A mountain-sized asteroid hurtling toward Earth will miss us, but it will be close – astronomically speaking at least.
Asteroid 2004 BL86 is estimated to be about 500 metres across, and on Jan. 26 will come as close as 1.2 million kilometres from Earth. While that is about three times the distance that separates us from our Moon, this cosmic encounter will be one for the record books, since it is the closest for any known and tracked space rock this large until 2027.
"Monday, Jan. 26 will be the closest asteroid 2004 BL86 will get to Earth for at least the next 200 years," said Don Yeomans, manager of NASA’s Near Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California.
"And while it poses no threat to Earth for the foreseeable future, it’s a relatively close approach by a relatively large asteroid, so it provides us a unique opportunity to observe and learn more,” Yeomans said in a press statement.
Asteroid 2004 BL86 was initially discovered on Jan. 30, 2004 by a telescope of the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico.
The wayward space rock is considered a potentially hazardous asteroid since it does come so close to our planet.
If something this size were to hit the Earth, its impact would be catastrophic. The energy of the impact would be equal to about 5000 megatons and carve out a crater about six kilometres wide. The destructive force would be enough to destroy a small U.S. state, but the effects would be much more far-reaching if it hit an ocean, because major tsunami waves would wash over many coastal cities across an entire hemisphere.
Luckily, impacts from asteroids in this size range occur every few hundred thousand years.
The asteroid is expected to be observable to amateur astronomers with small telescopes and strong binoculars.
The asteroid will reach its closest point to Earth at 11:20 a.m. EST on Jan. 26, so Canadians will have to wait until nightfall to hunt it down.
BL86 will be travelling through the constellations Hydra and Cancer visible in the south-southeast sky and should be between two bright celestial guideposts – planet Jupiter and the the star Sirius. By early next morning around 1 a.m. it will be making a close pass of the famed Beehive star cluster. Travelling at speeds of 56,000 km/h, it will appear to traverse the width of the full moon in just ten minutes. So the best way to identify positively that you have found the asteroid is to watch it move quickly across the backdrop of fixed stars.
In the overnight hours its estimated brightness is pegged to be around 9.5 magnitude, making it just visible with large binoculars and an easy target through small backyard telescopes.
"I may grab my favourite binoculars and give it a shot myself," Yeomans said.
If you do get clouded out or don’t have binoculars or telescopes, you can catch all the action online thanks to a live webcast from robotic telescopes stationed around the world via the Virtual Telescope Project.