What is the James Webb Space Telescope?
Under construction right now, the James Webb Space Telescope is NASA’s next great space observatory and the successor to the Hubble Space Telescope. Stationed a million miles from Earth in the coldness of space, Webb will sense infrared radiation with a sharpness that rivals Hubble’s vision in visible light.
Webb will use its keen infrared vision to
- observe light from the first stars and galaxies
- track the evolution of galaxies throughout cosmic history
- reveal the birth of stars and planets
- look for the ingredients of life on faraway planets
What makes Webb unique?
Webb will detect infrared light. Also known as heat, infrared light shows us things we can’t see in visible light. Infrared light penetrates through clouds of dust and allows us to see way, way back in time.
Webb’s detectors will be kept extremely cold so that no errant heat interferes with observations. Webb will reside a million miles from Earth and far beyond the Moon to avoid their heat. A five-layer sunshield will block out sunlight and deflect heat. A huge temperature difference will exist between Webb’s hot, sunward side and its cold side.
Webb will be a very large telescope with a very large mirror. The observatory’s sunshield will be the size of a tennis court. Webb will be so big that it has to fold up to fit into its rocket and will then unfold in space.