Part 19

Recitation of the Holy Scripture.

It is God who erected the heavens without pillars that you can see; then He established Himself above the Throne and made subject the sun and the moon, each running its course for a specified term. 

He arranges each matter 

He details the signs that you may be certain of the meeting with your Lord. 

And it is He who spread the earth. He causes the night to cover the day. Indeed in that are signs for a people who give thought.  

And to God prostrates whoever is within the heavens and the earth, willingly or by compulsion, and as well as their shadows, in the mornings and the afternoons.

End of Recitation of the Holy Scripture.

O people as I told you that these few programs are just to give you an idea of the various things various creation of your Lord around you and within yourselves and that this will also help you later to understand the religious scriptures in a better way. Now let me tell you little more about stars and what different shapes they can assume at the end of their life as a star.

At the end of their life stars transform into a different form depending on the mass of the star. So for you, the primary thing to understand at least seven celestial objects white dwarfs, red giants, black holes, neutrino stars, Pulsars, nova, and supernova is that they all are transformed form of a star at the end of its life. The lifespan that God designed for the living beings had also been allocated for the stars. I already told you in part 16 that every day almost 275-400 million stars die and nearly 400 million new stars are born only in our observable universe. You will better understand this if you again listen to part 16 and 18 where I explained the basic structure of matter and presence of 99.999% space between fundamental particles of matter. That will also help you understand all coming topics related to the transformation of stars which actually happen because of this property of matter to compress itself with gravity.  

Stars that have a lot of mass may end their lives as black holes or neutron stars. A low or medium mass star with mass less than about eight times the mass of our Sun becomes a white dwarf. Stars with less mass at the end of their life throw out the outer area as a planetary nebula, and the core becomes a white dwarf. So a white dwarf is a star at the end of its life which throw out its outer surface and the remaining core, center, the remaining portion is called white dwarf because it is small and very dim. The strange thing is that if you add more mass to a white dwarf, its size decreases with that instead of increasing. This is because of increased gravitational collapse due to increase in total mass. It is as dense as you reduce the size of the sun to earth’s size or 100 people squeezed in a teaspoon. This makes white dwarfs one of the densest bodies of matter, surpassed only by neutron stars and black holes. Is this all mysterious vast and complicated system designed and running on its own. Nay, it is all by the Will and command of your Lord. So which of the favors of your Lord will you deny?

A red giant star is a dying star in the last stages of stellar evolution. Medium mass stars, like our Sun, live by fusing the hydrogen within their cores into helium. This is what our Sun is doing now. When the star runs out of hydrogen in its core to fuse, it  then starts fusing the helium and remaining hydrogen in a shell surrounding the core. The energy produced by this fusion causes the star to expand outward to many times its original size. But now this outer envelope is lower in temperature, giving them a reddish hue and thus they are called Red Giants. The Sun will only spend one billion years as a red giant, as opposed to nearly 10 billion years it spent busily burning hydrogen. In only a few billion years, our sun will turn into a red giant star, swell and engulf the inner planets, possibly even Earth. Red giant stars reach sizes of 100 to 1,000 times the size of the sun and a little over half as hot as the sun. In roughly 5 billion years, the sun will start the helium-burning process, transforming into a red giant star. When it will expand, its outer layers will consume Mercury and Venus, and reach Earth. For Muslims in this is also a sign as mentioned in their prophet’s sayings that near Judgment Day the sun will become so close to earth that it will only be at a distance of one bow or two. Is this all mysterious vast and complicated system designed and running on its own. Nay, it is all by the Will and command of your Lord.

O people another form that stars can transform at the end of their lives is a black hole. The simplest definition of a black hole is an object that is so dense and tightly packed with matter that not even light can escape its surface. Black holes are the only objects in the universe that can also trap light. They get formed when a massive star collapses in on itself, becoming so dense that it bend and distort the fabric of space and time. Billions of billions of earth can go into a black hole and convert to nothingness.  A black hole is such a strange thing in this universe that even time stops there inside a black hole. Black holes are what occurs when the universe divides by zero and consumes anything that tries to notice. Black holes happen when you put too much matter in one place, and it breaks both the matter and the place with gravity. Black holes eat everything around its gravitational pull and suck the matter from nearby stars. In physics, Escape velocity is defined to be the minimum velocity an object must have to escape the gravitational field of a massive body, that is, in our case can escape the earth without ever falling back. There are two things that affect the escape velocity, the mass of the object and the distance to the center of that object. For example, a rocket must accelerate to 11.2 km/s almost 40,000 km/h to escape Earth’s gravity. If we shrink the Earth’s mass into a sphere with a radius of 9 mm, the escape velocity would be the speed of light. The radius at which a mass has an escape velocity equal to the speed of light is called the Schwarzschild radius. Any object that is smaller than its Schwarzschild radius is a black hole. You can say that anything with an escape velocity higher than the speed of light is a black hole. For becoming a black hole the mass of our sun would need to be pressed into a volume with a radius of about 3 km. Similarly, If you could squeeze the Earth down to the size of a marble tile, it would collapse on itself and become a black hole. 

There are two fundamental parts to a black hole: the singularity and the event horizon. The event horizon is the “point of no return” encompassing the black hole. It is not a physical surface, but a sphere enveloping the black hole that marks where the escape velocity is equal to the speed of light. Once any stuff is inside it, that stuff will fall to the center. With such a strong gravity, the matter squeezed to just a point. That point is called the singularity. It is extremely small, so it has actually an infinite density.  

The black hole in our galactic center is thought to have a mass of 4 millions suns and diameter of 17 million Km. Such black holes are like hubs around which many galaxies including our milky way rotates. So actually all stars and galaxies are rotating around giant black holes. O humankind these are actually knots your Lord has put there in the fabric of space and cosmos which keep it tight and balance against the expansion of the universe. For Muslims in this is also a sign as mentioned in Last Scripture