system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does mass have anything to do with gravity?

I was watching a Vsauce video and learned that any two objects, like two baseballs, are attracted to each other because of their mass, and the bigger the mass, the more gravity an object has. What does mass have to do with gravity, and what causes gravity? Why does something just attract other things around it?
gpt
imagine holding a big tissue paper loosely on all four corners but such that the tissue paper is flat. Then you put a blueberry in the middle. The tissue paper sinks slightly. Now you put a plum, and the tissue sinks more. Now an orange, and the tissue sinks even more.

Leave the orange there and put the blueberry just where the tissue starts to curve in. The blueberry rolls to the orange.

Enjoy your fruit while you read this part.

The tissue paper is called the spacetime fabric. It's in space and it's everywhere. Everytime you put something on that fabric, it distorts the fabric slightly and attracts things towards it, like how the blueberry rolls towards the orange. That is gravity or at least what the best theories explain it to be. Of course on earth the blueberry rolls because of earth's gravity. But you can imagine it in space where there is no gravity. You can substitute the orange and blueberry with the sun and earth, the colors are already there. 

The earth is only in orbit because of the sun's gravity. It is slowly pulling earth towards it only being held back by the forward momentum of the earth. ~~However, the sun is not pulling the earth towards itself because the sun is burning trillions of tons of gas every day and is therefore losing alot of mass~~, which brings me to next part. Things with less mass have less 'gravity' or a lower tendency to pull things towards it. 

You can use g=GM/r² to find how strong the gravitational field strength of an object is. G is a gravitational constant which doesn't change, m is mass and r is the radius of said object. So the higher the mass, the stronger the gravity.