| albedo |
the degree to which a planet, asteroid, or the like reflects light. [1/2 definitions] |
| alien |
a living being from another planet or other place in the universe; extraterrestrial. [2/6 definitions] |
| Amalthaea |
one of the smallest of the planet Jupiter's moons. [1/2 definitions] |
| aphelion |
the point that is farthest from the sun in the orbit of a planet or comet. |
| Ariel |
one of the five moons of the planet Uranus. [1/2 definitions] |
| bipolar |
having two poles, as a planet. [1/2 definitions] |
| Callisto |
the second largest of the moons of the planet Jupiter. [1/2 definitions] |
| celestial body |
a natural object found outside earth's atmosphere, such as a planet, moon, star, or asteroid. |
| Charon |
the only known satellite of the planet Pluto. [1/2 definitions] |
| conjunction |
in astronomy and astrology, the lining up of two or more celestial bodies, esp. the sun and a planet, along a line as viewed from Earth. [1/4 definitions] |
| crust |
the outer portion of the earth or other planet, or of a moon. [1/7 definitions] |
| Deimos |
the smaller of the two moons of the planet Mars. |
| Dione |
one of several moons of the planet Saturn. |
| earth |
(often cap.) the fifth largest planet in the solar system, which is third in order from the sun and has a diameter of about 7,930 miles. [2/4 definitions] |
| earth mother |
(sometimes caps.) the planet earth conceived of as the source of all life. [1/2 definitions] |
| Enceladus |
one of several moons of the planet Saturn, having more reflective brightness than any other body in the solar system. |
| equator |
any similar circle around a planet or other sphere. [1/2 definitions] |
| escape velocity |
the minimum speed by which an object can become free from the field of gravity of a planet, star, or the like. |
| Europa |
one of the largest moons of the planet Jupiter. [1/2 definitions] |
| evening star |
a bright planet, esp. Venus, seen in the western sky at or soon after sunset. |
| exoplanet |
a planet that orbits a star that is not our sun. |