Those of you with cometophobia (you guessed it, fear of comets) will want to avoid this story. Astrophysicist and nerd hero Neil deGrasse Tyson just wrote a guest opinion piece for Wired Science about the possibility of asteroids wiping out life on Earth in the foreseeable future. According to deGrasse Tyson, hundreds of tons of space rock vaporize in the Earth's atmosphere every day, and it's only once every hundred million years that we risk impact with an asteroid that could wipe out all life on the planet. What's more mathematically possible, though still unlikely, is a close encounter with a killer asteroid that may be dragged toward us by Earth's gravitational pull as the rock swings by along its orbit around the sun. NASA is keeping a close eye on these, including one rock ominously dubbed Apophis.
But Neil deGrasse Tyson's point isn't that we should freak out about these potential killer rocks, but be smart in the way we think about how we would repel them from a collision course. The solution most sound, as it turns out, isn't shooting the asteroid with nukes or even digging deep into the asteroid to blow it up from within. From the column:
The odds-on favorite solution, however, is the gravitational tractor. This involves parking a probe in space near the killer asteroid. As their mutual gravity draws the probe to the asteroid, an array of retro rockets fires, instead causing the asteroid to draw toward the probe and off its collision course with Earth.
The cost of survival, as it is with liberty, is constant vigilance. It's important that we track as many of these potential colliding comets as possible, and then learn as much as we can about them before deciding how to take action.
In other Neil deGrasse Tyson news, he recently convinced James Cameron to fix a scene in the upcoming Titanic 3D re-release, pointing out that the star field in one scene was not accurate for how the sky looked above the Atlantic ocean on that night in 1912.