https://www.youtube.com/watch?v=D-v_K1k8Se0&feature=share

I had a looooooooong discussion with one of my friends today... for some reason he could not grasp this concept... maybe I explained it to him wrong... be that as it may... I don't think I can do it any better... Hope the remarks help someone, along with the clip...

Everything is ACTION-REACTION.... there is no ACTION WITHOUT AN EQUAL AND OPPOSITE REACTION.
A boat/submarine/fish/man can swim in water because of the resistance the water(fluid-liquid medium) gives him(buoyancy/density are intrinsic)...
A bird/bee can fly because of the resistance the fluid(a gas in this example) know as air offers to the bird's beating wing... On the same principle the planes(jet or blades) and helicopters can fly, or the rockets... the air(fluid) around them offer enough resistance that the objects can propel themselves on the resisting fluid in which they are immersed and surpass the density deficit and 'fly' trough the fluid...
Now... what do you think will happen with the bird if you put it in a PERPETUAL (next to) ZERO pressure chamber - a VOID chamber a.k.a. a VACUUM chamber? Can the bird still fly? How about the plane? how about the jet plane? How about the helicopter? Can any of those still fly without a fluid environment and a fluid's resistance? What will happen to the buoyancy? Will it rise or will it drop to zero? And now the BIG question... WHAT WILL ROCKETS DO? Will they still be able to move? Are they gonna break the ACTION-REACTION laws of physics? How will they be able to move in a perpetual Void of interplanetary space? WHAT WILL OPPOSE THEIR ACTION so that they can move??? WHAT?!?!?!?!?!

Clarification:
Negative Pressure - a fancy word for the difference between two environments with different pressures, in which, the environment with lower pressure is considered 'negative pressure'.
VOID - is the TRUE ZERO PRESSURE SYSTEM ENVIRONMENT - there can be nothing lower than ZERO... just like ZERO DEGREES KELVIN... be mindful of that. (ZERO atoms and molecules of fluid)
VACUUM - the Vacuum is, ACTUALLY, THE EFFECT of the VOID... the ZERO PRESSURE ENVIRONMENT(theoretical or practical)
A technical detail - the pressure Travels from Higher to Lower pressure environments in an attempt to equalize and balance the difference of pressure. So, in essence, it is not that the VOID, actively, sucks the pressure out of any system in open contact, but the higher pressure system(gaseous fluids in this example) will rush to fill the whole VOID space(infinite space), giving the appearance of a VACUUM EFFECT. The VOID stays unchanged. And if the SPACE is INFINITE so must be the nature and potential of the Void(with it's Vacuum like effect) - to remain infinitely VOID regardless of any quantity of fluids anyone would put into it.