The more distant in space we look, the farther back we're looking in time.
And so we're designing the James Webb Space Telescope to see past the point where
Hubble could see and to see the very first stars and galaxies to light
up after the Big Bang. The James Webb Space Telescope is designed as an
infrared telescope because infrared is really where the key science questions
will be answered. To see those very very distant galaxies
the light from those galaxies has been red shifted. The expansion of the universe
stretches space-time, the light from the galaxies gets stretched
as well. And so longer wavelengths of light are redder.
So at some point in the distant past the light from those galaxies
has been shifted - red shifted – all the way out of the visible spectrum
into the infrared part of the spectrum. So having an infrared telescope
in space is one of the things that will allow us to see those very first galaxies.
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