The First Galaxies: What We Know And What We Still Need To Learn
“As we look farther back in time, we find that younger galaxies formed stars at faster rates than galaxies do today. We can measure the star-formation rate, and find that at earlier and earlier times, it was more intense. But then we find it hits a peak when the Universe is about two billion years old. Go younger than that, and the rate goes down again.”
We’ve come incredibly far in our quest to learn how the Universe came to be the way it is today. We can see out in space for tens of billions of light years, to galaxies as they were when the Universe was only a few percent of its present age. We can see how galaxies evolve, merge and the stars inside change. And we can see to even before that, when no stars or galaxies existed at all. But how did we get from there to here? There are still plenty of gaps in the story. We’ve never seen the first stars or galaxies; we’ve never witnessed the start of cosmic reionization; we’ve never seen the star formation rate jump from zero to a real, finite number. Yet with James Webb and WFIRST on the horizon, these gaps in our knowledge may – if we’re lucky – all disappear.
Come get the story on what we know about the first galaxies, and what we hope and have left to still learn!
