According to Nasa scientists we have two options to protect Earth from deadly asteroids

Nasa thinks one day we might need to nuke any Earth-bound asteroids to save humanity. Photo / 123rf

It sounds like an idea that should remain firmly in the realm of Hollywood but NASA thinks one day we might need to nuke any Earth-bound asteroids to save humanity.

Scientists gathered this week at the American Geophysical Union meeting which included researchers from Los Alamos National Laboratory and Nasa's Goddard Spaceflight Center who spoke, among other things, about how to prevent humans going the same way as the dinosaurs.

And when it comes to planetary defence, sending a nuclear rocket to intercept an oncoming asteroid is at the top of the list of ideas.

It's basically one of two options. Either we can shoot an object at the offending asteroid to nudge it onto a trajectory away from us. Or we can send a nuclear missile to blow it up into little, far less threatening, pieces.

Outside of those two options, we're about as vulnerable as it gets when it comes to large space rocks hurtling towards us.

That point was driven home by Dr Joseph Nuth, a researcher with Nasa's Goddard Space Flight Center.

"The biggest problem, basically, is there's not a hell of a lot we can do about it at the moment," he said.

While smaller space shrapnel can be common and burn up on approach, potential extinction-inducing impacts are much more rare.

"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," he told the meeting, The Guardian reported.

It's not entirely uncommon for asteroids to get knocked into our neighbourhood. In fact according to Mr Nuth Earth had somewhat a close encounter in 1996 when a comet flew into Jupiter and again in 2014 when a comet passed "within cosmic spitting distance of Mars".

Earlier in the year, Nasa announced it was planning to launch a probe to study an "Armageddon" asteroid named Bennu that could one day pulverise the Earth.

Dr Cathy Plesko, a scientist at Los Alamos National Laboratory who also spoke during the meeting said she favoured the deflection option, a technique she equated to a "giant cannonball".

"Cannonball technology is actually very good technology, intercepting an object at high speed actually ends up being more effective than high explosives," she said.

Either way it looks like we're relying on rocket power to save the planet from any unwanted asteroid visitors, as long as we detect the threat in time.