Astronomers Calculate Russian Meteorite's Orbit, Find It Has 80 Million Cousins

The Chelyabinsk meteorite came from a well-known family of Earth-crossing space rocks known as the Apollo asteroids.

By Rebecca Boyle Posted 02.26.2013 at 6:02 pm 2 Comments

Asteroid Orbits Both the asteroid 2012DA14 and the Chelyabinsk meteorite came from the asteroid belt, but from different orbits. Earth's orbit is shown in green. NASA

Thanks to dozens of video reports, scientists are getting a pretty good handle on the life history of the massive meteorite that exploded above Russia earlier this month. They know it is rocky and a common type, and now they know where it probably came from. Scientists are scrambling to publish papers describing its origins in the middle of the solar system.

The asteroid chip that became the recent meteorite came from a spot in the asteroid belt near Jupiter, about 2.5 times further from the sun than Earth is, according to NASA.

At the University of Antioquia in Colombia, astronomers Jorge I. Zuluaga and Ignacio Ferrin produced a preliminary reconstruction of its orbit around the sun. It came from a well-known group of asteroids that frequently cross paths with Earth, known as the Apollo asteroids. Astronomers have seen about 240 that are larger than a kilometer in diameter, but speculate that about 2,000 similarly sized space rocks exist. As for rocks of Chelyabinsk size? There could be 80 million.

The space rock’s trajectory can also be determined through infrasound, astronomers said. Infrasound ripples spread through the atmosphere as the meteorite exploded, and by examining their patterns, scientists can figure out which direction the meteor traveled and how much energy it unleashed. Elephants and homing pigeons can hear it, but all humans can do is turn to the infrasound stations monitored by the Comprehensive Test Ban Treaty Organization.

“We would like to know not only where it came from, but how big it was, how coherent it was, where it stated breaking up, where its terminal impact was,” said Bill McKinnon, professor of Earth and Planetary Sciences at Washington University in St. Louis. “People have studied the entry of these sort of meteors before, but they’re usually not quite so big. We haven’t had a chance to have such a good instrumented look at these things ... they don’t undergo terminal deceleration over a city of a million people.”

Nobody could see it coming because it careened toward Earth from the same direction as the sun, so no telescopes could have detected it. But video cameras throughout Russia captured its entry, and Zuluanga and Ferrin use these to reconstruct the space rock’s orbit. They used trigonometry to determine its speed, height and position--it entered at a shallow 30-degree angle--and then they calculated its height, elevation and geolocation at its so-called “brightening point,” when it becomes bright enough to cast a shadow in the videos. They plugged this data into a model that computes the gravitational influence of the moon, Earth and other planets, and figured out it was an Apollo group asteroid. Their paper is posted to the physics arXiv preprint server, and McKinnon notes there are probably many more to come.

Chelyabinsk Meteorite Orbit: Jorge I. Zuluaga and Ignacio Ferrin

[via Technology Review, NASA]

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2 Comments

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gizmowiz

02/27/13 at 12:46 am

There are tens of thousands out there with our number on it.

Which is a good thing since we can use 'captured' rocks to destroy incoming rocks.

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gizmowiz

02/27/13 at 9:10 pm

Well one of it's cousin could soon be making BIG trouble for us!!

How so?

NASA has recently discovered a Comet named C/2013 A1 (Siding Spring) that is going to pass within 67,000 miles of Mars and once additional measurements are made -- the 'probability cone' for impact may actually include Mars itself and so it could actually collide with Mars.

Why is that a problem for us when Mars is so far away?

Because this Comet is 125 times more volume than the one that killed the dinosaurs 65 million years ago here on Earth--and will be traveling at 126,000 mph when it approaches Mars.

To put that in perspective--the 6 mile wide asteroid that hit Chixilub created a 180 mile crater. If this one does indeed hit Mars it will create a crater over 1000 miles across and throw up an enormous amount of material out into space---millions of rocks from inches across to hundreds of feet across. And much of that will exceed the escape velocity and become 'Martian Asteroids'.

Thus we could be in the path of a huge Martian Asteroid swarm as it heads away from Mars in multiple directions in about 6 to 7 months later when the Earth swings around the sun.

To see this in a diagram visit this link http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013A1;cad=1;orb=1;cov=0;log=0#orb

The energy of the impact is estimated at 20 billion megatons. That's more than an order of magnitude bigger than the biggest Shoemaker Comet that hit Jupiter.

Comet C/2013 A1 is nearly 34 times larger than largest Comet that hit Jupiter (Shoemaker 9)--the largest of which was 9.3 miles across and created a plume bigger than the Earth itself.

So if this Comet DOES hit Mars will be able to see the light show from Earth during broad daylight as it will shine brighter than the sun for a moment--almost like a Super Nova as seen from millions of light years away--it will be a stupendous explosion and the energy released will be truly awesome. This Comet won't have the energy slow down from an atmosphere like on Earth or the massive 'digester' atmosphere that is on Jupiter.

So Earth could very well get hit from the 'fallout'.

Which would be a meteor storm unlike anything the Earth has experienced in millions if not hundreds of millions of years.

Insane huh?

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