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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A collection of ionized gases and dust in interstellar space
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Questions regarding Neptune, the 8th and furthest major planet orbiting Earth's sun.
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Questions regarding a family of extremely low-mass, electrically neutral particles described in the Standard Model of particle physics.
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Questions regarding a degenerate star that is mainly composed of neutrons.
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Questions regarding the theory of gravity as proposed by Newton, in which the force of gravity depends only on the mass of bodies, a constant, and the distance between them, and depends on one equatio…
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Questions about reflecting telescopes using a concave primary mirror and a flat diagonal secondary mirror.
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Questions regarding the action or process of observing a single object carefully to glean information.
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Questions regarding structures designed to aid in the observation of astronomical objects.
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Questions regarding the large "cloud" of small bodies that forms a sphere around the solar system.
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Questions regarding an object 'falling around' another object, due to a combination of gravity and momentum.
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Questions about the parameters needed to specify the characteristics of an orbit.
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Questions regarding the large-scale change of orbits over time, as in the Nice Model.
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A clockwork device that produces a small scale model of the orbits of objects in the solar system
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Questions about the apparent displacement of a celestial body with respect to its background when observed along two different lines of sight.
Questions related to the unit of measurement, parsec, which is approximately 3.26 times the distance of a light year.
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Questions about photography of celestrial objects by amateur astronomers.
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Questions on astronomical objects orbiting a star massive enough to be rounded, not massive enough to cause fusion, and which have cleared its orbit of planetesimals.
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Questions about the processes, theories and evidence for the formation of planetary bodies.
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Questions about rings of debris that encircle the equatorial regions of some planets.
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Questions regarding celestial bodies in orbit around a star.
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Questions regarding the former 9th (now dwarf) planet Pluto.
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Questions about the early phases of the star formation process. A protostar is a large mass of gas that results of the contraction of a molecular cloud.
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Questions regarding neutron stars which emit regular pulses of electromagnetic radiation.