| Word | Meaning |
|---|---|
| Paaliaq | moon of saturn |
| Pallene | moon of saturn |
| Pan | moon of saturn |
| Pandora | moon of saturn |
| Particle | |
| Pasiphae | moon of jupiter |
| Pasithee | moon of jupiter |
| Perdita | |
| Periodic Comet | |
| Phobos | moon of mars |
| Phoebe | moon of saturn |
| Photosphere | |
| Planet | Spherical object which orbits a star. Planets can vary greatly in size although are never larger than the star they orbit. Planets can be rocky or gaseous. Smaller planets tend to have solid surfaces whereas larger planets are balls of mostly gas. There are eight planets known to orbit the Sun and at least 270 planets known to orbit other stars (these planets are known as extrasolar planets or exoplanets). |
| Planetary Nebula | |
| Pluto | Tiny world orbiting the Sun in a very elliptical orbit, going as close as 4,443,000,000 km from the Sun to as far as 7,682,900,000 km away from it. Regarded as the ninth planet in the Solar System since its discovery in 1930 until being reclassified as a Dwarf Planet in 2006. Pluto takes 248 years to complete an orbit around the Sun. With a diameter of 2,280 km, Pluto is smaller than Earth's moon. Orbiting Pluto are 3 known moons: Charon, Hydra and Nix. |
| Poles | |
| Polydeuces | moon of saturn |
| Portia | |
| Praxidike | |
| Prometheus | moon of saturn |
| Prospero | |
| Proteus | |
| Psamathe | |
| Puck |
