Infrared cirrus consists of wispy, filamentary structures seen in infrared in all parts of the sky, but particularly well at high galactic latitudes away from all of the other infrared emission associated with the galactic plane. First detected by the Infrared Astronomy Satellite at wavelengths of 60 and 100 microns, the cirrus is named after its cloud-like appearance and is believed to be due to dust grains in otherwise cool (15 to 30 K), diffuse atomic hydrogen clouds that have been warmed slightly by ultraviolet light from nearby stars.