新的沈積物說明了火星上有水流
Light Deposits Indicate Water Flowing on Mars<br />
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<img src="http://i18.tinypic.com/40nm4wk.jpg" border="0" onclick="zoom(this)" onload="attachimg(this, 'load')" alt="" /><br />
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影像版權: Mars Global Surveyor <br />
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<font color="navy">Explanation:</font><br />
What's creating light-toned deposits on Mars? Quite possibly -- water! Images of the same parts of mid-latitude Mars taken over the years but released only last week have shown unexpected new light-toned deposits where there were none before. One clear case is shown above, where the same crater on Mars is shown as photographed in 1999 August and again in 2005 September. The unusual deposit is visible only on the more recent photograph. Apparent tributaries near the bottom bolster the leading hypothesis that water gushed out of the crater wall, flowed down the crater, and soon evaporated into the thin Martian atmosphere. Although frozen water-ice has been known near the Martian poles for years, free flowing surface water like this was not expected to be seen in the mid-latitudes of Mars. If confirmed, such water springs might make more of Mars hospitable to life and human visitation than previously believed. <br />
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<font color="navy">說明:</font><br />
什麼原因導致了火星上有明亮的沈積物呢？極有可能是因為 -- 水。 同樣是火星某個中緯度地方的影像，上禮拜發表的影像中卻出現了以前沒看過的，而且色調比較亮的新沈積物。其中一張影像就是上圖，這是1999年8月和2005年9月所拍攝火星上的同一個區域。只有在最近的幾張照片中才看得到這些異常的沈積物。接近底部的沈積也支持了水流會從火山口湧出，順著火山流下，並迅速地蒸發至火星大氣中的主流假設。雖然人們早就知道火星的極冠附近有水冰的存在，但我們卻從來沒看過像這樣在火星中緯度表面流動的水流。如果這件事得到確認的話，這些水泉將會使火星比之前人們想像的要更適合生命居住，也更適合人們去拜訪。 <br />
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<font size="2">資料來源: Scientific American<br />
Department of Physics, NCKU</font>