682 Encyclopedia of the Solar System
FIGURE 1 At wavelengths visible to the human eye, the night sky (above) is dominated by black space and
point-like stars (Courtesy of A. Mellinger). From space, in the thermal infrared the same area of sky (below)is
dominated by clouds of interstellar dust and extended solar system structures. Both images span 30× 20
degrees near the First Point of Ares. The false-color thermal image was constructed from scans made by the
Infrared Astronomical Satellite. Interstellar dust, known as ‘cirrus’ is cold (indicated by red). Warm (blue)
interplanetary dust reveals rings of dust around the solar system arising from asteroid collisions (one of which is
seen as the broad band extending diagonally across the top of the image), and long contrail-like structures
consisting of cometary debris (one is seen below the band).
