According to the Kardashev scale humanity is only rates .72 (with 1.0 being a civilization cable of harnessing all power from its planet). We are about 3 or 4 hundred years from that. So we are quite far from running out of resources since we have not yet begun to utilize them all. Also that doesn’t take in to account the possibility of using off-world resources to sustain us, the sun for example- much of its energy is filtered out by our atmosphere but the Moon has almost no atmosphere and would be a great place to put massive solar collectors that could power cities on earth. Admittedly we are quite far from achieving that but in only 60 years we’ve gone from launching fruit flies on V2 rockets, to building space stations and sending probes to other planets. Really we are just a few advancements away from being in a position to utilize the resources of our star system. This just gives us an excuse to go out there and do it.
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