A small Solar System body (SSSB) is an object in the Solar System that is neither a planet nor a dwarf planet, nor a satellite of a planet or dwarf planet:
All other objects, except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies" ... These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.This encompasses all comets and all minor planets other than those classified as dwarf planets, i.e.:
- the classical asteroids, with the exception of Ceres;
- the centaurs and trojans;
- the trans-Neptunian objects, with the exception of Pluto, Haumea, Makemake and Eris.
The term was first defined in 2006 by the International Astronomical Union.
It is not presently clear whether a lower size bound will be established as part of the definition of small Solar System bodies in the future, or if it will encompass all material down to the level of meteoroids, the smallest macroscopic bodies in orbit around the Sun. (On a microscopic level there are even smaller objects such as interplanetary dust, particles of solar wind and free particles of hydrogen.)
Except for the largest, which are in hydrostatic equilibrium, moons differ from small Solar System bodies not in size, but in their orbits. Moons' orbits are not centered around the Sun but around other Solar System objects such as planets, dwarf planets, and even small Solar System bodies themselves.
Some of the larger small Solar System bodies may be reclassified in future as dwarf planets, pending further examination to determine whether or not they are in hydrostatic equilibrium.
The orbits of the vast majority of small Solar System bodies are located in two distinct areas, namely the asteroid belt and the Kuiper belt. These two belts possess some internal structure related to perturbations by the major planets (particularly Jupiter and Neptune, respectively), and have fairly loosely defined boundaries. Other areas of the Solar System also encompass small bodies in smaller concentrations. These include the near-Earth asteroids, centaurs, comets, and scattered disc objects.
Famous quotes containing the words small, solar, system and/or body:
“The rebellion is against time pollution, the feeling that the essence of what makes life worth livingthe small moments, the special family getaways, the cookies in the oven, the weekend drives, the long dreamlike summers Mso much of this has been taken from us, or we have given it up. For what? Hitachi stereos? Club Med? Company cars? Racquetball? For fifteen-hour days and lousy day care?”
—Richard Louv (20th century)
“The solar system has no anxiety about its reputation, and the credit of truth and honesty is as safe; nor have I any fear that a skeptical bias can be given by leaning hard on the sides of fate, of practical power, or of trade, which the doctrine of Faith cannot down-weigh.”
—Ralph Waldo Emerson (18031882)
“How natural that the errors of the ancient should be handed down and, mixing with the principles and system which Christ taught, give to us an adulterated Christianity.”
—Olympia Brown (18351900)
“A woman watches her body uneasily, as though it were an unreliable ally in the battle for love.”
—Leonard Cohen (b. 1934)