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.

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.

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.

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

Think positively.Always focus on the positive side of any situation.

Chasing the external to achieve joy is a death-trap for personal-development.

And what, you ask, does writing teach us? First and foremost, it reminds us that we are alive and that it is a gift and a privilege, not a right.

That's part of American greatness, is discrimination. Yes, sir. Inequality, I think, breeds freedom and gives a man opportunity.

Campaign may invite a certain skepticism about democracy, but it will surely restore your faith in cinema verite.

If there is one doctrine I have preached more than another, it is the doctrine of the Perseverance of the Saints even to the end.

Pros like myself played football not for money or glory, but for the simplest reason: the love of the game.

Hold what you've got and hit them where you can.

Creativity is at the root of love and meaning in this life.

The BEST training program in the entire world will be a DISMAL FAILURE if people fail to hold up their end of the deal. The success of ANY training program is ultimately the trainee's responsibility.