Science and Technology › Space
हिन्दी — Read in HindiAstronomy 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
All 4 articles shown; the 0 that changed from 1 to 30 September 2026 are marked.Show only these
The Sun: corona, flares and storms
Copy link to The Sun: corona, flares and stormsPrelims
The corona is the Sun's outermost atmosphere, too faint to see against the glare of the solar disc.
- A total eclipse, seen from the narrow path of totality, is the best way to see it from the ground; a coronagraph blocks the disc artificially.
- Its magnetic field drives solar flares, the sudden release of magnetic energy built up in the Sun's atmosphere, and coronal mass ejections, clouds of plasma thrown towards Earth.
- These disturb satellites, navigation and communications.
- Flares are classed by intensity, C, M and X, and geomagnetic storms on a G1 (minor) to G5 (extreme) scale; the two are graded separately.
- Auroras form when charged particles caught by Earth's magnetic field collide with oxygen and nitrogen near the poles.
- From India's low latitude, observers look at a region where oxygen glows red, so auroras appear crimson.
Two scales
| Scale | Grades, weakest to strongest | This event |
|---|---|---|
| Flare class | C, M, X | M1.8 flare |
| G scale of geomagnetic storms | G1 (minor) to G5 (extreme) | G2 storm forecast |
What changed
13 Aug 2026BriefA total solar eclipse crossed Greenland, western Iceland, northern Spain, north eastern Portugal and northern Russia, Europe's first in 27 years; it was not seen from India. The Hindu, 13 Aug 2026: Total solar eclipse over northern Spain (opens in a new tab)
8 Jun 2026BriefA plasma cloud from an M1.8 flare reached Earth with a G2 storm forecast by the US National Oceanic and Atmospheric Administration (NOAA). Auroras were expected over Kashmir, upper Uttarakhand and Ladakh; a G5 storm in 2024 produced auroras visible in India. The Indian Express, 8 Jun 2026: Billion-tonne plasma cloud blazing towards Earth: Solar flare expected today (opens in a new tab) · The Hindu, 8 Jun 2026: Northern lights in India? Here's how to see Auroras tonight (opens in a new tab)
UPSC has asked
- Prelims 2025: solar flares and coronal mass ejections striking the outer atmosphere
- Prelims 2022: effects of a major solar storm on the Earth
Dark energy and the Roman Space Telescope
Copy link to Dark energy and the Roman Space TelescopePrelims
The Nancy Grace Roman Space Telescope is a NASA telescope, launched on 30 August 2026 to survey dark energy, dark matter and exoplanets from Lagrange Point 2. The James Webb Space Telescope also works there, while Hubble orbits the Earth.
- The universe is about 5 per cent ordinary matter, 27 per cent dark matter and 68 per cent dark energy.
- Dark energy is the name for whatever speeds up the expansion, discovered to be accelerating in 1998 from Type Ia supernovae, the explosions of white dwarfs.
- 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
17 Jun 2026BriefA study in Monthly Notices of the Royal Astronomical Society using Type Ia data confirms the expansion is still accelerating, rebutting a 2025 study that concluded dark energy is weakening. The Hindu, 17 Jun 2026: The universe's expansion is still accelerating, researchers say (opens in a new tab)
Indian Astronomical Observatory, Hanle
Copy link to Indian Astronomical Observatory, HanlePrelims
The Indian Astronomical Observatory at Hanle in Ladakh, at 4,517 metres, is run remotely from Bengaluru by the Indian Institute of Astrophysics and gives more than 250 usable nights a year with very little water vapour.
What changed
29 Jul 2026BriefThe 2 metre Himalayan Chandra Telescope at Hanle has completed 25 years. The budget has announced a 3.7 metre upgraded telescope and a 13.7 metre National Large Optical Infrared Telescope, both at Hanle. PIB, 29 Jul 2026: Celebrating 25 years of the Himalayan Chandra Telescope in Hanle (opens in a new tab)
See also: The Hanle Dark Sky Reserve
3I/ATLAS, an interstellar comet
Copy link to 3I/ATLAS, an interstellar cometPrelims
3I/ATLAS is the third interstellar object seen passing through the solar system, after 1I/'Oumuamua (2017) and 2I/Borisov (2019).
- Isotope ratios reveal a body's birthplace: hydrogen isotopes indicate the temperature and radiation where it formed, carbon isotopes the composition of its parent gas cloud.
What changed
23 Jun 2026BriefA Nature study using the James Webb Space Telescope estimates the comet formed 10 to 12 billion years ago, probably the oldest known object to pass through the solar system. Its water holds about 30 times more deuterium than solar system comets and it is rich in organic molecules. The Hindu, 23 Jun 2026: Interstellar comet 3I/ATLAS is much older than the solar system itself (opens in a new tab)
Also filed elsewhere
- Space weather forecasting from Aditya-L1 · on Moon, Sun and planetary missions
Space weather forecasting is the attempt to read the Sun's atmosphere for a sign of a solar flare hours before it erupts.
- The Hanle Dark Sky Reserve · on Chemicals, noise, light and soil pollution
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.