1	Inner planets		_____	a cool giant star.
2	Solar eclipse		_____	a small piece of debris from a comet or asteroid in interplanetary space.
3	Asteroid		_____	the Moon's shadow falling on Earth, producing a region of darkness in daytime.
4	Lunar eclipse		_____	the primordial explosion of space at the beginning of time.
5	Outer planets		_____	the remains of a giant star that has collapsed on itself, so dense that light cannot escape from it.
6	Planet		_____	a group of stars that forms an identified pattern.
7	Meteor		_____	the shadow of the Earth falls on the moon, producing relative darkness of the full moon.
8	Meteoroid		_____	a dying star that has collapsed to an Earth-like size and is slowly cooling off.
9	Comet		_____	also known as a shooting star, the streak of light produced from a meteoroid.
10	Big Bang		_____	the planets close to the sun: Mercury, Venus, Earth and Mars.
11	Nebular Theory		_____	a large assemblage of stars, interstellar gas, and dust held together by gravity.
12	Constellation		_____	an imaginary sphere surrounding Earth to which the stars are attached.
13	Red Giant		_____	the name of the galaxy to which we belong.
14	Galaxy		_____	a small, rocky body that orbits the sun.
15	Star		_____	a mass of gas and plasma held together by its own gravity that produces its own light through thermonuclear reactions.
16	Light-year		_____	the distance light travels in one year.
17	Black hole		_____	a body composed of ice and dust that orbits the sun.
18	White dwarf		_____	the idea that the Sun and planets formed together from a cloud of gas and dust, a nebula.
19	Celestial sphere		_____	Jupiter, Saturn, Uranus, and Neptune.
20	Milky Way		_____	the major bodies orbiting the Sun that are massive enough to be spherical.