Years of science fiction have produced a mindset that it is human destiny to expand from Earth, to the Moon, to Mars, to the stars.

Above all, I would not expect a wise race, at great expense, to set loose an army of self-replicating robots.

The factor most ignored in discussing interstellar flight is the kinetic energy that must be invested in the ship to make its tons of matter move at a substantial fraction of the speed of light.

In the past, on Earth, it has largely been to exploit foreign resources and to expand the domestic territory.

Antimatter is not a source of energy for us, it's a method of storing energy, compact but inefficient.

Present annual world energy consumption is about equal to the annihilation energy of 4 tons of matter.

It would be a pity if, frustrated by the price of travel, we elected to become a society that never made contact, that never gave SETI a fair chance.