| A | B |
|---|
| Asteroids | Small bodies composed of rock and metal in orbit about the sun. |
| Comets | Small bodies composed of ice and rock in various orbits about the sun. |
| ESA | European Space Agency. |
| Galaxy | An assembly of stars and related matter and gas, all held |
| Kessler Syndrome | together by mutual gravity. |
| Light-year | A prediction of a future cascading of collisions in orbit. |
| Moon | The distance that light travels in one year, about 6 trillion miles. |
| NGO | A natural satellite of a planet. |
| Planet | Non-Government Organizations. |
| Satelite | An orbiting body large enough to become round by the force of its own gravity and large enough to dominate the vicinity of its orbit. |
| UN | A small body which orbits a larger one. A natural or an artificial moon. |
| Universe | United Nations. An organization established on 24 October 1945 by 51 countries committed to preserving peace through international cooperation and collective security. |
