Claimed moons of Earth

Not to be confused with Earth trojan.
This asteroid's orbit keeps it near the Earth, but not orbiting it in the usual sense. When analyzing its orbit from the perspective of different bodies, the presumed quasi-satellite does seem to have a more stable location near the Earth
The orbit of 2020 CD3 around the Earth. The white band is the orbit of the Moon.

Claims of the existence of other moons of Earth—that is, of one or more natural satellites with relatively stable orbits of Earth, other than the Moon—have existed for some time. Several candidates have been proposed, but none have been confirmed. Since the 19th century, scientists have made genuine searches for more moons, but the possibility has also been the subject of a number of dubious non-scientific speculations as well as a number of likely hoaxes.[1]

Although the Moon is Earth's only natural satellite, there are a number of near-Earth objects (NEOs) with orbits that are in resonance with Earth. These have been called "second" moons of Earth or "minimoons".[2][3]

469219 Kamoʻoalewa, an asteroid discovered on 27 April 2016, is possibly the most stable quasi-satellite of Earth.[4] As it orbits the Sun, 469219 Kamoʻoalewa appears to circle around Earth as well. It is too distant to be a true satellite of Earth, but is the best and most stable example of a quasi-satellite, a type of NEO. They appear to orbit a point other than Earth itself, such as the orbital path of the NEO asteroid 3753 Cruithne. Earth trojans, such as 2010 TK7, are NEOs that orbit the Sun (not Earth) on the same orbital path as Earth, and appear to lead or follow Earth along the same orbital path.

Other small natural objects in orbit around the Sun may enter orbit around Earth for a short amount of time, becoming temporary natural satellites. As of 2024, the only confirmed examples have been 2006 RH120 in Earth orbit during 2006 and 2007,[5] 2020 CD3 in Earth orbit between 2018 and 2020, and 2024 PT5 in Earth orbit during 2024.[6][7]

  1. ^ Drye, Paul (2009-01-24). "Earth's Other Moon". passingstrangeness.wordpress.com. Retrieved 2011-10-23.
  2. ^ Lloyd, Robin, More Moons Around Earth?, space.com, archived from the original on 2012-12-08
  3. ^ Elizabeth Howell (28 February 2020). "How scientists found Earth's new minimoon and why it won't stay here forever". Space.com. Retrieved 23 November 2022.
  4. ^ Agle, DC; Brown, Dwayne; Cantillo, Laurie (15 June 2016). "Small Asteroid Is Earth's Constant Companion". NASA. Retrieved 15 June 2016.
  5. ^ Kwiatkowski, T.; Kryszczyńska, A.; Polińska, M.; Buckley, D. A. H.; O'Donoghue, D.; Charles, P. A.; Crause, L.; Crawford, S.; Hashimoto, Y.; Kniazev, A. (2009). "Photometry of 2006 RH120: an asteroid temporary captured into a geocentric orbit". Astronomy & Astrophysics. 495 (3): 967–974. Bibcode:2009A&A...495..967K. doi:10.1051/0004-6361:200810965. ISSN 0004-6361.
  6. ^ "MPEC 2020-D104: 2020 CD3: Temporarily Captured Object". Minor Planet Electronic Circular. Minor Planet Center. 25 February 2020. Retrieved 25 February 2020.
  7. ^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (7 April 2020). "On the orbital evolution of meteoroid 2020 CD3, a temporarily captured orbiter of the Earth–Moon system". Monthly Notices of the Royal Astronomical Society. 494 (1): 1089–1094. arXiv:2003.09220. Bibcode:2020MNRAS.494.1089D. doi:10.1093/mnras/staa809. S2CID 214605877.