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The Mars Reconnaissance Orbiter's HiRISE instrument has taken many images that strongly suggest that Mars has had a rich history of water-related processes. Many features of Mars appear to be created by large amounts of water. That Mars once possessed large amounts of water was confirmed by isotope studies in a study published in March 2015, by a team of scientists showing that the ice caps were highly enriched with deuterium, heavy hydrogen, by seven times as much as the Earth. This means that Mars has lost a volume of water 6.5 times what is stored in today's polar caps. The water for a time would have formed an ocean in the low-lying Mare Boreum. The amount of water could have covered the planet about 140 meters, but was probably in an ocean that in places would be almost 1 mile deep.〔http://www.sciencedaily.com/releases/2015/03/150305140447.htm〕〔. Villanueva, L., Mumma, R. Novak, H. Käufl, P. Hartogh, T. Encrenaz, A. Tokunaga, A. Khayat, M. Smith. Strong water isotopic anomalies in the martian atmosphere: Probing current and ancient reservoirs. Science, 2015 DOI: 10.1126/science.aaa3630 〕 A major discovery by HiRISE was finding evidence of hot springs. These may have contained life and may now contain well-preserved fossils of life. ==Branched channels== Research, in the January 2010 issue of ''Icarus'', described strong evidence for sustained precipitation in the area around Valles Marineris.〔(【引用サイトリンク】title=Icarus, Volume 210, Issue 2, Pages 539–1000 (December 2010) )〕 The types of minerals there are associated with water. Also, the high density of small branching channels indicates a great deal of precipitation because they are similar to stream channels on the Earth. Image:Ius Channels.jpg|Channels near the rim of Ius Chasma, as seen by HiRISE. The pattern and high density of these channels support precipitation as the source of the water. Location is Coprates quadrangle. Image:Candor Channels.jpg|Channels in Candor plateau, as seen by HiRISE. Location is Coprates quadrangle. Click on image to see many small, branched channels which are strong evidence for sustained precipitation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Evidence of water on Mars found by Mars Reconnaissance Orbiter」の詳細全文を読む スポンサード リンク
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