ON THE 40TH anniversary of the lunar landing, the planet Jupiter was hit by a milewide asteroid, leaving a large black scar roughly the size of the Pacific Ocean on Jupiter's surface. The collision, which was discovered by an Australian amateur astronomer and came as a surprise to scientists, is a reminder that the universe is a dangerous place. Jupiter, the fifth planet from the sun, is 318 times larger than Earth and acts as a stellar vacuum cleaner, with a gravitational pull that attracts most of the asteroids that pass by. In March, however, Earth faced a close call as an asteroid named 2009 DD45 passed within 45,000 miles, mere inches on a cosmic scale. Its trajectory was discovered only three days in advance. The most famous recent example of Earth being hit by a so-called NEO (near-Earth object) is the 1908 Tunguska Event, when an asteroid with a diameter of 45 to 70 meters exploded over Tunguska in Siberia, unleashing the energy of 10 megatons of TNT, equivalent to a hydrogen bomb, and leveling about 100 million trees over an area of 800 square miles. If it had struck four hours later, St. Petersburg would have been wiped out. So far, some 6,200 NEOs have been discovered in our solar system, of which 1,000 are deemed "potentially hazardous," and 784 are registered as more than a half-mile wide. NASA's Jet Propulsion Laboratory keeps a running tally of NEOs at neo.jpl.nasa.gov/stats/. Scientists believe there are plenty of similar NEOs that have yet to be discovered, and as the Jupiter collision proved, they might not be discovered before it is too late. At present, astronomers are tracking the asteroid 99942 Apophis, which has a slight chance of striking Earth in April 2036. Though it is reasonably small by asteroid standards — about 300 meters across — a collision would unleash a force about 60,000 times that of the Hiroshima nuclear bomb, enough to destroy an area the size of France.
For more information, visit http://www.theatlantic.com/doc/200806/asteroids.
EVEN THOUGH THE United States has not signed the international environmental treaty known as the Kyoto Protocol, emissions here have been better controlled than in other countries. According to the U.S. Energy Information Administration, carbon dioxide emissions from the burning of fossils fuels only increased by 0.7 percent in the United States from 2000 to 2006, compared to 27.7 percent in India, 45.8 percent in Malaysia and 103 percent in China. Overall, emissions in Europe (up 4.9 percent) and Asia (up 52.3 percent) followed suit. By 2030, India and China are expected to account for 34 percent of the world's emissions, as growing populations move out of poverty and join the middle-class life enjoyed on average in richer, industrialized nations, thereby increasing their demand for energy. According to Drew Thornley, author of the new report "Energy & the Environment: Myths and Facts," international environmental treaties that penalize conventional energy sources make little sense if other countries swamp American reductions. The same goes for ambitious political initiatives. Rather, it would seem, we do better than others without adopting an international carbon-cutting regime.
For more information, visit www.american.com/archive/2009/june/emissions-control-myths-and-realities.
For more information, visit http://in.reuters.com/article/worldNews/idINIndia-41050320090715?sp=true.