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(Guardian)   Everything you ever wanted to know about Einstein's famous equation, but were too insecure to ask. Bonus: article notes equation correction   (theguardian.com) divider line 29
    More: Spiffy, Einstein, kinetic energy, special relativity, equations, nuclear power stations, natural sources, atomic bombs, electrical charges  
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3480 clicks; posted to Geek » on 05 Apr 2014 at 9:27 AM (23 weeks ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2014-04-05 09:46:23 AM
1kg of "stuff" contains around 9 x 10^16 joules, if you could somehow transform all of it into energy.

I love how these articles always contain some 'what if you could completely convert mass to energy' number.  You can't. You still have to obey all other conservation laws - boson number, charge, spin, etc - so you really don't convert 'mass' to energy in nuclear fission/fusion.  What you release is some of the binding energy between particles as they change to a more stable arrangement.

It's easiest to understand if you look at the binding energy per nucleon curve for elements, inverted.

img.fark.net
Everybody wants to get to the most stable form, iron.  So you're not really destroying particles and converting them to pure energy - you're just taking the particles you have and getting them to snuggle closer together.
 
2014-04-05 09:52:22 AM
Didn't find TFA particularly interesting or informative.

One of my favorite explanations of E=mc2 comes from the minutephysics YouTube channel: Einstein's Proof of E=mc2
 
2014-04-05 09:56:32 AM
HAHA somebody mispelled dogma and had to correct article. Science IS religion
 
2014-04-05 10:00:54 AM
You can't get there from here
 
2014-04-05 10:03:22 AM

LewDux: HAHA somebody mispelled dogma and had to correct article. Science IS religion


HAW HAW
 
2014-04-05 10:12:53 AM
syrynxx: Everybody wants to get to the most stable form, iron.  So you're not really destroying particles and converting them to pure energy - you're just taking the particles you have and getting them to snuggle closer together.

How romantic!
 
2014-04-05 10:27:16 AM

syrynxx: It's easiest to understand if you look at the binding energy per nucleon curve for elements, inverted.


That is a fantastic graph.  Thanks.
 
2014-04-05 10:55:47 AM

syrynxx: 1kg of "stuff" contains around 9 x 10^16 joules, if you could somehow transform all of it into energy.

I love how these articles always contain some 'what if you could completely convert mass to energy' number.  You can't. You still have to obey all other conservation laws - boson number, charge, spin, etc - so you really don't convert 'mass' to energy in nuclear fission/fusion.  What you release is some of the binding energy between particles as they change to a more stable arrangement.

It's easiest to understand if you look at the binding energy per nucleon curve for elements, inverted.

[img.fark.net image 818x633]
Everybody wants to get to the most stable form, iron.  So you're not really destroying particles and converting them to pure energy - you're just taking the particles you have and getting them to snuggle closer together.


Came here to make that point. Leaving satisfied.
 
2014-04-05 11:11:36 AM

eraser8: mc2




Mind blown
 
2014-04-05 11:30:09 AM

diaphoresis: syrynxx: 1kg of "stuff" contains around 9 x 10^16 joules, if you could somehow transform all of it into energy.

I love how these articles always contain some 'what if you could completely convert mass to energy' number.  You can't. You still have to obey all other conservation laws - boson number, charge, spin, etc - so you really don't convert 'mass' to energy in nuclear fission/fusion.  What you release is some of the binding energy between particles as they change to a more stable arrangement.

It's easiest to understand if you look at the binding energy per nucleon curve for elements, inverted.

[img.fark.net image 818x633]
Everybody wants to get to the most stable form, iron.  So you're not really destroying particles and converting them to pure energy - you're just taking the particles you have and getting them to snuggle closer together.

Came here to make that point. Leaving satisfied.


So does this mean Mr. Fusion on the DeLorean must leave behind chunks of Iron everytime there's a temporal displacement?
 
2014-04-05 11:34:29 AM
this article has been amended to correct an equation...

what! they got it wrong? emc2 did they add something or forget something?
 
2014-04-05 11:47:19 AM

WTP 2: this article has been amended to correct an equation...

what! they got it wrong? emc2 did they add something or forget something?


i.imgur.com
 
2014-04-05 11:56:12 AM
There was nothing in that article that explained to me why my relatives are such yokels.
 
2014-04-05 12:09:03 PM

Ivo Shandor: WTP 2: this article has been amended to correct an equation...

what! they got it wrong? emc2 did they add something or forget something?


We're all done here.
 
2014-04-05 12:13:24 PM

dionysusaur: syrynxx: Everybody wants to get to the most stable form, iron.  So you're not really destroying particles and converting them to pure energy - you're just taking the particles you have and getting them to snuggle closer together.

How romantic!


Yeah, but it's basically a big, sweaty gay pile, with some asexuals thrown in, and when things cool off a bit the lesbians swarm around the outside at a safe distance.
 
