fast they travel, how high they are. what kinds of century if i can call forces they can experience. science, remember, are based on things that are testable. reproducible, and falsifiable. now we have testable information. a game changer. >> tucker: so given what we know about their physical behavior, about the physics involved in the way these aircraft fly, what do you think the chances are they were created by human beings? >> i think there is only two alternatives left now. one is perhaps they are hypersonic drone vehicles. after all, the russians, the chinese, and the u.s. are experimenting with hypersonic drones that can travel between 5 and 20 times the speed of sound. that's one alternative. but the other alternative is part of this game changer. we scientists have identified 4,000 planets orbiting other stars at