{"id":15757,"date":"2024-12-20T06:50:44","date_gmt":"2024-12-20T11:50:44","guid":{"rendered":"https:\/\/www.fas37.org\/wp\/?p=15757"},"modified":"2024-12-20T06:50:44","modified_gmt":"2024-12-20T11:50:44","slug":"the-earths-2nd-moon","status":"publish","type":"post","link":"https:\/\/www.fas37.org\/wp\/the-earths-2nd-moon\/","title":{"rendered":"The Earth\u2019s 2nd Moon?"},"content":{"rendered":"\n

FAS Astronomers Blog. Volume 32. Number 11.<\/strong><\/p>\n\n\n\n

Although, it really didn’t count as an official moon, a small object entered into a temporary orbit about the Earth and was called \u201cthe Earth\u2019s second moon.\u201d Asteroid 2024 PT5<\/sub> was captured by the Earth\u2019s gravity on September 26, 2024. It stayed around for a couple of months before leaving on November 25, 2024. At 32 feet wide, it probably would have gone unnoticed by most of us, except for the wide press coverage it has received over the last few months.<\/p>\n\n\n\n

There have been a few other references to an \u201cEarth\u2019s second moon.\u201d According to the folks at Wikipedia<\/a>, the Earth has captured two other \u201csecond moons\u201d, 2006 RH120<\/sub> (2006 to 2007) and 2020 CD3<\/sub> (2018 to 2020).<\/p>\n\n\n\n

The Earth also has \u201cquasi-satellites\u201d – so named because they appear to be orbiting the Earth, while they are actually orbiting the Sun. Earlier this year (2024), object 2016 HO3<\/sub> Kamo\u2019oalewa was discovered and fell into this category. Last year (2023) object 2023 FW13<\/sub> was also found. Tanya Hill, in the Conversation<\/a>, notes five others: 2003 YB107<\/sub>, 2004 GU9<\/sub>, 2006 FV35<\/sub>, 2013 LX28<\/sub>, and 2014 OL339<\/sub>.<\/p>\n\n\n\n

Back in 1997, object 3753 Cruithne was discovered following the Earth in its orbit around the Sun. It does (sort of) orbit the Earth in a long \u201chorseshoe orbit\u201d lasting 770 years. Cruithne wasn\u2019t discovered until 1986 and its orbit was first tracked in 1997. At only three miles in diameter and a closest approach of 7 1\/2 million miles, it isn\u2019t something you will spot in the night sky or even through a telescope.<\/p>\n\n\n\n

In addition to all these \u201cmoons,” there are several asteroids that follow orbits, which from time to time, come close to the Earth. They fall into the category of Near-Earth objects – those that cross the Earth\u2019s orbit and, for some, pass close to the Earth. Every once in a while one will come close enough that we will hear about it in the press. However, don\u2019t worry, You Don\u2019t Need to Duck<\/a> – the folks at NASA<\/a> are keeping an eye out for these.<\/p>\n\n\n\n

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Selected Sources and Further Reading<\/span><\/p>\n\n\n\n