Biscuit tins, rolling pins and pastry jiggers: a brief history of baking utensils they had less time for elaborate food preparation, says Walter. Dr. Hawking did that largely through his book “A Brief History of Time: From the Big Bang to Black Holes,” published in It has sold more  Missing: urdu ‎| ‎Must include: ‎urdu. Buy A Brief History of Time on ✓ FREE SHIPPING on qualified orders.


Author: Gideon Watsica
Country: Panama
Language: English
Genre: Education
Published: 5 August 2015
Pages: 844
PDF File Size: 27.3 Mb
ePub File Size: 49.71 Mb
ISBN: 536-4-22203-644-1
Downloads: 38245
Price: Free
Uploader: Gideon Watsica


Some scientists have tried to make a theory that combines the electromagnetic force, the weak nuclear force, and the strong a brief history of time in urdu force. This theory is called a grand unified theory or a GUT. This theory tries to explain these forces in one big unified way or theory.

Black Holes[ edit ] A picture of a black hole and how it changes light around it. Black holes are talked about in this chapter. Black holes are stars that have collapsed into one very small point. This small point is called a singularity. Black holes suck things into their center because they have very strong gravity.

Some of a brief history of time in urdu things it can suck in are light and stars. Only very large stars, called super-giants, are big enough to become a black hole.

The star must be one and a half times the mass of the sun or larger to turn into a black hole. This number is called the Chandrasekhar limit.

If the mass of a star is less than the Chandrasekhar limit, it will not turn into a black hole; instead, it will turn into a different, smaller type of star.

The boundary of the black hole is called the event horizon. If something is in the event horizon, it will never get out of the black hole. Black holes can be shaped differently. Some black holes are perfectly spherical - like a ball.

Virtual Library (Urdu-English): A Brief History of Time (URDU) By Stephen W. Hawking

Other black holes bulge in the middle. Black holes will be spherical if they do not rotate.


Black holes will bulge in the middle if they rotate. Black holes are difficult to find because they do not let out any light.

They can be found when black holes suck in other stars. When black holes suck in other stars, the black hole lets out X-rayswhich can be seen by telescopes.

A Brief History of Time - Wikipedia

In this chapter, Hawking talks a brief history of time in urdu his bet with another scientist, Kip Thorne. Hawking bet that black holes did not exist, because he did not want his work on black holes to be wasted.

He lost the bet. Hawking realized that the event horizon of a black hole could only get bigger, not smaller. The area of the event horizon of a black hole gets bigger whenever something falls into the black hole.

He also realized that when two black holes combine, the size of the new event horizon is greater than or equal to the sum of the event horizons of the two other black holes. This means that a black hole's event horizon can never get smaller.

وقت کا سفر A Brief History Of Time Stephen Hawking

Disorder, also known as entropyis related to black holes. There is a scientific law that has to do with entropy. This law is called the second law of thermodynamicsand it says that a brief history of time in urdu or disorder will always increase in an isolated system for example, the universe.

The relation between the amount of entropy in a black hole and the size of the black hole's event horizon was first thought of by a research student Jacob Bekenstein and proven by Hawking, whose calculations said that black holes emit radiation.