Hidden ‘Goldilocks’ black hole exposed by early universe explosion

  • Categories
    Science & Technology
  • Published
    6th Apr, 2021

Context

Analysis of light of a gamma-ray burst, which dates back three billion years ago, has revealed the presence of a previously undetected black hole.

About

  • Key-highlights of the finding
  • Intermediate-mass black holes: The discovered black hole is Intermediate-mass black holes which is an elusive category of black holes that were considered non-existing until a few years ago.
    • In 2020, the Hubble Space Telescopeprovided a piece of evidence for an IMBH.

Intermediate-mass black holes (IMBHs) are a class of a black hole with a mass approximately 100 to 100,000 times that of the Sun.

The technique used

  • The gravitational lensing technique was used to detect the black hole.
    • Under this technique, the gravity around a massive body bends light that comes from a source behind.
    • It is then used to identify the intermediate-mass black hole (IMBH) which lensed the gamma-ray burst. 

What is a gamma-ray burst?

  • The gamma-ray burst that is known as GRB 950830 was detected in 1995.
    • GRBs are the most energetic form of electromagnetic events in the universe having short bursts of gamma rays that ejected at the speed of light. 
    • Gamma-ray bursts are formed when a high-mass star collapses and creates a neutron star or black hole. ?

What is Gravitational lensing?

  • When the light from distant galaxies or events like gamma-ray bursts passes by massive objects in the universe such as stars or black holes then Gravitational lensing is expected to occur.
  • The gravitational tug of these massive bodies can bend the light and causes the source to look distorted.
    • Weak: When gravitational lensing is weak, it distorts the distant object or galaxy to appear magnified or stretched out.
    • Strong: When it is strong, it bends light to such a degree that multiple images of the same galaxy are visible. 

Blackhole and its subtypes

  • A black hole is a region of space-time where gravity is extremely strong that no object can escape from it.
  • Types: There are two types of black holes which become three with the discovery:
    • Stellar-mass black holes: These are the black holes with a mass of fewer than 100 times that of the Sun.
    • Supermassive black holes (SMBH): These are the ones with a mass greater than 100,000 times that of the Sun.

Both stellar black holes and SMBHs are commonly found.

Some of the discovered black holes

  • The first-ever black hole detected was Cygnus X-1 in 1964.
  • The closest black holeto Earth is a part of the system HR 6819 and is active just 1,000 light-years from earth
  • The smallest known black hole is GRO J0422+32. It was discovered in 1992 at around 7,800 light-years from us.
  • A supermassive black hole called Sgr A* and is 26,000 light-years from Earth. It holds a mass of at least 40 lakh times the Sun’s.

© 2020 Basix Education Pvt. Ltd. All Rights Reserved