Russian 'meteor' was actually a tiny asteroid, NASA says (45 feet across, 10,000 tons & 40,000 mph)

The Los Angeles Times ^ | February 16, 2013 | Monte Morin

[2ndDivisionVet]

At a news conference Friday, NASA scientists said the object that exploded over Russia was a “tiny asteroid” that measured roughly 45 feet across, weighed about 10,000 tons and traveled about 40,000 mph.

The object vaporized roughly 15 miles above the surface of the Earth, causing a shock wave that triggered the global network of listening devices that was established to detect nuclear test explosions.

The force of the explosion measured between 300 and 500 kilotons, equivalent to a modern nuclear bomb, according to Bill Cooke, head of the Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Ala.

“When you hear about injuries, those are undoubtedly due to the events of the shock striking the city and causing walls to collapse and glass to fly, not due to fragments striking the ground,” Cooke said.

Scientists believe the object originated from the asteroid belt, a vast collection of debris orbiting between Mars and Jupiter that consists of leftover bits from the formation of the solar system. The asteroid probably traveled for a year before it burst into the atmosphere Friday. As yet, no fragments have been recovered, but experts believe the asteroid was rocky in nature, and not formed of dense iron and nickel...

[doorgunner69]

If you have a solid piece of rock with a cavern of boiling water inside, it’s only a matter of time before the pressure builds up enough to cause a powerful explosion.

Yeah, but, that heating takes time. It would have to be damn near instantaneous. Time that is hard to visualize with something coming in that fast. The outer layers would ablate and protect the interior from much heating, how space capsules survive reentry of course.

The energy is certainly there, as evidenced from Karakatoa doing it's thing when water got into the magma chamber. But that huge chunk of rock did not sit and cook.

Without know the true velocity and angle it came in at, how long it took to transit the atmosphere is unknown, but could not have been more than a few seconds and probably a lot less.

[LibertyRocks]

On the videos I watched I heard the very loud sound that accompanied the shockwave (almost simultaneous with the glass shattering) and another much quieter one about 5-10 sec. later - perhaps the echo you mentioned? However, that specific video was taken beside the school and close to the zinc factory, so the second boom may have been the sound of the wall/roof caving in.

A different video looked to be taken a little outside the city, and the sound/shockwave resembled the sound of rolling thunder more than a singular explosion.

What I found the most interesting was how long after the explosion it took for the shockwave/soundwave to travel. Don’t get me wrong, I know light travels faster than sound. I’m familiar with counting time between lightning and thunder to get approximated distance from the strike, but there was just so much time between the explosion and the shock-/sound-wave that it was surprising to me.

- sorry for any typos, or confusion. I’m posting from our nintendo wii via our tv as my comp’s down with a busted video card.

[TigersEye]

I had forgotten those linguistic roots but that’s how I was originally taught the difference too. Each tied to the respective scientific disciplines relevant to the state of the rock/s in question.

[444Flyer]

The physics behind this are pretty amazing. The sound was trailing far behind the first event. And it was almost a ricochet type in hearing.

[444Flyer]

Maybe the fracturing of the original rock was like a shotgun shell. Out from the original shell (asteroid) which fragmented on the way down and out into pieces (the shot), it created an overlap of sound waves because they came at differing velocities?

[MD Expat in PA]

It really doesn’t take very much time for an object traveling at that rate of speed, est. at 40,000 MPH to heat up as soon as it hits the upper atmosphere and begin to vaporize along with any trapped liquids or gasses and sometimes as we saw yesterday, with explosive force. I think I read that it was traveling for about 30 to 40 seconds before it broke up and produced the sonic shock wave.

Size plays a role as does composition – most small meteors burn up completely high up in the atmosphere, i.e. ablate were as a much larger one has a better chance of staying together and hitting the ground creating a crater. And all meteors are not all made alike in density and composition and some may actually be cometary fragments that contain larger amounts of trapped liquids in the form of ice – and angle also plays a role. And meteors are not as you might be thinking, one big solid chunk of very hard dense rock like a piece of solid granite with any water or gas neatly trapped in the center, rather they are loose masses of rock and trapped ice and frozen gasses, if any, are dispersed throughout. And if I understand correctly, the meteor wouldn’t even need trapped liquids to produce what we saw over Russia yesterday, rather the rock its self as it vaporizes, the solids turning to gas, very quickly and breaks apart suddenly is enough to produce the “explosion” which isn’t so much an explosion but a very huge sonic boom. Even low flying supersonic military jets have been known to cause sonic booms big enough to break windows, the Space Shuttle also caused some pretty big sonic booms during re-entry.

And of course meteors are very cold before they hit our atmosphere and heat up very quickly. Think of what happens every Thanksgiving when someone puts a frozen turkey into a deep fryer full of hot oil. : ),

And a space capsule reentry is much different. First of all it isn’t going nearly that fast, aprox. 25,000 MPH plus the capsule is engineered in such a way to slow it down and the heat shields protects it from burning up (as you said “ablatement”) and it is steered as to come in at an optimal angle – not too steep as to burn up and not to shallow as to bounce back into space.

[TigersEye]

The difference between an asteroid and a comet, for example, is that comets travel far faster than asteroids, and are in a higher orbit. They come from the edge of the solar system, barely inside the gravity well of the sun.

By pure coincidence I caught the tail end of a show about the Tunguska event on H2 channel a short time ago. They mentioned another difference between asteroids and comets and that is their composition. They didn't extrapolate much but their point was that they found 14 elements or minerals in the sap of trees in the Tunguska event area, in the 1908 time frame, that are common to stony asteroids but not comets.

