Exploring the Biochemistry of Calorie Restriction
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Correction Appended: Jan. 29, 2008
If you're the kind inclined to worry, here's a real hand-wringer for you: Sometime as early as February, 7,000 lbs. of flaming metal are going to start raining out of the sky, and nobody can say exactly where on Earth it's going to happen. The upside is, there's almost no rational reason you should give it a second thought.
The approaching fireball of debris comes to us courtesy of an unnamed U.S. spy satellite launched in December 2006, which reached orbit perfectly well, but then suffered a breakdown that caused ground controllers to lose communication with it. "It's not necessarily dead, but it's deaf," John McDowell, an astronomer with the Harvard-Smithsonian Center for Astrophysics unhelpfully told The New York Times. A deaf satellite, after all, is almost as bad as a dead satellite, when it comes to telling it to fire its thrusters so that it can stay in orbit, or at least come down in a safe place like the middle of the ocean. Without communications, the satellite becomes a falling cannonball colliding with the atmosphere at 17,500 mph.
That very atmosphere, however, helps ensure that we're in very little danger from being struck by this craft or any other incoming junk. Even billions of years after the formation of the solar system, space is still something of a shooting gallery, with meteors careening everywhere. The Earth is a very fat, very slow target for such flying rubble, but the high speed of the approaching rocks and the density of the planet's air cause anything but the biggest pieces of debris to burn up on their way down, producing nothing more dangerous than shooting stars.
That's not to say we're at zero risk from space junk. In the 50 years since the launch of Sputnik, the world's first satellite, and Explorer I, America's first satellite, rocket builders from all over the world have fired so much heavy hardware into space that the planet is now surrounded by a belt of litter consisting of some 10,000 objects four inches or more in diameter and many tens of thousands of smaller ones. Taken together, they're estimated to represent more than 900,000 lbs. of flying and possibly falling rubbish.
In 2006, wreckage from a plummeting Russian spy satellite whizzed dangerously close to a Latin American Airbus carrying 270 passengers. That near-miss took place over the Pacific Ocean, which is considered among the safest places in the world to bring down satellites due to its unpopulated vastness. The worst uncontrolled reentry in history occurred in July 1979, when Skylab, America's abandoned, 78-ton space station which had long since run out of maneuvering fuel came down earlier than planned, raining debris across the Australian outback.
Often, however, satellites and other spacecraft are brought down in a much more controlled way, their trajectories tweaked and adjusted before their terminal plunge so that they strike a precisely selected and safely empty spot. In 2000, the 17-ton Compton Gamma Ray Observatory was gently steered back to earth this way. In 1970, one of the most storied spacecraft of all the Apollo 13 lunar module, which served as a lifeboat for the crew when their command module was crippled by an explosion sparked fears of nuclear contamination since it was on a return path to collide with Earth still carrying radioactive instruments that were supposed to have been left on the surface of the moon. As reentry approached and the astronauts clambered back into the command module through the tunnel that linked the two ships, the soon-to-be-jettisoned lunar module was already being targeted for a landing in a deep ocean trench off the coast of New Zealand. There it splashed down and sank and there it remains.
The comparatively small spy satellite now wobbling its way home will not have nearly so precise a landing but it is likely to have an equally uneventful one. Seventy percent of the Earth's surface is water, meaning that there ought to be a 7 in 10 chance that the craft will drop in the drink. The fact that satellites are usually targeted for flight over land narrows those odds some, but the equally important fact that the majority of the Earthly land mass is uninhabited widens them back up. That plus the small size of the doomed craft probably means its death will be nothing more than a pleasant sky show for the few people lucky enough to see it. If you're the kind inclined to worry, you might have to pick another problem.
The original version of this story incorrectly stated that the U.S. spy satellite expected to fall back to Earth weighs 20,000 lbs. It weighs 7,000 lbs.
