An asteroid larger than a blue whale will skim past Earth on Friday at less than one-fifth the distance between our planet and the moon.
The asteroid, 2018 CB, was only discovered by Nasa on Sunday and will blaze by Earth at just 39,000 miles (64,000 kilometres).
It is between 50 and 130 feet (15 and 40 metres) wide and an expert has warned that an asteroid of this size would only get this close to our planet ‘once or twice a year’.
According to Nasa the asteroid will pass by at around 17:30 EST (22:30 GMT).
The space agency describes asteroids as ‘hazardous’ if they come within 4,600,000 miles (7,403,00km) of our planet.
It was first spotted by the Nasa-funded Catalina Sky Survey (CSS) near Tucson, Arizona.
The space agency has assured people it does not pose an actual threat of colliding with our planet.
‘Although 2018 CB is quite small, it might well be larger than the asteroid that entered the atmosphere over Chelyabinsk, Russia, almost exactly five years ago, in 2013,’ said Paul Chodas, manager of the Center for Near-Earth Object Studies at NASA’s Jet Propulsion Laboratory in Pasadena, California.
‘Asteroids of this size do not often approach this close to our planet – maybe only once or twice a year.’
In February 2013 a 19-metre meter (62-feet) meteor exploded in the skies above Chelyabinsk in Russia.
The meteorite broke up into multiple pieces as it entered the atmosphere, scattering space debris and creating a shock wave estimated to be as strong as 20 Hiroshima atomic bombs.
Finding out about the orbit trajectory, size, shape, mass, composition and rotational dynamics would help experts determine the severity of a potential impact.
However, the key to mitigating damage is to find any potential threat as early as possible.
Nasa is currently moving forward with a refrigerator-sized spacecraft capable of preventing asteroids from colliding with Earth. A test with a small, nonthreatening asteroid is planned for 2024.
This is the first-ever mission to demonstrate an asteroid deflection technique for planetary defence.
The Double Asteroid Redirection Test (DART) would use what is known as a kinetic impactor technique—striking the asteroid to shift its orbit.
The impact would change the speed of a threatening asteroid by a small fraction of its total velocity, but by doing so well before the predicted impact, this small nudge will add up over time to a big shift of the asteroid’s path away from Earth.
