2014 AA orbit trajectory prior to striking Earth. Credit: MPC
Discovery images of asteroid 2014 AA, provided by the Catalina Sky Survey. 2014 AA is in the magenta circle.
“Let’s start 2014 with a bang! Hello and goodbye to asteroid 2014 AA” posted José Luis Galache, an astronomer at the Minor Planet Center in Cambridge, Mass.
On January 1, Richard Kowalski at the Mount Lemmon observatory in Arizona spotted an incoming asteroid, later dubbed 2014 AA. What’s special about 2014 AA is that this space rock was found before it got to planet Earth.
The observatory is part of the Catalina Sky Survey at the Univ. of Arizona’s Lunar & Planetary Laboratory. Furthermore, sharp-eyed Kowalski is also the discoverer of the only other asteroid — 2008 TC3 — to have been observed before entering Earth’s atmosphere. That was back in October 2008 with the object breaking up over northern Sudan.
Best estimate
As for the New Year’s Day event, luckily it was a very small asteroid,” Galache said. At a modest one to 3 meters across, it “almost surely burned up in the atmosphere, with the most that could reach the ground being small fragments.”
According to Galache’s posting, Peter Brown of the University of Western Ontario, later triangulated the impact spot of the object, based on data from infrasound detectors used by the Comprehensive Nuclear-Test-Ban Treaty Organization. That group keeps and ear out on who’s exploding what…and where.
Brown’s best estimate is that 2014 AA fell apart half way over the Atlantic, some 3,000 km East of Caracas, Venezuela, and 1,800 km West of the Cape Verde islands, according to the Galache website posting.
Unseen and untracked asteroids
Also underscoring the importance of 2014 AA is the B612 Foundation. It issued a statement: “We are reminded by this event that asteroids can and do strike Earth, perhaps in greater numbers than we realize.”
The purpose of the B612 Foundation is to reveal unseen and untracked asteroids before they find us. The private group is working with Ball Aerospace to develop the Sentinel Space Telescope, to be launched in 2018, and designed to provide a comprehensive map of the locations and trajectories of untracked threatening asteroids.
Next detection, when?
However, the goal of Sentinel is not to find asteroids as small as 2014 AA, which due to its small size was highly unlikely to be dangerous, but rather to find larger asteroids capable of massive destruction should they hit Earth.
It’s the intent of B612 that, by the end of the Sentinel’s planned lifetime, the space-based instrument will have discovered well over 90% of the asteroids that could destroy entire regions of Earth on impact (those larger than 350ft in diameter).
“Let’s not forget that asteroids the size of a car enter the Earth’s atmosphere a few times a year,” Galache advised. But what’s special about 2014 AA is that it was discovered before it got here. “Will we have to wait another 5 years to do it again?”
By Leonard David