0723 GMT December 17, 2018
The asteroid, dubbed Asteroid 2018 WD2, is expected to swing by our home planet in the evening hours, according to express.co.uk.
NASA’s scientists at the Jet Propulsion Laboratory (JPL) in Pasadena, California, have pinpointed the flyby to about 9:13 p.m. GMT (UTC). The large space rock is estimated to measure somewhere in the range of 55.7 feet to 121.4 feet (17 meters to 37 meters).
An asteroid this big is longer than four double-decker buses stacked in a row and is six-times the height of an average male giraffe.
Past asteroid and meteor impacts show space rocks measuring upwards of 65.6 feet (20 meter) can be extremely dangerous if they slip through the atmosphere undetected.
One such incident occurred five years ago over the Russian city of Chelyabinsk when a small meteor exploded over the city.
The ensuing shockwave blew out windows across Chelyabinsk, injuring more than 1,000 people with razor-sharp shards of glass.
NASA explained: “Only once every few million years, an object large enough to threaten Earth's civilization comes along.
“Impact craters on Earth, the moon and other planetary bodies are evidence of these occurrences.
“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 kilometer – a little more than 1/2 mile – were to hit Earth, it would likely cause local damage to the impact area.”
Any space rock larger than 0.62 miles to 1.2 miles (one to two kilometers) is when scientist really start to worry about the planet’s safety.
Thankfully the risk of Asteroid WD2 hitting the Earth today is absolutely minimal.
The asteroid will make a so-called Earth Close Approach but even at its closest, WD2 will only approach Earth from 0.00879 astronomical units (au).
One astronomical unit is the distance from the Earth to the Sun – about 93 million miles (149.6 million kilometers).
Asteroid WD will close this distance down to just 817,081.55 miles (1.3 million kilometers).
This is the equivalent of 3.42 Lunar Distances (LD) or 3.42-times the distance from the Earth to the Moon.
On the cosmic scale of distances, this might seem like a lifetime away, but astronomers consider this to be so-called Near Earth Object.
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 kilometers.”
The US space agency estimates the asteroid is barreling through space right now at breakneck speeds of 16,978.35 miles per hour or 7.59 kilometers per second.