| A | B |
|---|
| geocentric system | the model in which Earth is at the center of the system of planets |
| heliocentric system | the model in which the Sun is at the center of the system of planets |
| inertia | the tendency of a moving object to continue moving in a straight line or a stationary object to stay in place |
| solar wind | a stram of electrically charged particles produced by the sun's corona |
| prominence | a loop of gas that links different parts of sunspot regions |
| meteorite | a meteoroid that hits Earth's surface |
| nuclear fusion | the process in which hydrogen atoms form helium atoms and energy |
| photosphere | inner layer of the sun's atmosphere visible in photographs |
| chromosphere | the middle layer of the sun's atmosphere that looks like a red crescent at the beginning or the end of a total solar eclipse |
| sunspots | areas of gas on the sun that are cooler than the gases around them |
| corona | outer layer of the sun's atmosphere that looks like a halo and can be seen during a total solar eclipse |
| comet | a dirty snowball that travels in long, narrow ellipses in the solar system |
| asteroid | a chunk of rock that orbits the sun in the asteroid belt between Mars and Jupiter |
| meteor | a meteroid that passes into Earth's atmosphere and creates a streak of light across the sky |
| meteoroid | a chunk of rock that travels in space in no particular orbit |
| asteroid belt | a place between Mars and Jupiter where many asteroids are found |
