Where does the gravity go?

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.

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.

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!

They are proportional, therefore pure energy has mass. The amount of pure energy multiplied by the constant of proportionality (c²) is the amount of mass.

Same way the light from the sun radiates through space. It's all just photons.

Yes. A photon has mass, but not for that reason. It has energy and therefore mass. It has no rest mass (a term that most physicists dislike); if a photon were not moving (although a non-miving photon is fundamentally meaningless) it would be massless.Only things with rest mass experience the increase of mass with increasing speed. Pertaining to my original reply, assuming that "mass is converted to energy" means something (which it may not), the gravity continues to exist. The "shape" of the gravitational field may change if the energy is distributed differently in space than the original mass was.

Yes. When you expose liquid water to space two things happen. It starts evaporating like crazy and it radiates heat (photons at wavelengths we don't see with our eyes).All objects in all environments radiate heat, and things that are hot enough radiate a noticable amount in the narrow frequency range that our eyes see ... "red hot" and "white hot" come to mind. Hotter objects radiate more energy. All objects in all environment also receive radiant heat (photons) from the environment. The net effect depends on which way the most energy is moving.On Earth heat is also carried by conduction (heat moving through solids) and convection (liquids or plastic solids moving and carrying heat along with it). This doesn't happen in space (but see below).So the heat transfer equation for our water in space is:total heat loss = radiation loss - radiation gain - 0 (conduction) - 0 (convection).Since radiation loss is much bigger than radiation gain, the total heat loss is big. Between the evaporation and the radiation, you quickly get small pieces of ice. Which continue to evaporate and radiate, but the evaporation is slower and the effects of the radiation aren't as noticable (and the amount of radiation is smaller 'cause it's colder).There's another interesting effect that speeds the process up. Evaporation is just molecules flying out of a solid because they happened to have enough kinetic energy to escape and are at or near the surface. Temperature is the measure of the average kinetic energy of the atoms ... therefore the ones that escape are hotter than the ones which remain, on the average. So, the evaporation produces significant cooling (as evaporation does on Earth) which could be called convection.