On Tuesday May 15 our planet had a fleeting visitor: an asteroid about the size of a city block will pass by at about half the distance to the moon.
While there was no reason for concern about it hitting the Earth – NASA determined that it posed no threat – it was one of the closest passes of an asteroid this size yet observed.
The asteroid, which is officially named 2010 WC9, was at its closest to the Earth at 6:05 pm EDT Tuesday evening.
2010 WC9 is on the small side as far as asteroids go, measuring between 197 to 427 feet. But despite its unremarkable size, it’s quite notable in terms of its proximity.
As Eddie Irizarry reports for EarthSky, this flyby was the closest this particular asteroid has come to the Earth in over 300 years, whizzing past at a distance of 126,000 miles from our planet’s surface.
Though astronomers at the Catalina Sky Survey discovered this asteroid back in November 2010, it disappeared from sight a month later. The asteroid remained hidden from view until just last week.
Finally able to track the space rock’s path, astronomers quickly predicted the asteroid’s path, finding it would pass by Earth at a close, but not catastrophic, distance.
NASA classifies roughly 1,900 of known space rocks as Potentially Hazardous Asteroids (PAH), based on their calculated to threaten Earth. Thankfully, 2010 WC9 does not fall in this category.
As NBC’s David Freeman writes, asteroids of 2010 WC9’s size shouldn’t be too much cause for concern as they’re only thought to make contact with our planet just once every 6,000 years.
If this asteroid were coming close enough to hit Earth, though, it could really wreak havoc.
WC9 is estimated to be larger than the Chelyabinsk meteor, which exploded in the skies over Russia in 2013, producing a large shock wave and many small meteorites. The blast caused 1,500 injuries, which were mainly due to shattered glass, Deborah Byrd reported for EarthSky in 2016.
And depending on WC9’s makeup, if it were to collide with our planet, it could be powerful enough to make a crater almost a mile wide, Erin Ryan, an astrophysicist at NASA’s Goddard Space Flight Center, tells NBC.
For those who hoped to catch a glimpse of the space rock, WC9 proved elusive without a telescope. Given its small size and brisk pace of 28,655 miles per hour, the asteroid was not be visible to the naked eye when it passed by us.
But astronomy enthusiasts lacking telescopes were still be able to see it; Northholt Branch Observatories in London provided a look by livestreaming the event on Facebook.
There was no need to take cover – the odds of an asteroid strike remain vanishingly small.
But we did get the treat of taking a closer look at 2010 WC9 before it hurtled away on its orbit of the sun.