The asteroid, dubbed Asteroid 2018 WX1, is expected to pass in the morning of Friday, December 7. NASA’s scientists at the Jet Propulsion Laboratory are looking at a 9.09am GMT (UTC) flyby. The asteroid’s passage will be preceded by a much smaller, 91.8ft-wide (28m) barrelling past the planet at around 6.51am GMT. The bigger of the two asteroids is the more formidable object and is comparable in size to Big Ben’s Elizabeth tower in Westminster, London.
NASA’s astronomers estimate the speeding asteroid measures somewhere in the range of 134.5ft to 298.5ft (41m to 91m).
According to the space agency, asteroids in the upper range of this size estimate have the potential to wreak havoc upon impact.
NASA said: “Space rocks smaller than about 25 meters – about 82 feet – will most likely burn up as they enter the Earth's atmosphere and cause little or no damage.
“If a rocky meteoroid larger than 25 meters but smaller than one kilometre – a little more than 1/2 mile – were to hit Earth, it would likely cause local damage to the impact area.
“We believe anything larger than one to two kilometres – one kilometre is a little more than one-half mile – could have worldwide effects.
“At 5.4 kilometres in diameter, the largest known potentially hazardous asteroid is Toutatis.”
Asteroids measuring around 328ft (100m) across strike the Earth once every 2,000 years or so.
Thankfully there is no risk of the asteroid slamming into the planet anytime soon.
Instead, the asteroid will make a so-called Earth Close Approach tomorrow morning.
Earth Close Approaches involve all asteroids and comets flying by the Earth within 0.05 astronomical units (au) or 4.6 million miles (7.49 million km) of the planet.
Tomorrow, Asteroid WX1 will reach a minimum distance from Earth of 0.01235 au or 1.14 million miles (1.48 million km).
This is the equivalent of 4.81 Lunar Distances (LD) – 4.81-times the distance from the Earth to the Moon.
NASA said: “As they orbit the Sun, Near-Earth Objects can occasionally approach close to Earth.
“Note that a ‘close’ passage astronomically can be very far away in human terms: millions or even tens of millions of kilometres.”
Asteroid WX1 will zip by at breakneck speeds of 20,065.32 or 8.97km per second.
NASA then expects the asteroid to reappear close to Earth on August 9, 2019.