Re: If gravity bends light...
The speed of dark is obviously faster than the speed of light as you can demonstrate with a simple experiment:
Open your closet door. You can see light enter the closet, but dark moves so fast that you can't see it leave.
As for the heat question, Radiant heat is just another form of light, but shiftier, as it doesn't let us see it. Who knows what it's up to.
Conductive heat is just agitated matter. Some photons, usually from the shifty Radiant heat mentioned above, seek to keep matter agitated. Most respectable photons just move a little faster when they see agitated matter, they don't want to get involved.
Convective heat is just conductive heat trying to escape the gravity of the situation, therefore the same rules apply to it.
Sexual heat is the odd situation where intellect has shifted from between one set of limbs to between the other pair. This may cause passing photons to stop and stare, usually yelling "Get a Room!"
So, as you can see there is no easy answer to that question... Er, what was it again?