Space Flashcards
The sun, the planets, and smaller bodies
Solar system
A group of millions or billions of stars held together by their own gravity
Galaxy
Everything, space and all the matter and energy in it
Universe
An object that orbits a more massive object
Satellite
When an object strikes the surface of a larger object in space it explodes and leaves behind a round pit
Impact crater
The earth rotates around an imaginary line through it’s center
Axis of rotation
The motion of one object around another
Revolution
Patterns of temperature changes and other weather trends over the course of the year
Season
Sunlight shines on the southern and northern hemispheres
Equinox
A dark spot on the moon
Mare
Occurs when a shadow makes the sun or moon seem to grow dark
Eclipse
Is the darkest part
Umbra
Around the umbra is a spreading cone of lighter shadow
Penumbra
Is earth’s average distance from the sun
Astronomic unit
The shape of each orbit
Ellipse
Are Mercury, Venus, Earth, and Mars-the closest planets to the sun
Terrestrial planet
Are Jupiter, Saturn, Uranus, and Neptune-are made of mainly hydrogen, helium, and other gases
Gas giant
Small, solid rocky bodies that orbit close to the sun
Asteroid
A body that produces a coma of gas and dust
Comet
A brief streak of light produced by a particle entering earth’s atmosphere at a high speed
Meteor
A small object from outer space that passes through earth’s atmosphere and reaches the surface
Meteorite
Having or representing the earth as the center
Geocentric
Having or representing the sun as the center
Heliocentric
The force that objects exert on each other because of their mass
Gravity