February 9, 2015
The universe does not repeat itself. Every sunrise is unique, every snowflake singular, and every birthday yours alone.
Layered Rocks near Mount Sharp on Mars
Birthday · February 9, 2015
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APOD published February 9, 2015. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
What caused these Martian rocks to be layered? The leading hypothesis is an ancient Martian lake that kept evaporating and refilling over 10 million years -- but has now remained dry and empty of water for billions of years. The featured image, taken last November by the robotic Curiosity rover, shows one-meter wide Whale Rock which is part of the Pahrump Hills outcrop at the base of Mount Sharp. Also evident in the image is cross-bedding -- rock with angled layers -- which were likely facilitated by waves of sand. Curiosity continues to find many layered rocks like this as it continues to roll around and up 5.5-km high Mount Sharp.