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Planets/Stars Vocab
| Term | Definition |
|---|---|
| Meteoroid | a small piece of metal or stone that orbits the sun |
| meteor | a streak of light in the sky that forms when a piece of rock from space burns up in Earth's atmosphere |
| meteorite | a piece of rock or metal from space that strikes Earth's surface |
| star | a massive ball of gas in outer space that gives off heat, light, and other forms of radiation |
| comet | a body of ice and dust that travels in a long, narrow orbit around the Sun |
| asteroid | a small object made of rock or metal that orbits the sun |
| Hertzprung-Russell diagram | a diagram plotting the absolute magnitudes of stars relative to the different stages in a star's life cycle |
| planetary nebula | a large cloud of gas and dust in outer space ejected by an aging star near the end of its life cycle |
| solar nebula | the cloud of dust and gas created by the gravitational collapse of interstellar molecules from which it is believed the solar system was created |
| white dwarf | a relatively small, dense star at the end of its life cycle, which generates little or no energy and has contracted to its densest state |
| giant star | a star at the stage in its life cycle when it stops burning hydrogen, begins burning helium, and expands to a large, low-density star |
| supergiant star | a star that is larger, brighter, and more massive than a giant star, being thousands of times brighter than the Sun and having a relatively short lifespan |
| neutron star | a small-diameter, very dense star composed of neutrons held together by gravity |
| black hole | a space object with surface gravity great enough that not even light waves can escape it |
| galaxy | a group of solar systems, dust, and gas held together by gravity; our solar system is part of the Milky Way galaxy |
| Milky way galaxy | a group of solar systems, dust, and gas held together by gravity; our solar system is part of the Milky Way galaxy |
| sun spot | a cooler darker spot on the surface of the Sun |