Dueling Iridium Flares

November 16, 2005

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Provided and copyright by: Andre Mueller
Summary authors & editors: Andre Mueller; Jim Foster

The photo above showing two iridium flares was captured above Aachen, Germany (51°N, 6°E) on September 29, 2005. Iridium flares are brief but often bright reflections of sunlight off of low-Earth satellites. The Iridium satellites span a world-wide mobile phone network. Originally it was intended that a fleet of 77 satellites would encircle the globe -- 77 is the atomic number of the iridium. The idea being that if the Earth is the nucleus and the satellites are the electrons, the entire system would take on the appearance of an iridium atom. The reflected sunlight from one of these satellites' main antennas or solar panels can attain a magnitude of -9. This is approximately as bright as the half illuminated Moon and nearly 100 times brighter than Venus when it's at its brightest! The dual flares shown above were less than one degree apart (approximately 40 seconds). At the time the picture was taken, Iridium satellite #8 (right) and satellite #51 were both positioned over the North Sea, some 2,600 km away (about 1,610 miles), nonetheless, the geometry of their orbital position with the Sun was just right to produce these parallel flares. If you want to see one of these flares yourself, have a look at Heavens Above web site in the Related Links (below).

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