Why in News?
- Astronomers have spotted a supermassive black hole (SMBH) moving on its own.
What is a blackhole?
- Albert Einstein first predicted the existence of black holes in 1916, with his general theory of relativity. The term “black hole” was coined many years later in 1967 by American astronomer John Wheeler.
- A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
- Because no light can get out, people can’t see black holes. They are invisible. Space telescopes with special tools can help find black holes.
- A supermassive black hole is the largest type of black hole, with mass on the order of millions to billions of times the mass of the Sun.
What have astronomers found recently?
- The SMBH is moving with a velocity different from that of its surrounding galaxy.
- This is surprising because supermassive black holes usually are not expected to move with respect to the galaxies in whose centres they reside, according to what is known about them so far. Supermassive black holes have masses millions of times the solar mass and inhabit the centres of galaxies. The one at the centre of the Milky Way is named Sagittarius A*.
- Located at the centre of a galaxy named J0437+2456, this supermassive black hole, with a mass about three million times that of our Sun, is moving at a high speed.
- One of the possibilities is that this SMBH has just been created from the collision of two SMBHs, because in such cases the newborn black hole suffers a recoil, which might be what is being observed here. The other possibility is that this black hole may be a part of a binary black hole system – which has not been observed so far.
Will the sun become a blackhole?
- The Sun would need to be about 20 times more massive to end its life as a black hole. In some 6 billion years it will end up as a white dwarf — a small, dense remnant of a star that glows from leftover heat. The process will start about 5 billion years from now when the Sun begins to run out of fuel.
- Sun will start to run out of hydrogen in its core to fuse, and it will begin to collapse. This will let the Sun start to fuse heavier elements in the core, along with fusing hydrogen in a shell wrapped around the core. When this happens, the Sun’s temperature will increase, and the outer layers of the Sun’s atmosphere will expand so far out into space that they’ll engulf Earth.
- Subrahmanyan Chandrasekhar, an eminent Indian scientist proved that there was an upper limit to the mass of a white dwarf. This limit, known as the Chandra limit, showed that stars more massive than the Sun would explode or form black holes as they died.
- In 1983, Subrahmanyan Chandrasekhar was awarded the Nobel Prize in Physics for his work on the physical processes involved in the structure and evolution of stars.