Why Stars do not collapse?
The Sun (which is a star) is a mass of hot gases nearly 109 times the size of the earth. It is 3,30,000 times as heavy as the earth. It is, therefore, a huge ball of fire. This enormous mass of gaseous matter would be exerting an enormous amount of compression pressures on the Sun to make it collapse. Yet it survives. How?
The boundary, or event horizon, of a non-rotating black hole, has a radius equal to the Schwarzschild radius (Rs). Not even light can escape from within this region. A passing ray of light will be deflected by the gravitational field of the black hole. If it approaches 1.5Rs. it may be bent into a circular orbit (orbiting light rays from the “photon sphere”) while if it comes still closer it will fall into the event horizon.
On the star two forces happen to co-exist. The compression forces that the matter of the star develops are counteracted upon by the detonating energy released by the nuclear reactions taking place at the star. In this state, also known as the ‘main sequence’, the star is said to be in a balance as it is able to balance the two opposing forces —the gravitational force trying to compress and the expulsive internal pressures due to the release of nuclear energy counteracting this process. If these internal pressures were not built on the star, the star of the magnitude of the Sun would have collapsed in less than an hour. And it is this balance that makes the Sun formed about 4,600 million years ago to continue to give energy for another spell of equal duration. The temperature at the Sun is just right to trigger nuclear reactions and these reactions create the right required pressure to counteract the pressures of gravitational compression experienced on the star. And the Sun continues to liberate energy and shine.
Types Of Stars.
- Fixed stars.
- Binary (double star).
- Temporary stars (new stars).
- Variable Stars.