| albedo |
the degree to which a planet, asteroid, or the like reflects light. [1/2 definitions] |
| alien |
a living being from another planet; extraterrestrial. There is no evidence that aliens exist, but many people believe there is life on other planets. [2/5 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] |
| asteroid |
a small, rocky, planet-like body that circles the sun and is mostly found between the orbits of Jupiter and Mars. The size of an asteroid can vary from very tiny to six hundred miles across. |
| 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] |
| climate change |
a major change in Earth's climate that is of current concern and which is associated with an increase in carbon dioxide and certain other gases in Earth's atmosphere. These gases contribute to the increasing temperature of the planet. [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 layer of Earth, another planet, or a moon. [1/5 definitions] |
| Deimos |
the smaller of the two moons of the planet Mars. |
| Dione |
one of several moons of the planet Saturn. |
| earth |
the third planet from the sun. [2/3 definitions] |
| earth mother |
(sometimes caps.) the planet earth conceived of as the source of all life. [1/2 definitions] |
| earth science |
Earth science is the study of the planet Earth. Earth science is especially interested in what the planet is composed of, its weather, and how the planet developed and continues to change over time. Many different sciences, such as geology and meteorology--the study of weather--are part of earth science. |
| eclipse |
the blocking from view of the sun, a moon, or a planet by another heavenly body. In an eclipse of the sun, the sun is hidden from earth's view by the moon passing between the sun and the earth. [1/3 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] |