International Space Agencies – Missions and Discoveries

Sagittarius A*


From UPSC perspective, the following things are important :

Prelims level : Sagittarius A*

Mains level : Black-hole theory and its relevance

Sagittarius A*

  • It is a supermassive black hole that sits 26,000 light years away from Earth, near the Galactic Centre, or the centre of the Milky Way.
  • It is one of the few black holes where we can witness the flow of matter nearby.
  • Since the discovery of Sagittarius A* 24 years ago, it has been fairly calm.

Why in news?

  • This year Sagittarius A* has shown unusual activity, and the area around it has been much brighter than usual.
  • It may be that the Sagittarius A* has become hungrier, and has been feeding on nearby matter at a markedly faster rate, which one researcher described as a “big feast”.
  • A black hole does not emit light by itself, but the matter that it consumes can be a source of light.
  • A large quantity of gas from the S0-2 star, which travelled close to the black hole last year, may now have reached the latter.
  • Other possibilities of the heightened activity are that it could be growing faster than usual in size, or that the current model that measures its level of brightness is inadequate and is in need of an update.
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