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

A sample of the asteroid Ryugu returned to Earth by the Hayabusa2 mission was rapidly colonized by terrestrial microorganisms, new research has revealed.

Asteroid Ryugu was altered by water and contains organic molecules older than the Sun. The building blocks of RNA and Vitamin B3 have been found in its samples, together with polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, a molecule used in mothballs. Earthly bacteria don’t seem to care where the molecules originated from.

After almost two months of companionship, Earth has just lost its “mini-moon.” On Monday, the asteroid dubbed 2024 PT5 was tugged away from our planet and resumed its course in the sun’s orbit once more.

Earth is parting company with an asteroid that's been tagging along as a “mini moon" for the past two months. The harmless space rock will peel away on Monday.