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Life might have formed as early as 10-12 billion years ago

May 18, 2012
Courtesy of the Niels Bohr Institute - 
University of Copehhagen
and World Science staff

“A long time ago in a gal­axy far, far away” is the fa­mous in­tro­duc­to­ry line to the mov­ie Star Wars, but it may be tak­ing on a new real-life mean­ing.

Phys­i­cists are re­port­ing that con­di­tions al­low­ing life to form could have ex­isted in some ga­lax­ies as early as 10 bil­lion to 12 bil­lion years ago—in the first quar­ter of the his­to­ry of our uni­verse.

All ob­jects in the im­age are dis­tant ga­lax­ies – not stars. Ear­ly ga­lax­ies from the in­fan­cy of the uni­verse more than 12 bil­lion years ago evolved much more quick­ly than pre­vi­ously thought, new re­search sug­gests. This could mean that al­ready in the ear­ly his­to­ry of the Uni­verse, there was po­ten­tial for plan­et for­ma­tion and life. (Im­age: Hub­ble Space Tel­e­scope)


The re­search­ers drew the con­clu­sions af­ter stu­dy­ing ga­lax­ies that are so far away, those huge lengths of time are how long their light has tak­en to reach us. “So we see the ga­lax­ies as they were then,” said phys­i­cist Jo­han Fyn­bo at the Uni­vers­ity of Co­pen­ha­gen, who worked on the re­search.

“For one of the ga­lax­ies,” he added, an anal­y­sis of the spec­trum—or break­down by col­or—of its light sug­gested much of it is “en­riched with a high con­tent of heav­i­er el­e­ments,” he went on. This cre­ates “po­ten­tial for plan­et forma­t­ion and life.” 

Earth-like plan­ets can’t form with only the light­est el­e­ments, hy­dro­gen and he­li­um. But be­cause ac­cept­ed as­tro­nom­i­cal the­o­ries hold that it took some time for cos­mic pro­cesses to gen­er­ate heav­i­er el­e­ments, this means that plan­et forma­t­ion and life would face a cor­re­spond­ing de­lay in get­ting started. That de­lay, how­ev­er, may have been smaller than pre­vi­ously thought, if Fyn­bo and col­leagues are cor­rect.

For sev­er­al thou­sand years af­ter the Big Bang—an explosion-like event 13.7 bil­lion years ago that as­tro­no­mers be­lieve gave birth to the uni­verse—ev­ery­thing was a hot, dense soup of gas­es and par­t­i­cles, sci­en­tists say. But the uni­verse ex­pand­ed, caus­ing this soup to spread out and cool down. It re­mained thicker in some ar­eas than oth­ers, though, and these parts, thanks to their own gra­vity, con­densed in­stead of ex­pand­ing. They ul­ti­mately be­came stars and ga­lax­ies.

The ear­li­est of these probably con­sisted of prim­i­tive, gi­ant stars made of only hy­dro­gen and he­li­um, ac­cord­ing to as­tro­no­mers. Heav­i­er el­e­ments did­n’t ex­ist. These ap­peared lat­er, cre­at­ed by nu­clear pro­cesses in the stars. A star is a gi­ant ball of gas that pro­duces en­er­gy by com­bin­ing hy­dro­gen and he­li­um in­to heav­i­er and heav­i­er el­e­ments, with some en­er­gy re­leased each time. When this pro­cess can no long­er go on, the star dies and flings huge clouds of dust and gas in­to space. The clouds are re­cy­cled in­to new stars, with a high­er con­tent of heav­i­er el­e­ments.

As this pro­cess con­tin­ues, genera­t­ions of stars are born with pro­gres­sively more heavy el­e­ments and met­als. These el­e­ments, es­pe­cially car­bon and ox­y­gen, are cru­cial for plan­ets and life as we know it.

Un­til now, re­search­ers thought that it took bil­lions of years for stars to form and with that, ga­lax­ies with a high con­tent of el­e­ments heav­i­er than hy­dro­gen and he­li­um. But the new work in­di­cates this pro­cess went sur­pris­ingly quickly in some ga­lax­ies.

“We have stud­ied 10 ga­lax­ies in the early uni­verse and an­a­lysed their light,” said Fyn­bo. “Our ex­pecta­t­ion was that they would be rel­a­tively prim­i­tive and poor in heav­i­er el­e­ments, but we dis­cov­ered some­what to our sur­prise that the gas in some of the ga­lax­ies and thus the stars in them had a very high con­tent of heav­i­er el­e­ments. The gas was just as en­riched as our own Sun.”