2014-04-05 12:20:52 PM
And now the rant. First, the equation did not "give birth to the atom bomb". Radioactivity had already been discovered by some guy who left uranium salts sitting on top of a photographic plate, and that led to many experiments which classified the types of radiation (alpha, beta, gamma, ...) and gave us a model for an atom as a dense nucleus surrounded by an electron cloud. The neutron was discovered experimentally in 1932 by James Chawick and neutron-induced fission was discovered later that decade by Otto Hahn et al. Leó_Szilárd was one of the first people to realize that the fission process could lead to an energetic chain reaction.

Einstein's involvement in the atom-bomb development was political, not technical. His "E=mc2" did help to provide a theoretical basis for the phenomena which had been measured, but honestly nobody gave a shiat if the fission fragments weighed slightly less than the uranium which had gone into the device. All they really needed was the observation that lumps of U-235 got very hot when you whacked them into each other.

Rant part 2 - the article didn't even mention the long form of the equation, E2 = p2c2 + m2c4, where 'm' is rest mass and 'p' is momentum (for example the momentum of a massless photon).
 
2014-04-05 01:24:47 PM
Christ, is this guy still patting himself on the back for finding an error in something Einstein decided not to publish?
 
2014-04-05 01:27:09 PM

syrynxx: 1kg of "stuff" contains around 9 x 10^16 joules, if you could somehow transform all of it into energy.

I love how these articles always contain some 'what if you could completely convert mass to energy' number.  You can't. You still have to obey all other conservation laws - boson number, charge, spin, etc - so you really don't convert 'mass' to energy in nuclear fission/fusion.  What you release is some of the binding energy between particles as they change to a more stable arrangement.

It's easiest to understand if you look at the binding energy per nucleon curve for elements, inverted.

[img.fark.net image 818x633]
Everybody wants to get to the most stable form, iron.  So you're not really destroying particles and converting them to pure energy - you're just taking the particles you have and getting them to snuggle closer together.


What about matter-antimatter annihilation?  Setting aside the, um, engineering challenges of doing that to a 100 kg person.  Doesn't that produce nearly all gamma rays and neutrinos?  Close enough?
 
2014-04-05 01:39:52 PM

Ivo Shandor: Rant part 2 - the article didn't even mention the long form of the equation, E2 = p2c2 + m2c4, where 'm' is rest mass and 'p' is momentum (for example the momentum of a massless photon).


minutephysics also tackles this one:  E=mc² is Incomplete

/I swear I'm not on the payroll of minutephysics
 
2014-04-05 02:40:34 PM
I wish I could still remember half of the shiat I learned when I was in the Navy's nuclear power school. The price of having 2 years worth of material being crammed into a 6 month course I guess. Been debating on going back to school to finish a degree, I loved the material but I wasn't the fan of the Navy's breakneck speed of shotgunning as much information at you as possible and hoping enough of it sticks to not melt the reactor core while on watch...
 /csb
 
2014-04-05 04:15:10 PM

Ivo Shandor: WTP 2: this article has been amended to correct an equation...

what! they got it wrong? emc2 did they add something or forget something?

[i.imgur.com image 471x630]


Actually, if I remember correctly, Einstein's first wife helped him with some of the work.
Perhaps some of the proofs...I'm not sure.
 
2014-04-05 04:22:18 PM

Ivo Shandor: the long form of the equation, E2 = p2c2 + m2c4, where 'm' is rest mass and 'p' is momentum (for example the momentum of a massless photon)


The full form allows this handy representation of how the terms are related: (Source)

img.fark.net
 
2014-04-05 06:08:09 PM

drumhellar: Ivo Shandor: the long form of the equation, E2 = p2c2 + m2c4, where 'm' is rest mass and 'p' is momentum (for example the momentum of a massless photon)

The full form allows this handy representation of how the terms are related: (Source)

[img.fark.net image 437x298]


I don't know why but that just blew my mind.

/mind...blown.
 
2014-04-05 09:55:01 PM

chimp_ninja: What about matter-antimatter annihilation?  Setting aside the, um, engineering challenges of doing that to a 100 kg person.  Doesn't that produce nearly all gamma rays and neutrinos?  Close enough?


Yep, that is 100% matter-to-energy conversion.  To conserve energy from the perspective of an observer travelling at center-of-mass of an approaching particle-antiparticle pair, they have 0 net momentum (equal energy, opposite velocity vectors) so when they collide and turn into pure energy as gamma rays, the photons also have to have 0 net momentum, so it results in a pair of photons travelling in opposite directions.  The original conservation numbers of boson number, charge and all that are exactly the same-but-negative in an antimatter particle.

I'm really not sure what the state-of-the-art is in producing stable anti-matter elements, like anti-hydrogen.  To my knowledge the largest stable collection of antimatter molecules happened in a Dan Brown book - whatever that piece of crap after The DaVinci Code was.  And then he used his sport coat as a parachute out of an exploding helicopter and lived happily ever after.

Also AFAIK nobody knows why antimatter isn't all over the place.  The laws of physics are symmetric so there should be entire galaxies made out of antimatter.
 
