A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

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Questions about large, dense, massive collections of stars orbiting galaxies, thought to have formed in the early universe.
Questions about the region of space around a star where a planet can sustain life.
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Questions regarding the bending of light by mass or energy.
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Questions regarding the attractive force which exists between any two bodies of matter.
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Questions about the "Goldilocks Zone" around a parent star where conditions are just right for the potential of life developing.
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Questions regarding thermal energy and its effect on astronomical objects.
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Second lightest element in the periodic table
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Questions regarding the history of astronomy, including discoveries and scientists.
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Questions about gas-giant planets in very close orbit to their parent star (closer than Mercury).
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Questions regarding the Hubble Space Telescope, a visible light telescope orbiting Earth.
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Questions about the simplest and most abundant element in the Universe.
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a star with an enormous mass and luminosity, showing signs of a very high rate of mass loss.
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Questions regarding two objects colliding into each other with considerable force.
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Questions about the chances of collisions between two objects or groups of objects, based on factors such as velocity, mass and number density.
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Inclination defines the angle between the plane of the orbit of a planet or comet and another plane, usually that of the ecliptic.
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Questions about a mathematical distribution explaining how common different masses of stars are.
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Questions regarding the space or objects outside of galaxies.
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Questions about the gas that lays between stars in galaxies.
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Questions about spacecraft journeying to other stellar systems.
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Questions about the German astronomer famous for his three laws of planetary motion. Do not use this tag for questions about the Kepler spacecraft.
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Questions regarding Jupiter, the 5th and largest planet in Earth's solar system.
Questions related to Kuiper Belt Objects that exist in an annulus from 30AU to approximately 50AU from the Earth's Sun.
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Questions about the NASA space observatory famous for finding potentially habitable exoplanets. Do not use this tag for questions about Johannes Kepler.
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a disk-shaped belt of icy debris orbiting in the outer solar system, lying beyond the orbit of Neptune and extending to a distance of about 50 astronomical units, containing thousan…