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 regarding the Hubble Space Telescope, a visible light telescope orbiting Earth.
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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 water molecule (composed of two atoms of hydrodgen and one atom of oxygen) and its detection in celestial objects.
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Questions about the processes, theories and evidence for the formation of planetary bodies.
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Questions regarding celestial objects which emit regular pulses of electromagnetic energy.
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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 large "cloud" of small bodies that forms a sphere around the solar system.
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Questions about observations performed without the aid of any optical instrument.
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Questions involving a star along with all celestial material in its sphere of influence.
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Questions about computer programs that assist modeling and observing the dynamics of astronomy.
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Questions regarding the physical dimensions of a celestial object.
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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 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 the bending of light by mass or energy.
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Questions about spacecraft journeying to other stellar systems.
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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.
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Questions regarding the material at or near the center of an astronomical object.
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Questions about patterns formed by group of prominent stars in the night sky.
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Questions related to techniques and equipment related to amateur to professional astronomical photography.
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Questions regarding disks of gas, dust, and plasma around a central object, such as a black hole, which takes in the matter.
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Questions regarding telescopes in orbit around Earth, such as the Hubble Space Telescope.
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Questions about the outermost layer of a body.
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Questions about rings of debris that encircle the equatorial regions of some planets.
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Questions regarding specific terms, names, or naming conventions.
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Questions regarding one or more stars and the objects they locally interact with, including each other.
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