The world awoke to a pretty cool event Friday morning. At least, it was Friday morning at the epicentre of the event. Yes, I am indeed speaking of the meteorite that showered the Russian city of Chelyabinsk.
Thankfully, no one was killed by the meteorite. Instead, most injuries came from glass fragments: Shockwaves damaged buildings, blew out doors, collapsed walls and shattered windows.
The Russian Academy of Sciences estimates that the meteorite weighed about 10 tons and entered the Earth’s atmosphere at a speed of at least 54,000 kph (33,000 mph), shattering into several smaller pieces about 30-50km (18-32 miles) above ground.
Coincidentally, a rock imaginatively called 2012 DA14, hurtled past us, but within the orbit of some high station satellites on the same day. 2012 DA14 is 50 meters wide, or half the size of a soccer field. Had it struck us, it would have caused significantly more destruction.
Two in one day? What gives?
As it turns out, zillions of objects hit earth’s atmosphere every day.
|Asteroid Size||Frequency||Damage Potential|
|1 micron||Every 30 microseconds||Burns up in atmosphere|
|1 millimeter||Every 30 seconds||Burns up in atmosphere|
|1 meter||Every year||Tiny burst in air, no piece reaches ground|
|10 meters||Every 10 years||Moderate burst in air, some fragments may reach ground. The bolide that hit Russia on Feb. 15 was estimated to be 15 meters across.|
|100 meters||Every 1,000 years||Enormous burst in air, leveling large area, equivalent to a thermonuclear hydrogen bomb. Tunguska impact that hit a remote part of Russia in 1908 was one of these.|
|10 kilometers||Every 100 million years||Gigantic planet-wide destruction, mass extinction, enormous crater. The Chicxulub impactor that killed the dinosaurs was one of these.|
Scientists at NASA’s Near-Earth Object Program Office in Pasadena, Calif. estimate that an asteroid the size of 2012 DA14 flies this close every 40 years on average and that one will impact Earth, on average, about once in every 1,200 years. Hm. By those odds, we’re due. Will we have fair warning?
NASA has several ongoing programs with eyes to the stars for potential projectiles.
The NASA Near Earth Object Observation (NEOO) Program detects and tracks asteroids and comets passing close to Earth using both ground- and space-based telescopes. The network of projects supported by this program, commonly called “Spaceguard,” discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.
All observations from observatories worldwide are sent to the NASA funded Minor Planet Center, operated by the Smithsonian Astrophysical Observatory for the International Astronomical Union, where they are combined to maintain the database on all known asteroids and comets in our solar system.The NEO Program Office performs more precise orbit determination on the objects, and predicts whether any will become an impact hazard to the Earth, or any other planet in the solar system.
(Another cool thing the NEOO Program does is perform orbit analysis on the discovered Near Earth Asteroids (NEAs) at Goddard Space Flight Center to determine which ones may become good robotic or human spaceflight destinations in the near future.)
So what if NEOO discovers an asteroid on a collision course with Earth? Well, much of it depends on the size of thing, however, NASA has started several basic research and technology projects designed to research how they might best be deflected from an Earth impacting trajectory, or to develop the space technology required to do this.
These projects include some pretty cool stuff, such as “improved Solar Electric Propulsion (SEP) systems” that could push or pull an asteroid for an extended time. They are also working on close proximity operations and grappling mechanisms to work in and around asteroids and manipulate their surfaces. Let’s face it, this technology will also be useful for future robotic and human missions to these objects, and even potentially resource mining operations.
Well, while they’re playing with these awesome toys, let’s make sure someone’s paying attention to the skies…