Astronomers look for dawn of the universe

[jcdenton]

Astronomers look for dawn of the universe<br /><br />Astronomers may have detected the dawn’s early light — light from around the dawn of the universe, that is.<br /><br />Researchers from NASA’s Goddard Space Flight Center in Maryland believe they have captured traces of radiation from long-extinguished stars that were “born” during the universe’s infancy.<br /><br />The research represents the first tangible — but not conclusive — evidence of these earliest stars, which are thought to have produced the raw materials from which future stars, including our sun, were created.<br />The Big Bang, the explosion believed to have created the universe, is thought to have occurred 13.7 billion years ago. About 100 million years later, hydrogen atoms began to merge and ignite, creating brightly burning stars. Just what these stars were like wasn’t clear.<br /><br />“Where they lived, how big they were, how much light they emitted, whether they even existed, we weren’t sure,” said astrophysicist Alexander Kashlinsky, the lead author of the article appearing in Thursday’s issue of the journal Nature. “What we’ve done, we think, is obtain the first information about these stars.”<br /><br />Subtracting light<br />Kashlinsky’s team used NASA’s Spitzer Space Telescope to measure the cosmic radiation, which is infrared light invisible to the human eye, in a small sliver of the sky. The team then subtracted the radiation levels of all known galaxies and suggested that the leftover measurements include radiation given off by those earliest stars.<br /><br />The exercise was like taking a recording of a stadium full of loud people, then subtracting the noise of every person except one to hear the voice of that single individual.<br /><br />If the team’s conclusions are correct, the study will advance understanding of how the universe originally lit up.<br /><br />Avi Loeb, a Harvard astronomy professor who was not involved in the researc <div class="Discussion_UserSignature"> </div>

 

[newtonian]

jcdenton - The earliest stars should differ somewhat in spectral analysis, since only 3 elements would have existed at this time: hydrogen, helium, a small amount of Lithium.<br /><br />If spectral analysis indicated other elements then the light cannot have come from the first stars.<br /><br />What does spectral analysis of this starlight show?<br /><br />Also, the universe's first light would have been before the first stars - as photons existed before stars existed.<br /><br />One estimate for when the universe became transparent due to the "decoupling" of matter from radiation is 100,000 years after the big bang.<br /><br />The light from this burst is thought to have caused the cosmic microwave background radiation - diluted by expansion and redshifted to the microwave end of the electromagnetic spectrum.<br /><br />Thank you for your alert, post and link, btw!

 

[bonzelite]

good point you make about light before stars in the BB scenario.<br /><br />"first light" would be a white flash. like a white elephant. so they need to go look for that. not stars. and since it will be diluted, it would now probably be buried and unified within the so-called "background radiation." it's probably just part of that now. <br /><br />