Far infrared

Far infrared (FIR) is a region in the infrared spectrum of electromagnetic radiation. Far infrared is often defined as any radiation with a wavelength of 15 micrometers (µm) to 1 mm (corresponding to a range of about 20 THz to 300 GHz), which places far infrared radiation within the CIE IR-B and IR-C bands. Different sources use different boundaries for the far infrared spectrum; for example, astronomers sometimes define far infrared as wavelengths between 25 µm and 350 µm.

Visible light includes radiation with wavelengths between 400 nm and 700 nm, meaning that far infrared photons have less energy than visible light photons.

Applications

Astronomy

Objects with temperatures between about 5 K and 340 K will emit radiation in the far infrared range (see Wien's displacement law and Black-body radiation). This property is sometimes used to observe interstellar gases where new stars are often formed.

For example, the center of the Milky Way Galaxy is very bright in far infrared images because the dense concentration of stars there heats the surrounding dust and causes it to emit radiation in this part of the spectrum. Disregarding the center of our own galaxy, the brightest far infrared object in the sky is the galaxy M82, which radiates as much far infrared light from its central region as all of the stars in the Milky Way combined. This is due to the dust at the center of M82 being heated by an unknown source.

Far

Far or FAR may refer to:

Organizations

Science, technology, and medicine

Transportation

Television, film, literature, and music

Far`

Far` is a village in Al Madinah Province, in western Saudi Arabia.

References

Farø

Farø is an island in Denmark, located between the islands Sjælland and Falster. It has an area of 0.93 km² and has a population of four people (2006). Administratively it is part of Vordingborg Municipality.

The Farø Bridges (Farøbroerne) connect Sjælland with Falster via Farø, on the European Routes E47 and E55 combined. Junction 42 of E55 is located on the western side of Farø. The island is connected by causeway with the islands of Bogø and Møn by route 287 Grønsundvej.

Coordinates: 54°57′1″N 11°59′29″E / 54.95028°N 11.99139°E / 54.95028; 11.99139