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

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.

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

No one can deny the excitement of visiting another world.

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.

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.

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

An opportunity, no matter how small it is, is still worth a golden chance. So take it or have regrets for the rest of your life.

I grin, and he beams with

Almost as soon as it was lit it began to sound as though it were running down, but in fact it would continue to run down for a long time. He knew the feeling.

I once was absolutely useless, and God in His grace has made me useful.

We learn as professionals by repetition, by getting it wrong, getting yelled at and doing it again.

The Beatles weren't like any other band. Everybody in the band sang, which is why you knew everybody in the band.

Is the chemical aftertaste the reason why people eat hot dogs, or is it some kind of bonus?

A good song reminds us what we're fighting for.

When Sir Joshua Reynolds died All Nature was degraded; The King dropped a tear in the Queen's ear, And all his pictures faded.

There can be no settlement of a great cause without discussion, and people will not discuss a cause until their attention is drawn to it.