The James Webb Space Telescope (JWST) is the largest and most powerful space telescope ever built. Unlike the Hubble telescope, which mostly sees visible light, JWST sees the universe in infrared light.

Because light takes time to travel through space, looking at distant stars and galaxies is like looking back in time. JWST is so powerful that it can see light from the very first galaxies that formed after the Big Bang, over 13 billion years ago!

It uses a giant mirror made of 18 hexagonal pieces coated in gold, and a tennis-court-sized sunshield to keep its instruments incredibly cold. This cold is necessary to detect the faint infrared light from the distant universe without its own heat getting in the way.