By the time a near earth orbit asteroid came by the earth in 2029 its orbit was adjusted and in 2036 it missed the moon as well.
By 2040 almost 10 billion wizards have gone to the various star systems, leaving only 1 billion people on the earth.
Potter and Longbottem Nurseries have bought land in every country of the world. Even the Sahara Desert gets converted to greenhouse growing the Magicsl Marijuana. The drug cartels are swallowed up by the P & L Securities to guard the nurseries.
Earth being the only planet the the magical marijuana will grow on with the possible exception of the Moon with greenhouse built underground and greenhouses built all over the surface of mars.
Mars get a terraform short cut by exporting the CO2 in Venus atmosphere and teleporting it to mars. In time even Venus is also terraformed.
Soon they are exporting the MM product from P Nurseries across the galaxies.
A group of aliens come from out space using a outdated form of hyperspace technology and fly into the solar system. They notice cargo spaceship with the P Nuseries painted on the sides of them lining up next to controlled wormholes then entering them and going away at faster than light speed.
They have scanned Mars, Venus and Earth and have decided that these are garden planets growing crops and shipping it.
They decide to test out the crops, but 200 ship head there way and offer them free samples of the crop.
The alien invaders have an orgasmic experience from smoking the weed and then they pass out with ecstasy type dreams. By the time they have woken, several centuries have passed.