[RegulatorCountry]

I guess if we hadn’t been taught that, it would be easy to make the mistake that Medved and NASA(!) made. “Asteroid” just sounds big-@$$ed, and popular entertainment has certainly helped that perception along. It’s always an asteroid impact that destroys the world.

“Meteor” sounds sort of diminutive by comparison, like a “mini-asteroid,” so many take it to mean just that.

Then, we get to the meteorite, which sounds even more diminutive, a mistaken “meterorette” if you will. A little, itty bitty one ... petite.

I blame the French, lol.

[TigersEye]

It is kind of a funny distinction. A piece of rock can exist as an asteroid for millions of years. Maybe billions. But then it hits the atmosphere and it's a meteor for a minute or two at best. Most of them only last a few seconds.

It's about time the French took the blame they deserve.
Bush has been taking the load off of their shoulders for far too long. heh

[wastedyears]

I’ve read that book once, and I’d rather keep it to once. I was afraid that reading the book would give me nightmares that would wake me up, but thankfully I didn’t have any. Something like that is certainly a nightmare scenario.

[GeronL]

Oh No!

Earth is breaking up!!

[Gandalf_The_Gray]

Russia seems to be a landing spot for these objects...

The defunct USSR spanned 12 time zones which is half way around the world. Russia was a big slice of that, making it a very large target for incoming space junk.

I was surprised to hear that Antarctica is prime hunting ground for meteorite debris. I wouldn't expect them to be found there for the same reason bugs hit a car's windshield a lot more than they hit the side windows.

Regards,
GtG

[Chickensoup]

I was surprised to hear that Antarctica is prime hunting ground for meteorite debris. I wouldn’t expect them to be found there for the same reason bugs hit a car’s windshield a lot more than they hit the side windows.

__________________

I was aalways under the impression that there is no real front in space. That is a human construct to make sense of it. So there would be as many meteorites coming towards that side of the world as any other.

[Clay Moore]

I don’t think it is necessarily because there are that many more meteorites, it is just the fact that they stand out against the ice/snow.

[Figment]

That’s because Russia is vast.

Yes Russia is a large land mass. What I was referring to though, was the large objects that have hit there. There was a very large object of some type that hit in the early 1900’s that affected a huge area.

[wastedyears]

Was it neutron star material? Then again, that would weigh more than all the people on the planet combined. So it wouldn’t have been neutron star material, but its hardness would’ve been considerably higher than that of diamond.

Do you remember the name of that book as well? I might as well put sci-fi in its own slot in my personal food pyramid.

[Gandalf_The_Gray]

I was always under the impression that there is no real front in space. That is a human construct to make sense of it. So there would be as many meteorites coming towards that side of the world as any other.

You're right about the distribution of space junk as being random but don't forget we are moving through that cloud of junk at substantial speed.

Einstein called these thought experiments but really, anyone can do them.

Picture yourself high above the north pole looking down on the earth from a vantage point at a right angle to the plane of the earths orbit. The earth is traveling an orbital path with a radius of 93 million miles which is nearly circular. The circumference of that path is a bit over 584 million miles and the travel time is 365.25 x 24 hour days. The tangential speed of the orbiting earth is therefore the circumference divided by the orbital period which is about 66,700 miles per hour. Looking down at the earth from "above" the plane of the ecliptic, the hemisphere facing into the direction of travel is moving "forward" into the path of space junk moving through our orbital path and overtaking that moving junk at 66,700 mph. Conversely, the trailing hemisphere (looking back along our orbital path) is moving away from any space junk crossing our path which would have to catch up with us in order to score a hit.

Did you ever notice when the weatherman says there is going to be a meteor shower tonight they always tell you that best viewing is from midnight till dawn? Ever wonder why?

Go back to our "observation point" and look down again. Note the two hemispheres facing forward and trailing are both half in sun light and half in darkness. Noon is facing directly in toward the sun, midnight is facing directly outward from the sun. Look down very closely at midnight, do you see the little guy waving his right hand at you? Since he is looking at you he is looking North. His right hand is pointing east on the globe since that is where the sun rises, his left hand is pointing west toward sunset (we are rotating on axis CCW or widdershins if you like). So from sunset to midnight the earth is moving away from any meteors passing our orbit. From midnight to dawn we are chasing after them at 66,700 mph and sweeping up a lot more then catch us from behind.

Most of the stuff orbiting the sun stays confined to the plane of the ecliptic which is the remnant of the dust cloud that collapsed/condensed into the solar system. Comets and some of the stuff from way out there occasionally comes looping in at strange angles and that, no doubt, will be the one we will wind up hitting (OMG! ITEOTWAWKI! and I feel fine...)

I hope that clears it up a bit, you're right, you do need a frame of reference to make sense of it. I like the windshield concept 'cuz it's easy to visualize bugs hitting you (or you hitting bugs, macht nichts) while moving forward. It's also hard to picture a bug moving fast enough to hit the back window. If this seems hard to visualize, think of what it must have been like for those shepherds watching their flocks by night?

Regards,
GtG

PS That little guy waving up at you?
That was me...
G

[gitmo]

They had thought this thing was 10 tons, now 10,000 tons? Quite a difference.

They caught the thing on camera. That adds ten pounds right off the bat.

[wastedyears]

What’s that from?

[GeronL]

A cartoon called “Skyland”, earth or whatever planet it was supposed to be had broken up into many floating pieces.

http://en.wikipedia.org/wiki/Skyland