Home » News & Blogs » New observations hint at how early galaxies lit up cosmos
Bookmark and Share
Astronomy Now

New observations hint at how early galaxies lit up cosmos

9 May 2019, 14:00 UTC
New observations hint at how early galaxies lit up cosmos
(200 words excerpt, click title or image to see full post)

Deep field observations by NASA’s Hubble and Spitzer space telescopes show galaxies shining brighter than expected (in the early universe, hinting at a possible source of ionising radiation that helped turn the cosmos transparent. The inset shows a closeup of one such ancient galaxy. Image: NASA/JPL-Caltech/ESA/Spitzer/P. Oesch/S. De Barros/I.Labbe
NASA’s Spitzer Space Telescope has revealed that some of the universe’s earliest galaxies were brighter than expected. The excess light is a byproduct of the galaxies releasing incredibly high amounts of ionising radiation. The finding offers clues to the cause of the Epoch of Reionization, a major cosmic event that transformed the universe from being mostly opaque to the brilliant starscape seen today.
No one knows for sure when the first stars in our universe burst to life. But evidence suggests that between about 100 million and 200 million years after the big bang, the universe was filled mostly with neutral hydrogen gas that had perhaps just begun to coalesce into stars, which then began to form the first galaxies. By about 1 billion years after the big bang, the universe had become a sparkling firmament. Something else had changed, too: Electrons of the omnipresent neutral hydrogen gas had been stripped ...

Latest Vodcast

Latest Podcast

Advertise PTTU

NASA Picture of the Day

Astronomy Picture of the Day

astronomy_pod