THE COSMOS AND US - 4

Gravity is a fundamental property of any mass - a pull that it exerts on every other mass by the warping of space-time around itself. It pulls material together till the temperature rises from the increase in pressure, caused by the increasing proximity of material particles. Once temperature reaches a certain point, a nuclear reaction begins, fusing hydrogen into helium - and we have the beginning of a new star. There is an equilibrium reached, where the energy of fusion balances the pull of gravity, so a new sun can stay there for a very long time. Our own sun will last trillions of years, and then we’ll be back to kerosene to keep warm, unless we get some fusion of our own.

As hydrogen is converted to helium, it eventually gets depleted, and the reaction runs down. When the hydrogen runs low, there is no fusion energy to balance the gravity, and the star collapses on itself. What happens get depends on whether the star is large or small compared to our sun. If the star is small, it will flare up in size as a new cycle begins, turning helium into carbon, a mix of fission and fusion.

4.2 times the size of our sun is known as ChandraShekar’s limit. Above this limit, the gravity is large enough that when the hydrogen cycle is over, the collapse will trigger a new nuclear cycle - the carbon cycle. When this cycle is triggered, the star explodes, throwing material out into space. This is called a SUPERNOVA. The explosion disturbs new clouds of gas, triggering the birth of many new suns. More importantly it throws the material into space that planets are made of; leading to the eventual birth of our kind of life.

Note the intelligence to make this happen comes from within the Universe itself - not from outside. The forces and tendencies are built in to the fabric of space and time. No, it’s no accident, neither do we have to look to an outside God. Ours is an inside job. The kingdom is within. Both Galileo and Darwin are vindicated.

There are many billions of Galaxies, each with trillions of stars. Some are dying now, some just forming. Some are going to go Supernova, and seed our Galaxy some more. Some, like our own sun, will grow old and die, and turn into a cold dwarf star one day. This is star evolution, and it matches the evolution of life on Earth. In fact, it is part of the process.

More to follow .....