Jump to content


Photo
- - - - -

How in the world did Einstein come up with E=mc2


  • Please log in to reply
13 replies to this topic

#1 GeminiinimeG

GeminiinimeG

    Meson

  • Senior Members
  • 81 posts
  • LocationCalifornia

Posted 6 September 2005 - 05:53 PM

:D Ok I have a question, Just like the title says how in the world did einstein come out with his theory??? Its not like you wake up one day and say well the speed of light must be this and the total ammount of energy in a given ammount of mass is this. HOw did he do it :D
  • 0

#2 insane_alien

insane_alien

    Genius

  • Senior Members
  • 10,094 posts
  • LocationScotland

Posted 6 September 2005 - 06:53 PM

by many, many derivations and hardwork
  • 0
Tired of waiting around for a reply on the forums? Use IRC, 'I don't know how' is no longer an excuse.

"Special" Relativity, stupid ideas seem smarter when they come at you really fast.

#3 GeminiinimeG

GeminiinimeG

    Meson

  • Senior Members
  • 81 posts
  • LocationCalifornia

Posted 6 September 2005 - 07:01 PM

It seems rather amazing that a human being possessed such knowledge :confused:
I hope i can one day surpass that ammount of brain power :cool:
  • 0

#4 swansont

swansont

    Shaken, not stirred

  • Moderators
  • 27,894 posts
  • LocationWashington DC region

Posted 6 September 2005 - 08:05 PM

Einstein observed that c is invariant in electrodynamics - for the wave equation to work in Maxwell's equations, the wave speed must always be c in any coordinate system - and applied that to mechanical systems by looking at the ramifications of this on coordinate-space and time. His seminal paper is entitled "On the Electrodynamics of Moving Bodies"
  • 0

#5 Bettina

Bettina

    Organism

  • Senior Members
  • 1,401 posts
  • LocationNortheast USA

Posted 6 September 2005 - 08:48 PM

by many, many derivations and hardwork


I go with this theory too. Almost like natural selection. I liken it to looking up and seeing a cessna fly by. It looks so simple. So much so, that a teen can fly it.

However, when the Wright brothers were trying to make one fly, they didn't know what a plane should look like or even how to put one together. Where did the wing go, birds don't have vertical fins or rudders. Did it need a forward or rear stabilizer. How do you turn it, etc etc.

They just kept trying different methods and when one worked, they kept adding to it. Dang, all the fun stuff has already been invented.

Bettina
  • 0

#6 bascule

bascule

    Genius

  • Validating
  • 8,433 posts
  • LocationThe center of the universe (from my frame of reference)

Posted 6 September 2005 - 09:09 PM

Ok I have a question, Just like the title says how in the world did einstein come out with his theory???


He seemed very well read on the latest papers being published by top physicists of the time, and I guess he just saw how all of their results interconnected into a single theory.
  • 0

#7 Tom Mattson

Tom Mattson

    Molecule

  • Senior Members
  • 765 posts

Posted 6 September 2005 - 09:25 PM

Swansont's answer is the right one. At the turn of the (20th) century one of the big questions in physics was how to reconcile Newton's mechanics, Galileo's relativity, and Maxwell's electrodynamics.

Galilean relativity leaves the form of the equations Newtonian mechanics unchanged for all inertial frames, but not those of EM theory. Physicists were trying to decide between a number of options:

1.) Are Galileo and Newton correct, and Maxwell wrong?
2.) Are Galileo and Newton correct, and Maxwell correct only in a single preferred inertial frame?
3.) Are there two different correct theories of relativity, one that maintains the form of Newton's laws and another that maintains the form of Maxwell's equations?
4.) Are Newton and Galileo wrong, and Maxwell correct?
5.) Is Galileo wrong, and Newton and Maxwell correct?

The experimental evidence in favor of Maxwell--especially in moving frames--did not warrant #1 or #2. #3 can be rejected out of hand once it is understood that electrodynamics really is the mechanics of charged particles, so the distinction between mechanics and EM theory is really just a matter of whether or not the moving bodies are charged. The experimental evidence of the day also did not warrant #4, since Newton's laws worked spectacularly well (violations of Newton's laws at the quantum level are not being considered here). So we were left with #5: Galilean relativity is just plain wrong.

