I am going to give you the Newtonian version, which is good enough for most purposes, and easier to understand than the current theory. If you want to read up on this, you can start here, but I recommend just continuing reading this post for the moment.
Gravity is attraction to mass. It is proportional to mass, and inversely proportional to distance. Thus, a larger mass has a greater attraction than a smaller mass. The attraction is less the further apart the things are.
When you jump, the earth pulls you back, so you come back down. That is because it is very massive relative to you.
Gravity only pulls, it never pushes. It is not like magnetism in that way. Everything with mass exerts a pull on everything else with mass, though distance makes some things practically irrelevant to some other things.
There is no up or down to this. You think of up and down simply because you are (at least approximately) on the surface of something that is very massive relative to you. So "down" is toward the earth, and "up" is away from the earth. Notice, someone standing on the north pole and someone standing on the south pole would be pulled in "opposite" directions, because they are both attracted to the earth. There is no up or down to gravity per se, there is just attraction of mass to mass.
(Uncle K may either dispute some of this or give it his seal of approval. Listen to him.)
Gravity is attraction to mass. It is proportional to mass, and inversely proportional to distance. Thus, a larger mass has a greater attraction than a smaller mass. The attraction is less the further apart the things are.
When you jump, the earth pulls you back, so you come back down. That is because it is very massive relative to you.
Gravity only pulls, it never pushes. It is not like magnetism in that way. Everything with mass exerts a pull on everything else with mass, though distance makes some things practically irrelevant to some other things.
There is no up or down to this. You think of up and down simply because you are (at least approximately) on the surface of something that is very massive relative to you. So "down" is toward the earth, and "up" is away from the earth. Notice, someone standing on the north pole and someone standing on the south pole would be pulled in "opposite" directions, because they are both attracted to the earth. There is no up or down to gravity per se, there is just attraction of mass to mass.
(Uncle K may either dispute some of this or give it his seal of approval. Listen to him.)
"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.
