MEDIA RELEASE
Two clumps of primordial gas from the dawn of time have been detected in deep space by astronomers using the 10-meter telescopes at the W. M. Keck Observatory.
The gas clouds are too diffuse to form stars and show virtually no signs of containing any “metals,” which is astronomer-speak for all elements heavier than hydrogen and helium – the two simplest and lightest elements in the universe. In fact the only elements astronomers have detected in the clouds are hydrogen and its heavier isotope, deuterium.
The lack of metals strongly suggests that the gases are reservoirs of the pristine material left over from the Big Bang. Because stars fuse atoms to make heavier elements, these gases have never been involved in any star making in the 2 billion years between the Big Bang and their discovery.
In other words, they are the remnant gases that are unchanged since they were created in the first few minutes after the Big Bang.
“Despite decades of effort to find anything metal-free in the universe, Nature has previously set a limit to enrichment at no less than one-thousandth that found in the Sun,” said astronomer J. Xavier Prochaska of the University of California Observatories-Lick Observatory, U.C. Santa Cruz. “These clouds are at least 10 times lower than that limit and are the most pristine gas discovered in our universe.”
Prochaska has coauthored a paper reporting on the discovery with Michele Fumagalli of the U.C. Santa Cruz and John O’Meara of Saint Michael’s College in Vermont. The paper was published by the journal Science, on the Science Express website.
“We’ve searched carefully for oxygen, carbon, nitrogen and silicon – the things that are found on Earth and the Sun in abundance,” Fumagalli said. “We don’t find a trace of anything other than hydrogen and deuterium.”
Exactly how they can detect dark, cold, diffuse gas about 12 billion light-years away is a story in itself.
“In this case we actually have to do a bit of a trick,” Prochaska explained. “We study the gas in silhouette.”
A more distant quasar provides the light for this. The quasar light shines though the gas and the elements in the gas absorb very specific wavelengths of light, which can only be found by splitting the light into very detailed spectra to reveal the dark lines of missing light.
In other words, said Fumagalli, “All of the analysis is on the light we didn’t get.” The clouds absorb only a small fraction of the quasar light that makes it to Earth. “But the signatures of hydrogen absorption are obvious, so there’s no doubt there’s a lot of gas there.”
The blobs of pristine gas are good news to astronomers because they are confirmation of the theory of what the first elements were and how they were created in the Big Bang.
Hydrogen, helium, lithium and boron are the lightest elements on the periodic table of elements and they were all created for the first time in what’s called the Big Bang nucleosynthesis (BBN).
“That theory has been very well tested at Keck as regards to hydrogen and its isotope deuterium,” said O’Meara. “One of the conundrums of that previous work, however, is that the gas also showed at least trace amounts of oxygen and carbon. The clouds that we have discovered are the first to match the full predictions of BBN.”
The discovery also reveals how different the early universe was from today – where it’s very hard to find any place without some “metals” caused by generations of element-building fusion reactors, a.k.a. stars.
“What excites me about this discovery is that there is an almost a range of 1,000,000 in the metallicity in gases at that time in the universe,” said Fumagalli.
In other words, there were places like our Solar system – where metals are very abundant – and there were also places very unlike today, where metals were still virtually non-existent and the gases were unchanged since almost the beginning of time.
The W. M. Keck Observatory operates two 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Big Island of Hawaii.
The twin telescopes feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectroscopy and a world-leading laser guide star adaptive optics system which cancels out much of the interference caused by Earth’s turbulent atmosphere.
The Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.
Two clumps of primordial gas from the dawn of time have been detected in deep space by astronomers using the 10-meter telescopes at the W. M. Keck Observatory.
The gas clouds are too diffuse to form stars and show virtually no signs of containing any “metals,” which is astronomer-speak for all elements heavier than hydrogen and helium – the two simplest and lightest elements in the universe. In fact the only elements astronomers have detected in the clouds are hydrogen and its heavier isotope, deuterium.
The lack of metals strongly suggests that the gases are reservoirs of the pristine material left over from the Big Bang. Because stars fuse atoms to make heavier elements, these gases have never been involved in any star making in the 2 billion years between the Big Bang and their discovery.
In other words, they are the remnant gases that are unchanged since they were created in the first few minutes after the Big Bang.
“Despite decades of effort to find anything metal-free in the universe, Nature has previously set a limit to enrichment at no less than one-thousandth that found in the Sun,” said astronomer J. Xavier Prochaska of the University of California Observatories-Lick Observatory, U.C. Santa Cruz. “These clouds are at least 10 times lower than that limit and are the most pristine gas discovered in our universe.”
