It has been the province of motion films, sci-fi thrillers, and at the least one precise mass extinction occasion - the unstoppable asteroid heading in the direction of Earth.
However in a matter of weeks, NASA will probably be holding a world-first real-life check to see if the planet could be defended towards that precise state of affairs.
There is no want to start out constructing a bunker - the asteroid NASA is is not going to slam into us, however it'll present an ideal alternative for the area physique to check its Double Asteroid Redirection Check (DART) venture.
Here is what it is advisable know.
What's DART?
DART is "the world's first full-scale mission to check know-how for defending Earth towards potential asteroid or comet hazards", in response to the NASA web site.
The spacecraft was launched on a SpaceX rocket final November, focusing on a recognized asteroid that poses no risk to Earth.
"DART is one facet of NASA's work to organize Earth ought to we ever be confronted with an asteroid hazard," NASA planetary defence officer Lindley Johnson mentioned.
"In tandem with this check, we're getting ready the Close to-Earth Object Surveyor Mission, a space-based infrared telescope scheduled for launch later this decade and designed to expedite our capacity to find and characterise the possibly hazardous asteroids and comets that come inside 30 million miles of Earth's orbit."
How will it work?
DART is at present en path to the Didymos asteroid system, which is fashioned of two asteroids. One, the moonlet Dimorphos, 160m in diameter, orbits the bigger Didymos (780m in diameter).
Each are only a contact smaller than the estimated 96km diameter scientists estimate an asteroid would wish to wipe out all life on Earth.
Dimorphos is DART's goal. The spacecraft will navigate to the smaller asteroid and deliberately crash into it.
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A CubeSat machine supplied by the Italian Area Company will probably be launched earlier than the crash to seize photos of the influence and particles.
And in about 4 years' time, the European Area Company will conduct detailed surveys of each asteroids, with specific give attention to the crater left by DART's collision and a exact dedication of Dimorphos' mass.
The purpose is to "barely change the asteroid's movement in a approach that may be precisely measured utilizing ground-based telescopes."
When will this occur?
September 26, in response to NASA's newest replace.
DART will probably be travelling at a brisk six kilometres per second - about 21,600km/hr.
Scientists estimate the kinetic influence will shorten Dimorphos' orbit round Didymos by a number of minutes.
"DART is popping science fiction into science truth and is a testomony to NASA's proactivity and innovation for the advantage of all," NASA administrator Invoice Nelson mentioned.
"Along with all of the methods NASA research our universe and our dwelling planet, we're additionally working to guard that dwelling, and this check will assist show out one viable option to defend our planet from a hazardous asteroid ought to one ever be found that's headed towards Earth."