Black Holes have been my interest ever since I have started reading about Space and its mysteries. The following is something which everyone interested in Space and related stuff should know!
In 1915, Einstein put forward his revolutionary General Theory of Relativity. In this, space and time were no longer separate and independent entities. Instead, they were just different directions in a single object called space-time. This space-time was not flat, but was warped and curved by the matter and energy in it. In order to understand this, considered a sheet of rubber, with a weight placed on it, to represent a star. Theweight will form a depression in the rubber, and will cause the sheet near the star to be curved,rather than flat. If one now rolls marbles on the rubber sheet, their paths will be curved, rather than being straight lines. In 1919, a British
expedition to West Africa, looked at light from distant stars, that passed near the Sun during an
eclipse. They found that the images of the stars were shifted slightly from their normal positions. This indicated that the paths of the light from the stars had been bent by the curved
space-time near the Sun. General Relativity was confirmed.
Consider now placing heavier and heavier, and more and more concentrated weights on the rubber sheet. They will depress the sheet more and more. Eventually, at a critical weight and size, they will make a bottomless hole in the sheet, which particles can fall into, but nothing can get out of.
What happens in space-time according to General Relativity is rather similar. A star will curve and distort the space-time near it, more and more, the more massive and more compact the star is. If a massive star, which has burnt up its nuclear fuel, cools and shrinks below a critical size, it will quite literally make a bottomless hole in space-time, that light can't get out of. Such objects were given the name Black Holes, by the American physicist John Wheeler, who was one of the first to recognise their importance, and the problems they pose. The name caught on quickly. To Americans, it suggested something dark and mysterious, while to the British, there was the added resonance of the Black Hole of Calcutta. But the French, being French, saw a more risqué meaning. For years, they resisted the name, trou noir, claiming it was obscene. But that was a bit like trying to stand against le weekend, and other franglais. In the end, they had to give in. Who can resist a name that is such a winner?
In 1915, Einstein put forward his revolutionary General Theory of Relativity. In this, space and time were no longer separate and independent entities. Instead, they were just different directions in a single object called space-time. This space-time was not flat, but was warped and curved by the matter and energy in it. In order to understand this, considered a sheet of rubber, with a weight placed on it, to represent a star. Theweight will form a depression in the rubber, and will cause the sheet near the star to be curved,rather than flat. If one now rolls marbles on the rubber sheet, their paths will be curved, rather than being straight lines. In 1919, a British
expedition to West Africa, looked at light from distant stars, that passed near the Sun during an
eclipse. They found that the images of the stars were shifted slightly from their normal positions. This indicated that the paths of the light from the stars had been bent by the curved
space-time near the Sun. General Relativity was confirmed.
Consider now placing heavier and heavier, and more and more concentrated weights on the rubber sheet. They will depress the sheet more and more. Eventually, at a critical weight and size, they will make a bottomless hole in the sheet, which particles can fall into, but nothing can get out of.
What happens in space-time according to General Relativity is rather similar. A star will curve and distort the space-time near it, more and more, the more massive and more compact the star is. If a massive star, which has burnt up its nuclear fuel, cools and shrinks below a critical size, it will quite literally make a bottomless hole in space-time, that light can't get out of. Such objects were given the name Black Holes, by the American physicist John Wheeler, who was one of the first to recognise their importance, and the problems they pose. The name caught on quickly. To Americans, it suggested something dark and mysterious, while to the British, there was the added resonance of the Black Hole of Calcutta. But the French, being French, saw a more risqué meaning. For years, they resisted the name, trou noir, claiming it was obscene. But that was a bit like trying to stand against le weekend, and other franglais. In the end, they had to give in. Who can resist a name that is such a winner?
Solar System
It was during my 1st grade that I was introduced to the concept of Solar System. My Teachers explained it to me in such a way that I believed it to be flat without any distortions, which isn't true. Solar System is curved due to the gravitational force between the planets.
Flat Model :
On a table place balls of various sizes in a such a way that they represent the Solar System with the central position occupied by a big ball. This ball represents Sun. Remaining balls as the planets. Generally planets move in their orbits becoz of the gravitational force between the planet and sun and angular velocity of planet. The net force acting between these two makes the planet to move around the Sun in their specific path called as Orbit. Hence if the angular velocity of the planet is reduced, it wud fall directly on Sun. All this phenomena is not observed with the balls on table. Even if they are made to move with certain angular velocity with gentle push, they would move as if each ball is independent and doesn't have any influence over the other balls. The randomness increases with each second and we will not be able to explain the actually Solar System with this model.
We can avoid all this drawbacks if we consider the curved model!
Curved Model :
In this take a bowl and place the big ball at the bottom of the bowl. Instead of taking other 8 balls for planets, take 1 ball for convenience. Now project the ball on the curved part of bowl and observe.
The ball moves on the curved surface and looses angular velocity continuously. When it reaches zero, the ball falls into the big ball at the center. The same thing happens in the Solar System. When a planet doesn't move with sufficient angular velocity, the net force on the planet acts in the direction of gravitational force towards Sun. Hence, the planet would fall into the Sun. This force is more pronounced if the planet is nearer to Sun since Force acting between two bodies is inversely related to the square of the distance of separation, according to Newton's Law.
Gravity is comparable to the curvature in the bowl. If the bowl(Solar System) is more curved, more is the force with which the ball(planet) falls in to the Big Ball(Sun) if the angular velocity is less!
Einstein's statement " Gravity is a distortion in Space " proves the same. More the distortion(curvature) more is the force of gravity. Also this theory is in accordance with the concept of Black Holes. They are stars which distort the space around them so much that even Light cannot escape its gravity!
Flat Model :
On a table place balls of various sizes in a such a way that they represent the Solar System with the central position occupied by a big ball. This ball represents Sun. Remaining balls as the planets. Generally planets move in their orbits becoz of the gravitational force between the planet and sun and angular velocity of planet. The net force acting between these two makes the planet to move around the Sun in their specific path called as Orbit. Hence if the angular velocity of the planet is reduced, it wud fall directly on Sun. All this phenomena is not observed with the balls on table. Even if they are made to move with certain angular velocity with gentle push, they would move as if each ball is independent and doesn't have any influence over the other balls. The randomness increases with each second and we will not be able to explain the actually Solar System with this model.
We can avoid all this drawbacks if we consider the curved model!
Curved Model :
In this take a bowl and place the big ball at the bottom of the bowl. Instead of taking other 8 balls for planets, take 1 ball for convenience. Now project the ball on the curved part of bowl and observe.
The ball moves on the curved surface and looses angular velocity continuously. When it reaches zero, the ball falls into the big ball at the center. The same thing happens in the Solar System. When a planet doesn't move with sufficient angular velocity, the net force on the planet acts in the direction of gravitational force towards Sun. Hence, the planet would fall into the Sun. This force is more pronounced if the planet is nearer to Sun since Force acting between two bodies is inversely related to the square of the distance of separation, according to Newton's Law.
Gravity is comparable to the curvature in the bowl. If the bowl(Solar System) is more curved, more is the force with which the ball(planet) falls in to the Big Ball(Sun) if the angular velocity is less!
Einstein's statement " Gravity is a distortion in Space " proves the same. More the distortion(curvature) more is the force of gravity. Also this theory is in accordance with the concept of Black Holes. They are stars which distort the space around them so much that even Light cannot escape its gravity!
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