The James Webb Telescope

This article is a description of the James Webb Telescope and how it changed modern astronomy.


1/4/20232 min read

About the Telescope

The James Webb telescope is the most powerful telescope ever built. It is as tall as a three-story building and about 66 feet long. The telescope “sees” by using 18 gold-plated mirrors to reflect infrared light towards a centerpiece that can absorb the waves and turn them into images. The telescope detects infrared, or heat, radiation that are outside of the visible light spectrum.

The Heat Shield

Because the James Webb telescope detects infrared light, if the sun's heat reached the sensor, it would ruin the images. In order to work properly, the temperature of the gold mirrors and sensor piece must be freezing. The goal temperature to reach is 7 Kelvins or -447 degrees Fahrenheit, which is nearly as cold as absolute zero (-459.67°F). It achieves this temperature using the heat shield of aluminum-coated Kapton blocking heat from the sun.

Why a Ten Billion Dollar Telescope?

The James Webb telescope is a successor to the Hubble telescope. Being 100 times more powerful, it is capable of much clearer images and seeing much farther into the universe than its predecessor. Its purpose is to help expand our knowledge of how planetary systems form and how stars are born over time. So how does it look back in time, you might ask? Webb observes stars and galaxies as far as billions of light years away from Earth. This means that the light reaching us from the galaxies was produced many billions of years ago, and we are seeing the past state of the stars and their galaxies. This allows us to watch the formation of stars that occurred billions of years ago and understand more about our universe.

Images from the James Webb Telescope

Webb's First Deep Field

"Cosmic Cliffs" in Carina

Southern Ring Nebula

Stephan's Quintet