Description: Infrared astronomy is a branch of astronomy that looks at infrared light. It is more sensitive to cool objects than observations in visible light and can observe very distant galaxies whose light has been redshifted a lot. Infrared observations are less affected by extinction and can thus see deeper into interstellar clouds of gas and dust.

Molecules in Earth's atmosphere absorb much of the infrared light coming from space and thus infrared astronomy on the ground is done mostly in wavelength ranges where this absorption is lower. Both Earth and its atmosphere radiate in the infrared so special techniques are required to remove this background radiation. For infrared radiation with longer wavelengths, this background plus atmospheric absorption makes observing on the ground almost impossible. As a result many infrared observations are carried out using space telescopes. However, for the longest infrared wavelengths ground-based observations are possible from very dry sites. This is typically called submillimeter astronomy.

Related Terms:

• Electromagnetic Radiation
• Infrared (IR)
• Infrared Telescope
• Redshift
• Interstellar Extinction
• Submillimeter Astronomy

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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