2013: Year in Space (31 images)

A look back on the years's launches, space explorations and discoveries.
Updated: Oct. 21, 2013 at 2:01 PM
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Observations with NASA's Chandra X-ray Observatory have revealed a massive cloud of multimillion-degree gas in a galaxy about 60 million light years from Earth. The hot gas cloud is likely caused by a collision between a dwarf galaxy and a much larger galaxy called NGC 1232. If confirmed, this discovery would mark the first time such a collision has been detected only in X-rays, and could have implications for understanding how galaxies grow through similar collisions. An image combining X-rays and optical light shows the scene of this collision. The impact between the dwarf galaxy and the spiral galaxy caused a shock wave, akin to a sonic boom on Earth that generated hot gas with a temperature of about six million degrees. UPI/G. Garmire/NASA
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