly forming stars. The reddish-pink dots at the top of the cloud are very young stars embedded in a cocoon of cosmic gas and dust. Blue spots throughout the image are background Milky Way stars along this line of sight.

When Barrado y Navascués first saw this image of Barnard 30, he was so impressed that he decided to use it for the cover of his upcoming astronomy textbook.

"I found the original black and white science images breathtaking, fascinating," said Barrado y Navascués.

"Once I saw the color image, it was clear it had to be the cover of the book. From the aesthetical point of view, [the image] is beautiful, it catches the eye. From the astronomical point of view, it has everything an astronomer wants – high- and low-mass stars, brown dwarfs and a dark dust cloud. It is a gift from nature."

The inspiration for Barrado y Navascués' textbook came from his one-year-old astronomical reference blog, Cuaderno de Bitacora Estelar. The blog is one of the most widely read astronomy blogs in Spanish, with a large audience in Europe, South America and United States. He decided to turn his blog into a textbook a few months ago when a Spanish editorial company asked him to.

"After hesitating and a lot of thinking about how to do it, we decided to go ahead," said Barrado y Navascués. "As far as we know, it is one of the first blogs to be converted into a book in Spanish. It is possibly the first academic blog to undergo such a conversion and, for sure, the first related to astronomy."

As for Barnard 30 and the other infant stars hatching in Orion's head, Barrado y Navascués says that this region "will no doubt become one of the cornerstones of stellar astrophysics, one of the most relevant young stellar clusters."

New form of matter; part superconductor, part laser

Physicists at the University of Pittsburgh have demonstrated a new form of matter that melds the characteristics of lasers with those of the world’s best electrical conductors. The work introduces a new method of moving energy from one point to another as well as a low-energy means of producing a light beam like that from a laser. The Pitt researchers and their collaborators at the Bell Labs of Alcatel-Lucent in New Jersey detail the process in the May 18 issue of the journal Science.

The new state is a solid filled with a collection of energy particles known as polaritons that have been trapped and slowed, explained lead investigator David Snoke, an associate professor in the physics and astronomy department in Pitt’s School of Arts and Sciences. Snoke worked with Pitt graduate students Ryan Balili and Vincent Hartwell on the project.

Using specially designed optical structures with nanometer-thick layers—which allow polaritons to move freely inside the solid—Snoke and his colleagues captured the polaritons in the form of a superfluid. In superfluids and in their solid counterparts, superconductors, matter consolidates to act as a single energy wave rather than as individual particles. In superconductors, this allows for the perfect flow of electricity. In the new state of matter demonstrated at Pitt—which can be called a polariton superfluid—the wave behavior leads to a pure light beam similar to that from a laser but is much more energy efficient.

Traditional superfluids and superconductors require extremely low temperatures, approximately negative 280 and negative 450 degrees Fahrenheit for a superconductor and superfluid, respectively. The polariton superfluid is more stable at higher temperatures, and may be capable of being demonstrated at room temperature in the near future.

The Pitt research builds on current efforts in physics laboratories around the world to create materials, which mix the characteristics of superconductors and lasers. Snoke’s work provides a new method to trap and manipulate the energy particles. Applied to technology, this technique could provide new ways of controlled transfer of optical signals through solid matter.

Snoke’s polariton trap was devised with a technique similar to that used for superfluids made of atoms in a gaseous state known as the Bose-Einstein condensate. Three scientists shared the 2001 Nobel Prize in Physics for producing the condensate.

The galaxy next door—our destined home?
May 10, 2007
Special to World Science

As­tro­no­mers have run new sim­u­la­tions to see what could hap­pen when an ex­pected col­lision takes place be­tween our gal­axy and an­other big one—pos­si­bly with­in our de­scen­dants’ life­times.

The sur­pris­ing re­sults: lit­tle of the ce­les­tial fire­works that were wide­ly ex­pected to oc­cur as great gas clouds crunch to­geth­er to form new stars. In­stead, a more out­land­ish pos­si­bil­i­ty arose.

The com­put­er sim­u­la­tions in­di­cated there is a one in 37 chance we’ll end up liv­ing in that oth­er gal­ax­y—majestic An­drom­e­da, said the re­search­ers, T. J. Cox and Abra­ham Loeb of the Har­vard-Smith­son­ian Cen­ter for As­t­ro­phys­ics in Cam­b­ridge, Mass.

“Fu­ture as­tro­no­mers in the so­lar sys­tem might see the Milky Way,” our pre­s­ent gal­axy, “as an ex­ter­nal gal­axy in the night sky,” Cox and Loeb wrote in a pa­per on their find­ings. In oth­er words, the Milky Way would be no more the fa­mil­iar sil­very strip across the heav­ens, but a dis­tant smudge of light.

