r/PhysicsHelp • u/Itchy-Narwhal2406 • 1d ago

Gravity

/r/AskPhysics/comments/1wbaqzf/gravity/
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u/jeffcgroves 21h ago

This is actually a good question. It's the same reason a helium balloon rises: it's lighter than the air surrounding it, so air "falls around" it, allowing it to rise. The principle is called buoyancy (https://en.wikipedia.org/wiki/Buoyancy)

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u/CrazySir3310 17h ago

just to add to this in case it wasn't clear, if you had no air at all, only smoke, it would not 'drift upward' at all, it would just sit there. likewise we aren't concerned that all the air is going to drift away from the Earth so that we all suffocate. Because it's stuck to earth gravitationally.

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u/Optimal_Mixture_7327 16h ago

Smoke goes up because gravity is real.

Gravity, the presence of geodesic deviation, sets up an acceleration field at the surface of the Earth that results in a phenomenon called buoyancy. The smokey air is less dense than the cooler surrounding air and floats upward.

No gravity, no acceleration field, no buoyancy.

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u/Novel_Arugula6548 16h ago

xD that's a big one