Star formation started after 750 million years of the formation of Universe; Research
This research has been published online in the journal Nature.
In this study, researchers analyzed most distant known quasar with the help of infrared spectrometer, which they placed onto the Magellan Telescope, a massive ground-based telescope in Chile. This quasar is about 13 billion light-years from Earth and helped to study the universe in its infancy. Researchers found no evidences of heavy elements such as carbon and oxygen in the neighboring gaseous clouds that are up to about 750 light years of distance. These heavy elements are the building blocks for planetary bodies and finally life such as found on Earth.
“The first stars will form in different spots in the universe … it’s not like they flashed on at the same time,” Robert Simcoe, an associate professor of physics at MIT, said in a statement. “But this is the time that it starts getting interesting.”
The spectrometer, used in this study, was able to split the light coming from that distant quasar into different wavelengths, which was then plotted on a graph. Scientists then compared the wavelengths with the light given off by different chemicals.
“Each chemical has its own fingerprint,” Simcoe said. “Based on the pattern of what light is absorbed, it tells you the chemical composition.”
After studying the “intrinsic spectrum” of the quasar and comparing it with the present data, scientists found that the hydrogen was there but oxygen, silicon, iron or magnesium were not present.
“[The birth of the first stars] is one of these important moments in the history of the universe,” Simcoe says. “It went from looking like the early universe, which was just gas and dark matter, to looking like it does today, where there are stars and galaxies … it’s the point when the universe started to resemble what it looks like today. And it’s sort of amazing how early that happens. It didn’t take long.”
It is the first time that the universe in its very much infancy was found lacking heavy elements.
“Prior to this result, we have not seen regions of the universe this old and devoid of heavy elements, so there was a missing link in our understanding of how the elemental content of the universe has evolved with time,” John O’Meara, an associate professor of physics at St. Michael’s College in Vermont, added. “[This] discovery possibly provides such a rare environment where the universe had yet to form stars.”
Simcoe, R., Sullivan, P., Cooksey, K., Kao, M., Matejek, M., & Burgasser, A. (2012). Extremely metal-poor gas at a redshift of 7 Nature, 492 (7427), 79-82 DOI: 10.1038/nature11612