The Universe

A brightness scale used to measure of how a bright star would be if it were scene from a standard distance

The brightness of a star as scene from Earth

A large collection of stars, dust, and gas bound together by gravity

Hertzsprung-Russell diagram, a graph that shows the relationship between a star’s surface tempature and absolute magnitude

The distance light travels through space in one year; about 9.46 trillion kilometers

The actual brightness of an object such as a star

the region on the diagram where stars spend most of their lives; it has a diagonal pattern

A large cloud of dust and gas in interstellar space; a region in space where stars are born

The core of a supernova that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons

A relatively large spherical body that orbits a star

A highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation

The motion of a body that travels around in space; one trip along an orbit

the spin of a body on its axis

The collection of large and small bodies that orbit our central star, the sun.

A large celestial body that is composed of gas and that emits light; the sun is a typical star

The distance between two adjacent troughs or crests of a wave.

A gigantic explosion in which a massive star throws its outer layers into space, but its core remains

Space and all the matter and energy inside of it

The hot, dense, dim core of matter that remains from the collapse of a low-mass star

A galaxy shaped like a pinwheel, with a bulge in the center and spiral arms extending outwards.

A spherical or elongated galaxy with a bright center and very little dust or gas.

A galaxy with an irregular shape that doesn’t fit into any other category.

All the different wave lengths and frequencies of electromagnetic radiation, from radio waves to gamma rays.

The theory that all matter and energy in the universe are compressed into an extremely small volume that 13 billion to 15 billion years ago exploded and began expanding in all directions.