Sometime in 2021, NASA’s James Webb Space Telescope will launch, deploy, and begin science operations.
With seven times Hubble’s light-gathering power, better resolution, and extended infrared capabilities, numerous cosmic records will fall.
Although it will almost certainly make unforeseen discoveries, Webb is poised to shatter four separate cosmic records.
1.) Most distant galaxy. Presently, the Hubble Space Telescope holds the record, discovering GN-z11 from just 407 million years after the Big Bang.
Webb’s infrared eyes will see through the cosmic dust that obscures Hubble’s vision, revealing galaxies as little as 200–275 million years old.
2.) The smallest exoplanets’ atmospheres. With enough light, advanced telescopes can measure exoplanet atmospheres via transit spectroscopy.
Hubble can measure Saturn-like worlds around Sun-like stars, but Webb will get mini-Neptunes around Sun-like stars, plus Earth-sized worlds around red dwarfs.
3.) The earliest stars. The very first stars should consist of hydrogen and helium alone, untouched since the Big Bang.
With capabilities to see faint, distant objects at infrared wavelengths, Webb should discover truly pristine stars.
4.) Imaging the smallest planets. Direct imaging requires bright planets well-separated from their parent star.
With Webb’s tools, especially its coronagraph, the smallest exoplanets to date will be directly revealed.