The threat of a catastrophic asteroid impact probably isn’t very high on anyone’s list of potential doomsday scenarios right now, given what 2020 has greeted us with. But that doesn’t mean scientists aren’t constantly assessing responses for if and when a gigantic hurtling mass of rock decides to bump up against planet Earth.
For example, researchers at the Massachusetts Institute of Technology recently created a new framework — or “decision map” — to help analyze threatening asteroids and determine the best response (and timing) for dealing with them.
The ultimate goal would be to divert an asteroid before it could pass what’s known as Earth’s gravitational keyhole. This is a region of space that, if an asteroid were to pass through it, would alter the asteroid’s orbit and cause it to later hit Earth during a future orbital pass.
This is key (aheh). The study’s lead author, aerospace engineer Sung Wook Paek, believes dealing with a potential doomsday asteroid before it hits the gravitational keyhole is much preferred to attempting a “last-minute deflection”:
“People have mostly considered strategies of last-minute deflection, when the asteroid has already passed through a keyhole and is heading toward a collision with Earth. I’m interested in preventing keyhole passage well before Earth impact. It’s like a preemptive strike, with less mess.”
Less mess, indeed!
According to MIT, to get the least mess, their system considers “an asteroid’s mass and momentum, its proximity to a gravitational keyhole, and the amount of warning time that scientists have of an impending collision.” They then plug these variables into a simulation to determine which mission type would be most successful.
These possible missions include 1.) deflecting the asteroid with a projectile, 2.) sending a probe up for further measurements to aid the design of a future projectile, or 3.) sending two probes, one to take measurements and another to shift the path of the asteroid slightly (hopefully making a future deflection more successful).
As for whether or not we’ll ever actually need to divert an incoming apocalypse-level asteroid, while the odds are low, NASA administrator Jim Bridenstine believes we should take the matter seriously.
During a speech at last year’s International Academy of Astronautics Planetary Defense Conference, Bridenstine reminded everyone of the 2013 Chelyabinsk incident, which led to thousands of damaged buildings and over 1,500 injured people — and that particular exploding meteor was only 65 feet (20 meters).
NASA reportedly isn’t aware of any large asteroids that are currently on a collision course with Earth. There are, however, contenders that might pose problems in the future (check out their Earth Impact Monitoring page for more on that).
99942 Apophis, for example, which MIT used as one of their test subjects during their simulation, has a 1 in 150,000 chance of hitting us on April 12, 2068. That asteroid has a diameter of around 1,214 ft (370 meters).
Bennu, their other asteroid of choice, has a higher probability — but that’d be some time between the year 2175 and 2199, so I’m personally not too worried about it.
Despite those low odds, I suppose we never know when something we haven’t noticed yet might pop up.