2020 May 24


Valles Marineris: The Grand Canyon of Mars
Image Credit:
NASA, USGS, Viking Project

Explanation: The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth’s Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Several geologic processes have been identified in the canyon. The featured mosaic was created from over 100 images of Mars taken by Viking Orbiters in the 1970s.

Tomorrow’s picture: interstellar monster

NASA, USGS, Viking Project

说明: 太阳系最大的峡谷,在火星的表面划出一道宽又深的凹痕。名为水手峡谷的这个雄伟裂谷,伸展的长度超过3,000公里,最宽处有600公里宽,并往下刨了约8公里深。相较之下,位于美国.亚利桑那州的大峡谷,长约只有800公里、30公里宽、1.8公里深。水手峡谷的成因目前尚无法确定,但最为大家接受的假说认为:远在数十亿年前火星冷却时,一道小裂缝后来演变成现今的峡谷。科学家已在此峡谷中,辨认出数种地质演化过程。上面这张拼嵌主题影像,是由100多张1970年代海盗号轨道船所拍的火星影像组合而成。

明日的图片: interstellar monster

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