krisse

Thanks for the link. Will check it out as soon as I have some time off my studies..

These pages has some interesting vid lectures as well:

http://www.vega.org.uk/video/sort/az/

http://www.wlap.org/

http://www-project.slac.stanford.edu/streaming-media/

[math]F = G\frac{M_1 M_2}{d^2}[/math]

 

Does this equation make the presumption that the Earth is a point gravity source? It seems so becuase taking d down to low values (i.e. close to the center of the Earth) there would be practically no gravity due to it being cancelled out in every dirction' date=' though the formula suggests that it should approach infinite force. Is there a modification of this formula that takes into account the radius of the masses? (presuming they are spherical)[/quote']

 

No, you are missing something here. When you move in through the earth the mass responsible for the attractive force ([math]M_2[/math]) towards the center ([math]d->0[/math]) approaches 0 - such that the whole fraction approaches 0 <=> net gravitational force at center -> 0.

 

The density is another matter. Fluctautions in the mass density would cause the gravitational field to differ from place to place and thereby move the particle in irregular paths through the body.

 

(Sorry - I really suck at the [ math ] tags)

You have to define 'Information' before you can measure its value.

Is information something that exists only in our minds? Are 0's and 1's actual information before we process it?

Are there any information stored (hidden variables) in particles before we measure it? Quantum Mechanics suggests that there aren't - and that particles only attain 'real' properties when measured or otherwise observed.

If you are referring to entropy the question is of quite a different matter. And I would believe that the number might be measurable unless we assume that the universe is infinite, which of course would imply that entropy also be infinite. But in a closed system, such as you reefer to, I think that entropy might be measurable.

"The Ghost in the Atom" - An very interesting edited radio interview with some of the greatest pioneers in quantum mechanics.

"The Inflationary Universe" by Alan H. Guth - A great book by the co-founder of the inflationary "big bang" theory.

"The Elegant Universe" - Also by Brian Greene, and a more detailed description of the basic principles of string theory.

"Journey into Gravity and Spacetime" by John Archibald Wheeler - A semi-technical approach to special relativity by the master of GR for the layman of general science.

- These are all popular science books, if you want to go technical I have a lot more to recommend. Also I believe you can get a great deal of info from browsing Amazon.com reading comments.

If you if you want to go into detail on relativity (which you should) this site has a great walkthrough of some of the greatest books on the topic:

http://math.ucr.edu/home/baez/physics/Administrivia/rel_booklist.html

Happy studying ;P