News From Space: Asteroid Misses Earth (Again!)

2000EM26_1Yesterday, an asteroid estimated to be the size of three football fields passed Earth by. Traveling at 43,000 kilometers per hour and passing at a distance of 8.8 lunar distances of Earth, the asteroid showed up just one year after a similar asteroid exploded over Russia and injured 1,200 people. The only problem was, the good people of Earth missed the show!

Slooh, an online “community observatory” that streams images from ground-based telescopes online during celestial events, was supposed to broadcast the approach of the asteroid as it raced past the planet, starting at 9 p.m. ET (2 a.m. MT).  Unfortunately, Slooh’s flagship observatory on Mount Teide in Spain’s Canary Islands was iced over and unable to catch the asteroid – named 2000 EM26 – as it passed us by.

2000EM26_2014_logoShortly thereafter, Slooh’s robotic telescope tried to snap pictures attempted to snap pictures of the asteroid but failed to capture an image at the predicted position. And now, the asteroid has gone missing in the deep sea of space, giving rise to the nickname “Moby Dick”. This means that either the asteroid’s predicted path was in error, or the object was much fainter than expected.

Paul Cox, Slooh’s technical and research director, said that the asteroid should be somewhere in the visible star field. And rather than accept failure at retracing its path, he and the other folks at Slooh are calling upon amateur astronomers to conduct a photographic search for it in the next few nights. Finding it is not just a matter of honor, but of determining how much the space rock has shifted over time.

2000EM26_2Since the asteroid was last observed 14 years ago for only 9 days, it isn’t too surprising that uncertainties in its position could add up over time, shifting its position and path to a different part of the sky by now. As Cox pointed out:

Discovering these Near Earth Objects isn’t enough. As we’ve seen with 2000 EM26, all the effort that went into its discovery is worthless unless follow­up observations are made to accurately determine their orbits for the future.  And that’s exactly what Slooh members are doing, using the robotic telescopes at our world­-class observatory site to accurately measure the precise positions of these asteroids and comets.

Naturally, there were some who worried that this elusive rock might threaten Earth, given its proximity to our own orbit and the fact that it’s path may have changed. But there is no reason to fear, as these changes are not likely to bring it into our path and it won’t be returning anytime soon. And before it does, we ought to have eyes on it again and be able to accurately chart its course.

2000EM26And above all, similar sized asteroids, including ones passing even closer to Earth, zip by every month. 2000 EM26 received a lot of coverage yesterday in part because it arrived close to the anniversary of the Chelyabinsk meteorite fall over Russia. And though it remains hidden for now, eyes are on the sky to find the asteroid again and refine its orbit.

Hopefully the beast won’t get away next time!



Update on Asteroid Apophis: No Apocalypse by 2036

apophisDiscovered back in 2004, the Apophis asteroid garnered lots of attention when initial calculations of its orbit indicated that there was a 2.7 percent chance that it would hit Earth when it did a flyby in 2029. After running additional calculations based on the asteroids data, scientists were able to rule out a 2029 impact, but there was still a remote possibility that it might hit Earth during another flyby in 2036. However, that estimate has also been revised.

Thanks to the European Space Agency’s Herschel Space Observatory, a number of thermal infrared observations were captured of Apophis at different wavelengths. Taken together with optical measurements, Hershel was able to refine earlier estimates of the asteroid’s properties, which included its overall diameter. Initially, it was estimated to be 270 m on a side but now stands at a robust 325 m, an increased which translates into a 75% increase in its volume.

The thermal readings on the asteroid also provided a new estimate of the asteroid’s albedo, which is the a measure of its reflectivity. Knowing the thermal properties of an asteroid indicates how its orbit might be altered due to subtle heating by the Sun. Known as the Yarkovsky effect, the heating and cooling cycle of a small body as it rotates and as its distance from the Sun changes can instigate long-term changes to the asteroid’s orbit.

All of this taken together, has allowed NASA, the ESA and other space authorities to rule out the possibility of an impact by 2036 as well. Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory:

“We have effectively ruled out the possibility of an Earth impact by Apophis in 2036. The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future.”

But the flyby on April 13, 2029 will be one for the record books, says NASA. On that date, Apophis will achieve the closest flyby of an asteroid of its size when it comes to within 31,300 kilometers (19,400 miles) of the Earth’s surface. And in the meantime, an smaller asteroid (40 meters in diameter) named 2012 DA14 will make an ever closer flyby as it passes Earth at a distance of 27,670 km (17,200 miles).

So people can rest, safe in the knowledge that no asteroids are likely to hit us anytime soon. But at the same time, apocalyptics can rest assured that there will be plenty of remote chances to exploit for the sake of their unusual brand of paranoia. As Yeomans said:

“With new telescopes coming online, the upgrade of existing telescopes and the continued refinement of our orbital determination process, there’s never a dull moment working on near-Earth objects.”