Astronomy Basics

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Astronomy

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The study of celestial objects, space, and the universe as a whole.

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Planet

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A large celestial body that orbits a star, such as Earth, Mars, or Jupiter.

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Star

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A massive, luminous sphere of plasma held together by gravity, like the Sun.

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Galaxy

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A large system of stars, gas, dust, and dark matter, bound together by gravity; our galaxy is called the Milky Way.

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Orbit

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The path an object takes as it moves around another object in space, such as a planet orbiting a star.

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Satellite

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A natural or artificial object that orbits a planet; the Moon is a natural satellite of Earth.

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Asteroid

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A small rocky body that orbits the Sun, mostly found in the asteroid belt between Mars and Jupiter.

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Comet

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A small icy body that, when passing close to the Sun, heats up and releases gas and dust, forming a glowing coma and tail.

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Black Hole

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A region in space where the gravitational pull is so strong that nothing, not even light, can escape from it.

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Universe

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All of space and everything in it, including stars, planets, galaxies, and all forms of matter and energy.