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:
× 4 × 5 × 2
track and display the current time.
× 10
Questions regarding the cosmic microwave background, or CMB, the leftover radiation that is taken by many as proof of the Big Bang.
× 3 × 20
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…
× 2
× 4
Questions about patterns formed by group of prominent stars in the night sky.
× 12 × 7
Questions regarding the material at or near the center of an astronomical object.
× 3
× 5
× 18
Questions regarding the phenomenon in the early universe characterized by an extreme expansion of space.
× 43
Questions about the origin, history, evolution and fate of the Universe.
× 11
Questions regarding the as-yet-unknown energy permeating the universe that is responsible for its expansion.
× 16
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.
× 8
a process of inspecting, cleaning, transforming, and modeling data with the goal of discovering useful information, suggesting conclusions, and supporting decision making.
× 3
× 4 × 4
× 2
A measure of the ratio of an object's mass with its volume.
× 36
Questions regarding the amount of space between two objects, the units, or measurement thereof.
× 5
a relatively inexpensive Newtonian telescope, in which the tube assembly slips freely in the lower base.
× 2
× 8
× 3 × 14
Questions regarding the universe shortly after it's formation
× 72
Questions regarding the planet on which humans live, the third planet from the sun.
× 15
Questions about solar system planets/moons and exoplanets that exhibit similar features to the Earth.
× 3
× 2
× 2
Questions about Europa, a moon of Jupiter with a planet-wide ocean under a thick ice crust.