Sometimes, objects from space come really close to Earth but are not immediately pulled in by our planet’s gravity. They often orbit for a short period of time before being either pulled into the atmosphere or hurled back out into space. These objects are called temporarily captured orbiters (TCOs), but are commonly referred to as natural Earth satellites or minimoons.
There are a whole bunch of rocks out there, zipping past Earth, so it stands to reason that some of them are going to penetrate the atmosphere at some point. Most of these end up as bolides – a meteor that explodes in mid-air before it can reach the ground.
Fireballs explode in Earth’s atmosphere all the time, usually unremarkably. This fireball might have been mistaken for any other bolide, if not for a network of cameras monitoring the sky to search for just such events It was thanks to images taken by these cameras – called the Desert Fireball Network – that astronomers were able to ascertain the fireball was no ordinary exploding space rock, but rather an Earth minimoon.
We’ve detected temporary moons around other planets – Jupiter is particularly adept at minimoon capture – but here on Earth, minimoon detections are extremely rare. This is only the second time ever that a minimoon has been spotted on record!
Only one time, in 2006, have researchers observed a minimoon orbiting Earth. The object, named 2006 RH120, was seen through a telescope circling the planet. The object orbited Earth for about 11 months before it wriggled free from Earth’s gravity and was flung back out into space.
By studying the flight paths of minimoons, researchers could better understand how we might be able to better prevent objects from getting close to Earth and how we might be able to more easily access these objects and the resources that they may possess.
While a very rare phenomenon, with more telescopes coming online in the near future, it’s possible more minimoon fireballs will be discovered, helping construct a more complete picture of Earth’s minimoon situation at any given time.
Sources: Space.com , Science Alert,
