Does energy has gravitational force?

[abhiras]

does energy has gravitational force??

firstly sorry for bad english.
we all know that mass and energy are interconvertables...

does energy has gravitational force??

if not..
then what about law of conversation of mass-energy...
suppose there is mass M..and another mass m does |x| joules of work against gravitation force of M & came 2 rest...& now has a potential energy of |x| joules...
& by some means if we convert M to energy...is now potential energy which is directly proportional to M decreases...against law of conservation

 

[espen180]

In General Relativity, gravity is not a "real" force, but a fictitous force on the same level as the centrifugal force. Simply put, mass and energy both contribute to gravity, and even gravity itself contributes to gravity!

 

[rcgldr]

Well for one think, light doesn't react to gravity in the same way that objects with mass do. Light will bend in a gravitational field, but it won't change speed. An object with mass will change both speed and direction due to a gravitational field (except for a circular orbit).

 

[DaveC426913]

Well for one think, light doesn't react to gravity in the same way that objects with mass do. Light will bend in a gravitational field, but it won't change speed. An object with mass will change both speed and direction due to a gravitational field (except for a circular orbit).

Well, no. In the GR model of gravity, light and matter both behave exactly the same, changing neither speed nor direction through space-time - they both follow a stright line along the geodesic. It is our distorted view of spacetime that makes us perceive elliptical orbits as changing in curvature and speed.

 

[rcgldr]

Well, no. In the GR model of gravity, light and matter both behave exactly the same

From what I understand, there is no gravity field associated with the existence of photons, but objects with mass do coexist with gravity fields. Another issue is how light is affected with general relativity:

Although the bending of light can also be derived by extending the universality of free fall to light, the angle of deflection resulting from such calculations is only half the value given by general relativity.

http://en.wikipedia.org/wiki/General_relativity#Light_deflection_and_gravitational_time_delay

 

[DaveC426913]

From what I understand, there is no gravity field associated with the existence of photons, but objects with mass do coexist with gravity fields. Another issue is how light is affected with general relativity:

Although the bending of light can also be derived by extending the universality of free fall to light, the angle of deflection resulting from such calculations is only half the value given by general relativity.

Yes. Matter curves spacetime. Both photons and matter then follow the curvature of spacetime.

 

[Nabeshin]

From what I understand, there is no gravity field associated with the existence of photons

No. From a simple argument, we know photons carry energy and we know energy shows up in the Einstein equations. For more,
http://en.wikipedia.org/wiki/Electromagnetic_stress-energy_tensor

Also, it is quite trivial to "extend" GR from massive bodies moving in curved spacetime to non massive bodies. In your geodesic equation you simply use a null parametrization instead of a timelike one and the geodesics you get out are the correct ones for light rays (or any massless particle).

 

[cragar]

It makes sense that photons create a Gravitational field because if we had an electron and positron collision and they produced a photon, the G field from the e- and e+ would be transferred to the photon .

 

[cragar]

Is it possible that a gravitational field which has energy creates another G-field?

 

[K^2]

Not only possible, but necessary. That's why General Relativity is non-linear.

It makes sense that photons create a Gravitational field because if we had an electron and positron collision and they produced a photon, the G field from the e- and e+ would be transferred to the photon .

Non-sequitur. Electric field ceases to be, so why should you jump to a conclusion that G-field hangs around? And in fact, the G-field produced by the two (or more) photons resulting from e/p annihilation is very different from the G-field produced by electron and positron. More generally, the gravitational field of a particle depends on its energy AND rest mass. Electrons and positrons have rest mass. Photons do not. Different fields.

 

[cragar]

I figured you'd be the one to answer my question , but isn't energy conserved in the reaction and the energy is what creates the G-field , Can we ever destroy a G-field.