You need energy to produce a force that compensates gravity. So if you apply that force for a huge amount of time, will gravity ever be depleted?
In: 39
try to think of gravity less like a force pulling things and more like just the direction of ***momentum*** (we could talk about warping space-time but I feel like that doesn’t fit a ELI5 post)
when an object gets pushed/thrown/etc energy is imparted into it causing it to accelerate in a given direction, thanks to momentum as long as no other energy or force acts upon the object the object will continue moving at a set speed and in a set direction, but that direction ***curves*** rather than being a straight line, curving towards other objects of high mass, to change the direction an object is moving, to adjust it ***away*** from the direction of its momentum, costs energy
so for an aircraft to hover in place in the air it does cost energy even though it isn’t changing position or speed because it is pushing against its momentum, in a way it is *kind of* accelerating, just in the opposite direction of gravity by around the same amount, in order to compensate against where the object would otherwise naturally move if allowed to
basically gravity isn’t *spending energy* to pull things, it’s just momentum, an objects mass causing it to move in a direction as long as there is nothing else affecting its movement
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