A 2015 study by researchers from New York University that was published in the journal Monthly Notices of the Royal Astronomical Society has revealed that many of the mass extinction events on Earth have been caused by comet strikes.

Unfortunately despite advances in technology, humans remain ill-equipped in protecting themselves should a life-threatening comet or asteroid strikes planet Earth again.

Joseph Nuth, from NASA's Goddard Space Flight Center, sounded the alarm at the American Geophysical Union meeting on Monday, Dec. 12 saying that Earth is woefully prepared should an interplanetary threat such as a comet or asteroid strikes Earth.

"A comet or asteroid collision could wipe out the various species on the surface of the Earth," Nuth said.

Saving Planet Earth

Nuth has proposed measures that can potentially save lives. He said that humanity needs to prepare for a potential comet strike now or at least in the near future because deflection efforts may prove impossible if preparations are done too late.

Nuth recommended building two spacecraft. One of the spacecraft, the so-called observer, would be launched to study potentially dangerous comets. The findings could help astronomers determine the object's orbital path, allowing them to better assess the threat that it poses.

Nuclear Bomb

If the threat is considered serious enough, the other spacecraft, the interceptor, would be launched to deflect the comet. The interceptor needs to be able to carry a nuclear bomb, which could be necessary to deal with large space objects that are detected with little warning time.

Lasers

An alternative for deflecting an incoming a comet sans launching a spacecraft involves using powerful laser blasts that can vaporize parts of the comet's surface from a distance. The eruption of gaseous jets may help push the object away from its original trajectory.

Computer simulations conducted by Qicheng Zhang, from the University of California, Santa Barbara, and colleagues who conducted a study on this matter revealed that the same ground-based laser system that engineers plan for the Breakthrough Starshot project would be capable of deflecting some comets. The space project plans to use a giant laser from our planet to push nano spacecraft to nearly the speed of light.

"Laser ablation of a near-Earth object (NEO) on a collision course with Earth produces a cloud of ejecta that exerts a thrust on the NEO, deflecting it from its original trajectory," Zhang and colleagues wrote in their study published in the Publications of the Astronomical Society of the Pacific.