Do celestial objects experience drag from the near vacuum of space?

For instance do the planets around the sun experience drag from the near vacuum of space? Or do the (hydrogen) atoms in interplanetary have a mean velocity near orbital speeds? And if so would (small) celestial objects orbiting the sun in the opposite direction (not sure if these would all me comets, or also might be asteroids) experience a significant drag?

When searching for whether if this question has been asked before I also found this question in which the best answer also mentions gravitational waves. Would combining drag and gravitational waves significantly increase the dissipation of the orbital energy, compared to just gravitational waves? And would this mean that every orbit would eventually collide?

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Hmmm... I think you didn't notice that orbital decay caused by gravitational waves is very very negligible that the planet is barely disturbed until the end of whole universe ;-) –  Waffle's Crazy Peanut Jul 8 '13 at 15:45
@CrazyBuddy, I mentioned it so someone might be able to compare it with the possible drag. –  fibonatic Jul 8 '13 at 15:53
But doesn't radiation pressure (and solar wind) from the sun scales proportionally to $r^{-2}$, just like gravity and therefore give the sun an effective lower gravitational parameter? –  fibonatic Jul 8 '13 at 15:51
Not sure what you mean by that - yes, both effects scale as $r^{-2}$, but the solar wind has a variable intensity depending on solar activity and photon pressure is subject to shadows - a solar sail sitting in the shadow of the Earth wouldn't work very well... so putting them in as a correction to the gravitational potential is at best a very crude approximation. –  Kyle Jul 8 '13 at 16:52