I heard that IRAS discovered evidence of a 10th planet or planet X. Is this true?
No, IRAS did not detect evidence for a 10th planet in our solar system. We have received this question so often that a separate web site has been created to provide a detailed answer. To see it click here.What is IRAS?
The Infrared Astronomical Satellite (IRAS) was the first infrared telescope ever sent into space. It was a joint project of the United States, Great Britain and the Netherlands. During its ten month mission, IRAS scanned more than 96 percent of the sky four times, providing the first high sensitivity all sky map at wavelengths of 12, 25, 60 and 100 microns. IRAS increased the number of cataloged astronomical sources by about 70%, detecting about 350,000 infrared sources.What Discoveries did IRAS make?
IRAS discoveries included a disk of dust grains around the star Vega, six new comets, and very stronginfrared emission from interacting galaxies as well as wisps of warm dust called infrared cirrus which could be found in almost every direction of space. IRAS also revealed for the first time the core of our galaxy, the Milky Way.Where can I see images from IRAS?
The IRAS gallery of images can be found at http://coolcosmos.ipac.caltech.edu/image_galleries/IRAS/irasgallery.html.Why was IRAS built?
In the 1970s, astronomers around the world began to consider the possibility of placing an infrared telescope on a satellite in orbit around the Earth. This telescope would be above the Earth's atmosphere and could view the sky at the far-infrared wavelengths which were difficult to detect on Earth. It could view a large area of the sky and observe regions for a longer period of time. For further information see our web site http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/orbit.html.