Mountain sized asteroid to fly-by Earth

The giant space rock will be visible even through small amateur telescopes

The asteroid will be visible for the entire night of 26-27 January 2015. Credit: NASA/JPL-Caltech. JPL orbit solution #43, with star chart graphics produced using C2A
Published: January 25, 2015 at 12:00 pm

A large asteroid will buzz past the Earth on the evening of Monday 26 January 2015. The huge asteroid, named 2004 BL86, is 550m in diameter but will fortunately pass by 1.2 million km from the planet, about three times the Earth-Moon distance.


This will be our closest call with an asteroid this size until 2027.

Rather than being a cause for panic though, this asteroid is shaping up to be an exciting event.

The closeness of the pass means that we will be able to get a fantastic view of the asteroid up close, without having to travel all the way to the asteroid belt to do so.

The rock will be monitored by telescopes around the world, such as the Arecibo radio telescope in Puerto Rico.

These telescopes will be tracking the asteroids path and determining its size, taking advantage of the 'up close' view to get as much data on the object as possible.

"For objects that get this close, that are this large, the radar observations are really analogous to a spacecraft flyby in terms of the calibre of the data that we can get," says Lance Benner of NASA's Jet Propulsion Laboratory in Pasadena, California when talking to

How to observe the asteroid

But it’s not just professional telescopes that will be able to see the asteroid.

It should be visible through powerful binoculars or a small telescope (3-inches or larger) as it heads north through the constellation of Cancer at a rate of about 2.5° an hour.

Though the closest approach will be at around 4PM UT, the asteroid will be at its brightest from between 1 to 6AM UT.

The best way to catch the asteroid is to point your telescope at a bright star along the space rock’s path and wait until it passes by.

The asteroid will be moving fast enought that you will be able to see it moving relative to a fixed point, so there will be no mistaking it.

For those who don’t mind getting up early the asteroid will be passing the eastern edge of the Beehive Cluster (M44) between 5:00-5:30AM.


If you want to work out when and where your best viewing opportunity is, take a look at binoculars or a small telescope.


Ezzy Pearson is the News Editor of BBC Sky at Night Magazine. Her first book about the history of robotic planetary landers is out now from The History Press.

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