A New Age: The James Webb Space Telescope
In 2020, the James Webb Space Telescope will be placed in space at a distance of 1.5 million kilometers (930,000 miles) from earth, enabling scientists to gather data on a universe they’ve literally never seen before. The 6.5 m wide mirror array atop the instrument module will capture and study light being emitted and absorbed at the infrared frequency. The Hubble Space Telescope and various ground-based telescopes around the world are limited in that they most effectively view parts of the night sky that are illuminated by visible light only.
Infrared light radiates from sources of heat, such as stars and galaxies, and is invisible to the human eye. Analyzing light at this frequency will provide clues about evolving star fields and newly forming stars, even those obscured within clouds of molecular dust. Exoplanets could be orbiting these stars at a distance that makes them habitable for life forms to exist, and the JWST will provide more detailed information about these planet’s atmospheres and conditions near the surface.
The JWST will allow scientists to actually see backward in time to study the formation of the universe
The Universe in “Rewind”
Stars, galaxies, and other deep-sky objects far in the distance began emitting visible light millions or billions of years ago. As the universe continuously expands, these objects get farther away and impossible for us to see. But as visible light travels through an expanding universe, it’s wavelength gets longer, causing it to become infrared light. Scientists call this “redshifting.” By locating and studying these redshifted stars and galaxies, they will be viewing the oldest and most distant objects in the known universe.
Because the JWST is so precisely studying heat energy in space, the spacecraft itself has to be kept as cool as possible (-220 C or -370 F). A five-layer aluminum and silicon heat shield will protect the mirrors from the sun’s heat. The project is currently in the testing phase, as the mirrors and heat shield have to be packed into a rocket for liftoff and then carefully unfolded over a span of 29 days when it reaches its destination.