The scientific study of the universe.
Italian astronomer and mathematician who was the first to use a telescope to study the stars.
A decrease in the wavelength of radiation emitted by an approaching celestial body.
Has a bulge in the center and arms that spiral outwards as the galaxy rotates.
Has an undefined shape and contains lots of young stars, dust, and gas.
Can be in different shapes ranging from round, to flattened, elongated spheres and contain older stars and very little gas and dust.
A bright trail or streak that appears in the sky when a meteoroid is heated by friction with the earth's atmosphere. Also called a falling star.
An irregularly shaped rock that orbits the Sun, mostly occurring in a band between the orbits of Mars and Jupiter.
The galaxy containig the solar system, visible as a broad band of faint light in the night sky.
Object that is composed of a mass of ice and dust and has a long luminous tail.