Par­a­dox­i­cal­ly, this might give us a much bet­ter view of our old ga­lac­tic home than we had when we lived there. The Milky Way vis­i­ble in our night sky is but a small part of our galaxy, and it blocks our view of the rest.

The Milky Way, Andromeda and about 40 smaller com­pan­ion ga­lax­ies make up our ga­lac­tic neigh­bor­hood, wrote the as­tro­no­mers. As such, this is “the near­est lab­o­r­a­to­ry, and there­fore the most pow­er­ful tool, to study the for­ma­tion and ev­o­lu­tion of ga­lac­tic struc­ture.”

Be­cause these “lo­cal group” ga­lax­ies are linked by grav­i­ty, they break a gen­er­al rule, that ga­lax­ies through­out the uni­verse are re­ced­ing from one anoth­er. In par­tic­u­lar, An­drom­e­da is ap­proach­ing us at an es­ti­mat­ed 120 km (75 miles) per sec­ond—though it re­mains 2.5 mil­lion light years away, so the fam­i­ly re­un­ion is still a ways off. A light year is the dis­tance light trav­els in a year.

As­tro­no­mers gen­er­ally don’t ex­pect a head-on col­li­sion. Rath­er, the two star­ry be­he­moths would cir­cle each oth­er clos­er and clos­er, drawn in by each oth­er’s grav­i­ty. This would lead to a few close brushes be­tween the two, dis­tort­ing their shapes, fol­lowed by a fi­nal merg­er in­to a big, in­el­e­gant blob.

The two ga­lax­ies are like­ly to merge with­in five bil­lion years, thus “with­in the Sun’s life­time,” Cox and Loeb wrote in their pa­pe­r, posted on­line and sub­mit­ted to the re­search jour­nal Month­ly No­tices of the Roy­al As­t­ro­no­m­i­cal So­ciety.

By the end of the sec­ond close en­coun­ter, there is a 50 per­cent chance our Sun will be dragged along with its plan­ets and oth­er stars in­to a long “ti­dal tail” ex­tend­ing out from our gal­axy, and caused by An­drom­e­da’s grav­i­ta­tion­al pull, the re­search­ers wrote.

But there is al­so a 2.7 per­cent chance, they added, that our So­lar Sys­tem won’t even stay in the gal­axy. With its grav­i­ty, An­drom­e­da could steal our So­lar Sys­tem al­to­ge­ther: “it could be more tight­ly bound to An­drom­e­da than to the Milky Way.” Of course, af­ter the merg­er is eventually over, we would re­turn to our old, bashed-in and some­what un­rec­og­niz­able ga­lac­tic home. We would like­ly find our­selves at the fringes of the com­bined gal­axy, added Cox and Loeb, who dubbed this fu­ture con­glom­er­a­tion “Milk­o­me­da.”

Gal­axy col­li­sions aren’t ex­pected to pose much dan­ger to their in­hab­i­tants. “Plan­e­tary sys­tems ride out col­li­sions,” said Uni­ver­si­ty of Ha­waii as­tron­o­mer Josh­ua Barnes in a 2005 pre­s­entation at Hi­lo, Ha­waii. “Their cen­tral stars may be launched in­to tid­al tails or scat­tered in ran­dom di­rec­tions, but grav­i­ty acts so grad­u­al­ly that plan­e­tary or­bits are not dis­turbed.”

Cox and Loeb al­so played down the pos­si­bil­i­ty of any great burst in star for­ma­tion, which some ex­pected to re­sult from col­li­sions of gas clouds in the two ga­lax­ies. Stars form from re­gions of such clouds where the gas be­comes more com­pact, and starts to fall to­geth­er un­der its own grav­i­ty. Al­though such bursts of star for­ma­tion are com­mon with gal­axy col­li­sions, both Milky Way and An­drom­e­da are too “gas-poor” for much of this, Cox and Loeb wrote.

But there is enough gas, they added, to possibly make the black hole or holes at the cen­ter of the merged gal­axy light up more brightly. Black holes are ex­tra­or­di­nar­i­ly com­pact ob­jects whose in­tense grav­i­ty sucks in ev­erything near­by. New gas mov­ing into the area would thus fall in­side. The gas would heat up in the pro­cess and start emit­ting pow­er­ful ra­di­a­tion, which could af­fect life forms, de­pend­ing on their dis­tance. Cox and Loeb’s pa­pe­r did­n’t ex­am­ine these pos­si­bil­i­ties in de­tail.

