火星上白色的山脈
White Ridges on Mars <br />
<br />
<img src="http://i5.tinypic.com/2cdxv6b.jpg" border="0" onclick="zoom(this)" onload="attachimg(this, 'load')" alt="" /><br />
<br />
影像版權: HiRISE, MRO, LPL (U. Arizona), NASA <br />
<br />
<font color="navy">Explanation: </font><br />
<font color="dimgray">What created these white ridges on Mars? The images showing the white ridges, including some of the highest resolution images ever taken from Martian orbit, were recorded last year by the Mars Reconnaissance Orbiter (MRO). A current leading hypothesis is that the white ridges formed as water flowed through underground cracks and bleached and hardened the edges of surrounding rocks. Over millions of years, surface winds eroded the darker rock leaving the raised white ridges. Such water-created light-colored markings are well known here on Earth. The hypothesis is particularly interesting as underground water could have helped to support microbial life on the red world. The above image resolves surface features as small as one meter across in Candor Chasma region of huge Valles Marineris on Mars. </font><br />
<br />
<font color="navy">說明:</font><br />
<font color="dimgray">這些火星上的白色山脈是怎麼形成的？這些影像是去年由火星偵察軌道號 (Mars Reconnaissance Orbiter, MRO)所拍攝，是目前在火星軌道上所拍攝到擁有最高解析度的影像，影像中可以看到一些白色的山脈。目前較為主流的假說認為，這些白色山脈是由於地下水流突然噴出，並使得附近石頭的邊緣脫色的結果。百萬年來，火星表面上的風不斷侵蝕較黑的岩石，所留下來的，是較新升起的白色山脈。這種由水生成的淡色地標在地球上也很常見。這個地下水的假說相當有趣，也是支持這顆紅色行星上有微生物的說法。上圖的解析度大約是一公尺，拍攝的區域是火星上水手峽谷的Candor裂谷處。 </font><br />
<br />
<font size="2">資料來源: Scientific American<br />
Department of Physics, NCKU</font><font color="white"><font size="1"><br />
</font></font>