- Why in news
- On 30 January 2026, the Ministry of Science & Technology reported that Indian Institute of Astrophysics researchers studied a stealth CME of 19 March 2023 that caused an intense geomagnetic storm on Earth about 3 days later.
- What it is
- A Coronal Mass Ejection (CME) is a large expulsion of plasma and magnetic field from the Sun's atmosphere. A stealth CME is a weak eruption that gives no clear signs on the Sun, such as X-ray flares or radio bursts, yet can still disturb Earth's magnetic field. A geomagnetic storm is a temporary disturbance of Earth's magnetosphere, which can affect satellites, communications and power grids.
- Stealth CME
- A weak CME with no standard warning signs such as X-ray flares or radio bursts, so it is hard to detect on the Sun.
- Share of storms
- About 10% of intense geomagnetic storms do not seem to come from any large-scale eruption on the solar disk.
- Role of coronal hole
- A coronal hole near the source region, an opening in the Sun's magnetic field lines, likely helped the CME reach Earth instead of dissipating near the Sun.
- Who studied it
- The Indian Institute of Astrophysics (IIA), an autonomous institute under the Department of Science and Technology.
- Why it was intense
- A southward magnetic field component and enhanced plasma density drove the intense storm.
- Astronomical Unit
- 1 AU is the average Sun-Earth distance, about 150 million km.
Don’t confuse with CME vs solar flare: A CME is an expulsion of plasma and magnetic field. A solar flare is a burst of radiation. Both can occur together but are different.
Don’t confuse with CME vs solar wind: Solar wind is a continuous stream of charged particles from the Sun. A CME is a sudden, large eruption.
Science and technology: 57 Prelims questions since 2013; most test the concept behind the news, not the news itself. In Mains, 12 news-triggered questions.
Why it matters
- Understanding stealth CMEs improves space weather prediction, protecting satellites, communication systems and power grids.
Problems
- Stealth CMEs leave no detectable signature on the Sun, so current observation sensitivity cannot flag them in advance.
Way forward
- Use multi-spacecraft observations and better sensitivity to improve forecasting of space weather.
Put in your answer
Space weather risk: CMEs can disrupt satellites, communication systems and power grids on Earth.
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UPSC’s own questions that come close to this issue, from our Prelims and Mains banks.
No practice question for this one; the card may still help an answer. Why: Space weather concept; sci_tech is 57 of 327 Prelims questions, mostly on concepts, but this single study offers little new to test.
Worth revising until Prelims 2027: most news questions come within two years of the event.