A hundred years ago, the electric telegraph made possible-indeed, inevitable-the United States of America. The communications satellite will make equally inevitable a United Nations of Earth; let us hope that the transition period will not be equally bloody.

Moses Kaldor had always loved mountains; they made him feel nearer to the God whose nonexistence he still sometimes resented.

When you finally understand the universe, it will not only be stranger than you imagine, it will be stranger than you can imagine.

It will be possible in a few more years to build radio controlled rockets which can be steered into such orbits beyond the limits of the atmosphere and left to broadcast scientific information back to the Earth. A little later, manned rockets will be able to make similar flights with sufficient excess power to break the orbit and return to Earth. (1945) [Predicting communications satellites.]

I'm sure the universe is full of intelligent life. It's just been too intelligent to come here.

Attempting to define science fiction is an undertaking almost as difficult, though not so popular, as trying to define pornography... In both pornography and SF, the problem lies in knowing exactly where to draw the line.

Good morning, doctors. I have taken the liberty of removing Windows 95 from my hard drive.