While the possibility of a catastrophic asteroid slamming into Earth is extremely rare, it may only be a matter of time before this threat becomes a reality.
But experts have warned that humans are not prepared for an asteroid impact, and should one head for Earth, there`s not much we can do about it.
A Nasa scientist has said that our best hope is building an interceptor rocket to keep in storage that could be used in deflection missions.
Dr Joseph Nuth, a researcher at Nasa`s Goddard Space Flight Centre in Maryland was speaking at the annual meeting of the American Geophysical Union earlier this week.
He said: `The biggest problem, basically, is there`s not a hell of a lot we can do about it at the moment.`
While dangerous asteroids and comets rarely hit Earth, Dr Nuth warned that the threat was always there.
He said: `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.`
In the past, comets have come very close to hitting Earth.
In 1996, a comet narrowly missed our planet, instead flying into Jupiter, and again in 2014, a comet passed `within cosmic spitting distance of Mars`, according to Dr Nuth.
And comets are often only discovered when it`s too late to launch a deflection mission.
Dr Nuth said: `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.`
Dr Nuth advises that Nasa should build an interceptor rocket alongside an observer spacecraft, which he says could cut the five-year delay to launch in half.
And if a rocket could be devised that could launch within a year, Dr Nuth says it `could mitigate the possibility of a sneaky asteroid coming in from a place that`s hard to observe, like from the sun.`
This is not the first time that experts have warned that the Earth is unprepared for an asteroid strike.
In September, director of the Office of Science and Technology Policy, John Holdren, warned that an impact could `do a lot of damage to the Earth.`
The expert noted two catastrophic events in recent history that took the world by surprise – the Chelyabinsk strike in 2013, and the Tunguska fireball in 1908.
While scientists have made great strides in detecting potentially hazardous Near-Earth Objects, Mr Holdren explained that there is still much work to be done.
`We are not fully prepared, but we are on a trajectory to get much more so,` Mr Holdren said.
Events like the Chelyabinsk strike and the Tunguska explosion are extremely rare, he said, with the first thought to occur once every hundred years and the latter every 1,000.
But, `if we are going to be as capable a civilization as our technology allows, we need to be prepared for even those rare events, because they could to a lot of damage to the Earth.`
Despite how unusual these events may be, these strikes could have devastating effects on the planet, and Earth must be prepared.
The expert warned: `Ultimately, we may need to deflect an asteroid on a collision course with the Earth.