Schematic diagram of the Universe’s history, highlighting reionization, which occurs in earnest only after the formation of the first stars and galaxies. Before stars or galaxies formed, the Universe was full of light-blocking, neutral atoms. While most of the Universe doesn’t become reionized until 550 million years afterwards, a few fortunate regions are mostly reionized at earlier times. Image credit: S. G. Djorgovski et al., Caltech Digital Media Center.

5 Surprising Facts About The First Galaxies In The Universe

Even though we’ve never seen them, here’s what we already know.

“Suddenly whole new programs open up, things you can do that you could never do before. It’d be great scientifically, it’d be great for the nation, for educators, for students, and it’d be just great for the public at large.”
-Garth Illingworth

One of the most remarkable facts about our Universe is that it hasn’t been around forever. The clumps and clusters of matter we see — planets, stars, gas clouds, galaxies and more — grew out of smaller bits of matter that have gravitationally grown and merged over time. If we look to objects at greater and greater distances, the light from them takes longer to reach our eyes, meaning that the light arriving today was emitted millions or even billions of years ago. As we look back in space, we’re also looking back in time. At some point, we’ll reach a distance so great that there were no stars or galaxies back then. Although it will take the James Webb Space Telescope to view those very first galaxies, there are five surprising facts we already know must be true about these most distant objects of all.