Black hole stupidity

[sol invictus]

I was under the impression that it would be much smaller than a proton. The wiki suggests they would be on the order of a Planck length.

You're completely correct - it wouldn't be able to swallow a whole proton in one gulp until its radius got to be of order the proton's size. It could, however, swallow one of the quarks that make up the proton, and (because of color confinement) that would probably lead to it eating the entire thing. I haven't thought that through carefully, though.

But there's a simple estimate one can do - look up the radius of your favorite kind of micro black hole. Get the speed with which it oscillates through the earth, and then (using the density of protons in the earth, or quarks if you prefer) calculate how long it would be before the hole runs into one (assuming it doesn't evaporate). It's an amazingly long time.

 

[DrRocket]

Yes.



There are really a few different issues here. Firstly, the whole "you can't prove a negative" thing isn't actually true. For example, if my hypothesis is that there is a sock in my drawer, I can go and open the drawer and if it is empty, I have proved a negative. What you can't prove is a general negative, which is bascially one that would require an infinite amount of checking. For example, if my hypothesis is that it is possible to put socks in drawers, no matter how many drawers I check, I can never prove the negative since I can't check in every single drawer in the universe.

I agree with your basic position. Moreover, you can even prove some general negatives.

The following have been proved rigorously in mathematics:

1. You cannot construct a square with the same area as a given circle usiing a ruler and straight edge.

2. Pi is not the root of any polynomial with rational coefficients. Neither is e.

3. There is no real number whose square is -1.

4. There is no continuous vector field that is everywhere non-zero on the 2-sphere (or cowlicks are inevitable).

This carries over to physics if you accept the general principles of physics as true. For instance, you can say that based on general relativity no massive object will be found traveling at the speed of light.

And if you accept reasonable evidence as proof you could say that there is no human being who is 52 feet tall.

We "prove" negatives all the time, depending on the level of rigor that one requires for "proof". The statement that it is impossible to prove a negative is often made by people who are trying to defend an indefensible or nonsensical position.