A spacecraft will smash into an asteroid tonight as part of a mission to protect the planet.
While the asteroid - named Dimorphos - poses no threat to Earth, the aim of the NASA mission is to demonstrate that dangerous incoming rocks can be deflected by deliberately crashing into them.
The spacecraft, known as Double Asteroid Redirection Test (Dart), is expected to collide with the 560ft wide asteroid at 14 minutes past midnight tonight.
Dimorphos orbits a larger asteroid Didymos, the orbit takes around 11 hours and 55 minutes.
But astronomers are hoping that Dart, while destroying itself in the process, will shorten the orbit time by about 10 minutes.
Nasa said: “Dart’s target asteroid is not a threat to Earth but is the perfect testing ground to see if this method of asteroid deflection - known as the kinetic impactor technique - would be a viable way to protect our planet if an asteroid on a collision course with Earth were discovered in the future.”
There currently somewhere around 27,000 asteroids in near-Earth orbit.
Rocks that are 460ft and larger in size and come nearer than 4.7 million miles are classed as potentially hazardous.
The Dart mission will be the first ever full-scale demonstration of asteroid deflection technology. The spacecraft recently captured its first images of Didymos and Dimorphos.
It was about 20 million miles away from the asteroid system when it took the photos in July. It has taken 10 months for Dart to come close to Dimorphous after launching last November on SpaceX’s Falcon 9 rocket.
The asteroids will be around 6.8 million miles from Earth when the collision happens. Dart will accelerate at about 15,000 miles per hour before colliding with Dimorphos.
In 2024, the European Space Agency (ESA) will launch its Hera spacecraft, which will go on a two-year journey to the asteroid system to gather information in the aftermath of the crash.
The agency said: “By the time Hera reaches Didymos, in 2026, Dimorphos will have achieved historic significance: the first object in the Solar System to have its orbit shifted by human effort in a measurable way.”
