The Brief

Rocks found on Mars may provide the strongest evidence yet of past life on the Red Planet, but more testing is needed to back up those findings.

Until the samples are retrieved by robotic spacecraft or astronauts, scientists will have to rely on Earthly stand-ins and lab experiments to evaluate the possibility of ancient Martian life.

NASA’s ambitious plan to return the samples is on hold as the agency seeks cheaper, quicker options.

NASA’s Perseverance Mars rover has discovered rocks in a dry river bed that could have signs of ancient microscopic life.

But until those samples are brought back to Earth, no conclusions can be reached, scientists said Wednesday.

Signs of past life on Mars

What we know:

Collected last summer, the sample is from reddish, clay-rich mudstones i

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