Ik this might be a difficult one but I genuinely want to wrap my head around this
In: 9
Space and time are one and the same thing, or at least they’re so entwined that what affects kne also affects the other. Gravity isn’t so much a force as it’s the warping effect mass has on spacetime. The stronger the gravity, the more spacetime is warped, and thus the slower time passes.
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Imagine you have a really big clock and a really small clock. The big clock is heavy and the small clock is light. If you drop the big clock, it will fall to the ground faster than the small clock because it is heavier and has more gravity. This means that time will pass more quickly for the big clock than it will for the small clock.
There’s not really a “how” here. It just is the case.
One way to understand it is that (general) relativity is based on two ideas:
* The speed of light is always constant: everyone in the Universe observes light to be traveling at a constant speed everywhere in the Universe.
* Gravity warps space, changing the lengths of lines.
Since the speed of light is a constant, and the speed of light is (the distance light travels) / (the time it takes for light to travel that far), a change in distance must also imply a change in time. So if gravity warps space to change the lengths of lines, it must also warp time and change the lengths of durations.
Newton’s first law states an object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force.
But on Earth, we see objects seemingly start to move downwards spontaneously. So to explain that, we said there’s an attractive force called gravity that everything with mass has.
Einstein said, actually it’s not a force. So Newton’s first law was wrong? Nope. Einstein says things with mass simply bend space itself. So an object going in straight line only looks like it’s curving because space is curved. Like how a straight line on a globe looks curved when you flatten it out to a map.
But then why do objects that aren’t moving start moving? Well, an object at rest is simply an object moving in a straight line *through time*. Mass doesn’t just curve space, it curves space*time*.
By explaining gravity as a curvature in spacetime, Einstein can explain everything we see in real life without actually having any actual forces get involved.
I will try to explain this the best I can
Space=Time
No space means no time. If there’s nothing there, then time cannot act on it, since time is things moving forward.
Now gravity can affect space, therefore it can bend time if it is strong enough.
Think of a road, and cars move on the road. The road is space.
The cars moving on the road is time. Cars will always move from point a to point b.
Now there’s a bend in the road. The bend is caused by gravity.
The car will still move from point a to point b, but the bend will increase the time it takes for the things to move.
Imagine a pool table that’s tilted slightly. There’s a second one that’s flat.
On the flat table, I can roll a ball from one side and hit some spot on the opposite edge of the table. It takes a straight path and, besides changing the speed in which I roll the ball, the straight path is the fastest path.
Now on the tilted table, I attempt the same thing: rolling the ball straight towards the specific spot on the opposite edge. This time, the tilt causes the ball to arch to the left side – this is like gravity accelerating a particle. Now, I can still make the ball hit the same spot, but I have to have it travel away from the direction of the lean so it arches back down to hit the spot.
Now let’s make a special rule: the ball always travels the same speed; it doesn’t slow down or speed up according to the slope of the table. Since the ball travels in an arch instead of a straight path, this interaction from one side of the table to the other *takes longer* than the flat table “gravity-less” interaction.
This analogy works based on different tilt orientations (compare the ball rolling one direction versus the other) as well as the table under acceleration instead of a tilt.
note that time is affected by gravity in a very slight manner. In general, time passes more slowly in a region of higher gravity than it does in a region of lower gravity. This is known as the gravitational time dilation effect and has been experimentally verified. According to Einstein’s theory of relativity, time passes more slowly near a massive object such as a black hole. This is because the curvature of space-time caused by the object’s gravity affects the path that light takes and thus alters the flow of time.
Easiest way to put it is, imagine space as a grid of squares all throughout, like a math notebook, but in 3d. With all perfectly straight lines.
When an object has mass, its existence in space curves those lines and twists them, making them longer and not straight anymore. And since the shortest path from point A to point B is a straight line, any curvature of those lines makes for a longer trip. And the more mass an object has, the bigger the curvature of the lines, and bigger effect it has.
But those lines arent only space, they are spacetime. Affecting both space and time. So if the line is longer, you will travel further and it will take you longer time to go from A to B.
So to put simply, gravity is the property of mass to curve spacetime.
If this makes you feel better OP, the linkage between gravity and time will ensure that your mother will never age!
<insert fire emoji>
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