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Chapter 15: The Deaths of Massive Stars
Supernovae
Three supernovae have been seen with the naked eye in our Galaxy. The most brilliant occurred in the constellation Taurus and was observed in 1054 by Chinese astronomers.
On this site you will find many papers on supernovae. From this page, go to the "SN1987A: Blastwave" page. You probably won't understand everything there, but report on what the astronomer is attempting to explain.
Visit the Supernovae web site
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Schwarzchild Radius
You'll remember from the text that as a star decreases in size without losing any mass, its escape velocity becomes greater. When its radius becomes so small that its escape velocity is greater than the velocity of light in vacuum, the star has crossed its Schwarzchild radius and it is now a black hole. An object with a different mass has a different Schwarzchild radius.
1) Determine how small the Sun would have to get to reach its Schwarzchild radius and become a black hole. 2) Approximately what is this distance in miles? (Follow the "Next" buttons to learn more about black holes.)
Visit the Escape Velocity for Light web site
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Black Holes
In the 1970's Stephen Hawking proposed that black holes may evaporate.
1) Why don't black holes suck up the entire universe? 2) What would a person see while observing another person falling into a black hole? 3) What is a white hole?
Visit the Black Holes Frequently Asked Questions web site
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Chances of Seeing a Pulsar
On this site you will find a tutorial on pulsars with animations, including an animation of a pulsar's rotation. If the Earth were above the pole of the pulsar, we would not see it flash.
For the pulsar in the animation, estimate the fraction of the pulsar's surroundings that the beam hits. (You do not need to consider the distance from the pulsar to answer this.)
Visit the NASA/Marshall Space Flight Center Astronomy: Pulsar Tutorial web site
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