Every small child know that the Earth has only one moon. But that is technically not true.
by [Jaime JaimeJunior[(http://www.facebook.com/jaime.guimaraesjr) CC0 Public Domain via PublicDomainPictures.net
Not only does the Earth have one stable moon sometimes it catches other objects that are called TCFs (Temporarily Captured Flybys) and TCOs (Temporarily Captured Objects). Detecting them is quite hard as usually, that are quite small objects with an average diameter of just a few meters that orbit between the Earth and the Sun and sometimes get caught by the Earths gravity. Either they fall into the Earth’s atmosphere and burn up or they start orbiting the Earth.
If the object manages to finish at least one full orbit around our planet the scientists call this a micromoon but only rarely do these get detected. One of the most famous ones is an asteroid called 2006 RH120 which was detected back in 2006 by the Cataliny Sky Survey. This asteroid orbited the Earth several times until in June of 2007 the asteroid gathered enough energy to leave its orbit.
This was the event that allowed an international team of scientists from the U.S., Sweden, Finnland and Spain to publish a study in which they take a deeper look at the micromoon phenomena and also tried to predict how many micromoons may the Earth actually have.
Sources:
- https://www.frontiersin.org/articles/10.3389/fspas.2018.00013/full
- https://en.wikipedia.org/wiki/2006_RH120
