An asteroid first tracked in 2010 and faded into view 10 days later appears again and makes its closest approach to earth on May 15.
The asteroid, identified as 2010 WC9, skimmed past Earth at 6:04 p.m. EDT. The May 15 flyby became the closest distance to Earth that the asteroid would make for at least two centuries. Even at its proximity, it remained invisible to the naked eyes.
Hours before its arrival, NASA estimated that the Asteroid 2010 WC9 would be at a speed of about 8 miles per second but would be no closer to Earth's surface than about 120,000 miles. This is about half the distance between Earth and the Moon.
Animated Asteroid 2010 WC9 Flyby
Asteroid 2010 WC9 is an Apollo-type space rock, which means that it has its own orbit outside the main path where other asteroids are commonly found. This also meant that without an aid of a telescope, people did not have the opportunity to see it unless they waited for live broadcast held by various space agencies.
The Northolt Branch Observatories in London, England, has created an animation based on the data collected during their live broadcast.
The observatories' preliminary analysis of their data showed that the asteroid's brightness varied significantly due to light curve variations.
"This suggests that it rotates rapidly (with a period less than 20 minutes) and that it has a rather elongated shape (we see an amplitude of about 1 magnitude)," the observatory said.
Lost And Found Asteroid
Asteroid 2010 WC9 was first discovered on Nov. 30, 2010, by the Catalina Sky Survey near Tucson, Arizona. However, it faded from view 10 days after being detected.
In 2010, calculations done by NASA ruled out the possibility of the asteroid colliding to Earth by 2018 even if astronomers could not predict the exact velocity of its impending approach.
On May 8, astronomers discovered an anonymous asteroid that they temporarily called ZJ99C60, only to realize that it was the asteroid 2010 WC9 making a comeback.
'Massive' Asteroid
Asteroid 2010 WC9 is about 200 to 400 feet across or about the size of New York City's Statue of Liberty. It could also be longer than a football field. Because of this "massive" size, people had in fact feared about its possible collision to Earth weeks before its flyby. This possibility, however, had been repeatedly dismissed by astronomers.
The description of it being "massive" also appears to be an exaggeration, as NASA described it as being a "small" asteroid.
Nevertheless, 2010 WC9 is larger than the asteroid that entered Earth's atmosphere in 2013 and exploded 14 miles above the ground. It approached the Earth at about 11 miles per second and released an energy of around 440,000 tons of TNT. The energy's shock blew out windows and damaged buildings in Chelyabinsk, Russia, where there were about 1,600 people left injured.
