the direction of time
The origin and fate of the universe
chapter 4
Black Holes Ain't So Black
An interesting fact which I learned through this read was that, if an astronaut was to fall in the black hole, the mass of the black hole would increase. Eventually, the equivalent to the mass of the black hole would be let out through radiation
This would be one of the most difficult and discouraging chapters I have ever read. It would happen to be either due to my lack of knowledge on black holes in the field of quantum physics, or simply because I do not even know what quantum physics is. First, it took me very long to read this chapter as I spent a lot of time analyzing it and trying to understand it. Then after that I spent very long watching YouTube videos and read up on articles for many aspects of this chapter. When I tried putting it all together... I still was unable to. This chapter really set me off pace on my project. It took me an additional week to do, and when it was all ready to be published, Google crashed and I lost all my research that I worked on for so long- with urls.
The chapter constantly speaks of the second law of thermodynamics, I further did research on what it was and found that it is "the entropy of an isolated system never decreases in the course of every natural change." Despite being aware of the definition of entropy, I was not able to use it for the concepts which Hawking talks of. For example; "just throw some matter with a lot of entropy" I do not understand what entropy means here.
Black hole radiation was probably the easiest thing in this chapter as it was easier to research. Through the novel and chapters I discovered that in 1974 Hawking predicted that energy fluctuations from the vacuum causes the generation of particle-antiparticle pairs of virtual particles near the event horizon of the black hole. One of the particles falls into the black hole while the other escapes before they have an opportunity to annihilate each other. The result is radiation. I also thought it was really cool how the smaller the black hole is, the more radiation it emits off!
This chapter made me really stressed out. It constantly spoke of the uncertainty principle. I could not understand what it was. I researched and found that it is " any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical..." I did not understand any of that. I read further did research and got that it is "succinct statement of the "uncertain relation" between the poistion and the momentum (VxM) of a subatomic particle.It was an easier definition but still quiet hard. I finally kind of got what it was after the follwoing YouTube video.
http://www.theguardian.com/science/2013/dec/01/what-is-the-second-law-of-thermodynamics
http://physics.about.com/od/astronomy/f/hawkrad.htm
\http://www.theguardian.com/science/2013/nov/10/what-is-heisenbergs-uncertainty-principle
http://www.aip.org/history/heisenberg/p08.htm
http://news.nationalgeographic.com/news/2014/01/140127-black-hole-stephen-hawking-firewall-space-astronomy/
chapter three
Third Lecture: Black Holes
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This Chapter of Stephen Hawking's book talks all about how Black Holes were discovered, who made the significant discoveries and when. In 1783, John Michell, pointed out that a star that was massive and compact would have such a strong gravitational field that light could not escape it. Any light emitted by the star would get dragged back by the stars gravitational force. The chapter then highlights the life cycle of a star in where it it explains the formation and the resistance of black holes. It then speaks of Chandrasekhar and his limit along with many other ideas implemented by scientists.
This chapter would be the first chapter upon which I actually had great difficulty reading. The terminology used in this chapter was not only fresh, but also hard to decipher and piece together. I had to initially research what is a black hole, despite it being given in advanced terms in the book. I discovered that "A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying." After this information, I was able to further learn and expand my knowledge with the insight and a little bit of background on the subject.
https://www.youtube.com/watch?v=0rocNtnD-yI
http://hubblesite.org/reference_desk/faq/answer.php.id=62&cat=exotic
http://curious.astro.cornell.edu/question.php?number=694
https://www.youtube.com/watch?v=ev9zrt__lec
http://www.space.com/17661-theory-general-relativity.html
http://casswww.ucsd.edu/archive/public/tutorial/GR.html