Space shuttle Columbia has crashed, raising questions about research on the space shuttle and the International Space Station. Should we do space science by robots or manned vehicles?

What was the long-term impact of the Exxon Valdez spill in Alaska? Did the cleanup help, or make matters worse? Who are you going to believe in a case like this?

Missile defense: Protective shield, or dangerous myth? New tests do little to solve the problem.

Agricultural genetic engineering could change the equation between weeds, insects, toxic agricultural chemicals and yields. Is GM food a good idea?

Biological weapons are microscopic killing machines containing viruses, fungi or bacteria — or the toxins made by these organisms. Read the history — and future — of living WMDs.

Food-borne diseases sicken 76 million Americans each year. Would it be safer to pass our food through the irradiator?

History of chemical weapons and Gulf War Syndrome. What could explain the widespread symptoms among veterans?