Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2024 July 31
Part of a large rock on Mars is shown being mostly
orange. On the rock are several irregular light-colored areas
surrounded by a dark border. The spots are only millimeters
across but might carry big implications. 
Please see the explanation for more detailed information.

Leopard Spots on Martian Rocks
Image Credit: NASA, JPL-Caltech, MSSS, Perseverance Rover

Explanation: What is creating these unusual spots? Light-colored spots on Martian rocks, each surrounded by a dark border, were discovered earlier this month by NASA's Perseverance Rover currently exploring Mars. Dubbed leopard spots because of their seemingly similarity to markings on famous Earth-bound predators, these curious patterns are being studied with the possibility they were created by ancient Martian life. The pictured spots measure only millimeters across and were discovered on a larger rock named Cheyava Falls. The exciting but unproven speculation is that long ago, microbes generated energy with chemical reactions that turned rock from red to white while leaving a dark ring, like some similarly appearing spots on Earth rocks. Although other non-biological explanations may ultimately prevail, speculation focusing on this potential biological origin is causing much intrigue.

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