Asteroid insurance

You may think the prospect of firing a missile at an asteroid to stop it from snuffing out a fraction of humanity is mere science fiction, but NASA and the Obama administration are advancing a framework for just such an operation. In his 2011 budget, the president asked Congress to more than triple the $5.8 million previously set aside for the detection of asteroids and comets that orbit in Earth's neighborhood-in part to "reduce the risk of harm to humans."

At the direction of Congress, NASA has been cataloguing near-Earth objects (NEOs) for the past 12 years and has identified 818 asteroids with colossal diameters of a kilometer or more, up from the 242 identified in 1998. An asteroid need only be 25 meters (82 feet) in diameter to survive Earth's atmosphere and reach the surface: By 2020, NASA's goal is to track 90 percent of the thousands of NEOs that are 140 meters or larger (think bigger than a football field, including end zones).

In October a NASA task force recommended that the administration create a $250 million Planetary Defense Coordination Office and invest immediately in the construction of an infrared satellite designed to track NEOs. The satellite would cost half a billion dollars, dwarfing even Obama's increased investment in the field during a time of budget turmoil.

A few weeks ago John Holdren, Obama's science czar, offered Congress his recommendation that NASA work with the Department of Defense and the Federal Emergency Management Agency in developing a strategy to destroy or divert the path of any threatening space rock-some suggest using nuclear weapons or a "gravity tractor" spacecraft-and a system to warn the public of an incoming asteroid.

Since no dangerous NEOs are known to be on a collision course with Earth, is a "planetary defense" strategy simply hubris-or is it as sensible as defending against hurricanes? At any rate, FEMA already has an emergency alert message drafted for the occasion.

Bioplastic havoc

Remember those unnaturally noisy (and allegedly biodegradable) SunChips bags? Frito-Lay has sacked most of the bags while it searches for some quieter eco-friendly material, but it could face another problem: Contrary to some reports, a new study has shown that many plant-based plastics could be as damaging to the environment as their petroleum counterparts when the production process is taken into account. With manufacturing factored in, researchers found that four types of bioplastics were the worst contributors to ozone depletion, compared to seven traditional plastics. They produced more carcinogens, were more energy-intensive, and, because they relied on plants, increased pesticide and fertilizer use.

Once in their final form, of course, bioplastics outperformed their competition for biodegradability and overall "eco-friendliness." But if you're determined to have a chip bag that's green, first consider what it costs to make it.

Pollution eaters

Deciduous trees like poplars and maples find some air pollution delicious: A global survey of ecosystems revealed that deciduous plants absorb and metabolize larger amounts of oxygenated volatile organic compounds (36 percent more) than scientists have realized. Trees can change their absorption rate of the compounds as well. Physical and chemical stress-such as ozone pollution-causes trees to increase the production of metabolizing enzymes. The pollutants the trees recycle are among a class of airborne chemicals thought to be harmful to human health and the environment.