207 reputation
215
bio website math.stackexchange.com/users/…
location Champaign, IL
age 35
visits member for 3 years, 5 months
seen yesterday

Amateur mathematician, professional software engineer. Interested in all kinds of math, becoming a better mathematician, and helping others do the same.

email: jdb1729 (at) gmail.com

let's be friends: http://facebook.com/jdb1729


May
29
comment Why is global conservation of energy not considered a tautology?
Luboš, in mathematics, theorems and tautologies are not the same thing. A theorem is a tautology in the form of an implication whose precedent is some conjunction of axioms. For example, it is not possible to prove that arithmetic is consistent without using even stronger axioms such as those of set theory. In that sense, the consistency of arithmetic is open, because it is falsifiable. On the other hand, there is no reason to doubt the consistency of first-order logic itself. You are certainly right that everyone would be screwed! mathpages.com/home/kmath347/kmath347.htm
May
29
comment Why are extra dimensions necessary?
Note that the product of a 3-sphere and a 1-sphere is not the same thing as a 4-sphere, nor is it a 4-torus. So in some sense the extra dimension is topologically distinct, independently of how it might be turned into a differentiable manifold.
May
29
revised Why are extra dimensions necessary?
add better link to archive.org with multiple formats, make it clear that this is a a free download site
May
28
comment Why are extra dimensions necessary?
I don't know about string theory but like Fakrudeen I would appreciate an explanation in layman's terms. Does string theory really posit that space is a topological n-sphere with n > 3? The point I am making is not that extra dimensions don't exist, just that if they do they must be distinguishable in some way from the three we know and love (which as far as I know are all indistinguishable from each other).
May
28
revised Why are extra dimensions necessary?
typo
May
28
revised Why are extra dimensions necessary?
typo
May
28
answered Why are extra dimensions necessary?
May
28
comment Conservation law of energy and Big Bang?
A screwdriver, for it to be called a screwdriver, has to drive screws, so if a thing does not drive screws, it is not a screwdriver, so screwdrivers do not exist. The fallacy is that you are substituting "energy" for "it". I think I am getting the point about GR now, but this is starting to get silly again.
May
28
comment Lightning and nuclear fusion
rubenvb, can you provide any reference for your suggestion that nuclear fusion is involved in lightning? Also what do you mean by molecular fusion? The existing answers haven't addressed this part, I guess because it's not clear where this idea is coming from. (I am not the one who downvoted.)
May
28
comment Why is global conservation of energy not considered a tautology?
I guess you are referring to KE = m c^2 gamma and that seems to refute my statement that it's just a linear combination. And it's not quite as simple as en.wikipedia.org/wiki/Grue_and_bleen because time itself is in question! Plenty to think about here.
May
27
comment Why is global conservation of energy not considered a tautology?
All of the answers are wonderful, and all point me to the wilderness instead of the path, but this one is the most helpful. The "conservation of mass" analogy is simple, it relates well to my existing intuition, and it suggests interesting questions.
May
27
accepted Why is global conservation of energy not considered a tautology?
May
27
awarded  Citizen Patrol
May
27
comment purely hypothetically, could a quantum being appear to be human? I ask for the purpose of research on a novel
scifi.SE is a better forum for this.
May
27
comment purely hypothetically, could a quantum being appear to be human? I ask for the purpose of research on a novel
This question is inappropriate in its current form. To post this type of question here you will need to include more details about the proposed science-fiction plot and make the question more specific. See for example physics.stackexchange.com/questions/10433/…
May
27
comment Why is global conservation of energy not considered a tautology?
At one point we believed that mass and energy (according to the old definition of "energy" which excluded mass) were independently conserved. Then it was discovered otherwise, but the conservation law was recovered by redefining energy to include mass. Shouldn't energy defined as the sum of every time-invariant scalar quantity? Why not convert B to Joules and explain the redshift by saying that the photons create a neutron sometimes? Of course we demand evidence of this, and the epicycles continue, but why is one thing energy and not another just because no conversion process is known?
May
27
accepted Atomic mass of Copper-63?
May
26
comment Atomic mass of Copper-63?
Furthermore I have a personal interest in learning more about how to do this sort of research in general. C Earnest's answer is my favorite so far. user9325's answer simply shows that one of the URLs contradicts its own extra data, but that is no reason to accept the 62.929 value; it is only a reason to reject the other. On the other hand, all the other answers support the 62.929 value with secondary sources.
May
26
comment Atomic mass of Copper-63?
Luboš, if you read the comment threads that I have linked to, you will see that people are attempting to debunk this cold-fusion claim on the basis of this typo. Whether or not you believe in this nonsense it paints physicists and the discipline of physics in a poor light. My motivation in asking this question is to provide a better reference than NIST for this value so that this mistake will not be repeated in future discussions. I wholeheartedly believe that SE is capable of this.
May
26
comment Why is global conservation of energy not considered a tautology?
Yet another way to phrase this objection: isn't it the case that both the assertion and denial of conservation of energy are philosophical and not physical statements? I find the former more palatable because it is true in everyday experience and were it to be demonstrated otherwise, "energy gods" is a short string compared to any long proof that conservation of energy is violated on the basis of some other unproven theory. So it is either conservation or energy gods by Occam's razor.