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 2025: solar flares and coronal mass ejections striking the outer atmosphere
- Prelims 2023: Cepheids, nebulae and pulsars
- Prelims 2022: effects of a major solar storm on the Earth
Showing 2 of 5 subjects, those that changed from 1 to 15 September 2026.Show all
The Nancy Grace Roman Space Telescope
Copy link to The Nancy Grace Roman Space TelescopePrelims
The National Aeronautics and Space Administration (NASA) launched the Nancy Grace Roman Space Telescope on 30 August, to survey dark energy, dark matter and exoplanets. Most of what it is sent to measure cannot be seen at all, which is why it carries two instruments rather than one.
- It works from Lagrange Point 2, as the James Webb Space Telescope does, while Hubble orbits the Earth.
- About 5% Ordinary matter. Stars, planets, gas, us
- About 27% Dark matter. Unseen mass holding galaxies together
- About 68% Dark energy. Speeding up the expansion
Wide Field Instrument
- An infrared camera
- Maps galaxies through gravitational lensing, the bending of light by the gravity of unseen mass in between
Coronagraph
- Blocks starlight to reveal planets around stars
What changed
Dark matter inside dead stars
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Dark matter is detected only through its gravitational pull, so a proposal about what it is has to be tested by what it would do to things already visible. One such thing is a star that has finished burning and is still there.
- An Indian study proposed that ultra heavy dark matter captured inside a dead star could collapse into a tiny black hole that swallows it.
- It looks at millisecond pulsars and white dwarfs, where dark matter falling in outweighs what the black hole loses to Hawking radiation.
- Many such stars have lasted billions of years, which rules out dark matter that would have destroyed them sooner.
What changed
Also filed elsewhere
- Space weather forecasting from Aditya-L1 · on Moon, Sun and planetary missions
A solar flare gives no useful warning once it has erupted, because its radiation crosses to Earth in about eight minutes.
- The Hanle Dark Sky Reserve · on Chemicals, noise, light and soil pollution
Ladakh's administration notified the Hanle Dark Sky Reserve (HDSR) in December 2022, India's first and still its only one.