Our Solar System

Science

asteroid

a body of rock and metal that orbits the Sun

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astronomical unit

the average distance between Earth and the Sun, about 150 million km, or 93 million miles

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axis

the imaginary line around which Earth rotates, it runs through Earth from pole to pole

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comet

a body of ice, rock, and dust that orbits the Sun

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constellation

a pattern or shape formed by a group of stars

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corona

the outermost layer of the Sun’s atmosphere

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eclipse

an event where one object in space passes through the shadow of another object

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equinox

the two days a year when the Sun is directly over the equator, making day and night equal

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galaxy

a massive system of stars, gases, and dust held together by gravity

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gas giant

a large planet made up mostly of gases, like Jupiter or Saturn

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meteor

a streak of light created when a meteoroid is heated by Earth’s atmosphere

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meteorite

a meteoroid that lands on the surface of Earth, a moon, or a planet

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moon phase

changes in the shape of the moon as seen from Earth

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orbit

the path of one body around another, like Earth’s orbit around the Sun

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penumbra

a region of lighter shadow around the darkest part of a shadow

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revolution

the motion of one body around another, like the Earth around the Sun

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solar system

a group of planets and other objects that revolve around a sun

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solstice

the twice yearly event when the Sun reaches its greatest distance North or South of the equator

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sunspot

a spot on the Sun which appears darker because it is not as hot as other areas

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terrestrial planet

one of the four rocky planets of the inner solar system, Mercury, Venus, Earth or Mars

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umbra

the darkest part of a shadow

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universe

everything that exists, including the stars, planets, and energy

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