Chances are, the aliens will not want to land on our backyard, or even the White House lawn, with their flying saucers. They may have tiny, robotic self-replicating probes which can reach near light speed and can proliferate around the galaxy. So instead of the Enterprise and huge star ships, the aliens might actually send tiny probes to explore the universe. One might land on our lawn and we won't even know.
Michio KakuTechnologies that may be realized in centuries or millennium include: warp drive, traveling faster than the speed of light, parallel universes; are there other parallel dimensions and parallel realities? Time travel that we mentioned and going to the stars.
Michio KakuWe're headed for what is called Type 1 Civilization, planetary civilization. Type 2 would be stellar civilization, like Star Trek. Type 3 Civilization would be galactic, like Star Wars. We are Type 0. We get our energy from dead plants, oil and coal. But the question is: Will we make it? Will we make the transition from Type 0 to Type 1? It's not clear.
Michio KakuMy point is, no one can stop the Internet. No one can stop that march. It doesn't mean that it's going to be smooth, though.
Michio Kaku