The difference between meteorites, meteors, and meteoroids is one of altitude relative to a celestial surface: in space, it's a meteoroid; in the atmosphere, it's a meteor; and on the surface, it's a meteorite. (See here and here for more information.)

The International Astronomical Union (IAU) defined the term Small Solar System Body (SSSB) in 2006 with Resolution B5 as

(3) All other objects³,except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

[Footnote 3] "These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs),comets, and other small bodies."

And, although this official definition clearly states, "All other objects ... orbiting the Sun", I'm not sure how verbatim this definition is meant to be treated.

What I mean by this is, well, for example, in Law, all definitions are, by default, unless previously stated, treated in an context of exactness. But although science is oftentimes based on specificity, it is not always, and the degree thereof in this context is thus not wholly clear to me.

  • $\begingroup$ The common-sense response, I suppose, would be that meteorites are, like anything on the surface of the earth, not "objects orbiting the Sun". They were SSSBs, but aren't now. Meteors are either (very) briefly in transition, or else no longer "objects" in that sense once they enter the atmosphere. I'm not sure the distinction really matters, actually. $\endgroup$ Oct 28, 2015 at 16:43
  • $\begingroup$ I figured they wouldn't be, for the record; but I was wondering anyway because I recognise I'm not always right. Also, it doesn't matter whether anyone else thinks the distinction matters; I was wondering for my own benefit of understanding and for that reason & that reason alone it matters enough to warrant this post. $\endgroup$ Oct 30, 2015 at 16:03

1 Answer 1


Your question is really well answered by this article at the Encyclopedia Britannica website, written by Prof. Ed Tedesco of the Planetary Science Institute.

Two quotes that resonate well are...

The small bodies populate the solar system in vast numbers and include ... the fragments of these bodies—commonly called meteoroids—over a continuum of sizes down to microscopic grains known as interplanetary dust particles or micrometeoroids.


The term small body is sometimes restricted to objects that can be observed telescopically while still outside Earth’s atmosphere. In practice, this results in a lower limit of a few metres on the diameter of a small body.

So in general you can assume that anything other than the Sun, planets, minor planets, and their moons is a small solar system body. But in practice it makes sense to limit the minimum size for a SSSB, and the "observable telescopically" caveat provides that limit so that we don't have to include single molecules or one grain of sand in the list.

  • $\begingroup$ I'm not really sure we're on the same page here. I wasn't talking about difference in size, but difference in altitude. Basically, they're called meteoroids if they're in space, as soon as they enter a body's atmosphere they're called meteors, and once they impact the surface they're called meteorites. (1/2) $\endgroup$ Oct 28, 2015 at 15:18
  • $\begingroup$ What I'm asking is whether or not meteorites and meteors are considered small Solar System Bodies (SSSB), according to the IAU definition thereof. I ask this because the IAU definition states they have to be "orbiting the Sun", which beside the fact that everything orbits the Sun (let's not split hairs here) does not necessarily include those objects that aren't in space, such as meteorites and meteors, depending on how verbatim the IAU definition is intended to be treated. $\endgroup$ Oct 28, 2015 at 15:19
  • $\begingroup$ Satellites are not considered SSSB's, so as soon as the meteroid ends up in Earth orbit it is no longer an SSSB -- so no, meteors and meteorites are not SSSB's. I am orbiting the Sun but I am not an SSSB, nor is the Earth's Moon. I think the more interesting question is whether or not man-made objects are considered SSSB's? $\endgroup$ Oct 28, 2015 at 22:25
  • $\begingroup$ Are you familiar with a body's sphere of influence or Hill sphere? $\endgroup$ Oct 28, 2015 at 22:27
  • $\begingroup$ I was never asking if satellites are considered SSSBs; I know they're not. And no, man-made objects have nothing to do with my question. I'm only asking about meteoroids and meteors, which are obviously not man-made. $\endgroup$ Oct 30, 2015 at 16:05

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