Sometimes images of distant objects in the universe look like out-of-focus paint daubs on black paper. Not terribly interesting visually, but if you know what you’re gazing at, those blobs in space tell a fascinating tale of life in the cosmos less than a billion years after the Big Bang. They may look like shards of light and color, but these objects are now identified as some of the earliest star-forming galaxies in the cosmos.
Now astronomers are debating whether the hottest stars in these early galaxies may have provided enough radiation to “lift a curtain” of cold, primordial hydrogen that cooled after the Big Bang, ushering in the epoch of reionization, a time when the universe became transparent to light. Understanding the role these galaxies played in the EOR is a problem that has perplexed astronomers over the past decade.
The epoch of reionization is thought to have ended 0.5 to one billion years after the Big Bang. Astronomers have been looking for its signature in everything from radio astronomy signals to infrared emissions. The major difficulty in understanding exactly what the story is out there at the end of the first act of galaxy formation. Because the galaxies are so far away, they are very faint and extremely difficult to find. Now Hubble, and very likely other infrared-enabled observatories, along with a scattering of radio telescopes, are pushing the envelope of discover out at dawn of creation.