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 computer programs that assist modeling and observing the dynamics of astronomy.
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Questions regarding Albert Einstein's theory that posits, among other things, the equivalence of mass and energy.
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Questions about the observed frequency range of the electromagnetic radiation of a celestrial object.
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Questions about the processes, theories and evidence for the formation of planetary bodies.
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A collection of ionized gases and dust in interstellar space
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Questions about Mercury, the first planet from Earth'd sun. Also the smallest major planet in the Solar System,
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Questions about patterns formed by group of prominent stars in the night sky.
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Questions regarding two objects colliding into each other with considerable force.
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Questions regarding the brightness of an object.
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Questions regarding neutron stars which emit regular pulses of electromagnetic radiation.
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Questions regarding telescopes in orbit around Earth, such as the Hubble Space Telescope.
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Questions regarding casually watching the stars.
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Questions regarding one or more stars and the objects they locally interact with, including each other.
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Questions regarding the physical dimensions of a celestial object.
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Questions about rings of debris that encircle the equatorial regions of some planets.
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Behaviour and properties of light, and its interaction with matter, particularly in detection of light.
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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 regarding gravitationally bound systems of hundreds to thousands of galaxies as well as interactions between such systems.
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Questions relating to the discovery of a new 9th planet (Not Pluto) hypothesized in the Solar System.
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Questions regarding the bending of light by mass or energy.
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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 about the outermost layer of a body.
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Questions regarding specific terms, names, or naming conventions.
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Questions regarding an object orbiting around another object due to the force of gravity.
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Questions regarding the Hubble Space Telescope, a visible light telescope orbiting Earth.
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Questions regarding bodies smaller than planets but larger than other bodies, that do not meet at least one of the IAU's criteria for being a planet.