Earth is essentially defenseless in the face of comets and asteroids that bring little warning, a NASA scientist has warned. The researcher believes building an interceptor rocket and an observer spacecraft could avert such a catastrophe, however.
“The biggest problem, basically, is there’s not a hell of a lot we can do about it at the moment,” Dr. Joseph Nuth, a researcher with NASA’s Goddard Space Flight Center, said at the fall meeting of the American Geophysical Union (AGU) in San Francisco on Monday.
According to Nuth, comets have largely been ignored by people “interested in defending the planet.”
Meanwhile, comets have a potential of getting close to Earth, but we may not have the time and resources to repel them.
Nuth recalled in 1996, the Earth had “a close encounter” with a Shoemaker-Levy 9 comet that smashed into Jupiter. The same threat still looms over our planet, less than two decades since. In January 2013, Comet Siding Spring, or C/2013 A1, also had “a close interaction” with Earth.
Then, in October 2014, Comet Siding Spring passed “within cosmic spitting distance of Mars,” threatening NASA spacecraft orbiting planet at the time.
The total time from when Siding Spring was discovered to its closest approach to the Red Planet was less than 22 months. According to Nuth, that is not enough time to take action.
“If you look at the schedule for high-reliability spacecraft and launching them, it takes five years to launch a spacecraft. We had 22 months of total warning,” he said. In other words, rocket scientists need at least five years to design, build and launch a spacecraft to deflect or destroy a comet.
In January 2016, Nasa established its Planetary Defense Coordination Office (PDCO), tasking it with detecting potentially hazardous objects (PHOs).
However, Nuth wants to still go further, recommending an interceptor rocket and observer spacecraft be built next. Keeping those in storage would reduce reaction time, which he says is “imperative” to success. Those steps would cut the five-year schedule in half. Plus, having a rocket in storage, which is ready to be launched within a year “could mitigate the possibility of a sneaky asteroid coming in from a place that’s hard to observe, like from the sun.”
At the same time, Nuth noted that large and potentially dangerous asteroids and comets are extremely rare.
“There are so few large things, in essence. They are the extinction-level events, and that’s especially true for things like comets,” he said.
Larger objects also have less probability to hit Earth, compared to “small things.”
“When we are talking things like dinosaur killers, they’re 50 to 60 million years apart, essentially,” he explained. “You could say, of course, we’re due, but it’s a random guess at that point.”