A moderately large object that orbits a star; it shines by reflected light.
Technical term for an object that orbits a planet.
Process by which small objects clump together to form a larger object.
Term for matter that flows out from the sun.
Philosopher and mathematician who proposed laws of gravity and motion based on his observations of planetary movement...
Type of dating used to determine the age of moon rocks.
The study of Earth and other planets...
Planet closest to the sun; Made of metal and rock with a large iron core.
A non-moon object that orbits the sun, has sufficient mass to have become round, but has not cleared its orbit. Ex. Pluto.
The direction that most planets move...
Makes up over 99.9% of solar system’s mass; composed mostly of H/He gas (plasma).
Outermost planet in our solar system.
Gas giant planet with a density less than water.
Change in color spectrum that indicates that an object is moving away...
An interstellar
cloud of gas
and/or dust.
A relatively small and rocky object that orbits a star.
Term for a planet turning on its axis.
Gas giant planet with an extreme axis tilt and a nearly vertical ring system.
A great island of stars in space, all held together by gravity and orbiting a common center.
Planet that is a near twin to Earth in size, but with a permanently shrouded surface.
Term for a planet (or other body) moving around a central star.