NOTE: I HAVE READ THE FAQ
Anyways, let's go back to the death of a star, long ago. If it is a big star (the example star is going to be a big one) it gets bigger and bigger and then BOOM! it explodes. Now of coarse stars are mainly hydrogen gas particles. The pieces of gas float around the universe for a while, possibly millions of years. Eventually, one of the pieces happens to collide with another particle. The particle can be dust, gas, or whatever just something. Now that they there are two, it has double the amount of gravity. Now that piece of dust/gas/whatever floats around more, collecting more gas/dust/whatever. Over time it gathers more and more particles, giving it more and more gravity. HOWEVER, usually when it is forming a piece will just break off, which collects it's own particles. BUT because the original piece is bigger, and because of gravity, it spins around the original. Now the original piece gets so huge and, when something becomes big enough, it creates it's own heat. That becomes our sun. All the broken off pieces become our planets, including the Earth. So as you can see, if gravity didn't exsist, the entire universe would be absolutly nothing.
And also, if you are going to leave some useless/annoying post, just get lost and ruin one of my other posts.