Scientists find traces of first stars that came 250 million years after big bang
New Delhi : In a complex universe - full of galaxies, black holes and quasars - there is the existence of life and its emergence has always been a big question for the researchers and scientists. For tens of millions of years, the universe was a dark expanse, full of ionized hydrogen and helium. But at some point - researchers aren’t sure when - these swirling gasses ignited the first stars. The period is known as Cosmic Dawn.
Jonathan Amos at the BBC reports states that scientists have finally found traces of emergence of those first stars, suggesting they came to life roughly 250 million years after the Big Bang.
According to Ethan Siegal at Forbes reports, present telescopes like the Hubble Space are just not enough to explore the deepest depths of space and time. The oldest and furthest galaxy directly detected is GNZ-11, which formed just 400 million years after the Big Bang. But scientists believe that the first stars began to flicker on sometime between 380,000 years after the Big Bang and the emergence of early galaxies like GNZ-11.
It has been a belief of many astronomers that first stars lit up around 200 million years after the Big Bang. But, none have managed to prove it with any evidence.
For this new study in the journal Nature, an international team of astronomers relied on indirect evidence, searching instead for signatures of oxygen and helium—elements that can only be created in the cores of stars.
As Amos explains, the researchers turned their sights to galaxy MACS1149-JD1, which lies billions of light years away, using two Earth-bound telescopes: the Atacama Large Millimetre/Submillimetre Array (Alma) and the European Southern Observatory’s Very Large Telescope (VLT).
They found that over billions of years, the expansion of the universe shifts that light. And by analyzing that shift, researchers figured out the age of the oxygen and hydrogen signatures, even though they can’t directly see the galaxy.
According to a press release, the team then used infrared spectroscopy from NASA’s Spitzer and Hubble Space Telescope to look at the brightness of JD1. Using that brightness and the best model of star development they were able to deduce the age of the stars in JD1.