Oooo, here's a three-fer!

[M29]

Originally Posted by R.D. Silverman

What kind of fruitcake spends the time to write 63 pages of Illucid
word salad?????

This kind http://www.jeffreyncook.com/ ?

[m_f_h]

They should associate with Martin Musatov, who found several huge Mersenne primes, also solved the RH and some minor stuff (P=NP etc...):
http://74.125.47.132/search?q=cache:...&hl=en&ct=clnk
http://74.125.47.132/search?q=cache:...&hl=en&ct=clnk

[cheesehead]

Originally Posted by ewmayer

Merely postulating "the structure of space/time is [foo]", i.e. postulating a spacetime geometry, is not enough - you also need classical conservation of energy, specifically a generalization thereof compatible with said geometry.

... in order to prove that E = mc² has a real physical meaning, yes ... but not to prove that E = mc² is mathematically correct relative to the axioms of relativistic geometry and the mathematical expression of classical conservation of energy.

Conservation of energy is a physical postulate, not a mathematically provable statement in the sense of purely geometrical theorems.

So, if Jeff Cook had specified that the physical meaning of E = mc² had only recently been shown correct for the physics of quarks within baryons, we would have no quarrel (in regard to that) with him. But that's not what he wrote. He referred to the formula's proof in the context of mathematics, not physics.

[mart_r]

Where can I find a sample calculation that shows me how much energy I could extract from, let's say, one ounce of chocolate?

[CRGreathouse]

Originally Posted by mart_r

Where can I find a sample calculation that shows me how much energy I could extract from, let's say, one ounce of chocolate?

Google sez: 2.5 quadrillion joules
http://www.google.com/search?q=1%20ounce%20*%20c^2

Frink sez: 18 million gallons of gasoline (equivalent)
http://futureboy.homeip.net/fsp/frin...soline&lookup=

[Orgasmic Troll]

Originally Posted by CRGreathouse

Google sez: 2.5 quadrillion joules
http://www.google.com/search?q=1%20ounce%20*%20c^2

Frink sez: 18 million gallons of gasoline (equivalent)
http://futureboy.homeip.net/fsp/frin...soline&lookup=

uhm. So an ounce of gasoline has the same amount of energy as 18 million gallons of gasoline?

[ewmayer]

Originally Posted by Orgasmic Troll

uhm. So an ounce of gasoline has the same amount of energy as 18 million gallons of gasoline?

Indeed, that involves an apples-to-oranges comparison of nuclear vs chemical bondage ... My dominatrix would whip - or better, would refuse to whip - me if she ever caught me doing such specious comparisons.

[retina]

Originally Posted by ewmayer

My dominatrix would ... refuse to whip ...

Ah, the classic S&M stand-off.

"Beat me, beat be ... please". "No!"

[CRGreathouse]

Originally Posted by ewmayer

Indeed, that involves an apples-to-oranges comparison of nuclear vs chemical bondage

Right, that was the intention -- that's why I chose those units. Most people (including myself) don't have a good intuitive sense for how much 10^15 joules is. But knowing that 10^9 joules is about the energy in 7-8 gallons of gasoline (when burned) gives a much better sense -- that's a top-up of a fuel tank, not nearly so hard to imagine. So an ounce of chocolate might be 9 million gas tanks' worth of power, a magnitude similar to the gasoline usage of a country for a day.

2e16? No obvious visceral meaning there.

[davieddy]

Originally Posted by ewmayer

Indeed, that involves an apples-to-oranges comparison of nuclear vs chemical bondage ... My dominatrix would whip - or better, would refuse to whip - me if she ever caught me doing such specious comparisons.

I don't consider the comparison between nuclear and chemical
binding energy as "specious" (woody word?) as the one I think is being
made here, namely comparing the energy from burning a mass m of
petrol with E=mc^2.

I know the energy released in a nuclear explosion is popularly attributed
to E = mc^2, but I prefer to look at it through the other end of the telescope, in view of nucleon number remaining constant:

The enormity of nuclear binding energy (compared to chemical)
still results in only a piddling "mass defect" given by E/c^2.

[xilman]

Originally Posted by davieddy

I don't consider the comparison between nuclear and chemical
binding energy as "specious" (woody word?) as the one I think is being
made here, namely comparing the energy from burning a mass m of
petrol with E=mc^2.

I know the energy released in a nuclear explosion is popularly attributed
to E = mc^2, but I prefer to look at it through the other end of the telescope, in view of nucleon number remaining constant:

The enormity of nuclear binding energy (compared to chemical)
still results in only a piddling "mass defect" given by E/c^2.

In the hope of muddying the waters further, I note that there are a number of ways of extracting energy from a given mass of gasoline. Some ways produce more useful energy than others.

For example, the gasoline could be burnt in oxygen to produce any of a variety of different chemicals depending on the relative proportion of the reagents, the temperature and pressure of the reaction while it takes place and after it has completed. Use relatively little oxygen at low temperatures and you produce elemental carbon, water (liquid and/or vapour), carbon monoxide, carbon dioxide and sundry hydrocarbons in various proportions. Use an excess of oxygen at very high temperatures and you get a mix of CO, OH and monatomic oxygen in various proportions. The energy output of these various combustions is really quiet varied.

Remaining with chemical combustion, burning gasoline in chlorine, or fluorine, or N_2O or .... will give similarly varied results.

One could then fuse the hydrogen into helium-4 (or deuterium or helium-3 or ...), again with varying yields of energy, though complete reaction would generate rather more energy than chemical reactions.

Try a bit harder, and you could fuse the carbon as well, getting even more energy.

Squash the gasoline hard enough and in large enough quantities, and you get a nice compact ball of neutrons and rather a lot of energy. Squash even harder, and a rather useful black hole results. Rather useful, in that by throwing in more gasoline you can get out even more energy than is produced by fusion-burning the same quantity of gasoline. If I remember correctly, something like 0.1mc^2 can be extracted by this process.

An even better approach is to wait for your gasoline-produced black hole to evaporate and get back pretty much all of the mass-energy of the gasoline.

I don't see that conservation of nucleon number (more properly baryon number) has much to do with the final mechanism. (Or lepton number, for that matter, which is just as well conserved or not as is baryon number both for chemical and nuclear reactions.)


Paul

(And, anyway, I think you mean "enormousness" rather than "enormity".)