Watching the universe grow up Snapshots through time using radio waves

How did the first generation of stars and galaxies form in our Universe? Astronomers don’t know. They have ideas, to be sure, which are hard to confirm with observations because prior to the formation of the first stars and galaxies, it’s not clear what they can look at! In the last few years, much progress has been made in trying to detect radio waves from hydrogen atoms that existed in the early Universe. The existence of hydrogen precedes the formation of the first stars and galaxies, and therefore allows direct observations of the formation process. This new technique (known as “21cm cosmology”) has yet to become a standard tool in the astronomical community.

Speaker: Adrian Liu, UC Berkeley