The aliens watched earth for a long time. Then they decided that it would be good to reveal themselves. But they needed to make it so they could trade with humans and share technology. The aliens are nice so wanted this to be fair for both parties. They of course have no use for money based on paper with pictures of dead rulers. The best form of money for aliens is based on the universal laws of math and code…and with provable work based on the laws of energy and it’s value in the universe. So they sent an alien down to earth. He pretended to be Satoshi. And gave us Bitcoin. Free. Open source. Fair. Based on math, code and energy. Once it realizes it’s potential as global money we will be ready to trade. And the aliens will come down and introduce themselves.