NASA has announced a new telescope to replace the Hubble Space Telescope that has been orbiting Earth since 1990.The new James Webb Space Telescope (JWST) will cost $12.3 billion.
The diameter of JWST’s primary honeycomb-shaped mirror measures 21-feet, or about three times the size of its predecessor. Made of 18 smaller gold-plated mirrors, it boasts a surface area that is seven times that of the Hubble, making it the largest telescope mirror to fly into space.
The JWST will also have a mirror that is designed to collect infrared light. This is important because stars and planets that are still forming are often hidden behind dense layers of dust that absorb visible light, making them virtually impossible to observe.
However, infrared light can penetrate the cosmic dust and allow us to peek at what lays behind.
The JWST will not be orbiting the Earth like the Hubble. Instead, it will be going around the Sun from what astronauts call the second Lagrange point, or L2. There are a number of important reasons for doing this.
The combined gravitational forces of the Sun and Earth help hold the spacecraft almost still, which means that it needs relatively less fuel. JWST’s first mission will be to capture images of Alpha Centauri, the star closest to the Sun, to try and detect water vapour on its orbiting planets.