GS Paper 3:
Topics Covered: Awareness in space.
Scientists from the Event Horizon Telescope (EHT) facility revealed the first image of the black hole at the centre of the Milky Way in press conferences held around the world.
- This image of the black hole referred to as Sagittarius A* (SgrA*) gave further support to the idea that the compact object at the centre of our galaxy is indeed a black hole.
What is Sagittarius A*(SgrA*)?
Sagittarius A* is a supermassive black hole at the center of our galaxy i.e. the Milky Way. It is located near the border of the constellations Sagittarius and Scorpius.
- SgrA* possesses 4 million times the mass of our sun and is located about 26,000 light-years and 5.9 trillion miles (9.5 trillion km)—from Earth.
What is a black hole?
- A black hole is an object in space that is so dense and has such strong gravity that no matter or light can escape its pull. Because no light can escape, it is black and invisible.
- There’s a boundary at the edge of a black hole called the event horizon, which is the point of no return — any light or matter that crosses that boundary is sucked into the black hole. It would need to travel faster than the speed of light to escape, which is impossible.
- Anything that crosses the event horizon is destined to fall to the very centre of the black hole and be squished into a single point with infinite density, called the singularity.
What is Event Horizon?
A black hole’s event horizon is the point of no return beyond which anything—stars, planets, gas, dust and all forms of electromagnetic radiation—gets dragged into oblivion.
About Event Horizon Telescope:
- Event horizon telescope consists of eight radio observatories around the world, including telescopes in Spain, the US and Antarctica
- In 2006, an international team of more than 200 researchers, led by Harvard University astronomers, launched the Event Horizon Telescope (EHT) project with a sole aim: to capture a direct shot of a black hole.
- Thirteen partner institutions worked together to create the EHT, using both pre-existing infrastructure and support from a variety of agencies.
- The EHT observations use a technique called very-long-baseline interferometry (VLBI) which synchronises telescope facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope observing at a wavelength of 1.3 mm.
There are supermassive blackholes, which are several million solar masses in size, at the centres of galaxies, and these are known as Active Galactic Nuclei. Learn more about them here.
- About the General Theory of Relativity.
- When was the first gravitational wave detected?
- LIGO- mission objectives, observatories and funding.
- What are event horizon and singularity in the context of a black hole?
- LIGO India- proposed site, partners and objectives.
- Where is the Virgo locator located?
Discuss the applications and significance of findings of the Laser Interferometer Gravitational-Wave Observatory (LIGO) detector.
[Q.5) Sagittarius A*(SgrA*), which was in news recently, is a:
- New Galaxy.
- Dwarf planet.
- None of the above. ]
Sources: the Hindu.