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 one of the two main angles(coordinates) of an object perceived by an observer on Earth.
A measure of the ratio of an object's mass with its volume.
particulate matter that can be found between stars and can be contrasted with molecular or atomic gas, and with ionised plasma. For planetary dust storms, use [du…
Questions regarding Albert Einstein's theory that posits, among other things, the equivalence of mass and energy.
Questions regarding the brightness of objects in a defined passband.
Questions about the measuring the position of stars, and the techniques used to do this.
Questions about the NASA space observatory famous for finding potentially habitable exoplanets. Do not use this tag for questions about Johannes Kepler.
Questions about the water molecule (composed of two atoms of hydrodgen and one atom of oxygen) and its detection in celestial objects.
Questions regarding the physical dimensions of a celestial object.
Questions regarding objects whose orbits bring them in close proximity to Earth, posing potential hazard.
Questions about observations performed without the aid of any optical instrument.
Questions regarding disks of gas, dust, and plasma around a central object, such as a black hole, which takes in the matter.
Questions about the dynamical processes leading to the assembling of a celestial object.
Questions regarding a substance that takes up space, has volume, and has mass. Matter usually occurs in 5 forms, namely plasma, gas, liquid, solid, and bose-einstein condensate.
Questions about the "Goldilocks Zone" around a parent star where conditions are just right for the potential of life developing.
Questions about planets that do not orbit around a star. These planets travel through space.
Questions regarding the process of assigning an identifying set of characters to an astronomical object.
Questions regarding casually watching the stars.
Questions about reflecting telescopes using a concave primary mirror and a flat diagonal secondary mirror.
Questions regarding two objects colliding into each other with considerable force.
Questions about streams of plasma released from the Sun or other stars (stellar winds).
Questions regarding the plane containing the orbit of the Earth around the Sun.
Questions regarding the theory of gravity as proposed by Newton, in which the force of gravity depends only on the mass of bodies, a constant, and the distance between them, and depends on one equatio…
Questions regarding the inner portion of a galaxy; in the Milky Way, this is the area around Sagittarius A*.
like stars but never achieve nuclear fusion because they are too low-mass.
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.
Questions about the apparent displacement of a celestial body with respect to its background when observed along two different lines of sight.
Questions regarding Neptune, the 8th and furthest major planet orbiting Earth's sun.
Questions regarding the National Aeronautics and Space Administration, the American civilian space agency.
Questions regarding the large-scale change of orbits over time, as in the Nice Model.
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.