Black hole
- A black hole is a place in space where gravity pulls so much that even light cannot get out.
- The gravity is so strong because matter has been squeezed into a tiny space.
- This can happen when a big star is dying. Because no light can get out, so they are invisible.
- In the center of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and the laws of physics as we know them cease to operate.
- In 2019 scientists got the first optical image of a black hole through Event Horizon Telescope.
- It has captured the just outside region of a black hole, located 55 million light-years from Earth, at the center of a galaxy named Messier 87.
- The image shows a photon (light quantum) can orbit the black hole without falling in. This is called the ‘last photon ring’
- Sagittarius A* is the second black hole whose photographs have been captured by the Event Horizon Telescope project.
Significance of black hole in space research
Evolution of galaxy:
- Astrophysicists have gained new insights by calculating how black holes influence the distribution of dark matter, how heavy elements are produced and distributed throughout the cosmos, and where magnetic fields originate.
Star formation:
- In particular, Supermassive black holes play an important role in star formation within galaxies.
Gravitational waves:
- Scientists have detected that gravitational waves are generated when two black holes collide, and found that the ringing pattern of the wave predicts the cosmic body’s mass and spin.
General theory of relativity:
- The discovery of black holes has opened the door to several new lines of scientific investigation, enabling quantitative estimates of black hole related parameters. It has provided another laboratory to test the predictions of the Einstein’s general theory of relativity