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.
Questions regarding large spheres of plasma undergoing fusion.
Questions regarding the closest star to Earth, at the centre of the Solar System.
Questions regarding an object 'falling around' another object, due to a combination of gravity and momentum.
Questions regarding points of extremely high mass density, which creates an extremely strong gravitational field from which light cannot escape.
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.
Questions about the techniques and practice of observing the night sky.
Questions regarding systems of large numbers of stars held together by gravity.
Questions regarding the attractive force which exists between any two bodies of matter.
Questions related to the physical instruments for astronomical observations.
Questions regarding the planet on which humans live; the third planet from the Sun.
Questions involving the physics of the universe, especially the nature of astronomical objects, energy fields, and/or regions, rather than their positions or motions in space.
Questions about the observation of celestial objects by non-professional astronomers.
Questions regarding all of time and space and its contents.
Questions about the origin, history, evolution and fate of the Universe.
Questions regarding electromagnetic radiation in the visible spectrum.
Questions regarding relatively small rocky bodies in an orbit around the Sun.
Questions regarding the amount of space between two objects, the units, or measurement thereof.
Questions regarding the Milky Way Galaxy, the galaxy that Earth's solar system is in.
Questions regarding the 4-dimensional background structure of our universe.
Questions involving basic astronomical concepts or information.
Questions regarding a layer of gasses surrounding a celestial object.
Questions about observation performed in the radio frequency range of the electromagnetic spectrum (between 10 MHz and 1GHz).
Questions about photography of celestial objects by amateur or professional astronomers. Questions about photography of other objects are off-topic but might be asked on our sister site Photography St…
The near-vacuum extending between the planets and stars, containing small amounts of gas and dust. Also called outer space to refer to the physical universe beyond the Earth's atmosphere.
Questions regarding stars which increase suddenly in energy output due to an explosion which ejected much of its mass.
Questions on systems to uniquely determine position of a point or other geometric element on a manifold such as Euclidean space.
Questions regarding the currently prevalent cosmological model for the origin of the universe.
Questions about relativistic theory of gravity. General relativity describes gravity as a geometrical property of space and time.
Questions regarding Jupiter, the 5th and largest planet in the Solar System.
Questions regarding the action of or an object rotating along an axis.
Questions about the increase with time of distance between two distant points in the Universe.
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…