Spahr lectured at the CfA, which opened its doors to the public for its monthly “Observatory Night.” The event included an hour-long lecture by Spahr and an opportunity to use the Center’s high-powered telescope to view Saturn, an Iridium satellite flare, and the International Space Station.
Central to Spahr’s lecture was a survey of how far the Minor Planet Center, which identifies asteroids and their trajectories, has come in the past two decades with the aid of a supercomputer, observatories around the world, and even amateur astronomers.
In 2008, Spahr, along with the help of his four-person team, accurately predicted where a two-meter-wide asteroid would strike within 20 kilometers of the actual impact site.
“The good news is that nearly 100 percent of asteroids one mile across are known and tracked by us,” Spahr said. “I don’t want people to get the idea that I’m running around screaming that asteroids are going to hit.”
Spahr also dispelled some myths about the possibility of a doomsday scenario à la “Armageddon” or “Deep Impact.”
“If you’ve seen ‘Armageddon,’ they say that an asteroid the size of Texas is going to hit and that it’s coming out of nowhere,” Spahr said. “Well, we found the last asteroid the size of Texas 211 years ago. It’s nice for movies but totally improbable.”
Spahr also added that cinematic solutions to averting calamity are fictitious.
“You really don’t want to nuke an asteroid,” Spahr said. “Even though it’d be fun, it’s much more effective to just put a heavy object next to the asteroid and drag it away from its predicted trajectory. I think the desire to nuke them stems from the end of the Cold War. They didn’t know what to do with all of the leftover nukes, so they started thinking about nuking asteroids.”
Christine E. Pulliam, who works as a public affairs specialist for the CfA, summed up Spahr’s work and highlighted its importance.
“He’s really one of the unsung heroes of the astronomical world,” Pulliam said. “He’s seen it all—the ‘Oh my God, the asteroids are coming!’—and he never panics.”
Polly S. Stevens, who is taking a course on near-Earth objects through the Harvard Institute for Learning in Retirement, said she generally felt comforted by the lecture, but thinks that it’s more guesswork than is let on.
“There’s a big divide between cautious scientists and people saying asteroids are going to bombard us,” Stevens said. “However, [Spahr] didn’t really talk about how different-sized asteroids would affect us.”
Jim Brookshire, whose son studies at MIT and paid for his transportation from Virginia to Cambridge as a birthday present, said the lecture made him feel safer about the possible threat of apocalypse by asteroid.
“I like to think that I help people sleep at night,” Spahr said. “But I don’t reduce the probability of an asteroid hitting, I just tell you that it’s not likely.”