Galaxies and Stars

3. the force exerted by gravity on an object.
4. a measure of a star's brightness, using a logarithmic scale.
6. a series of star types to which most stars belong, represented on a Hertzsprung–Russell diagram.
8. an invisible force that pulls objects toward each other.
9. the rate at which something's speed or direction changes.
11. a place in space where gravity pulls so much that even light can not get out
14. a regular, repeating path that one object in space takes around another one.
15. a binary star is a system of two stars gravitationally bound and orbiting a common center of mass, also known as the barycenter.
16. the dense, small, and faint remnant of a star that has exhausted its nuclear fuel.
17. a cataclysmic explosion of a star, marking the end of its life cycle.

1. a highly dense stellar remnant formed from the collapsed core of a massive star after a supernova explosion.
2. a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.
4. the amount of matter that makes up an object.
5. a very large star of high luminosity and low surface temperature.
7. a large cloud of dust and gas, primarily composed of hydrogen and other ionized gases, that resides in the space between stars.
10. a recognized pattern of stars in the night sky, often named after mythological figures, animals, or objects.
12. the total amount of energy a star emits into space per second.
13. a graph that plots the absolute brightness (or luminosity) of stars against their surface temperature (or spectral type).