IAS Gyan

Daily News Analysis


29th July, 2023 Science and Technology

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Context: Markarian 421 is a supermassive black hole that is located about 400 million light-years away from Earth. It is one of the brightest sources of gamma rays and X-rays in the sky because it has a powerful jet of high-energy particles that is pointing directly towards Earth.


What is a Supermassive black hole?

  • A supermassive black hole is a very massive object that has such a strong gravitational pull that nothing, not even light, can escape from it.
  • Supermassive black holes are usually found at the centres of galaxies, where they can grow by swallowing gas, dust, stars, and planets. They can have millions or billions of times the mass of our sun.

What is a jet of high-energy particles?

  • A jet of high-energy particles is a stream of matter and radiation that is ejected from the vicinity of a black hole at very high speeds, close to the speed of light. The jet is formed by the interaction of the black hole's strong magnetic field and the rotating disk of material that surrounds it. The disk is called an accretion disk because it feeds the black hole with matter.

Why is Markarian 421's jet pointing towards Earth?

  • Markarian 421's jet is pointing towards Earth because Earth is in its line of sight. This makes it a special type of supermassive black hole system called a blazar. Blazars are very bright and variable sources of gamma rays and X-rays because we see the jet's radiation boosted by a phenomenon called relativistic beaming. This means that the jet's radiation appears brighter and more energetic when it is moving towards us, similar to how a car's headlights appear brighter when it is approaching us.

What can be learnt from Markarian 421's jet?

  • Markarian 421's jet is a fascinating object to study because it can reveal important information about the physics of black holes and their environments. For example, by observing how the jet changes over time, scientists can learn about the dynamics and structure of the accretion disk and the magnetic field around the black hole. They can also learn about the processes that accelerate and emit high-energy particles in the jet, such as shocks and turbulence. Furthermore, they can use the jet as a probe to study the intergalactic medium, which is the diffuse gas and dust that fills the space between galaxies.

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Q. The term “Markarian 421” was frequently seen in the news, It is related with;

A) A supermassive black hole firing a jet towards Earth

B) A distant galaxy with an active galactic nucleus

C) A newly discovered exoplanet

D) A comet passing close to the Sun

Answer: A

Explanation: A supermassive black hole firing a jet towards Earth. Markarian 421 is a blazar, which is a supermassive black hole with a powerful jet of high-energy particles pointed directly at Earth.