Theoretically speaking(based on my own understanding :<), it might be because O3 or ozone forms a thick layer thus make the earth look round or what, at the same time several gases are pushing up on the ozone to maintain its shape.
In religion, you can believe on anybody thinks of whatever the reason why the earth is fucking round.
Was that tl;dr nuff?
And because I was ninja'd within just 4 minutes, Ok, it's a red fruit that symbolizes modern gadgets that will be just a remote control of the future.
How can you earn money within 1 minute?