The ga­lax­ies are so far away that they nor­mally can’t be seen di­rect­ly, but the re­search­ers used a spe­cial meth­od. “There are some ex­treme ob­jects in the uni­verse called qua­sars. Quasars are gi­gantic black holes that are ac­tive and when mat­ter falls in­to them, they emit light that is as strong as thou­sands of ga­lax­ies. They are like a kind of light­house that lights up in the uni­verse and can be seen very far away,” ex­plained Jens-Kris­tian Kro­ga­ger, a doc­tor­al stu­dent at the uni­vers­ity who par­ti­ci­pated in the re­search.

You can use a qua­sar as a light source if it’s be­hind a gal­axy you want to ob­serve, he went on. “We then look at the light from the qua­sar and can see that some light is mis­sing. The mis­sing qua­sar light in the im­age has been ab­sorbed by the chem­i­cal el­e­ments in the gal­axy in front of it,” he said. The team’s find­ings were pub­lished on­line May 15 in the jour­nal Monthly No­tices of the Roy­al As­tro­nom­i­cal So­ci­e­ty Let­ters.


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“A long time ago in a galaxy far, far away” is the famous introductory line to the movie Star Wars, but it may be taking on a new real-life meaning. Physicists are reporting that conditions allowing life to form could have existed in some galaxies as early as 10 billion to 12 billion years ago—in the first quarter of the history of our universe. The researchers drew the conclusions after studying galaxies that are so far away, those huge lengths of time are how long their light has taken to get there. “So we see the galaxies as they were then,” said physicist Johan Fynbo at the University of Copenhagen, who worked on the research. “For one of the galaxies,” he added, an analysis of the spectrum—or breakdown by color—of its light suggested “large parts of the galaxy are enriched with a high content of heavier elements,” he went on. This creates “potential for planet formation and life.” Earth-like planets can’t form with only the lightest elements, hydrogen and helium. But because accepted astronomical theories hold that it took some time for cosmic processes to generate heavier elements in any substantial quantities, this means that planet formation and life would face a corresponding delay in getting started. That delay, however, may have been smaller than previously thought, if Fynbo and colleagues are correct. For several thousand years after the Big Bang 13.7 billion years ago—an explosion-like event that astronomers believe gave birth to the universe—everything was a hot, dense soup of gases and particles, scientists say. But the universe expanded, causing this soup to spread out and cool down. It remained thicker in some areas than others, though, and these parts, thanks to their own gravity, condensed instead of expanding. They ultimately became stars and galaxies. The earliest of these probably consisted of primitive, giant stars made of only hydrogen and helium, according to astronomers. Heavier elements didn’t exist. These appeared later, created by nuclear processes in the stars. A star is a giant ball of glowing gas that produces energy by combining hydrogen and helium into heavier and heavier elements, with some energy released each time. When this process can no longer go on, the star dies and flings huge clouds of dust and gas into space. The clouds are condensed and recycled into new stars, with a higher content of heavier elements. As this process continues, generations of stars are born with progressively more heavy elements and metals. These elements, especially carbon and oxygen, are crucial for planets and life as we know it. Until now, researchers thought that it took billions of years for stars to form and with that, galaxies with a high content of elements heavier than hydrogen and helium. But the new work indicates this process went surprisingly quickly in some galaxies. “We have studied 10 galaxies in the early Universe and analysed their light,” said Fynbo. “Our expectation was that they would be relatively primitive and poor in heavier elements, but we discovered somewhat to our surprise that the gas in some of the galaxies and thus the stars in them had a very high content of heavier elements. The gas was just as enriched as our own Sun.” The galaxies are so far away that they normally can’t be seen directly, but the researchers used a special method. “There are some extreme objects in the Universe called quasars. Quasars are gigantic black holes that are active and when matter falls into them, they emit light that is as strong as thousands of galaxies. They are like a kind of lighthouse that lights up in the Universe and can be seen very far away,” explained Jens-Kristian Krogager, a doctoral student at the university who participated in the research. You can use a quasar as a light source if it’s behind a galaxy you want to observe, he went on. “We then look at the light from the quasar and can see that some light is missing. The missing quasar light in the image has been absorbed by the chemical elements in the galaxy in front of it,” he saod. The team’s findings were published online May 15 in the journal Monthly Notices of the Royal Astronomical Society Letters.