We can see light from the atoms in the Universe before the first stars form. And no, I don’t mean from the CMB!
After the Big Bang, it took only a few hundred thousand years for the Universe to form neutral atoms. But it took tens or even hundreds of millions of years for the first stars to turn on, and a whopping 550 million years for those neutral atoms to all become reionized by that starlight once again.
Believe it or not, we can measure not only the starlight coming from the stars that do form through the now-infrared light they emit, but also the neutral atoms themselves through the power of 21-cm astronomy. I’m joined this week by Dr. Elizabeth Fernandez, research astronomer, science communicator and podcaster extraordinaire on her show, SparkDialog. (Check it out, here.)
Happy birthday to Pluto, discovered on this day in 1930.Pluto, first discovered in 1930, was no more than a distant dot in our most powerful telescopes.Clyde Tombaugh’s original images identifying Pluto […]