let's assume that either dark matter or something like that existed, and that it repels the matter that we are made up of (think opposite of magnets: instead of North repels North/South attracts north, matter attracts matter and antimatter repels matter)

assuming that we could obtain antimatter could we possibly stuff an amount of antimatter into a ship or something that is equal to the mass of the ship and it's contents, therefore making it have a total mass that is negligible? that would mean that this ship would be able to leave the earth's gravitational field with only air resistance.

 

however, the antimatter would also repel the ship and it's cargo, either making the cargo almost weightless if it was placed below the ship, but doubling the weight of the cargo if the antimatter was placed on top of the ship. most likely the antimatter would have to be situated on the topside of the ship otherwise the ship would have a strong tendency to flip upside-down. a plus of the antimatter on top is that when the ship is in space the antimatter would act as a passive artificial gravity field.

 

thoughts?

Sounds more like you need exotic matter, that is matter that violates the energy conditions found in general relativity (there are a few related but different forms of energy relations). In particular sounds like you need negative gravitational mass.

yeah, pretty much.

however, the antimatter would also repel the ship and it's cargo, either making the cargo almost weightless if it was placed below the ship, but doubling the weight of the cargo if the antimatter was placed on top of the ship. most likely the antimatter would have to be situated on the topside of the ship otherwise the ship would have a strong tendency to flip upside-down. a plus of the antimatter on top is that when the ship is in space the antimatter would act as a passive artificial gravity field.

 

Well, antimatter wouldn't do this, as was said exotic matter might do it. However, this part wouldn't work anyways, no more than you can pick yourself up by holding real tightly to yourself. If the stuff is attached to your ship, then you are canceling any forces that it applies on your ship. It could still act on Earth, however, and if you are using gravitation, the interaction with Earth would be much much stronger.