.So the space station is orbiting in our planet I understand that it’s being pulled down and its current inclination of orbit at the same time to where it’s technically in constant free fall and I also understand that Newton’s first law is an object in motion will stay out motion until force is acted upon it. But when I think about gravity I can’t seem to understand how it pulls does gravity have a particle or a link to the object it’s pulling in some way?
In: Physics
It’s a mystery. On a large scale, gravity can be thought of as warping of space-time itself. That’s general relativity. But there are some inconsistenies between relativity and quantum mechanics, which governs the very small scale. A graviton is a hypothetical elementary particle that would mediate the force of gravity. Gravity is the only one of the four fundamental forces that doesn’t have a known elementary particle associated with it. This is basically what all the fuss is about in the search for a “grand unified theory”.
The space station is actually moving in a straight line. That line turns out to be a loop though because gravity bends space itself such that a straight line isn’t straight. That also explains how light can get bent by gravity in spite of having no rest mass. Because the space the light travels through is also bent (hence gravitational lensing which shouldn’t exist under Newtonian gravity).
We don’t really know how it works under really small scales though from what I remember as there is no solutions for what gravity does on a quantum level.
Gravity isn’t an emitted field or anything like that.
Think of it like this:
The universe is a giant sheet of cloth that is stretched tight.
Marbles rest on top of that cloth.
Bigger marbles cause indentations in the cloth, the heavier the marble the deeper and wider the indentation becomes.
When marbles start moving across the top of the cloth they will start rolling into indentations, some indentations are only deep enough to slightly change the trajectory of the marble but the bigger indentations will cause smaller, slower moving marbles to get trapped. These are gravity wells, as more marbles accumulate in each indentation they get deeper and deeper.
What we perceive as “gravity” is the mass of objects around us actually causing space to warp.
Imagine space as a trampoline. You put a marble in the middle of it, it doesn’t warp all that much. Now put a bowling ball in place of the marble and you get more warping. Then get crazy and put a boulder in the middle of it. That’s crazy amounts of warping.
That’s gravity in a nutshell. There’s no gravity particle or substance that needs to transmit gravity because it’s changing space itself.
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