As the threat of global warming grows more urgent, a few scientists are considering radical—and possibly extremely dangerous—schemes for reengineering the climate by brute force. Their ideas are technologically plausible and quite cheap. So cheap, in fact, that a rich and committed environmentalist could act on them tomorrow. And that’s the scariest part.

The authors argue that the Obama administration's moves to pursue and strengthen nuclear arms control is weakening the U.S. nuclear deterrent and inviting attack.

Uranium exists on the moon, according to new data from a Japanese spacecraft. The revelation suggests that nuclear power plants could be built on the moon, or even that Earth's satellite could serve as a mining source for uranium needed back home.

Following a report last week that Iran is spying on domestic internet users with western-supplied technology, advocacy groups are pressuring federal lawmakers to scrutinize the use of the same technology in the U.S.

The latest multi-core processors and some smart software allow techniques used by physicists and engineers to simulate the real world in extreme detail, creating virtual worlds governed by real physics, rather than the simplified versions used today.

The United States and Russia are locked in a fundamental dispute over how to counter the growing threat of cyberwar attacks that could wreak havoc on computer systems and the Internet with Russia pushing for a ban on cyberwar tools and the U.S. arguing for treating the problem as a law enforcement issue.

There is enough space in the world to produce the extra food needed to feed a growing population and contrary to expectation, most of it can be grown in Africa, say two international reports published this week.

The authors suggest that a ban on ballistic missile tests could "enhance global security by increasing decision-making time, removing the threat of accidental missile launch, and having an immediate positive impact on the most volatile areas of emerging international arms competition."

Michio Kaku surveys the growing number nations planning competing missions to the moon (including Japan, China, India, and the U.S.) and argues that the growing lunar competition should motivate a re-examination of the 1967 Outer Space Treaty "before national rivalries and tensions heat up as we approach 2020."

The Obama administration plans to kill a controversial Bush administration spy satellite program that would have provided federal, state and local officials with extensive access to spy-satellite imagery — but no eavesdropping capabilities— to assist with emergency response and other domestic-security needs, such as identifying where ports or border areas are vulnerable to terrorism.