2003 SD220: Mile-Wide Asteroid 163899 to Whiz Past Earth Just Before Christmas

On December 22, a large asteroid, known as 163899 (2003 SD220), will make a close approach to our planet, according to data from NASA's Center for Near Earth Object Studies.

Luckily for us, the space rock—which is estimated to be between 0.6 and 1.3 miles in diameter—will come no closer than 1,756,864 miles to the Earth, meaning there is no risk of a collision.

Read more: NASA's OSIRIS-REx has landed on Bennu—an asteroid potentially on a collision course with Earth

If an asteroid of such a size did strike the Earth—an event that occurs roughly every million years—the impact would likely have catastrophic consequences for humanity. Aside from the massive destruction resulting from the initial impact, the global climate would be affected for years to come, leading to widespread crop failures, among other effects.

2003 SD220 is traveling at incredible speeds of around 14,000 miles per hour (relative to the Earth) and appears to be very elongated in shape, according to observations made by the Arecibo radio telescope in Puerto Rico. The asteroid also rotates very slowly, taking more than 11 days to complete a single rotation.

Asteroids are considered to be possible leftovers from the formation of the Solar System and thus are objects of interest for future space missions.

"Because [2003 SD220] comes close to Earth it is of interest to NASA as a possible future robotic or human mission target," Patrick Taylor, a researcher at the Arecibo Observatory, said in a statement.

Despite the fact that the asteroid will not strike Earth, it is defined as a "near-Earth object" (NEO) that is "potentially hazardous."

Near-Earth Objects are any asteroids or comets whose orbits take them within about 121 million miles of the sun and into proximity with the Earth.

If the orbit of a NEO at the time of its discovery is such that there is a (typically small) chance it will collide with Earth and cause significant damage, it is labeled "potentially hazardous," according to the Swinburne Astronomy Online Encyclopedia.

The asteroid, or other object, must have a minimum approach distance of less than 0.05 astronomical units, or roughly 4.6 million miles, to be classified as such, as well as being at least 460 feet in diameter.

Once potentially hazardous asteroids or other objects are discovered, they are monitored continually by observatories around the world. Over time, their orbits may be disrupted through gravitational interactions with other planets or bodies, increasing or decreasing the risk of a collision.

But even though the orbits of "potentially hazardous asteroids" are uncertain, "it is possible to estimate the size of these uncertainties and place corresponding limits on close-approach distance and time," according to NASA.

In total, the number of known NEOs exceeds 18,000, of which more than 1,800 are considered potentially hazardous. Researchers have detected around 90 percent of NEO's larger than a kilometer in size, none of which are predicted to collide with Earth. There are, however, thought to be many NEOs smaller than this that are currently unaccounted for.