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Remind me a lot of Cruithne[0] which IQ once incorrectly called the second moon of Earth. Like Zoozve it orbits the sun with the same period as a planet and in
by mcv 3y ago
Remind me a lot of Cruithne[0] which IQ once incorrectly called the second moon of Earth. Like Zoozve it orbits the sun with the same period as a planet and in a way that's strongly influenced by that planet, but while Zoozve kind of orbits Venus as a result (but in an orbit that crosses the orbits of Mercury and Earth and clearly couldn't possibly be maintained by Venus' gravity itself), Cruithne does the opposite: it kind-of orbits a point on the other side of the sun from Earth. Whenever it gets close to the Earth, it turns around. It's playing cat and mouse with the Earth, slowly overtaking it in a lower orbit until it nearly overtakes Earth, then switches to a higher, slower orbit and falls behind until the Earth nearly overtakes it, at which points it moves to a lower, faster orbit again.
From the Earth's perspective, it follows a horseshoe shape around the sun, with the Earth in the gap of the horseshoe. It's definitely not a moon, but I wonder if it could be considered a pseudo-satelite like Zoozve. They feel similar to me, though in an opposite way.
Edit: according to the Wikipedia link below, it does not follow a horseshoe shape like I originally learned, but more of a kind of bean shape that's varying between just in front of the Earth to half an orbit ahead of the Earth. Not sure where I got the horseshoe description.
[0] https://en.wikipedia.org/wiki/3753_Cruithne https://en.wikipedia.org/wiki/3753_Cruithne
- omnibrain 3y agoReading the Wikipedia article I wondered why there was no (proposed) mission to Cruithne. The Space Exploration Stack Exchange has the answer: It's difficult to reach. https://space.stackexchange.com/questions/41500/why-not-explore-cruithne https://space.stackexchange.com/questions/41500/why-not-expl...
- araes 3y agoWe ought to go to 2003 YN107 [1], it literally arrives at Earth's doorstep every 50 years. Although it's rather tiny at 30 m. The spiral patterns really neat to look at though. https://en.wikipedia.org/wiki/2003_YN107 https://en.wikipedia.org/wiki/2003_YN107
- pygy_ 3y agoThe orbit varies with time in a cyclic fashion and if you trace it for its whole cycle you get the horseshoe.
- mcv 3y agoThank you, that's it. In the short term it's a bean, but it the long term it moves from just behind the Earth to just in front in and then back again in that horseshoe shape. So there's two different weird effects going on here.