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 involving basic astronomical concepts or information.
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Questions regarding interactions between galaxies or between major parts of a galaxy.
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Questions regarding systems of large numbers of stars held together by gravity.
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Questions regarding the inner portion of a galaxy; in the Milky Way, this is the area around Sagittarius A*.
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Questions regarding gravitationally bound systems of hundreds to thousands of galaxies as well as interactions between such systems.
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flashes of gamma rays, produced by extremely powerful explosions in distant galaxies. They are among the most powerful events in the universe
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Questions regarding matter in its gaseous state, and how it behaves in astronomy (e.g. forming stars in giant molecular clouds).
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Questions regarding massive planets composed of layers of gases, such as hydrogen and helium, surrounding a solid/liquid core.
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Questions about relativistic theory of gravity. General relativity describes gravity as a geometrical property of space and time.
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Questions related to earth processes or related processes and principles.
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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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Waves in spacetime formed by the acceleration of massive bodies. A passing wave causes spacetime to be stretched and squashed by a very small amount. Typically we can only detect the most energic grav…
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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.