Where does the gravity go?

I'm not sure if this is appropriate for Big Bang/Cosmology, so I'll let the moderators decide:Gravity is a property of mass and mass can be converted into energy. When this happens, where does the gravity go? Does it just stop? I'm trying to remember if this is part of the experiments regarding gravitational waves but my physics is fleeing from me and I don't quite know how to express is formally to go look it up.I'm thinking it does just go away, but I'm wondering if there is a better physicist than I am who would know for certain. Since gravity is so weak, I doubt it could be felt on any sort of common level, but I'm still curious.

Thread moved here from the Proposed New Topics forum.

well. gravitation is the acceleration of objects (b) along the bend created in space by other objects (a). remember that weird episode of the simpsons when homer turns comput0red and there's that big green grid? well when an object (a) sits upon that grid it weighs it down a bit and the grid dips under it. if an object (b) is passing by it will either be drawn into the dip or will at least alter it's course a bit due to the edge. but if an object (b) is moving fast enough, it's course alteration will be so slight it won't matter. but this alteration is always calculable... sometimes it just takes a while. mmm math.but. (back to the actual question). in order for the gravitation to affect an object (b), that object (b) has to have mass. if the mass disappears, then the object (b) will not be affected. the exception in this is of course light. light is energy, but it has the peculiar property of behaving like particles. weird light.but think about it. does heat bend? no. it radiates out from it's source and causes every particle it touches to become more excited.This message has been edited by brennakimi, 02-26-2005 12:30 AMThis message has been edited by brennakimi, 02-26-2005 12:32 AM

I bet Eta could explain this better than I ...Energy is mass is energy is mass. There's a point of view in which any distinction between energy and mass is an artifact of our inadequate senses, and e = mc² is not a mere equation (stating that two different things are quivalent) but rather an identity (saying that two apparently different things are really identical and indistinguishable).But, assuming that "converting mass to energy" does actually have some meaning, the gravity doesn't go away. The energy has the same gravity that the mass did.Many of us are familiar with the precession of Mercury's orbit and the fact that relativity accounts for it better than Newtonian mechanics. I've seen it stated that one way of looking at this is that the Sun's gravitational field contains energy and therefore generates a gravitational field, which in turn generates a gravitational field, which in turn ... and so on in an infinite but, thank goodness, converging series. This "extra" gravity causes the extra precession of Mercury's orbit. I really don't know if the math truly bears that out, but it's a heckuva story.

Way out of my depth here....but when a supernova pops, how much mass gets converted to energy? 10^51 ergs, do I recall, which is equivalent to 10^30 grams of stuff? Or is a lot of that gravitational potential energy getting converted to neutrinos, etc.?What I'm driving at is, whence come the gravitational waves that we're seeking when a supernova blows? From the "disappearence" of mass or from something more subtle, like what you're suggesting?

if you remember from GR the source of gravity is not just mass but the total of mass and energy as summarised by the stress energy tensor T(mu,nu).For instance a hot brick has a little more gravitational pull than a cold brick since its total mass + energy has increased from when it was cold.When a supernova goes bang a lot of energy goes into neutrinos which freely stream away taking energy (mass equivalent with them.) Note that only a small percentage of the star is converted to energy. 10^51 ergs is about 10^30 grams of mass equivalent. That is only about 1/2000 th of the mass of the Sun.

Geez, I know that I replied last night, but it seems to have vaporized.G-waves are caused by accelerating mass, analogous to electromagnetic waves caused by accelerating charge. Neutron stars orbiting their common center of mass, asymmetric fast-rotating supernova remnants, and what-not. Jillian's Guide to Gravitational Waves.

Is heat affected by gravity?

Radiational heat is energy, is therefore mass, and therefore has and is affected by gravity.Conduction and convection heat is energy added to material things, and therefore adds to their mass, gravity, and the effect of gravity on them.Don't bet on measuring it!

Heat has mass? I'll be a monkey's uncle.See, this is why creos, and most other folks, believe in the supernatural: it's almost as easy to believe my dead aunt made that vase fall over last night than it is to believe that heat has mass.Especially after watching Patrick Swayze do that thing with the penny in Ghost.

i thought energy and mass were proportional. thus wouldn't pure energy have no mass?*edit*
i'm going to leave this here because i just realized that i'm confused. but. as velocity approaches the speed of light, mass drops to zero... is this not a demonstration of energy?This message has been edited by brennakimi, 02-27-2005 23:19 AM

You are, indeed, confused. The intertial mass of an object goes up as it speeds up. To infinity (but not beyond) as it approaches the speed of light.

Remember that light is "bent" in a gravitational field.

If you take heat as infra red radiation (which it was used as somewhere else ) then yes for sure.Now if it isn't in the form of IR photons then it is less clear to me but I don't see how that conclusion can be avoided. E does, after all, equal mc**2.

Gravity is God's glue that holds his universe together.

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In Jehovah God's Universe; time, energy and boundless space had no beginning and will have no ending. The universe, by and through him, is, has always been and forever will be intelligently designed, changed and managed by his providence. buzsaw