Crashes were all over the news around the time of my train trip, because a hunk of matter some 400 meters across had suddenly become a solar system media star: the likelihood that an asteroid dubbed 2004 MN4 would cause a really bad day in the year 2029 was briefly rated an unprecedented 4 (out of 10) on the Torino scale. Contrary to popular opinion, the Torino scale is not used to weigh muscle cars coming off the Ford assembly line. The scale in fact describes the level of threat from space stuff smashing into Earth. (Imagine the current and confusing color-coded terror alert system, only with numbers and for the most part based on the best available data.)
A Torino 4 translates to "a 1 percent or greater chance of collision leading to regional devastation." A 4 also means that astronomers are confident that more data will show a lesser threat. And when more data were evaluated a few days later, the consensus was that 2004 MN4 would miss us altogether, leaving us to find our own techniques for regional devastation.
Just a few months before 2004 MN4 had everyone figuring out how old they'd be in 2029, I had visited with the inventor of the Torino scale. Richard P. Binzel, a planetary scientist at the Massachusetts Institute of Technology, has a strong affection for Pluto, amateur astronomers and the Italian city of Torino, where he first proposed the impact scale at a conference in 1999. ("A 4 on the Binzel" sounds too much like a craps-table side bet, so they went with "Torino scale.")
Binzel revealed that he regularly entertains visitors convinced that they own a piece of outer space. "The basic story is that you get a phone call where someone says that they have found a meteorite or they have just inherited this meteorite that has been in the family for generations," Binzel said. "It's a family heirloom. But to their knowledge, it's never been reported to any scientific authority. And they would like it checked out, because if it's scientifically interesting they want the scientists to know about it, and maybe it's an important case."
An alleged meteorite may have been displayed in an important case. For example, the most memorable sample that showed up in Binzel's office was incorporated into a redesigned bowling trophy. "Instead of the guy in the trophy holding a bowling ball," Binzel recalled, "he was holding this rock. Like Atlas. Mounted and on the mantle for generations."
But despite the hopes and expectations of their owners, the 50 or so rocks Binzel has examined for civilians have turned out to have earthy origins. "In 15 years, no one has ever had [an] actual meteorite," he said. "So I'm careful to warn people that it's very likely they're going to walk out knowing it's not a meteorite." (A guest may still leave clutching something extraterrestrial, however--Binzel has on occasion rewarded the star-unstruck visitor with a tiny shard of an actual meteorite for his or her trouble.) And, Binzel noted, "to the credit of these people, they say, 'That's okay, all I want to know is the truth.' I've always been impressed by that."
Imagine millions of people letting go of a cherished belief simply because they're confronted with indisputable facts to the contrary. Well, before I go all John Lennon, I must say that even only 50 people able to incorporate reality into their worldview isn't bad. In fact, it fills me with a kind of hope for the future I haven't felt since the 2029 flyby of MN4 was downgraded to a 0 on the Torino scale.