"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
Looking farther and farther into the distant Universe is the equivalent of looking farther and farther back in time. Although Hubble has shown us galaxies from when the Universe is just 400 million years old, and satellites to measure the Cosmic Microwave Background can show us a snapshot at 380,000 years, we have no information about what’s in between. That means, to date, we have yet to see the Universe’s first stars and galaxies!
While James Webb will shed a new cosmic light on that era, allowing us to view these galaxies for the first time, there are some pieces of information that we already know. These galaxies must be tiny compared to the ones we have today; they will never be seen by Hubble, even with an infinite amount of observing time; they should already contain the seeds of supermassive black holes from their inception; and they very likely contain the most massive stars found in the entire Universe.