# eli5: is gravity endless?

84 views
0

Will for examlle the earth always pull on us, even in Millions of years or will it get weaker over time

In: 3

Force due to gravity exists between all particles – however the pull is so small most of the time that we don’t notice it because..

The force is dependent on mass.

The earth is huge (compared to us), and has wayyyyy more mass, so we experience the pull of gravity.

The moon has less gravitational force than the earth as it has less mass than the earth. The sun has more pull as it has more mass…and so on.

So, the gravity we feel on earth will be constant unless the mass of the earth changes dramatically.

Honestly? We don’t know.

The current most popular theories say that gravity is constant, so Earth will pull on everyone just as much in the far future as it will now.

However, our current theories have a few problems. Some people are developing “modified gravity” theories where the Gravitational Constant or other properties can change over time.

But if you’re asking if Earth’s gravity will ever “wear out” or “get used up” then the answer is no. Gravity is intrinsic to mass (and energy). Black holes, the Sun, and the Earth are not using up their gravity to suck things in. If the gravity of Earth ever changes, it will be because the properties of the universe changed, not because it got used up.

For all practical purposes, it’s basically never ending. If we lose our ozone and all the oceans evaporate, we’d lose some mass which would decrease the gravity by a small margin. Honestly, the planet will be destroyed when our sun finally explodes, there will still be relatively the same amount of gravity right up to that point. We will be long dead before then though. The entire planet will be.

Gravity is a relatively weak force of each atom being attracted to other nearby atoms. The effect is amplified by having a lot of mass gathered together. Gravity itself obeys the inverse square law in that it’s effects are inversely proportional to the square of the distance between two objects. When you get far enough away, you’re still affected by gravity, but the effect is so small that it might as well not exist, or other nearby bodies gravity will be stronger, such as the gravity of the sun when you get far enough from earth, or the supermassive black hole in the center of our galaxy when you get far enough from the Sun.

Everything is relative, while you may be here on earth sitting down and browsing Reddit and not moving much, relative to the sun, you are orbiting at 67,000 miles per hour, and relative to the Galaxy, you’re orbiting almost 500k miles per hour, all held in place by gravity

You’re affected by many sources of gravity but you only really notice the closest, massive object’s (earth) gravity because the pull is so strong when you’re this close

Gravity will never run out as far as we know unless mass itself were to disappear.

u/notmyaccount012

Gravity is endless as far as we can tell. The most distant gravitational detection we have made was from a merger between two black holes that was 5 gigaparsecs away from Earth. The ripples in spacetime made this merger event had been traveling since the universe was half the age it is now.

Gravity would not get weaker with time because time **IS** gravity.

To be more specific, gravity is the result of spacetime warping. Our current best theory for space/time/gravity is Einstein’s Relativity and it demonstrates the space / time are not two different things, but the same thing. Explaining that is beyond an eli5, but it is born out by being the single best tested scientific theory in human history.