Infrared astronomy
An all-sky image taken during the IRAS survey
Infrared Astronomy is the detection and study of the infrared radiation, or heat energy, emitted by objects in the universe. All astronomical objects have heat, so all objects emit infrared (IR) radiation. This makes IR astronomy the study of just about everything in the universe.
The human eye detects only 1% of light at 0.69 microns, and 0.01% at 0.75 microns. The IR band starts at 1 micron so, as humans effectively cannot see wavelengths longer than about 0.75 microns, we can’t see IR unless the source is extremely bright.
Like visible light, only a small portion of the IR light makes it through the atmosphere. The little bit that does is enough for astronomers to make observations and discover more information about the objects. Still, the best way to observe IR sources is through a space-based telescope.
To observe in IR, astronomers can use the same telescopes they use for optical astronomy, but with different filters and receivers that are fine-tuned to the IR part of the spectrum. Because it is relatively easy to change the telescope over to this type of set-up, a large number of observatories have an IR receiver or spectrograph which can be used (Hubble even had one on board!).
As only a small portion of matter in the universe (by distribution) radiates in the optical part of the spectrum, IR observations let us see what’s going on between the stars and galaxies. As well as better understanding the stars, galaxies, and nebulae we see, it also helps us understand the gasses and dust we don’t see.
The human eye detects only 1% of light at 0.69 microns, and 0.01% at 0.75 microns. The IR band starts at 1 micron so, as humans effectively cannot see wavelengths longer than about 0.75 microns, we can’t see IR unless the source is extremely bright.
Like visible light, only a small portion of the IR light makes it through the atmosphere. The little bit that does is enough for astronomers to make observations and discover more information about the objects. Still, the best way to observe IR sources is through a space-based telescope.
To observe in IR, astronomers can use the same telescopes they use for optical astronomy, but with different filters and receivers that are fine-tuned to the IR part of the spectrum. Because it is relatively easy to change the telescope over to this type of set-up, a large number of observatories have an IR receiver or spectrograph which can be used (Hubble even had one on board!).
As only a small portion of matter in the universe (by distribution) radiates in the optical part of the spectrum, IR observations let us see what’s going on between the stars and galaxies. As well as better understanding the stars, galaxies, and nebulae we see, it also helps us understand the gasses and dust we don’t see.