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 1 of 5 subjects, those that changed from 1 to 15 August 2026.Show all
The solar corona
Copy link to The solar coronaPrelims
A total solar eclipse crossed Greenland, western Iceland, northern Spain, north eastern Portugal and northern Russia, Europe's first in 27 years and not seen from India. Totality is what makes such a track worth travelling to, because it is still the best way to see the Sun's corona from the ground.
- A solar eclipse happens only at new moon, when the Moon passes between the Earth and the Sun.
- The inner corona is too faint to see against the glare of the solar disc.
- A coronagraph blocks that disc artificially, but scattered light often spoils the view.
- Only in totality, seen from the narrow path of totality, does the Moon block the whole disc.
- The corona's magnetic field drives solar flares and coronal mass ejections, which disturb satellites, navigation and communications on Earth.
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.