Correction Appended: January 29, 2008
As concern over global warming became more and more prominent in the U.S. over the past several years in the media, in opinion polls, in business and in state governments the one place where the issue seemed all but invisible was the one place that could really do something about it: Congress. But that began to change in 2007, and nowhere more so than in the Senate's key committee on the environment and public works, which drafts much of the country's environmental legislation. Up until last January, the committee was chaired by Oklahoma Sen. James Inhofe, a Republican who memorably called global warming "the greatest hoax ever perpetrated on the American people." When the Democrats took over Congress in the 2006 midterm elections, however, the chairperson's gavel was handed over to Sen. Barbara Boxer of California, and the floodgates opened. Boxer began a series of open hearings on the science of global warming, giving airtime to the sort of experts including former Vice President Al Gore who had been suppressed under Inhofe. "As soon as the change took place, I realized that this was going to be one of my number one goals," says Boxer. "Elections have consequences, and this was one of the consequences."
Hours and hours of hearings finally led to a legislative breakthrough in December: the passage out of the committee of the first bill that would put carbon caps on the U.S. economy. Co-sponsored by the Republican Sen. John Warner and the Independent Sen. Joseph Lieberman, the America's Climate Security Act would cap U.S. carbon emissions at 15% below 2005 levels by 2020, with a 70% cut projected for 2050. If enacted, those carbon caps would all but force U.S. businesses to invest in cleaner technology and greater energy efficiency, and would help the country take a leadership role in international climate negotiations.
Similar bills had been put forward over the past several years, only to die in committee. This time, however, Boxer was able to help pull together not only Democrats but a Republican as well, giving the bill some bipartisan support. That's key given how narrowly divided Congress has become, meaningful climate change legislation only has a chance if its supporters can draw allies from across the political aisle. Boxer is confident she can. "The environment has been an issue that has pulled together Republicans and Democrats in the past," she says. "Everyone has to breathe the same air."
The Climate Security Act has passed the first barrier to becoming law, but the road is only going to get tougher. To have a chance in the Senate, the bill needs at least 60 votes anything less, and opponents can stop it with a filibuster. That will require winning over more conservative Senators, while at the same time ensuring the bill doesn't become so watered down that it loses all effectiveness. And even if the bill were to pass the Senate, and then the House of Representatives, it still has to make it through President George W. Bush, who has shown little inclination to support it. Bush favors what he calls technological solutions to global warming, but without the pressure of carbon caps. "That's like saying let's meet at the field and play baseball, but you don't bring a mitt or a ball," says Boxer. "You can't play the game."
Critics like Bush tend to focus on the economic costs of reducing carbon emissions through increased energy prices but Boxer, and many of her supporters, believe that combating climate change can have a net positive effect on the economy. Boxer hails from California, which has already passed the strongest state legislation on climate change, cutting carbon emissions to 1990 levels by 2020. Far from hurting the state economically, Boxer notes, the carbon bill has helped California become the center for green innovation in the U.S., with Silicon Valley venture capitalists pouring billions into alternative energy start-ups. Those businesses will create new, green jobs that should make up for the short-term costs of cutting carbon. "The cure for global warming is positive," says Boxer. "That makes it easy for me to approach it with hope."
Emphasizing the hope, the positive possibilities of dealing with climate change, should also help Boxer broaden the appeal of the Climate Security Act. Americans are worried about global warming, but they're also worried about Iraq, the economy and health care. Make global warming into an economic issue, or an issue of national security, not just an environmental one, and there's a better chance of achieving broad, bipartisan support. Not all environmentalists are happy with the Climate Security Act it has been criticized by the Sierra Club, among other groups, as too weak. While it could be tightened, the reality is that only a moderate bill is likely to pass soon, and with science telling us that we may have less than 15 years to turn around carbon emissions, we can't afford to hold out for a perfect law. "The longer we wait to do what we need to do, the harder the transition will be," says Boxer. "We're running out of time." She's absolutely right, but at least Congress is no longer standing still.
The original version of this article stated that Senator James Inhofe represented Alaska. He actually represented Oklahoma.