This is the option that Einstein settled on. From there he postulated a new relativity, one that leaves Maxwell's electrodynamics invariant for all inertial frames. It turned out to force some changes on mechanics, but Newton's laws survived the revision. His view of space and time, however, did not.
  • 0
Tom

#8 arkain101

arkain101

    Suspended

  • Banned
  • 101 posts

Posted 19 September 2005 - 03:20 AM

I beleive it also had alot to do with imagination.. He quoted about it alot.

If you can think so far out of the box that you seem insane you can learn somthing no one would ever taken the chance to do so. Isnt that kind of the history of our geniouses? They were all so shamed for thinking "this madness".
I know using my imagination It gets stronger and stronger and better as you use that part of the brain and inventions arise and out of all the wacky ideas something can hits once and awhile.

#9 Maioux

Maioux

    Quark

  • Members
  • 25 posts

Posted 20 September 2005 - 11:48 PM

Rumor has it that Einstein alone did not come up with his theories, but it was he and 2 others. He took their theories are his own and submitted them. Unsure on how true that is, but I don't doubt it.
  • 0

#10 starbug1

starbug1

    Molecule

  • Senior Members
  • 493 posts

Posted 20 September 2005 - 11:53 PM

The think about geniuses is that those who aren't geniuses can never grasp what it would really be like. Ok, maybe you can give me the facts and quote me a thing or two, but that doesn't mean you really know. Of course, Einstein wrote down all of his work, but it really is fascinating to know the potential of the human mind. Either that or Einstein stole the E=mc2 idea from the patent office. :D
  • 0
----

Will: Hello. My name is Will, and I'm a Wikipediholic.
Group: Hi Will.


----

#11 Severian

Severian

    Scientist

  • Senior Members
  • 4,077 posts

Posted 21 September 2005 - 12:05 AM

I don't think Special Relativity was really that much of a leap. In fact, I think einstein gets a bit too much of the credit.

Remember that Maxwell wrote down his theory of electromagnetism in 1864, roughly 50 years before SR, but amazingly Mawell's equations are relativistically invariant. Lorentz noticed this (in 1903 I think, though how it took that long I have no idea) and came up with the Lorentz transformation. So Lorentz transformations (boosts etc) were around before Einstein even came on the scene. Einstein 'only' gave the Lorentz transformation a solid physical base by combining it with the results of the Michelson-Morely experiment.
  • 0

#12 CPL.Luke

CPL.Luke

    Primate

  • Senior Members
  • 1,669 posts
  • Locationamerican idiot

Posted 21 September 2005 - 12:37 AM

didn't lorentz create the lorentz contraction just to try and make the ether work?

I remember being told that he created the lorentz contraction in order to say that the wavelength of the light had been compressed just enough in the direction of the earths motion (michelson morley) in order to make it impossible to measure the velocity of the ether. He reportedly had commented on it that it was a rather ad hoc fix in order to maintain the idea of the ether.
  • 0
if you're ever driving at 49000 miles per second, for the love of god remember that green means stop.

#13 Saint

Saint

    Meson

  • Senior Members
  • 88 posts

Posted 21 September 2005 - 02:32 AM

I don't think Special Relativity was really that much of a leap. In fact, I think einstein gets a bit too much of the credit.

Remember that Maxwell wrote down his theory of electromagnetism in 1864, roughly 50 years before SR, but amazingly Mawell's equations are relativistically invariant. Lorentz noticed this (in 1903 I think, though how it took that long I have no idea) and came up with the Lorentz transformation. So Lorentz transformations (boosts etc) were around before Einstein even came on the scene. Einstein 'only' gave the Lorentz transformation a solid physical base by combining it with the results of the Michelson-Morely experiment.


Didn't Lorentz actually disagree with Einstein? I thought I had read that he never intended his transformation to be applied as Einstein did. I don't think he ever bought into relativity. That's what I read at least.
  • 0

#14 Severian

Severian

    Scientist

  • Senior Members
  • 4,077 posts

Posted 21 September 2005 - 09:28 AM

Yes, Lorentz never had any physical principle behind his transformation. It was just an observation of a symmetry in the Maxwell equations which seemed to fix the MM experiment. It took einstein to see the true physics.

Nevertheless, E=mc2 is part of the Lorentz transformation, so it wasn't really Einstein's.
  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users