Science and Technology › Space

Astronomy and cosmology

Astronomy and cosmology: telescopes and observatories, stars, black holes and neutron stars, exoplanets, dark matter and dark energy, the Sun's cycle and space weather, eclipses, comets and asteroids. Prelims has asked about Cepheids, nebulae and pulsars, and about solar flares.

UPSC has asked

Prelims 2023: Cepheids, nebulae and pulsars

corona: The Sun's outermost atmosphere, extending millions of kilometres into space and far hotter than the visible surface below it.

coronagraph: An instrument that blocks a bright disc so that what lies close beside it can be seen: the Sun's corona without an eclipse, or a planet beside another star.

coronal mass ejection: A huge burst of magnetised plasma thrown out of the corona into space, which can reach the Earth and disturb its magnetic field.

path of totality: The narrow strip on the Earth's surface from which the Moon is seen covering the Sun completely.

Lagrange Point 2: A point about 1.5 million km beyond the Earth, directly away from the Sun, where a spacecraft circles the Sun in step with it.

dark matter: Unseen matter that neither emits nor absorbs light and is detected only through its gravitational pull.

G scale: The G1 (minor) to G5 (extreme) scale of geomagnetic storm severity.

Deuterium: A heavy isotope of hydrogen.

Type Ia supernova: The explosion of a white dwarf, with roughly uniform luminosity, used to measure cosmic distances.

Also filed elsewhere

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The Hanle Dark Sky Reserve (HDSR) in Ladakh is India's first and only dark sky reserve, notified by Ladakh's administration in December 2022.