Un­cer­tain­ties in where the Sun ends up, they added, stem large­ly from un­cer­tain­ties in where it will be when An­dro­meda hits. The Sun’s dis­tance from the Milky Way cen­ter is pre­dict­able—it’s always about the same—but the rest is hard to pre­dict. So Cox and Loeb looked at all stars at that dist­ance from the cen­ter to gauge the odds of what will hap­pen to ours. An­dro­me­da’s dir­ec­tion, too, is known only roughly.

Wherever we wind up, Cox and Loeb added, stars out­side the Lo­cal Group may lat­er re­cede from view en­tire­ly, be­cause the uni­verse has been ex­pand­ing at an ev­er-growing rate. Thus with­in 100 bil­lion years—if an­yone is left to watch—Milk­o­meda, and the Lo­cal Group, “will con­sti­tute the en­tire vis­i­ble Uni­verse.”

MEDIA ADVISORY: M07-51a

NASA Updates Plans for Hubble 'Ring Of Dark Matter' Briefing

GREENBELT, Md. - NASA will hold a media teleconference at 1 p.m. EDT on May 15 to discuss the strongest evidence to date that dark matter exists. This evidence was found in a ghostly ring of dark matter in the cluster CL0024+17, discovered using NASA's Hubble Space Telescope. The ring is the first detection of dark matter with a unique structure different from the distribution of both the galaxies and the hot gas in the cluster. The discovery will be featured in the June 20 issue of the Astrophysical Journal.

Briefing participants are:
-- Dr. Myungkook James Jee, associate research scientist, Johns Hopkins University, Baltimore
-- Dr. Richard White, astronomer, Space Telescope Science Institute, Baltimore
-- Dr. Richard Massey, postdoctoral scholar, California Institute of Technology, Pasadena
Reporters should contact Ray Villard at the Space Telescope Science Institute at 410-338-4514 prior to the media teleconference for the call in number and passcode. Audio for the briefing will stream live on the Internet at:
http://www.nasa.gov/newsaudio

At the start of the briefing, images and supporting graphics will be posted on the Web at:
http://www.nasa.gov/mission_pages/hubble/news/dark_matter_ring.html

For more information about the Hubble Space Telescope, visit:
http://www.nasa.gov/hubble

A galactic fossil; Star is found to be 13.2 billion years old
Public Release Date; 10th May 2007
Henri Boffen

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How old are the oldest stars" Using ESO's VLT, astronomers recently measured the age of a star located in our Galaxy. The star, a real fossil, is found to be 13.2 billion years old, not very far from the 13.7 billion years age of the Universe. The star, HE 1523-0901, was clearly born at the dawn of time.

"Surprisingly, it is very hard to pin down the age of a star", the lead author of the paper reporting the results, Anna Frebel, explains. "This requires measuring very precisely the abundance of the radioactive elements thorium or uranium, a feat only the largest telescopes such as ESO's VLT can achieve."

This technique is analogous to the carbon-14 dating method that has been so successful in archaeology over time spans of up to a few tens of thousands of years. In astronomy, however, this technique must obviously be applied to vastly longer timescales.

For the method to work well, the right choice of radioactive isotope is critical. Unlike other, stable elements that formed at the same time, the abundance of a radioactive (unstable) isotope decreases all the time. The faster the decay, the less there will be left of the radioactive isotope after a certain time, so the greater will be the abundance difference when compared to a stable isotope, and the more accurate is the resulting age.

Yet, for the clock to remain useful, the radioactive element must not decay too fast - there must still be enough left of it to allow an accurate measurement, even after several billion years.

"Actual age measurements are restricted to the very rare objects that display huge amounts of the radioactive elements thorium or uranium," says Norbert Christlieb, co-author of the report.

Large amounts of these elements have been found in the star HE 1523-0901, an old, relatively bright star that was discovered within the Hamburg/ESO survey [1]. The star was then observed with UVES on the Very Large Telescope (VLT) for a total of 7.5 hours.

A high quality spectrum was obtained that could never have been achieved without the combination of the large collecting power Kueyen, one of the individual 8.2-m Unit Telescopes of the VLT, and the extremely good sensitivity of UVES in the ultraviolet spectral region, where the lines from the elements are observed.

For the first time, the age dating involved both radioactive elements in combination with the three other neutron-capture elements europium, osmium, and iridium.

"Until now, it has not been possible to measure more than a single cosmic clock for a star. Now, however, we have managed to make six measurements in this one star"," says Frebel.

Ever since the star was born, these "clocks" have ticked away over the eons, unaffected by the turbulent history of the Milky Way. They now read 13.2 billion years.

The Universe being 13.7 billion years old, this star clearly formed very early in the life of our own Galaxy, which must also formed very soon after the Big Bang.