The proliferation of commercial high-resolution satellite imagery has made it harder for aspiring nuclear states to conceal their nuclear testing preparations. In the case of North Korea, they have adapted by making no attempt to conceal their plans.
The U.S. and Israel have quietly shelved a project to deploy a high-energy laser weapon for missile defense, citing its bulkiness, high costs and poor anticipated results on the battlefield.
The Bush administration is seeking to develop a powerful ground-based laser weapon that would use beams of concentrated light to destroy enemy satellites in orbit. The largely secret project, parts of which have been made public through Air Force budget documents submitted to Congress in February, is part of a wide-ranging effort to develop space weapons, both defensive and offensive. No treaty or law forbids such work.
In the last decade or so, as scientists came to agree that the number of objects in orbit had surpassed a critical mass - or, in their terms, the critical spatial density, the point at which a chain reaction becomes inevitable - they grew more anxious. Now, experts say, China's test on Jan. 11 of an antisatellite rocket that shattered an old satellite into hundreds of large fragments means the chain reaction will most likely start sooner. If their predictions are right, the cascade could put billions of dollars' worth of advanced satellites at risk and eventually threaten to limit humanity's reach for the stars.
The Pentagon has formed a team of nuclear experts to analyze the fallout from a terrorist nuclear attack on American soil in an effort to identify the attackers, officials have said.
The U.S. government is preparing to spend more than $2 billion on a routine 10-year overhaul to extend the life of the aging warheads. At the same time, some weapons scientists say the warheads have a fundamental design flaw that could cause them to explode with far less force than intended.
Worried that the nation's aging nuclear arsenal is increasingly fragile, American scientists have begun designing a new generation of nuclear arms meant to be sturdier and more reliable and to have longer lives. Critics counter that the effort could needlessly resuscitate the complex of factories and laboratories that make nuclear weapons and could possibly ignite a new arms race.
Good overview of the status of the International Monitoring System, a global network of sensors in 89 countries that watch for nuclear tests and other seismic anamolies.
The collapse of the Earth's magnetic field, which both guards the planet and guides many of its creatures, appears to have started in earnest about 150 years ago. The field's strength has waned 10 to 15 percent, and the deterioration has accelerated of late, increasing debate over whether it portends a reversal of the lines of magnetic force that normally envelop the Earth.
Although it has been recently plagued with technical failures and mismanagment, experts argue NASA could be revitalized with a combination of bold leadership and visionary goals.