E=mc2

slipss · 23-11-2005 2:00am #1

Ehh if the awnser to this is too complicated its ok.

Ok I know a bit about this Energy=MassxSoL2 and I know how they relate to each other and all that stuff, but if SoL(speed of light) is really the speed of information, deos that mean its just the speed that we percieve things? or what?

So the question is "What deos the term 'the speed of information' mean in the equation?

Spear · 23-11-2005 11:31am

slipss wrote:

Ehh if the awnser to this is too complicated its ok.

Ok I know a bit about this Energy=MassxSoL2 and I know how they relate to each other and all that stuff, but if SoL(speed of light) is really the speed of information, deos that mean its just the speed that we percieve things? or what?

So the question is "What deos the term 'the speed of information' mean in the equation?

The speed of light and the speed of information aren't the same. Special relativity states that information cannot propogate faster that light as it violates causality. The speed of information does not appear in the equation, nor can it be substituted in.

ApeXaviour · 23-11-2005 12:29pm

slipss wrote:

deos that mean its just the speed that we percieve things?

I'd say perception is more a biological concept what with neurons, chemical/electrical transmitters in the brain and the processing of information. Very little to do with c really. Spear did a good job at explaining the difference between the mass energy equation and the speed of information imo.

Spear · 23-11-2005 1:07pm

ApeXaviour wrote:

I'd say perception is more a biological concept what with neurons, chemical/electrical transmitters in the brain and the processing of information. Very little to do with c really. Spear did a good job at explaining the difference between the mass energy equation and the speed of information imo.

Then it's the best use I've gotten from my degree to date.

ApeXaviour · 23-11-2005 2:34pm

Spear wrote:

Then it's the best use I've gotten from my degree to date.

Physics degree?

Or TP/Maths?

I'da thought with any of the above you'd be laughing no?

Spear · 23-11-2005 2:46pm

ApeXaviour wrote:

Physics degree?

Or TP/Maths?

I'da thought with any of the above you'd be laughing no?

BSci in Physics with Nuclear Astrophysics. Though only barely passed.

Son Goku · 24-11-2005 2:35pm

slipss wrote:

Ehh if the awnser to this is too complicated its ok.

Ok I know a bit about this Energy=MassxSoL2 and I know how they relate to each other and all that stuff, but if SoL(speed of light) is really the speed of information, deos that mean its just the speed that we percieve things? or what?

So the question is "What deos the term 'the speed of information' mean in the equation?

"c" appears here because human units occasionally need to be adjusted to suit each other.
In correct relativistic units the equation is E = M.

bazpaul · 09-12-2005 12:29am

Interesting reasoning, energy is simply mass and vice versa, not a fact everyone knows either

Son Goku · 09-12-2005 5:00pm

bazpaul wrote:

Interesting reasoning, energy is simply mass and vice versa, not a fact everyone knows either

A giant emphasis must be made though.

Energy and Mass are equivalent, not Energy and Matter.

Civilian_Target · 09-12-2005 5:30pm

slipss wrote:

So the question is "What deos the term 'the speed of information' mean in the equation?

Speed of information is a bit misleading - information has no speed - Quantum mechanics defines that information can be gathered on faraway objects instantaenously.

The c in E = mc² is for the speed of electromagnetic wave propogation and is the fastest speed at which any wave can propogate. Mass can never reach this speed, only get infinitely close.

Panserborn · 09-12-2005 6:28pm

Son Goku wrote:

Energy and Mass are equivalent, not Energy and Matter.

Oof, thats a head-wreacker for people like me with an interest in physics but no formal education in it

. In simple terms, whats the difference between mass and matter?

09-12-2005 6:33pm

Mass is an internal property of matter.

Son Goku · 09-12-2005 9:53pm

Panserborn wrote:

Oof, thats a head-wreacker for people like me with an interest in physics but no formal education in it . In simple terms, whats the difference between mass and matter?

Matter is literally just stuff.

Mass however is a property of stuff. It's basically what gravity acts on, so if you have no mass gravity doesn't effect you.

So Matter has Mass.

ApeXaviour · 10-12-2005 1:41pm

A good fundamental example to help you wrap your head around it. A proton and electron are both examples of subatomic particles (matter) but one has a whole lot more mass than the other. About 10^3 times

booth · 14-12-2005 10:30am

c is a constant, sufficiently large, to show that an incredible amount of energy is stored in everything no matter what it's mass (excuse the play on words).

e.g. a bag of sugar, i.e., 1Kg has a potential energy of 9 x 10^16 Joules

Spear · 14-12-2005 1:46pm

booth wrote:

c is a constant, sufficiently large, to show that an incredible amount of energy is stored in everything no matter what it's mass (excuse the play on words).

e.g. a bag of sugar, i.e., 1Kg has a potential energy of 9 x 10^16 Joules

C is the speed of light in a vacuum, it's not a conversion factor.

booth · 14-12-2005 2:07pm

Spear wrote:

C is the speed of light in a vacuum, it's not a conversion factor.

