I just can’t put my head around the fact that gravity isn’t just a force
EDIT : I now get how it gets stretched and how it’s comparable to putting a ball on a stretchy piece of fabric and everything but why is *gravity* comparable to that. I guess my new question is what is gravity ? 🙂 and how can weight affect it ?
In: Physics
>I guess my new question is what is gravity ? 🙂 and how can weight affect it ?
I’ll be honest here. While it’s possible to explain how gravity is a curve in spacetime by illustrating it as a ball on elastic fabric, you’re venturing into stuff that *can’t* be explained like you’re five because even modern day scientists aren’t sure of this stuff.
I am not a scientist or a physicist by any means, but I have a very (*very*) basic understanding of some of this stuff, so I will try to explain it in as simplified terms as I can, understanding that some of this may be over-simplified or factually inaccurate as a result. Some stuff can only be simplified so much.
Gravity is a curve in spacetime caused by the presence of mass. Objects with mass are essentially “accelerating” through spacetime. That’s why you’re pinned to Earth right now. Earth is accelerating through spacetime at a steady rate of 9.8m/s^2 and it’s essentially ‘pushing’ you along with it.
If you jump off of a building, you leave Earth’s frame of reference. You’re no longer accelerating through spacetime, but Earth still is, so you’re going to be there when it catches up and slams into you. Now, you’ll eventually reach terminal velocity if the building is tall enough, because as Earth accelerates through spacetime it’s pushing a big buffer of air in front of it, which is going to accelerate you in the same direction as Earth a little bit, though not fast enough to prevent the eventual impact.
We perceive and categorize that acceleration through spacetime as *gravity.*
To try and explain time dilation…spacetime is just that. It is space *and* time. When you move through one, you move through the other. Velocity (V) is a function of Distance (D) over Time (T). It can be written as V = D/T. For example, if D = 1 mile and T = 1 hour, then V = 1 mile per hour.
If you’re moving quickly relative to another person, then any action you take is going to be spread out across more spacetime relative to the other person. Since (D)istance in this case is static (the distance you moved relative to the other person), then when you alter (V)elocity, (T)ime *has* to change in order to keep the equation balanced. In essence, because you’re traversing spacetime faster than the other person, any action you take will be spread across more spacetime, which is perceived as time “passing more slowly” for you.
Taking what I said earlier about gravity being mass accelerating through spacetime, the reason gravity affects time is because an object in a gravity well is *traversing spacetime* at a different rate than objects outside of a gravity well.
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