PMU199Y

Essay 2

Essay 2 is worth 5% of your final grade and is about black holes. We will discuss black holes in next week's class.

Due by 2:10PM on October 15th.

Topic

Explain what a black hole is. (Hint: how would a black hole arise astrophysically? Is more than one kind of black hole possible?) [50%]
Explain what happens to particles that move in the gravitational field of a black hole. (Hint: explain the black in black hole. ) [40%]
What would an astronaut feel if she tried to poke her finger through a black hole horizon? (Hint: how fast do human nerve impulses travel?) [10%]

Length, format, etc.

Please write 2.5-3 pages of content, counting references. List your references at the end, after your essay text. Minimize pictures, diagrams or sketches; those included should take up no more than 0.5 page in total. Format, style, and intended readership should be the same as for your first assignment. You may assume that the audience for it has read your previous essay. Please focus your effort on providing clear, understandable, accurate explanations of the physics concepts.

Sources

This time, you will be expected to find a few sources by yourself, as well as using class notes and the textbook. I prefer articles written by people or groups at authoritative institutions like space agencies or universities. If you are in doubt about how authoritative a source is, please ask your professor by email. Here are a couple to get you started.

Anything by NASA, the US space agency (www.nasa.gov), for example http://science.nasa.gov/astrophysics/focus-areas/black-holes/
For a change, the Wikipedia article is actually not bad, but it is quite long and relatively advanced: http://en.wikipedia.org/wiki/Black_hole