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 the National Aeronautics and Space Administration, the American civilian space agency.
Questions regarding a type of elementary particle with 0 mass and is a quantum of the electromagnetic field. Photons always travel at constant speed in a vacuum.
Questions about the Hubble constant, the constant factor of the rate of expansion in the universe
Questions about the chemical reactions that occur in the interstellar medium.
Questions about the "adulthood" of stars. The main sequence is a distinctive band of stars that appears in a color-magnitude plot (known as Hertzsprung-Russell diagram). Stars appear in the main seque…
Questions related to earth processes or related processes and principles.
Questions regarding grouping objects together based on one or more shared property.
Questions regarding the large "cloud" of small bodies that forms a sphere around the solar system.
For questions about objects or phenomena outside Earth, generally on other planets.
Questions regarding the material at or near the center of an astronomical object.
Questions about the circumstellar disk orbiting in the outer Solar System, beyond the orbit of Neptune.
Questions about the space observatory GAIA.
Questions regarding a phenomenon when an object has an orbital period that is equal to its rotational period due to gravitational tidal forces.
Questions regarding the future and ultimate fate of the Universe, including the heat death, Big Freeze, Big Rip, or Big Crunch.
Questions relating to the discovery of a new ninth planet (not Pluto) hypothesized in the Solar System.
Questions about the simplest and most abundant element in the Universe.
Questions regarding matter in its gaseous state, and how it behaves in astronomy (e.g. forming stars in giant molecular clouds).
Questions about red giants, large luminous low-mass stars in a late phase of stellar evolution.
Questions about orbits with high eccentricities, which deviate greatly from perfect circles.
Questions regarding a sudden brightness increase due to the release of magnetic energy from the sun.
Questions regarding the space or objects outside of galaxies.
a general map or image of a region of the sky which lacks a specific observational target, but this tag also applies to surveys of a given class of objects, (e.g. TESS)
Questions on any of the 5 locations where a small object can maintain a stable orbital configuration with respect to two co-orbiting larger bodies.
Questions regarding undesired brightening of the night sky inhibiting observation of astronomical objects.
Questions regarding a manmade object sent to explore space and celestial objects.
Questions to do with how new atomic nuclei are created inside the universe.
Questions about spacecraft journeying to other stellar systems.
flashes of gamma rays, produced by extremely powerful explosions in distant galaxies. They are among the most powerful events in the universe