[phkahler]

>> Conservation of momentum (force*time) means they both experience the same force.

That's right. I'm just saying it hasn't been confirmed. Wouldn't that be some exciting new physics though? It could explain why there isn't any around, why galaxies apparently aren't made of it, and why there is annihilation radiation sourced from the edge of galaxies. ;-)

[Georgelemental]

Violating conservation of momentum like that would allow generating arbitrarily large amounts of energy for free.

[phkahler]

Yes it would. Maybe that's what's accelerating the expansion of the universe ;-)