# Einstein began looking for gravity in the electromagnetic waves

1. Jan 23, 2008

### asymmetric

I Read That Einstein Began Searching For An Explanation Of Gravity In The Em Waves....
I'm Not Aware That This Has Been Proven To Be Wrong.
I Only See That Em Has Been Related To The Weak Force..
Can Gravity Be Only After Em Waves Exist Or Does Gravity Exist At And Within The Weak And Strong Force Levels...

2. Jan 24, 2008

### Fredrik

Staff Emeritus
Why Are You Writing Like This? It's very annoying. I'm also not sure what you're asking.

Einstein didn't try to explain gravity in terms of electromagnetism. I'll leave it for someone else to explain what he actually did.

3. Jan 24, 2008

### Phymath

im not 100% sure but i think Einstein didn't try and explain gravity with em waves, but tried to make e&m a geometry rather then a field so that gravity and e&m could be one in the same

4. Jan 25, 2008

### haushofer

Maybe you are refering to the attempt of Kaluza and Klein to unify gravity and electromagnetism ?

According to general relativity, the gravity field is not just another classical ordinary field; it represents space-time geometry. So the theory is a lot more besides the Einstein equations. This is very different from electromagnetism; here the vector potential is described by Maxwell's equations, and this field lives in ( the cotangent space of ) space-time, but doesn't affect it according to the Maxwell equations. Kaluza and Klein tried the following: assume an extra dimension in space time, and use this degree of freedom to incorporate the vector potential in this 5-dimensional space-time metric. Calculate again the variation of the Hilbert action, and see what happens. With a right choice of incorporation, the Einstein-Maxwell equations appear.

What is also very peculiar about this, is that there are derivatives of the gravitational coupling "constant" pop up. This suggests that maybe this coupling is not a constant, but could be a scalar function.