London pioneered video surveillance in public, but it’s catching on fast. Many major cities have systems, and more are coming. What do these cameras learn? How do they interact with other sources of data? In this culture of disclosure should we even worry about privacy?

As Earth warms, should we try huge geoengineering projects to cool the climate? Would adding iron to fertilize ocean plants withdraw enough carbon dioxide to slow warming — or backfire?

Without phosphorus fertilizer, millions would starve. A shortage of copper — and electricity — could short-circuit our economy. Without many obscure elements, we would not have LCDs and cell phones. Should we act to prevent future shortages?

Bush proposes mission to moon and Mars, but how great are the scientific payoffs of this expensive, risky adventure? Would it be smarter – and cheaper – to send robots?

An international team of scientists selected the Homestake goldmine to be the world’s deepest underground lab, but the project may sink.

Monkeypox, AIDS, SARS: Are more diseases jumping from animals to people, or is it just our imagination?

Austrian researchers show quantum entanglement across the Danube River, providing new promise in cryptography and computing. At the smallest scale, you can throw out the usual rules of engagement. What’s up with spooky action at a distance?

As New York City decides about the World Trade Center site, we discuss the significance of a city skyline.

New photovoltaic (PV) cells combine polymer and inorganic semiconductors — could be cheaper to manufacture.

Forget Big Brother, your neighbor could be watching you! Newest tricks of the spy game.