Big Bang
The initial explosion that resulted in the formation and expansion of the universe
black hole
An object in space whose gravity is so strong not even light can escape.
blue shift
an increase in frequency
Nebula
A large cloud of dust and gas in space
nuetron star
the small, dense remains of a high-mass star after a supernova
nuclear fusion
The process by which two or more small nuclei fuse to make a bigger nucleus
Lightyear
the distance light travels in a year
planetary nebula
A huge cloud of gas that is created when the outer layers of a red giant star drift out into space
Protostar
the earliest stage of a star's life
red shift
a shift in the spectra of distant galaxies toward longer wavelengths
supernova
the brilliant explosion of a dying supergiant star
white dwarf
A small, hot, dim star that is the leftover center of an old star
asteroid
a small rocky body orbiting the sun
comet
A ball of frozen dust and rock that orbits the sun and has a tail that glows
Doppler effect
The change in frequency of a wave as its source moves in relation to an observer
electromagnetic
All of the frequencies or wavelengths of electromagnetic radiation
frequency
the number of complete wavelengths that pass a point in a given time
gas giant
a planet that has a deep, massive atmosphere, such as Jupiter, Saturn, Uranus, or Neptune
gravity
A force of attraction between objects that is due to their masses.
meteroid
a small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.
meteor
A streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere.
terrestrial planet
one of the highly dense planets nearest to the sun; Mercury, Venus, Mars, and Earth
solar system
sun, planets, and all the other objects that revolve around the sun