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.

Type to find tags:
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Questions about Europa, a moon of Jupiter with a planet-wide ocean under a thick ice crust.
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Questions regarding planets that lie outside the Solar System.
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Questions about the increase with time of distance between two distant points in the Universe.
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For questions about objects or phenomena outside Earth, generally on other planets.
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about the lack of evidence for alien life, despite the growing evidence that suitable planets are reasonably plentiful.
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Questions about the dynamical processes leading to the assembling of a celestial object.
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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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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 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.