In the movie Deep Impact, scientists learn that a distant comet is on a collision course with Earth. Political leaders launch a secret program to intercept the comet, even as they construct underground bunkers to ensure at least some humans will survive. People may think such a scenario is how an impending collision would, in reality, play out.
The truth is far more frightening.
You might think that armies of professional astronomers are busily scanning the skies to discover threatening meteoroids; the truth is that such research is very poorly funded. Much of the work relies upon amateur astronomers.
Consider the case of the meteoroid discovered on January 13th, 2004. On that date, four automated pictures were posted on the website of the Minor Planet Center, in Cambridge, Massachusetts. An amateur in Germany used these pictures to calculate that the object's brightness would increase forty times over the next twenty-four hours -- just as the headlights of a car speeding towards you will suddenly get brighter.
This object soon had a name: 2004 AS1. (Part of the problem scientists have in communicating science to the public is the use of such unwieldy, unmarketable terms.) NASA's Steve Chesley wrote an email to his colleagues suggesting that 2004 AS1 had a one in four chance of hitting the planet within the next few hours. Scientists seriously considered alerting President Bush, in order to initiate a national and worldwide emergency response.
As it turned out, 2004 AS1 did not hit our planet. Nine hours after the alarm first began, an amateur astronomer's photograph clarified the trajectory, showing that it posed no danger. Lessons learned: the initial alert and correct trajectory came from amateurs, and we had only a few hours warning.
What about larger objects? Wouldn't we have time if something really big were headed our way? The 1997 comet Hale-Bopp -- whose arrival spurred the mass suicide of the Heaven's Gate cult -- was about 25 miles in diameter. Had Hale-Bopp hit Earth, it would have, in the words of astronomer Phil Plait, "made the asteroid impact that wiped out the dinosaurs look like a wet firecracker."
Hale-Bopp was discovered only two years before its passage by Earth, not nearly enough time to divert the comet. So much for the Deep Impact scenario.
What is being done to identify potential threats? The good news is that Congress has passed two bills--1998's Spaceguard Survey, and 2005's George E. Brown Near-Earth Object Survey--to identify potential hazards. The bad news is that these programs have never been seriously funded.
A National Research Council report released last Friday revealed that only $4 million annually has been allotted to identify civilization-ending near-Earth objects (NEOs). Of the $3.1 trillion in the 2009 US federal budget, four million dollars represents only 0.000129%. To put it in more concrete terms, if your salary was $40,000 last year, you would have spent 5 cents protecting yourself.
The NRC report described this level of funding as "insufficient to detect the major NEOs that may present a tangible threat to humanity," and noted:
"Congress has mandated that NASA discover 90 percent of all near-Earth objects 140 meters in diameter or greater by 2020. The administration has not requested and Congress has not appropriated new funds to meet this objective."
Is 140 meters sufficient? The meteorite that formed Meteor Crater in Arizona is estimated to have been about 40 meters in diameter. The object which flattened 2,000 square kilometers in Siberia in 1908 was only a few tens of meters. 2004 AS1 -- unknown until it was nearly upon Earth -- is 500 meters in diameter. Imagine the casualties if one of these objects were to fall on New York or Los Angeles today. Of course, a direct hit on a city is unlikely -- a meteorite is much more likely to strike the ocean, generating a tsunami that would kill people along huge swaths of shoreline.
A minimal investment studying NEOs could have a major benefit. Yet, instead of increasing funding for basic scientific research, America is choosing to move the other direction. The Arecibo Observatory, for example, is one of major tools in NEO research; it may shut down next year due to a lack of funding.
We may be tempted to defer spending on science. We may think, like the crew of the Titanic, that we don't need to worry as our planet sails along, that anything big enough to cause serious harm will be visible from a long way off. We all know how well this thinking worked out for the Titanic.