Distant Gamma-Ray Burst Disturbed Earth's Upper Atmosphere

• 22 Nov 2023

Source: TH

Why in News?

According to recent researchers, gamma-ray burst (GRB) triggered by a supernova explosion in a galaxy situated nearly two billion light-years from earth, induced a notable disruption in the ionosphere of Earth.

What are the Major Takeaways from the Research?

• Background:
  • Approximately two billion years ago, in a distant galaxy outside our Milky Way, a large star met its end in a colossal explosion known as a supernova. This event released an immense surge of gamma rays.
  • The journey of these waves spanned across the cosmos, reaching Earth in 2022.
• Takeaways from the Research:
  • The effects of the gamma-ray burst were studied with the help of the China Seismo-Electromagnetic Satellite (CSES), also called Zhangheng, a Chinese-Italian mission launched in 2018.
    • It housed the Electric Field Detector (EFD) instrument, providing unprecedented resolution for analysis.
  • The GRB induced a remarkable disturbance in Earth's ionosphere, a zone extending 30-600 miles above the planet's surface, detected in October, 2022.
    • The European Space Agency's Integral (International Gamma-Ray Astrophysics Laboratory) and several satellites near Earth registered the impact, revealing a strong variation in the ionosphere's electric field.
  • The gamma rays lingered for about 13 minutes, affecting the ionosphere for several hours, even triggering lightning detectors in India.
    • Scientists identified this GRB as the most potent ever recorded.

What is a Gamma Ray Burst?

• About:
  • Gamma-ray bursts are short-lived explosions of gamma rays, the most energetic form of light.
  • Lasting from a few milliseconds to several hours, they shine hundreds of times brighter than a typical supernova and about a million trillion times as bright as the Sun.
  • Observed in distant galaxies, they are the brightest electromagnetic events known to exist in the universe.
• Types:
  • Astronomers classify gamma-ray bursts into long- and short-duration events. While the two types of events are likely created by different processes, both result in the creation of a new black hole.
    • Long-duration bursts last anywhere from 2 seconds to several hours. Although they are associated with the deaths of massive stars in supernovas, not every supernova results in a gamma-ray burst.
    • Short-duration bursts last less than 2 seconds. They appear to result from the merger of two neutron stars into a new black hole, or the merger of a neutron star and a black hole to form a larger black hole.

What is the Ionosphere?

• About:
  • The ionosphere is a region of Earth's upper atmosphere, spanning an altitude of approximately 30 to 600 miles (50 to 950 kilometers) above the Earth's surface.
  • The ionosphere is ionized by solar radiation that creates a layer of charged particles.
    • It is highly sensitive to changing magnetic and electrical conditions in space, usually connected to solar activity. It also expands and contracts in response to solar radiation.
• Significance:
  • Radio Propagation: The ionosphere affects the propagation of radio waves by reflecting and refracting them back to Earth.
    • This phenomenon enables long-distance communication via radio transmissions.
  • Protection from Solar Radiation: It shields the Earth's surface from harmful solar radiation, particularly from the sun's extreme ultraviolet rays.
  • Auroras Formation: Interactions between charged particles from the sun and the Earth's magnetic field in the ionosphere create phenomena such as auroras, which are luminous displays predominantly seen at high latitudes.

UPSC Civil Services Examination, Previous Year Question (PYQ)

Q. Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation? (2019)

(a) ‘Higgs boson particles’ were detected.
(b) ‘Gravitational waves’ were detected.
(c) Possibility of inter-galactic space travel through ‘wormhole’ was confirmed.
(d) It enabled the scientists to understand ‘singularity’.

Ans: (b)