Photons definitely are affected by gravity.barbzilla said:It isn't that outlandish. Photons are particles and yet they are not affected by gravity, this is primarily due to the higgs field though (at least that is what we believe, it is still being tested further). To get the best idea of how something would act without gravity, imagine that object as pure energy and you will have a fair understanding of the forces at work.K12 said:The idea of something having no gravity is so outside the way that the universe works that we can only really guess at how an object with "zero gravity" or "anti-gravity" would work at all. Inertia isn't a force... but then neither is gravity. Statements that are informative but technically inaccurate can be very useful sometimes.fisheries said:That would probably because there isn't an "inertial force", inertia is momentum.K12 said:Inertial force wouldn't keep you on the Earth if it was possible to suddenly switch off the effects of gravity for some object because forces act in a straight line. So yes you'd keep travelling at the horizontal speed you were already travelling due to the rotation of the Earth but.
Probably, if not for drag. If negating gravity removes the concept of mass entirely, rather than making one neutrally bouyant, they'd move away, and at speed. But then the object would have to be both not subject to gravity, and the surrounds would have to be to have bouyancy. Which isn't exactly realistic either.It wouldn't be the same as suddenly shooting up into the air, instead you'd gradually drift upwards you continue off at a tangent to the Earth's motion, essentially the Earth would have rotated out from under you. I'd expect the local effects of wind and friction to make a big difference to this though so it's hard to say... and you almost certainly couldn't make something that's anti-gravity anyway.
If only everything was a spherical object in a vaccuum not subject to gravity!
That is what makes gravitational lensing.
And while photons don't have rest-mass, they definitely have energy, which thanks to Einstein we know is equivalent with mass (E=M*C^2).
So because Photons have energy, and momentum, they are affected by gravity.