The Hubble Space Telescope was a game-changer, letting humankind peer back in time and tease mind-stretching secrets from the cosmos. But the James Webb Space Telescope—scheduled for launch into space later this year—promises to allow us see even further back. While Hubble was able to see what you could call toddler galaxies, the JWST will be able to look back 13.5 billion years and see infant galaxies—the first ones ever formed. It is expected to rewrite our astronomy textbooks in ways that we can’t yet even imagine.
UPDATE: NASA announced on June 1 that while it had been working toward an October 31, 2021 launch date, it will be delayed by a few weeks and instead take place in November or early December.