New Delhi:
A NASA scientist has warned that a surprise comet or asteroid may collide with the Earth and the human beings are not prepared to face it. He said this during a presentation with nuclear scientists which discussed how human beings might avert the cosmic dangers that might be hurtling towards our planet Earth.
“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.
Nuth, who took part at the annual meeting of American Geophysical Union, noted that the asteroids and comets that are large and potentially dangerous are extremely rare compared to those small objects that explode in Earth’s sky occasionally or strike its surface.
“But on the other hand they are the extinction-level events, things like dinosaur killers, they’re 50 to 60 million years apart, essentially. You could say, of course, we’re due, but it’s a random course at that point.”
Comets follow distant paths from earth but they get knocked to the neighbourhood sometimes. According to scientists, in 1996, the Earth had “a close encounter” after an aberrant comet flew into Jupiter. Then again in 2014, a comet passed “within cosmic spitting distance of Mars”.
22 months before its brush with a planet, that planet was discovered, not nearly enough time to launch a deflection mission, had it been on a course for Earth.
“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.”
A planetary defense office was recently established by NASA. Ruth has recommended that NASA build an interceptor rocket to keep in storage with periodic testing alongside an observer spacecraft.
Nasa could cut that five-year schedule in half, said Nuth. But that even reducing that schedule by a quarter would be “basically a hail-mary pass”, he added.
However, a rocket in storage and ready to launch 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”, he said.
Nuth said that the mission would require an approval from the Congress, stressing that he and his co-authors do not speak for Nasa administrators.
NASA has found about 90 per cent of near-Earth objects that are bigger than a kilometre. This is a size that could cause devastation on Earth.
Though, objects that are smaller are still extremely dangerous. NASA has discovered 874 1km-wide asteroids among 1,748 “potentially hazardous asteroids”.
When compared to icy comets, asteroids are much darker and rockier. They may fly within a band that stretches between Jupiter and Mars.
Two ways of deflecting an asteroid are a nuclear warhead or a “kinetic impactor, which is basically a giant cannonball”, Dr Cathy Plesko, a scientist at Los Alamos National Laboratory, said.
“Cannonball technology is actually very good technology, intercepting an object at high speed actually ends up being more effective than high explosives”.
To “blow it to smithereens”, Plesko said, would have dangerous side-effects, including shrapnel from the blast.
“We are very carefully doing our homework before finals week,” Plesko said. “We don’t want to be doing our calculations before something is coming. We need to have this work done.”
“We don’t have a lot of data about what the insides of asteroids or comets look like,” she said, “but based on what we know about physics and rock and ice we can guess.”
