Last year, researchers excitedly announced that they had found two organic compounds essential for living organisms in samples retrieved from an asteroid called Ryugu. The Japanese Space Agency's Hayabusa2 spacecraft obtained the samples from the space rock in 2019.

Scientists have found microorganisms crawling over a sample retrieved from the 200 million-mile-distant asteroid Ryugu. But they almost certainly came from Earth.

Samples taken from the space-returned piece of asteroid Ryugu were collected and prepared under strict anti-contamination controls. Inside the cleanest of clean rooms, a tiny particle was