ISRO Missions and Discoveries

What are Coronal Mass Ejections (CMEs)?


From UPSC perspective, the following things are important :

Prelims level: Coronal Mass Ejection, Aditya L1 and its various payloads

Why in the News?

  • India’s solar mission Aditya-L1 recently captured images of the Sun and it’s Coronal Mass Ejections (CMEs) during a solar storm in May.
    • The Active region AR13664 on the Sun erupted several X-class and M-class flares, which were associated with Coronal Mass Ejections (CMEs).

Coronal Mass Ejections (CMEs)

  • CMEs were discovered in 1971 and established their importance in solar-terrestrial relations later in the 1980s.
  • It consists of massive clouds of solar plasma and magnetic field lines.
  • It typically accompanies solar flares and filament eruptions.
  • The frequency of CMEs varies with the 11-year solar cycle, with about one a week observed during solar minimum and an average of two to three CMEs per day observed near solar maximum
  • They travel at thousands of km per hour.
  • They can lead to geomagnetic storms, aurorae, and in extreme cases, damage to electrical power grids.
  • Not all CMEs interact with Earth, but those that do can cause disruptions to satellite communications and power grids.
  • Halo CMEs are Earth-directed CMEs visible as rings in white-light coronagraph observations.

About Aditya-L1:

  • Aditya-L1 mission is India’s first space mission to observe the Sun.
  • It is ISRO’s 2nd space-based astronomy mission after AstroSat, which was launched in 2015.
  • It was launched on September 2nd 2023 to observe the Sun and the solar corona.
  • The L1 point is a location in space where the gravitational forces of two massive objects, such as the Earth and the Sun, balance each other out, allowing a spacecraft to “hover” in a stable orbit.

Launch Details: 

  • Polar Satellite Launch Vehicle (PSLV) with 7 payloads (instruments) on board.

The 7 payloads include: 

    1. Visible Emission Line Coronagraph (VELC): Images of the solar corona in visible light to study its structure and dynamics.
    2. Solar Ultraviolet Imaging Telescope (SUIT): Images the solar chromosphere and transition region in ultraviolet light to understand heating and dynamics.
    3. Solar Low Energy X-ray Spectrometer (SoLEXS): Measures solar X-ray spectrum to study solar flares and coronal mass ejections.
    4. High Energy L1 Orbiting X-ray Spectrometer (HEL1OS): Measures high-energy solar X-rays to understand particle acceleration.
    5. Plasma Analyser Package for Aditya (PAPA): Measures solar wind plasma properties to study its interaction with Earth’s magnetosphere.
    6. Aditya Solar Wind Particle Experiment (ASPEX): Measures energetic particle properties in the solar wind to study their effects on Earth’s atmosphere.
  • Solar Irradiance Monitor (SIM): Measures solar irradiance variations and their impact on Earth’s climate.


  • Aditya L1 will study the coronal heating, solar wind acceleration, coronal magnetometry, origin and monitoring of near-UV solar radiation and continuously observe the photosphere, chromosphere and corona, solar energetic particles and the magnetic field of the Sun.


  • Aditya is placed in L1 Halo orbit which is about 1.5 million km from the Earth. The orbit allows the mission to look at the Sun continuously.
  • L1 refers to Lagrangian/Lagrange Point 1, one of 5 points in the orbital plane of the Earth-Sun system.
  • Lagrange Points are positions in space where the gravitational forces of a two-body system like the Sun and Earth produce enhanced regions of attraction and repulsion.


[2017] The terms ‘Event Horizon’, ‘Singularity’, ‘String Theory’ and ‘Standard Model’ are sometimes seen in the news in the context of-

(a) Observation and understanding of the Universe

(b) Study of the solar and lunar eclipses

(c) Placing satellites in the orbit of the Earth

(d) Origin and evolution of living organisms on the Earth

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