2014-04-05 10:16:55 PM

syrynxx: Also AFAIK nobody knows why antimatter isn't all over the place.  The laws of physics are symmetric so there should be entire galaxies made out of antimatter.


Those 'laws' are also being constantly changed, updated, re-written, and completely trod under with frightening regularity, throughout the course of our species' lifespan.

We don't know they're any "more" right now than the Newtonians pre-Einstein. The same argument can be made for dark matter. Our rules seem to indicate that it is there, but we currently lack the technology to properly document or measure it.
 
2014-04-05 10:19:46 PM

syrynxx: chimp_ninja: What about matter-antimatter annihilation?  Setting aside the, um, engineering challenges of doing that to a 100 kg person.  Doesn't that produce nearly all gamma rays and neutrinos?  Close enough?

Yep, that is 100% matter-to-energy conversion.  To conserve energy from the perspective of an observer travelling at center-of-mass of an approaching particle-antiparticle pair, they have 0 net momentum (equal energy, opposite velocity vectors) so when they collide and turn into pure energy as gamma rays, the photons also have to have 0 net momentum, so it results in a pair of photons travelling in opposite directions.  The original conservation numbers of boson number, charge and all that are exactly the same-but-negative in an antimatter particle.

I'm really not sure what the state-of-the-art is in producing stable anti-matter elements, like anti-hydrogen.  To my knowledge the largest stable collection of antimatter molecules happened in a Dan Brown book - whatever that piece of crap after The DaVinci Code was.  And then he used his sport coat as a parachute out of an exploding helicopter and lived happily ever after.

Also AFAIK nobody knows why antimatter isn't all over the place.  The laws of physics are symmetric so there should be entire galaxies made out of antimatter.


Maybe the universe is polar and we're in the "matter" hemisphere.
 
2014-04-06 10:34:49 AM

Ambivalence: syrynxx: chimp_ninja: What about matter-antimatter annihilation?  Setting aside the, um, engineering challenges of doing that to a 100 kg person.  Doesn't that produce nearly all gamma rays and neutrinos?  Close enough?

Yep, that is 100% matter-to-energy conversion.  To conserve energy from the perspective of an observer travelling at center-of-mass of an approaching particle-antiparticle pair, they have 0 net momentum (equal energy, opposite velocity vectors) so when they collide and turn into pure energy as gamma rays, the photons also have to have 0 net momentum, so it results in a pair of photons travelling in opposite directions.  The original conservation numbers of boson number, charge and all that are exactly the same-but-negative in an antimatter particle.

I'm really not sure what the state-of-the-art is in producing stable anti-matter elements, like anti-hydrogen.  To my knowledge the largest stable collection of antimatter molecules happened in a Dan Brown book - whatever that piece of crap after The DaVinci Code was.  And then he used his sport coat as a parachute out of an exploding helicopter and lived happily ever after.

Also AFAIK nobody knows why antimatter isn't all over the place.  The laws of physics are symmetric so there should be entire galaxies made out of antimatter.

Maybe the universe is polar and we're in the "matter" hemisphere.


Now there's an insight that deserves more investigation.  Just remember your mantra, "The map is not the territory,"  or if you prefer, "It's only a model."
 
2014-04-06 01:24:45 PM
What Einstein didn't realise is that the "m" in his famous equation only applies to regular electro-weak matter. The general form of the equation also takes into account the Higgs field and looks like this: E = mc^2 + hc^5 where h is the imaginary Higgs mass. Thus a single higgs boson produces 1000 gigatonne of energy and can only be tested in space for safety reasons. 

Proposed test firing project "hammertime" will use the LHC to generate a higgs boson which will be allowed to pass through the earth and the moon before hitting a red mercury tamper in orbit around the moon while at the far side of the moon to prevent the gravity waves from reaching earth. The red mercury will be superheated by the higgs particle's gravity wake and will degenerate into a supersymmetrical "quark soup" within which the continued existence of a higgs particle would be a Hawking-paradox (in laymans terms, a configuration of localised spacetime whose existance nature abhors). Thus the higgs particle ceases to exist instantaneously, which would normally be impossible but is the only possible resolution of the hawking-paradox.


This instantaneous degeneration causes gravity waves to be emitted in a donut-shaped pattern at super-optical speed, gathering with them all massive particles including for example space dust. Eventually as the donut travels outwards it slows to light speed when all the energy has been converted into inertia of the matter, but due to the Einstean-Rosen-Podolski paradox, matter slowing to light speed from a higher velocity must convert into energy. Thus the gravity wave donut explodes in a manner similar to that of a typical nuclear explosion but with many millions of times more power.
 
2014-04-06 06:16:51 PM
That is the equivalent of more than 40 megatons of TNT. More practically, it is the amount of energy that would come out of a 1 gigawatt power plant, big enough to run 10 million homes for at least three years. A 100kg person, therefore, has enough energy locked up inside them to run that many homes for 300 years.

I prefer to have things explained in relation to Rhode Islands or Twinkies, thankyouverymuch.
 
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