Under classical mechanics, momentum must be conserved. In other words, to move the spaceship in one direction, it must throw some mass in the opposite direction. This is why rockets carry fuel - they move themselves by violently throwing hot gas away from themselves, generating thrust. » 8/01/14 11:39am 8/01/14 11:39am

My take is to take a phrase (preferably relatively long, say 10 words), and hash it, and then use the resulting hash as my password. The hash looks completely random (hold down the shift key for capitals and punctuation), and you can just hash the phrase again in case you forgot the password. » 7/09/14 6:36am 7/09/14 6:36am