A slow-moving object of unknown origin just completed an extremely close flyby of our planet, before heading back out into the solar system. And the mysterious space material is expected to return in March.
The strange ‘minimoon’ – which is officially dubbed 2020 SO – has been the subject of speculation ever since it was discovered by the Pan-STARRS survey on September 17. It has been classed as an asteroid but scientists still don’t have a complete understanding of what the object is. Some have speculated that it is part of an old rocket.