Meteoroid explosion in Russia

[FordPrefect]

NASA estimates the object had a size of 17 meters (55 feet) in diameter and a mass of around 10,000 tons before atmospheric entry.

http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html

 

[Urwumpe]

NASA estimates the object had a size of 17 meters (55 feet) in diameter and a mass of around 10,000 tons before atmospheric entry.

http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html

500 kT energy??? Thats the magnitude of a modern nuclear warhead. Has somebody typed a zero too much into the pocket calculator?

 

[T.Neo]

500 kT energy??? Thats the magnitude of a modern nuclear warhead. Has somebody typed a zero too much into the pocket calculator?

Just for comparison, what sort of effects would occur on the town of Chelyabinsk if this object at the the time of its explosion were replaced by a 500 kiloton explosion (neglecting radiation and radiological concerns of nuclear devices, of course)?

 

[FordPrefect]

500 kT energy??? Thats the magnitude of a modern nuclear warhead. Has somebody typed a zero too much into the pocket calculator?

Hmmh.. I was wondering too. Do we have to take into account, that the energy was released at a high altitude (40-20 kilometers) and along a similar distance (along the trail)?

Edit:
I am by far no expert, but it looks like there's an area on the trail, where it looks like glowing (plasma?).

 

[Urwumpe]

Just for comparison, what sort of effects would occur on the town of Chelyabinsk if this object at the the time of its explosion were replaced by a 500 kiloton explosion (neglecting radiation and radiological concerns of nuclear devices, of course)?

I just looked at it... a 600 kT air burst in 12 km altitude would result in the observed damages to the glass windows in 40 km distance, with the expected travel time of the burst, at least according to impact effects.

But it is pretty hard fitting the data of the impactor there to the observed event. A very shallow trajectory with porous rock results in a too high break up, also there are no expected fragments. With dense rock, the calculation is closer, but the impactor is much bigger than even NASA claims, with 80 meters.

I would say, the relation of air burst energy and window damage can be considered accurate enough, so 500 kT is really needed for explaining the damage.

 

[Keatah]

What would happen had this entered at a less oblique angle? Something like straight down so to speak.

---------- Post added at 05:29 AM ---------- Previous post was at 05:28 AM ----------

And furthermore, there are all kinds of rumors this is related to 2012 DA14. One hell of a coincidence, yes?

 

[Quick_Nick]

And furthermore, there are all kinds of rumors this is related to 2012 DA14. One hell of a coincidence, yes?

http://www.facebook.com/photo.php?f...2423332.103856.442058505818917&type=1&theater

As for the asteroid, see the last several pages.

 

[Urwumpe]

And furthermore, there are all kinds of rumors this is related to 2012 DA14. One hell of a coincidence, yes?

It is not related at all, except by the date. it simply happened 14 hours before an NEO passed close by Earth. We simply discover more and more asteroids to pass near Earth, so chances are higher that an asteroid will pass near Earth and a meteor happens.

 

[Artlav]

Unlike a nuke, here the energy was released over some seconds, rather than in one microsecond flash, so maybe that buffered the effect somewhat?
Power density vs total energy.

 

[Urwumpe]

Unlike a nuke, here the energy was released over some seconds, rather than in one microsecond flash, so maybe that buffered the effect somewhat?
Power density vs total energy.

Yes, that could be one aspect, though the main fragmentation happened in milliseconds. Still produced a louder bang.

The ration between flash and blast is likely also different.

 

[FADEC]

I would like to see it over my home town. Of course in a theoretical scenario without personal injury. But I really love such forces of nature. Doesn't scare me at all.

But it "only" was a "graze shot". What would happen if something like this enters the atmosphere almost vertically? How long would it take? 2-3 seconds?

 

[Screamer7]

I would like to see it over my home town. Of course in a theoretical scenario without personal injury. But I really love such forces of nature. Doesn't scare me at all.

But it "only" was a "graze shot". What would happen if something like this enters the atmosphere almost vertically? How long would it take? 2-3 seconds?

What struck me a lot is the share size of the dust cloud.
I always see that debris trail in movies, but did not realize that it can be so huge.
If you take the altitude the meteor exploded above the surface, I say it is a pretty big cloud of dust.
And what also was interesting of that dust cloud is that it formed a twin trail.
And I wonder what type of meteorite it was.
According to news footage and You Tube video's, it may be the rocky type.

Fadec and Keetah, try this web site.

http://impact.ese.ic.ac.uk/ImpactEffects/

 

[FordPrefect]

Another HD video appeared, this time the meteorite or its trail is not visible directly, but you get a good sense of the blast wave. Impressive sound...

http://youtu.be/Q4RUZRa3dO8

 

[Cairan]

Another HD video appeared, this time the meteorite or its trail is not visible directly, but you get a good sense of the blast wave. Impressive sound...

http://youtu.be/Q4RUZRa3dO8

Look closely at the smoke coming from the smoke stack... If I'm not mistaken you can see the effects of the shockwave on the smoke... :thumbup:

 

[N_Molson]

That event should remind us how bad we are prepared to deal with NEO... Would have the thing been a little bigger and exploded over major population centers, we terrans would have had a very very bad day... Improving detection assets is the priority IMHO.

Might be the time to train on deviating "near misses" like 2012 DA14 (though, of course, this can be dangerous, you don't want to change a "near miss" to a "dead center"). :hmm:

 

[Cairan]

Well, I guess having full doppler radar coverage of the near-Earth space would not be quite practical for events such as yesterday...

 

[Keatah]

What would have happened had this come straight down, I can't imagine it burning up or exploding since the time in the atmosphere is cut way down.

And my lady was suggesting it isn't a good thing to look at stuff like this directly. For fear of UV radiation damage to the retina. And also a good thing to plug your ears against the boom.

 

[steph]

The therapists are going to have their hands full after this one. Just imagine how many cases of post-traumatic stress will occur.
Seeing videos of the fireball and sonic boom is impressive enough, living it must be a life-changing event. Especially for people who didn't really grasp what was happening or got hurt.
I think they came close to what A. Clarke (or was it Asimov?) was describing in one of his books - people over a large area went deaf after a powerful airburst. The shockwave burst their eardrums.
They also came close to getting singed. A witness even reported a burning smell after the flash.

 

[Urwumpe]

I doubt there will be a high number of trauma patients. The human brain usually gets over such events rather quickly, since such things just happen. When a hurricane destroys a neighborhood, you also don't get a lasting trauma. Many are maybe shocked at the first sight, but most get back into normal parameters soon. Also,such a meteor airburst is an event, that you can easily talk about, which helps preventing trauma. It is not like a war experience, which is beyond the grasp of those, who have never seen the perspective (You talk about walking in the steps of death, but most civilians hear you describing an action movie, that wasn't that bad.)

 

[Thunder Chicken]

The latest reports are indicating the meteor hit at 64 km/s. If my math isn't off, that is approximately twice the orbital velocity of the earth relative to the sun. I'm not sure exactly what plane the meteor was in relative to the sun, but it suggests that the meteor was in a retrograde orbit relative to the sun.