How is E=mc^2 connected to the speed of light?

  • Thread starter Thread starter DeadCat_86
  • Start date Start date
DeadCat_86
Messages
2
Reaction score
0
In the mass-energy equivalent equation, E=mc^2, why is it related to the speed of light?
 
Physics news on Phys.org
That is the formula for rest energy predicted by Special Relativity.

From the postulates of SR (Invariance of c, physical laws are the same in all inertial frames) one can derive the equations describing energy:
E_{tot}=\gamma mc^2
E_k=(\gamma -1)mc^2
which lead to the conclusion that a mass has a rest energy E_0=mc^2 which is called the mass-energy equivalence.

So the the short answer is that it follows from the postulates of SR.

For a more in depth description detailing how the equation is derived, see
http://en.wikipedia.org/wiki/Mass-energy_equivalence#Background
 
Merry Christmas!

DeadCat_86 said:
In the mass-energy equivalent equation, E=mc^2, why is it related to the speed of light?

He DeadCat_86! Have a bouncy Christmas! :smile:

e is energy, which is ML2/T2, while m is of course just M,

so the conversion factor must have dimensions of L2/T2, ie it has to be a velocity squared …

and c is the only non-arbitrary velocity for such a general equation! :wink:
 
  • Like
Likes zdroide


tiny-tim said:
He DeadCat_86! Have a bouncy Christmas! :smile:

e is energy, which is ML2/T2, while m is of course just M,

so the conversion factor must have dimensions of L2/T2, ie it has to be a velocity squared …

and c is the only non-arbitrary velocity for such a general equation! :wink:

Dimensional analysis saves the day yet again!
 

Thread 'Euclidean geometry and gravity'

I asked a question here, probably over 15 years ago on entanglement and I appreciated the thoughtful answers I received back then. The intervening years haven't made me any more knowledgeable in physics, so forgive my naïveté ! If a have a piece of paper in an area of high gravity, lets say near a black hole, and I draw a triangle on this paper and 'measure' the angles of the triangle, will they add to 180 degrees? How about if I'm looking at this paper outside of the (reasonable)...
View full post »

Thread 'Jackson: justification of the Poynting vector by GR'

The Poynting vector is a definition, that is supposed to represent the energy flow at each point. Unfortunately, the only observable effect caused by the Poynting vector is through the energy variation in a volume subject to an energy flux through its surface, that is, the Poynting theorem. As a curl could be added to the Poynting vector without changing the Poynting theorem, it can not be decided by EM only that this should be the actual flow of energy at each point. Feynman, commenting...
View full post »

Similar threads

I E=mc^2 and acceleration
Replies
26
Views
2K
I Deriving e=mc^2, how is it possible?
Replies
2
Views
1K
B Is E=mc² the Formula for the Speed of Light?
Replies
17
Views
2K
I Uncovering a Decent Proof of E=mc^2
Replies
14
Views
2K
B Photon Energy Without Rest Mass – How?
Replies
19
Views
2K
I Discover the Relationship Between Mass and Energy in Electromagnetic Fields
Replies
8
Views
2K
I Best Derivation of E=mc^2 - Fdx = V^2 dm
Replies
17
Views
2K
B How does hawking radiation escape a black hole?
Replies
11
Views
2K
I Does Special Relativity Affect Mass?
Replies
1
Views
1K
B What is m in Kinetic Energy? Relativistic mass or Rest mass?
2
Replies
55
Views
6K

Hot Threads

Recent Insights

Back
Top