Long ago Mars was an oasis of running water.Today the Martiansurfaceis a sterile,barren desert. Here on Earth, who knows what climactic knobs we unwittingly turn,which might one day render Earth as dry and lifeless as Mars. (From the cover of Old Poison by Joan Francis)

UV is bad for molecules because its high energy breaks the bonds between a molecule's constituent atoms. That's why UV is bad for you, too: it's always best to avoid things that decompose the molecules of your flesh.

Like a snowplow in overdrive, a supernova shockwave might sweep away any gas clouds in its path.

Seventy percent of Earth's surface is water and over 99 percent is uninhabited, so you would expect nearly all impactors to hit either the ocean or desolate regions on Earth's surface. So why do movie meteors have such good aim?

I would expunge the word "aptitude" from our vocabulary, because if you're interested in something, that's all that matters. You'll spend more time doing it, that than anything else, and possibly more time doing it than anybody else. And that's all that matters, because in the end, if you love what you do, you'll be your best at it compared to anything else you might have chosen as a career.

(Space programs are) a force operating on educational pipelines that stimulate the formation of scientists, technologists, engineers and mathematicians... They're the ones that make tomorrow come. The foundations of economies... issue forth from investments we make in science and technology.

Physics is the only profession in which prophecy is not only accurate but routine.