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 chthonians, a hypothesised class of exoplanets that are the remnant cores of hot Jupiters.
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Questions regarding grouping objects together based on one or more shared property.
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track and display the current time.
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Questions regarding the cosmic microwave background, or CMB, the leftover radiation that is taken by many as proof of the Big Bang.
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Icy bodies that usually consist of methane, water, and other materials that originate from beyond the jovian planets, and occasionally fall into the inner solar system giving off a massive tail as mat…
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Questions about patterns formed by group of prominent stars in the night sky.
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Questions on systems to uniquely determine position of a point or other geometric element on a manifold such as Euclidean space.
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Questions regarding the material at or near the center of an astronomical object.
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Questions regarding the phenomenon in the early universe characterized by an extreme expansion of space.
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Questions about the origin, history, evolution and fate of the Universe.
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Questions regarding the as-yet-unknown energy permeating the universe that is responsible for its expansion.
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Questions about the source or effects of the matter that makes up 85% of the matter in the universe but appears to only interact gravitationally.
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a process of inspecting, cleaning, transforming, and modeling data with the goal of discovering useful information, suggesting conclusions, and supporting decision making.
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A measure of the ratio of an object's mass with its volume.
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Questions regarding the amount of space between two objects, the units, or measurement thereof.
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a relatively inexpensive Newtonian telescope, in which the tube assembly slips freely in the lower base.
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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 universe shortly after it's formation
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Questions regarding the planet on which humans live, the third planet from the sun.
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Questions about solar system planets/moons and exoplanets that exhibit similar features to the Earth.