Daily Current Affairs : 21-November-2023

Gamma-ray bursts (GRBs) are intense bursts of gamma-ray radiation originating from distant galaxies. Recently, a GRB from a supernova explosion in a galaxy nearly two billion light-years away has intrigued scientists due to its unexpected effect on Earth’s ionosphere.

Understanding Gamma-Ray Bursts
  • GRBs occur when the core of a massive star exhausts its nuclear fuel, leading to a collapse under its own weight, resulting in the formation of a black hole.
  • Short-duration GRBs, lasting less than two seconds, are caused by the merger of two neutron stars or a neutron star and a black hole. Longer GRBs, lasting hours, occur when a massive star collapses and gives birth to a black hole.
The Ionosphere: Earth’s Atmospheric Boundary
  • The ionosphere, located 30-600 miles (50-950 km) above Earth’s surface, is a crucial layer containing electrically charged gases known as plasma.
  • Serving as a boundary between the vacuum of space and Earth’s lower atmosphere, the ionosphere is highly responsive to changes in magnetic and electrical conditions in space.
Effects of GRBs on the Ionosphere
  • Gamma rays from the GRB lead to a significant variation in the ionosphere’s electric field, akin to the impact of solar flare events.
  • The ionosphere, sensitive to solar radiation, expands and contracts in response to changing magnetic and electrical conditions in space.
Potential Threats and Speculations
  • While GRBs from distant galaxies do not pose immediate threats to life on Earth, speculation arises about the potential dangers of a strong GRB originating within the Milky Way and directly affecting our planet.
  • The hypothetical scenario of a powerful GRB raises concerns about the possibility of mass extinctions.
Important Points:
  • Gamma-Ray Bursts (GRBs):
    • Intense bursts of gamma-ray radiation originating from distant galaxies.
    • Caused by the collapse of a massive star’s core, leading to the formation of a black hole.
    • Short-duration GRBs (less than two seconds) result from the merger of neutron stars or a neutron star and a black hole. Longer GRBs (lasting hours) occur when a massive star collapses, giving rise to a black hole.
  • The Ionosphere: Earth’s Atmospheric Boundary:
    • Located 30-600 miles (50-950 km) above Earth’s surface.
    • Contains electrically charged gases (plasma) and serves as a boundary between space and Earth’s lower atmosphere.
  • Effects of GRBs on the Ionosphere:
    • Gamma rays from a GRB cause a significant variation in the ionosphere’s electric field.
    • Similar impact to the electric field changes during solar flare events.
    • The ionosphere, sensitive to solar radiation, expands and contracts in response to changing magnetic and electrical conditions in space.
  • Potential Threats and Speculations:
    • GRBs from distant galaxies do not pose immediate threats to life on Earth.
    • Concerns arise about the hypothetical scenario of a strong GRB originating within the Milky Way and directly affecting Earth.
    • Speculation includes the potential for mass extinctions in the event of a powerful GRB.
Why In News

A gamma-ray burst (GRB) resulting from a star’s supernova explosion in a galaxy nearly two billion light-years away has unexpectedly created a disturbance in Earth’s ionosphere, unraveling the interconnected dynamics between celestial events and our planet’s atmospheric layers.

MCQs about Gamma-Ray Bursts and Earth’s Ionosphere

  1. What causes a gamma-ray burst (GRB)?
    A. Solar flares
    B. The merger of two neutron stars
    C. Tidal forces from nearby planets
    D. Volcanic eruptions
    Correct Answer: B. The merger of two neutron stars
    Explanation: GRBs result from the merger of two neutron stars or a neutron star and a black hole, as explained in the essay.
  2. Where is the ionosphere located, and what is its role?
    A. 0-30 miles above Earth, protecting against meteoroids
    B. 30-600 miles above Earth, serving as a boundary between space and the lower atmosphere
    C. At the Earth’s surface, regulating temperature
    D. Beyond 600 miles in space, blocking harmful radiation
    Correct Answer: B. 30-600 miles above Earth, serving as a boundary between space and the lower atmosphere
    Explanation: The ionosphere is situated 30-600 miles above Earth’s surface and acts as a crucial boundary between space and the lower atmosphere.
  3. How do gamma rays from a GRB impact the ionosphere’s electric field?
    A. They have no effect on the ionosphere
    B. They cause a decrease in the electric field
    C. They lead to a significant variation in the electric field
    D. They stabilize the electric field
    Correct Answer: C. They lead to a significant variation in the electric field
    Explanation: Gamma rays from a GRB cause a strong variation in the ionosphere’s electric field, similar to the effect during solar flare events.
  4. What is the concern regarding a strong GRB originating within the Milky Way?
    A. It may create a new star
    B. It could lead to global warming
    C. It poses a potential threat, including mass extinctions
    D. It has no impact on Earth
    Correct Answer: C. It poses a potential threat, including mass extinctions
    Explanation: There is speculation about the potential danger, including mass extinctions, if a strong GRB originates within the Milky Way.

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