Imagine finding out that a massive asteroid is making its way toward the Earth with the potential to wipe out all life on the planet. If this were a scene from a movie, some hero with supernatural powers would come and save the world — but it's not. The threat is very much real.
While newer technologies capable of detecting threats from space have been developed in recent years, NASA believes scientists are still vastly unprepared to deal with near-Earth objects (NEOs) potentially striking the planet.
Joseph Nuth, a researcher at the Goddard Space Flight Center, told attendees at the American Geophysical Union meeting on Monday, Dec. 12, that there is much to be desired when it comes to the Earth's ability to react to such an interplanetary threat.
"The biggest problem, basically, is there's not a hell of a lot we can do about it at the moment," Nuth said.
Near-Earth Objects
According to scientists, the possibility of seeing an asteroid or comet large enough to cause an extinction-level event on Earth is very rare. Recent estimates show that there is less than a 0.01 percent chance of such an object hitting the planet within the next 100 years.
However, with NASA detecting more and more NEOs in the vicinity of the Earth, the likelihood of an asteroid making contact with the planet could suddenly change. If even one of these massive objects catches researchers by surprise, there isn't much left to do but to prepare for a worst case scenario.
The Earth hasn't had much catastrophic encounters with errant asteroids and comets for the most part of its history, but there were two instances when the planet had close calls.
In 1996, a rogue comet designated as Shoemaker-Levy 9 struck Jupiter. The event is considered the first instance in which a collision between two solar system objects was observed by scientists.
The latest one happened in 2014 when another comet made a close flyby of Mars. This second NEO was detected only 22 months before it came dangerously near the planet.
Nuth said that NASA wouldn't be able to launch an effective deflection mission with that short timetable since it typically takes five years to mount such a response.
Planetary Defense
To avoid a scenario similar to the one in 2014, Nuth came up with a two-pronged approach.
The first approach involves improving the capabilities of researchers to detect asteroids or comets that could head toward the Earth. Nuth said researchers can send out an "observer spacecraft" into space with the purpose of observing any potential NEO threats.
The second approach involves launching a rocket that can intercept the NEO and test it from time to time. This would prevent an asteroid or comet from getting dangerously close to Earth from a direction that is difficult to observe, such as from the sun.
Dr. Cathy Plesko, a researcher at the Los Alamos National Laboratory, agrees that early detection is the key to keeping the planet safe from NEO threats. She and her colleagues at the laboratory are responsible for coming up with effective asteroid deflection scenarios using various computer models.
Plesko said nuclear warheads can be used to deflect an NEO by blowing up the asteroid or comet. However, a more reliable option would be to use a kinetic impactor, which operates much like a massive cannonball.
Using a kinetic impactor may take a longer time to refine compared to launching a nuclear strike at the NEO, but Plesko argued that it is a much better choice since it can intercept an asteroid at very high speeds.
