The James Webb Space Telescope (JWST) was launched on Christmas Day, 2021, but it came truly “alive” and transmitted data on July 12, 2022. NASA celebrated its second birthday by releasing an image from Webb’s vast gallery of images of two galaxies that are so close to each other that they interact like two dance partners. The Webb images are 100 times more detailed than those from the Hubble telescope which was launched in 1990.
The Webb telescope “looks back in time” since the objects that it is designed to observe are so remote that the distance is measured in light years—as in years that the light took to travel. So when we see a star that is one billion light years away, what we are witnessing is what the star looked like a billion years ago, and not what it may look like today. Those distant objects are traveling away from Earth so fast that the light is altered towards the red side of the spectrum. The light from the most distant objects are in the infrared range and no longer in the visible range, meaning that the older Hubble could not detect them. The Webb telescope uses infrared sensors to “see” what is invisible to the Hubble.
