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
Not my area of expertise but I understand where your hangup is so I’m going to try and build off the examples already present.
Time, as a concept, is just a point of relativity. A second is the period of time it takes for the second hand to get from 1 tick to the next, for example. Everything that we experience as “time” is really just stuff in existence moving at whatever rate it does, and us creating some concept that we can understand it by. A “day” is a day because its how long it takes for the earth to spin in a complete circle and we’ve all agreed that we’re going use that as a standard unit of measurement.
More importantly for this, time is how long it takes for certain processes to occur. I.e; human’s bodies doing what they do.
Gravity is a “force” that is relative to the mass. So heavier objects exert more force against the universe around them. At the local scale, this force is so minute, so minor, so insignificant that it’s effectively not there, so we don’t see time dilation in our regular day.
But at a universal scale, there are countless objects in universe that are large enough to exert this force in a measurable way (black holes, planets, stars, galaxies themselves, etc). And when we start to escape and enter these forces, time gets dilated pretty dramatically.
So using the fabric example, as you move closer to a source of gravity, that “force” gets exerted more. The gravity ball is whereever it is and we’ve put a clock in it. Now, for that clock hand to tick that 1 second amount of distance, it has to have more power to it. So even though it’s only ticked “1 second” worth of distance, it took “2 seconds” worth of time.
On a larger scale, like space travel. As you move away from celestial bodies, time keeps going “normally” for you. You hang out in space, then you swing back to earth where everyone has been under the influence of earth and the moon and the sun and so forth. When you get there, for the 3 years you were out, for everyone else to hit that 3 year point, it took them 6 years worth of time to travel there because all the gravity was slowing them down. So you land back and whamobamo, your body has only done 3 years of cellular processes and their bodies did 6 years worth of cellular processes, and now you’re younger.
Gravity doesn’t impact *time* because time is just a concept we’ve all agreed upon. But it makes it so stuff has to do more work to get from point a to point b, and we interpret that “work” at the passage o time.
Latest Answers