How Is Thermal Imaging Used by Astronomers?

Light Spectrum

Remote sensing is the process of sensing something without actually having to touch it. Remote sensing in modern technology is using instrument-based techniques to gather data. Thermal imaging is used to measure light waves. The most common device used is a camera that can see the electromagnetic spectrum. Telescopes, satellites, deep space probes and landing rovers are all equipped with this technology. The electromagnetic spectrum includes visible light as well as invisible light. The normal spectrum starts with ultraviolet light, moves into the visible light range and finishes with infrared light. Other waves are gamma rays, microwaves, radio waves and X-rays. Infrared light is invisible to the human eye, but humans can sense infrared light as heat on the skin.

The military originally developed thermal imaging to find targets at night. Thermal imaging is the process of assigning fake colors to different temperatures and light waves. White and red colors show the hotness of something and blue shows the coolness of something. What appears as black empty space to the naked eye is colored with reds, yellows and whites with thermal imaging.

Astronomers use thermal imaging to collect information about space that is not available from visible light. This system of imaging allows astronomers to look deeper into space. According to Growing Up With Science, "In 2004, scientists using infrared telescopes discovered the most distant galaxy in the universe yet known, more than 13.2 billion light-years away from Earth." It also allows them to discover more information about our galaxy, the Milky Way. Thermal imaging lets astronomers detect celestial bodies like newborn stars that may be surrounded by clouds of cosmic dust. These large clouds in space indicate hot gases floating around stellar nurseries.

As astronomers look at different planets and suns, thermal imaging can help them determine the gases that compose an atmosphere. Gases like helium create different thermal signatures. They can also tell the mineralogy of a planet. Thermal imaging also allows them to detect different regions on a planet like deserts, ice packs, oceans and active volcanic areas. It can also map the weather on a planet. So astronomers can use thermal imaging to tell what objects in space are made of, how heavy they are, how fast they are moving and which way they are moving.