One of the key things of the James Webb Space Telescope is designed to do is 
detect the very first stars and galaxies that were born in the very early universe. 
So this is a part of the universe that we haven't seen at all yet. 
We don't know what's out there. The more distant in space we look, the further back
we're looking in time. With Hubble we're about to push back and see pretty far
into the distant universe, but we do reach a limit. And so we're designing 
the James Webb Space Telescope to see past the point of Hubble and to see 
the very first stars and galaxies light up after the Big Bang.
We know that there is a time in the universe's past 
where the galaxies were the first to light up. Basically the
stars and galaxies send out ionizing radiation, which
clears out the fog of the hydrogen in the universe. So once that
hydrogen fog is cleared out, the stars and galaxies can shine through. 
And so getting to that point just beyond what we call the dark ages is one
of the major goals of the telescope.