Prochaska has coauthored a paper reporting on the discovery with Michele Fumagalli of the U.C. Santa Cruz and John O’Meara of Saint Michael’s College in Vermont. The paper was published by the journal Science, on the Science Express website.
“We’ve searched carefully for oxygen, carbon, nitrogen and silicon – the things that are found on Earth and the Sun in abundance,” Fumagalli said. “We don’t find a trace of anything other than hydrogen and deuterium.”
Exactly how they can detect dark, cold, diffuse gas about 12 billion light-years away is a story in itself.
“In this case we actually have to do a bit of a trick,” Prochaska explained. “We study the gas in silhouette.”
A more distant quasar provides the light for this. The quasar light shines though the gas and the elements in the gas absorb very specific wavelengths of light, which can only be found by splitting the light into very detailed spectra to reveal the dark lines of missing light.
In other words, said Fumagalli, “All of the analysis is on the light we didn’t get.” The clouds absorb only a small fraction of the quasar light that makes it to Earth. “But the signatures of hydrogen absorption are obvious, so there’s no doubt there’s a lot of gas there.”
The blobs of pristine gas are good news to astronomers because they are confirmation of the theory of what the first elements were and how they were created in the Big Bang.
Hydrogen, helium, lithium and boron are the lightest elements on the periodic table of elements and they were all created for the first time in what’s called the Big Bang nucleosynthesis (BBN).
“That theory has been very well tested at Keck as regards to hydrogen and its isotope deuterium,” said O’Meara. “One of the conundrums of that previous work, however, is that the gas also showed at least trace amounts of oxygen and carbon. The clouds that we have discovered are the first to match the full predictions of BBN.”
The discovery also reveals how different the early universe was from today – where it’s very hard to find any place without some “metals” caused by generations of element-building fusion reactors, a.k.a. stars.
“What excites me about this discovery is that there is an almost a range of 1,000,000 in the metallicity in gases at that time in the universe,” said Fumagalli.
In other words, there were places like our Solar system – where metals are very abundant – and there were also places very unlike today, where metals were still virtually non-existent and the gases were unchanged since almost the beginning of time.
The W. M. Keck Observatory operates two 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Big Island of Hawaii.
The twin telescopes feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectroscopy and a world-leading laser guide star adaptive optics system which cancels out much of the interference caused by Earth’s turbulent atmosphere.
The Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.
सबैभन्दा हलुका धातुको आविष्कार
वैज्ञानिकहरुले सबैभन्दा हलुका धातुको आविष्कार गरेका छन् । थर्मोकोल भन्दा १ सय गुणा कम हलुका रहेको यो धातु निकै हल्का भएपनि अरु धातुजस्तै बलियो रहेको युनिभर्सिटी अफ क्यालिफोर्नियाका अनुसन्धानकर्ताहरुले दाबी गरेका छन् ।
यो नयाँ धातु निकेल फोस्फोरसको सुक्ष्म अंशबाट निर्माण गरिएको हो । निकेल फोस्फोरसमा ९९.९ प्रतिशत हावा हुन्छ । आविष्कार गरिएको नयाँ धातुमा भित्तायुक्त नलीका संरचना छन् र एउटा नली मान्छेको रौँ भन्दा १ हजार गुणा पातलो छ र यो धातु समग्रमा जाली जस्तो छ । यो धातुको घनत्व ०.९ मिल्रि्राम प्रति क्युविक सेन्टिमिटर छ । विश्वमा यसअघि सबैभन्दा हलुका धातुको रुपमा रहेको सिलिका एयरोजेलको घनत्व १ मिल्रि्राम प्रति क्युविक सेन्टिमिटर छ । नयाँ धातु बलियो तथा लचक रहेकाले बाहिरी बल थेग्न सक्ने प्रकारको रहेको अनुसन्धानकर्ताहरु बताउँछन् । नयाँ धातु कम तौलका ब्याट्री निर्माण गर्न उपयोगी हुने र त्यस्ता ब्याट्री सफा परिवहनमा उपयुक्त हुने विश्वास गरिएको छ । साथै धेरै बाहिरी धक्का खेप्नुपर्ने संरचना निर्माणका लागि पनि यो धातुको प्रयोग गर्न सकिने अनुसन्धानकर्ताहरु बताउँछन् ।
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