Today, the fastest standard flight from Paris to Sydney requires one quick stop and takes about 22 hours. The SpaceLiner project by the German Aerospace Center hopes to cut that time considerably by launching a rocket with up to 50 passengers into the upper atmosphere and gliding down to the destination at 24 times the speed of sound. If successful, the total travel time would be 90 minutes. If it sounds ambitious, it is. The target launch for commercial use of the concept is 2050. That doesn’t diminish the potential that such technology could bring to a world that is still desperately separated…