The imposing space rock, dubbed Asteroid 2013 UG1, will zip past our home planet on the morning of Thursday, October 18.
NASA’s Jet Propulsion Laboratory (JPL) estimates the asteroid’s size somewhere between 301.8 ft and 688.9 ft (92m and 210m) in diameter.
The asteroid could be twice as tall as London’s Big Ben clock tower and the Statue of Liberty in New York.
The London Eye, Tower Bridge and the Great Pyramid of Giza could also all fit inside of the speeding asteroid.
And if that was not terrifying enough, if the asteroid crashed into Earth the toll could be absolutely catastrophic – even at NASA’s lower size estimate.
The 1908 Tunguska asteroid which flattened more than 772 square miles (607 square miles) of forest in Russia measured only 196.8 ft (60m) across, according to some estimates.
The potential threat to life is astounding, considering the land area of London is estimated to be around 606.99 square miles (1,572.1 square km), according to the London Data Store and Greater London Authority.
Thankfully the NASA-tracked asteroid will speed past the planet without connecting.
NASA estimates Asteroid UG1 will fly by from a distance of 0.02675 astronomical units (au) or 10.41 lunar distances (LD).
One astronomical unit is equal to the average distance between the Earth and the Sun, or more than 92.9 million miles (149.6 million km).
In this case, the asteroid will approach the Earth as close 2.48 million miles (four million km).
The distance is roughly the equivalent of 10.41-times the amount of space between the Earth and the Moon.
In other words, the asteroid will be 10-times farther away from the Earth than the Moon is.
The asteroid will reach its closest distance to Earth around 3.45am BST (2.45am UTC) on Thursday morning.
The distances in question might feel like a lifetime away but on the astronomical scale of things, the flyby is close enough for NASA to pay attention.
NASA dubbed the flyby a Close Earth Approach and the asteroid is a so-called Near-Earth Object (NEO).
The Smithsonian Astrophysical Observatory explained: “Near Earth Objects are asteroids or comets whose orbits sometimes take them close to the Earth’s orbit.
“An NEO could therefore someday collide with the Earth – and there are almost 7000 of them known, with several times that many predicted to exist.
“The impact of even a one-kilometre-sized NEO would probably destroy an average state.”
On Thursday, the asteroid will fly by at breakneck speeds of 30,019.6mph or 13.42 km per second.
Asteroid UG1 will return to Earth’s cosmic neighbourhood on the morning of December 29, 2021, followed by another flyby October 20, 2023.