I didn't say it was a conversion factor, I called it a constant, which it is, but for the relativity theories it was important for Eintein to use this value (squared) to show that there is a huge amount of energy in any material object.

IMO the most important thing to take from E=mc^2 is that Energy and mass are linked. Mass is a huge potential energy store.

nesf · 14-12-2005 7:35pm

Calling it a constant is reasonable enough imho. Unclear perhaps but not a cardinal sin really.

nesf · 14-12-2005 7:38pm

booth wrote:

IMO the most important thing to take from E=mc^2 is that Energy and mass are linked. Mass is a huge potential energy store.

They aren't linked, they are one and the same. It's just a historical issue that makes people think that they are seperate tbh.

As Son Goku said above it's easier to see using relativistic units and writing E = M. It gets the message across easier. The c² part of the equation in SI units seems to confuse people as to the meaning sometimes.

The Free Man · 14-12-2005 7:55pm

nesf wrote:

They aren't linked, they are one and the same.

was just about to post that. spot on nesf..

matter is a form of energy

Spear · 14-12-2005 9:49pm

nesf wrote:

Calling it a constant is reasonable enough imho. Unclear perhaps but not a cardinal sin really.

True, but his wording seemed to suggest something more akin to a conversion factor, rather than a fundamental constant of the universe.

nesf · 14-12-2005 10:38pm

Spear wrote:

True, but his wording seemed to suggest something more akin to a conversion factor, rather than a fundamental constant of the universe.

I agree, I was just leaning towards it being a typo tbh.

booth · 15-12-2005 10:01am

Sorry lads, was just trying to keep it simple. I don't think it implies from the wording or otherwise that it is a conversion factor and now you know i meant it was a constant.
So can somebody tell me whether we will reach the speed of light at some stage to test out Einstein's theory or how close have we come to reaching it.

Spear · 15-12-2005 2:12pm

booth wrote:

So can somebody tell me whether we will reach the speed of light at some stage to test out Einstein's theory or how close have we come to reaching it.

Nothing with mass can reach the speed of light.

Son Goku · 15-12-2005 3:17pm

booth wrote:

Sorry lads, was just trying to keep it simple. I don't think it implies from the wording or otherwise that it is a conversion factor and now you know i meant it was a constant.
So can somebody tell me whether we will reach the speed of light at some stage to test out Einstein's theory or how close have we come to reaching it.

We've accelerated particles to 99.999999999% of the speed of light and they still obey Einstein's special relativistic equations.

As said above though, observational evidence shows that nothing can reach the speed of light from the point of view of another observer.

booth · 15-12-2005 4:23pm

I see. I just read that the equation E=mc^2 wasn't even in Einstein's original paper. It was added on in a later supplement. Mad.

How did he do it though? What a genius!

Son Goku · 15-12-2005 6:39pm

booth wrote:

I see. I just read that the equation E=mc^2 wasn't even in Einstein's original paper. It was added on in a later supplement. Mad.

How did he do it though? What a genius!

To see what a real genius he was, E = mc^2 and special relativity aren't even his "masterpiece"

He came up with Special Relativty in 1905.
He found E = mc^2 a month later.
Before this he had described Brownian motion (mathematical proof of atoms) and the photoelectric effect.

Then in 1915 he completed his true work, the work that probably earns him the place as the greatest physicist, General Relativity:

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booth · 16-12-2005 10:06am

Just been reading on this topic and about his field equations. Really amazing stuff. I love that analogy about the rubber sheet, bowling ball and golf ball.

Cool - loads to read!

Civilian_Target · 18-12-2005 1:53am

Yeah - second only to Quantum Mechanics as the most important discovery of the 20th century.

nesf · 18-12-2005 3:59pm

Civilian_Target wrote:

Yeah - second only to Quantum Mechanics as the most important discovery of the 20th century.

I'd have gone with DNA personally

Or are we talking about a single discovery here? If so, then it's Relativity. QM was a progression of discoveries rather than a single piece of work.

The Free Man · 18-12-2005 4:03pm

nesf wrote:

I'd have gone with DNA personally

Or are we talking about a single discovery here? If so, then it's Relativity. QM was a progression of discoveries rather than a single piece of work.

i know its off topic, but i think that systemic theory is the best discovery.

Civilian_Target · 18-12-2005 9:01pm

nesf wrote:

Or are we talking about a single discovery here? If so, then it's Relativity. QM was a progression of discoveries rather than a single piece of work.

Aye - but it all took place this century, mostly people that haven't been heard of outside Physics circles (Heisenberg, Schrodinger, Bell etc.). AFAIK DNA was also a series of discoveries - but without Quantum Mechanics there's certainly no hope it could ever have been done.

Interesting that Einstein could not accept QM to be true, so much so that he formulated a theory against it.

E=mc2

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