Hello there physicists! Here are two questions I'd like you to answer please. If the population keeps increasing and if we keep building infrastructure, could the Earth's diameter decrease? In other words, could we crush the Earth like crushing a tin can in the palm of our hands? Surely the net mass of the Earth is constant; it's just that we have rearranged its minerals and ores into structures like buildings for our usage and they in fact both have the same mass. What about people? Do they add to the mass of the Earth or does a person's existence decrease another 'resource', so everything balances out? Does density matter? Is it possible to make something more dense and increase the mass of the Earth without decreasing something else in the process? ___________________________________________________________________________ If another planet slowly got closer to the Earth such that the Earth's atmosphere was touching the planet's atmosphere, would there be a reaction of some kind? Would heat be generated even if it moved at a rate of 1 cm per minute towards the Earth? Is is possible for the Earth's atmosphere to connect to the other planets atmosphere such that a symbiotic relationship could exist between both planets? Would both atmosphere mix together and produce a different kind of 'diluted' atmosphere shrouding both planets like adding orange juice to water? Thanks!