Re: evolution vs creation

In message <slrnh4i4e9.a93.mrjames@xxxxxxxxxxxxxxxx>, Michael James <mrjames@xxxxxxxx> writes
On 2009-06-28, Ernest Major <{$to$}@meden.demon.co.uk> wrote:
In message <olJ1m.3798$Rb6.2522@xxxxxxxxxxxxxxxxxxxx>, Perplexed in
Peoria <jimmenegay@xxxxxxxxxxxxx> writes
"R. Baldwin" <res0k7yx@xxxxxxxxxxxxxxxxxxxx> wrote:
Bob <bobthewebmaster@xxxxxxxxx> wrote:
E=mc2 doesn't really explain things either.

Certainly it does. E=mc2 explains mass-energy equivalence. Energy and
mass are equivalent and interchangeable, which has been demonstrated by
the detonation of nuclear weapons.

That statement (E=mc^2 <==> nuclear explosion) has always annoyed me.
I know you didn't invent it, but since you chose to propagate it, I'm going
to ask that you provide a sketch of the 'demonstration'. How do you
infer that the energy of the bomb came from mass? Did someone carefully
weigh the bomb before the blast and the debris afterward? Did they
explode the bomb inside a calorimeter so they could measure the energy
release?

Atomic weapons are measured in kiloton and megatons of TNT equivalent,
so presumably people can measure the energy yield of an atomic weapon
with a reasonable degree of accuracy.

We also know the masses of fissile nuclei and fission products with a
considerable decree of precision as well as accuracy. The third number
involved - the efficiency of the fusion chain reaction, i.e. the
proportion of fissile nuclei actually split - is I presume harder to
measure.

It seems to me to be fair to point to atomic weaponry as a qualitative
demonstration of E=mc^2 - but I accept your point that there are other
observations, such as nuclear reactors, which provide a more
quantitative demonstration.

I'm going from memory here, but I believe Robert Serber discusses this
issue in "The Los Alamos Primer". He makes the point that the energy that
we see released by uranium and plutonium fission comes from the electro-static
repulsion of the two fission products that gets converted into kinetic energy.
Of course we know that the reason U and Pu (and other actinides) can keep
themselves together in spite of this repulsion is the strong nuclear force.
And we also know that this binding energy released from the strong nuclear force
is represented as a mass defect in the products. But the release of energy from
fission is not a *necessary* consequence of the mass defect or E=mc^2. In that
he echoes PiP's original point.

I don't see the equivalence.

The mass-energy equivalence exists may not imply the inconvertibility of mass and other forms of energy. But the release of energy in fission remains an observation demonstration of mass-energy equivalence.

mike

--
alias Ernest Major

.

Relevant Pages

  • Re: Is Nuclear Bombs energy exactly = seperation of two charges (fission)??
    ... Because in nuclear fission the strong force is involved, ... Indeed, after things settle down after a nuclear explosion, there is no net separations of electromagnetic charges, but the nuclei have been re-arranged such that a large amount of energy was released, in the form of gamma rays, neutrons, nuclear debris, and their kinetic energies. ... A U^235 nucleus has a certain total mass. ...
    (sci.physics.relativity)
  • Re: Question for physicists (E=mc^2)
    ... >>the final nuclear fragments. ... nuclear binding energy is revealed in the ... >>Theory of Special Relativity is absolutely essential to the ... > measured mass of a TNT molecule, ...
    (sci.physics)
  • Re: Question for physicists (E=mc^2)
    ... instead of a nuclear bomb. ... >> Conventional bomb converts chemical binding energy to kinetic ... >> changge the principle (should we say that relativity is essential to ... >> the understanding of reactions with relative mass deficit greater than ...
    (sci.physics)
  • Re: Interstellar Travel (was: Definition Challenge)
    ... And, BTW, they *do* include nuclear energy. ... By reducing the mass, you only gain linearly. ... The distance and energy requiremtns. ...
    (talk.origins)
  • Re: E <=> MC^2 generally ...and also inside living things!
    ... >> just shuffle nuclear binding energy around, ... >> mass to energy conversion a tiny fraction of a percent. ...
    (sci.energy.hydrogen)