<p>The least stable orbits are likely the temporarily captured orbiters of Earth and other planets. These are bodies that have been captured by the Earth/Moon gravity well and move from solar orbits to terrestrial orbits. They normally have complex orbits that take them well beyond the orbit of the Moon and most don't last long.</p>
<p>Most such objects are small, typically less than 1 m in diameter. <a href="https://link.springer.com/chapter/10.1007/978-3-642-39244-3_6" rel="nofollow noreferrer">There are probably about 1000 such bodies with sizes of 10cm and up orbiting the Earth</a>. Normally, they are undetected but occasionally a larger object will be discovered.  Most recently, <a href="https://en.wikipedia.org/wiki/2020_CD3" rel="nofollow noreferrer">2020 CD3</a> was captured in the winter of 2015-16 and escaped Earth's gravity in May 2020.</p>
<p>The orbits of such temporary orbiters are not stable, they normally escape the Earth/Moon gravitational well after a few years, and return to heliocentric orbits.</p>

CC BY-SA 4.0
2020-07-06T03:07:19.907Z
For more on unstable minimoons see [Visitors that became satellites?](https://astronomy.stackexchange.com/q/33435/7982) and also [Have there been any documented mini-moons since 2006 RH120?](https://space.stackexchange.com/q/16738/12102)
uhoh
CC BY-SA 4.0
2020-07-03T20:26:38.513Z
2020-07-04T05:32:43.780Z
2020-07-04T05:32:43.780Z
James K
<p>My research is not giving me anything definitive. Are the Apollo asteroids orbits less stable than the Centaurs or any Trojans, or is another class of objects in less stable solar orbits? On what timescale are those orbits unstable?</p>

CC BY-SA 4.0
2020-07-04T18:11:30.563Z
What measure of instability are you considering?
Anders Sandberg
CC BY-SA 4.0
2020-07-05T01:21:48.550Z
@AndersSandberg I don't know enough about this to give you a knowledge answer to your question. Are there objects whose orbit vary within a six month period? If so that would be a good starting point.
Bob516
<orbit><asteroids><near-earth-object><trojan-asteroids><centaur>
Which solar system objects have the least stable solar orbits?
Bob516
# Which solar system objects have the least stable solar orbits?

(Asked by: username_0 on 2020-07-03)

My research is not giving me anything definitive. Are the Apollo asteroids orbits less stable than the Centaurs or any Trojans, or is another class of objects in less stable solar orbits? On what timescale are those orbits unstable?

**Tags:** orbit, asteroids, near-earth-object, trojan-asteroids, centaur

> **Comments:**
> **username_1**: What measure of instability are you considering?  
> **username_0**: @username_1 I don't know enough about this to give you a knowledge answer to your question. Are there objects whose orbit vary within a six month period? If so that would be a good starting point.  

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## 1 answers

### Answer by username_2 on 2020-07-03. Score: 3

The least stable orbits are likely the temporarily captured orbiters of Earth and other planets. These are bodies that have been captured by the Earth/Moon gravity well and move from solar orbits to terrestrial orbits. They normally have complex orbits that take them well beyond the orbit of the Moon and most don't last long.

Most such objects are small, typically less than 1 m in diameter. [There are probably about 1000 such bodies with sizes of 10cm and up orbiting the Earth](https://link.springer.com/chapter/10.1007/978-3-642-39244-3_6). Normally, they are undetected but occasionally a larger object will be discovered. Most recently, [2020 CD3](https://en.wikipedia.org/wiki/2020_CD3) was captured in the winter of 2015-16 and escaped Earth's gravity in May 2020.

The orbits of such temporary orbiters are not stable, they normally escape the Earth/Moon gravitational well after a few years, and return to heliocentric orbits.

> **Comments:**
> **username_3**: For more on unstable minimoons see [Visitors that became satellites?](https://astronomy.stackexchange.com/q/33435/7982) and also [Have there been any documented mini-moons since 2006 RH120?](https://space.stackexchange.com/q/16738/12102)  

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