Scientists are suggesting that the energy release of the recent meteor event in Russia was on the order of 500 kilotons, roughly 30 times the energy of the bomb dropped on Hiroshima. The shock wave was indeed impressive: surveillance cameras showed windows and curtains being blown violently into the interior spaces of buildings. But the Hiroshima bomb vaporized and crushed several square miles of infrastructure with a combination of blast and heat; the meteor just produced a shock wave, and so presumably the 30X energy was distributed over a much broader area - in part because of the height at which the meteor was producing its shock wave, and in part because of the path length over which that energy was released.
So have there been official estimates of high high that smoke trail was, and how long it was? Presumably there wasn’t much of a shock wave being generated (at least not a terribly destructive one) after the meteroid had slowed down enough to stop generating light and heat, so I would guess the beginning/end of the smoke trail are decent endpoints for identifying the release of destructive amounts of energy.
Plus it was traveling at upwards of 35,000 mph on an oblique trajectory to the Earth’s surface when it exploded high in the atmosphere. Which means most of its energy was also dispersed forward along that path.
And am I the only one who kinda thinks that most people aren’t quite appreciating the immensity of this event?! If it had happened here in the US and I had witnessed it, I would have though only one thing: OMG a rogue state has detonated an atomic bomb over America and I have about three seconds to live! :eek:
Just so we’re clear, did the meteor in fact explode, or was the ground-level blast wave purely due to the sonic boom emanating from a (largely) intact meteor as it travelled through the atmosphere at supersonic/hypersonic speeds?
Materials inside the meteor, especially ice and frozen carbon dioxide if present, boil due to the heat from atmospheric friction and the resulting pressures cause the meteor to explode, sometimes rather dramatically.
Sorry, this is not the cause of the explosion. At best it’s a very minor part of it. The main reason is that there’s just not enough time for heat to transfer from the bow shock to the interior. The whole thing, from atmospheric entry to explosion lasts about half a minute or so. Certainly not long enough to tranfer a significant amount of heat.
The explosion is caused by stresses from the bow shock breaking up the meteor and then all the pieces doing the same. This dumps most of the kinetic energy of the meteor into the atmosphere in very short time. Hence boom!
The use of the term “explosion” in this context is troublesome, as it implies an energetic dispersal, as from a chemical/nuclear explosion at the core of the object. The reality is simply aerodynamic disintegration, much like what happened to the space shuttle Columbia once it started tumbling - followed by the creation of a bow shock in front of each individual fragment, coalescing into one big-ass shock by the time it hit the ground.
I’ll go with “potentially very bad.” Video footage and news reports depict major infrastructure damage on the ground, including the collapse of a factory roof and windows being blown inward very energetically. That’s a pretty severe blast wave. Judging by this blast damage guide, the overpressure at ground level from the meteor was somewhere between 0.25 and 1 psi. Which doesn’t sound like a lot, but when you start actually evaluating surface areas and resultant forces, it adds up quickly. A Boeing 747 for example has a wing surface area of 5825 square feet, or 838,800 square inches - so a 1-psi overpressure wave travelling straight down from the upper atmosphere will produce 838,800 pounds of downforce if it hits the entire wing area simultaneously. That’s on par with the weight of the aircraft, and it would be a helluva transient event: the wings would be bounced downward, and then upward just as quickly once the blast wave has gone by. That’s assuming the shock wave hits evenly, which it probably wouldn’t. You might have it hit the front/rear of the plane first, or one wing tip, with the applied force traveling across the rest of the aircraft as the blast wave passes. Airflow into the engines might be disrupted, possibly causing a shutdown, although there are procedures for in-flight restarts, assuming no damage has taken place.
Not saying for certain a plane would crash, but I wouldn’t want to be on a plane for an event like that.
I saw once, about 16 years ago-I was driving on Rt 128, west of Boston-it crossed the sky, with a path that glowed bright green. It was striking, and it lasted a bout 15 seconds.
This occurred in a relatively open area. If it had exploded over a skyscraper city like New York there would have been many more serious injuries from flying glass. The shock wave rolling down the canyons may have caused structural damage as well and I imagine they would have amplified the sound as well.
But then isn’t that also due the fact that the atmosphere becoming steadily denser, increasing the stresses, and also, with a rock as small as this one, the possibilty that it might have been very irregularly shaped, adding even more stress?
Incidentally, the Tunguska event is thought to have been caused by an object about 100 meters long. This was thought to have been about 15 meters. The asteroid that missed us by 30,000 meters on the same day was about 150 meters long, about 3.5 times the mass. Had it hit, especially in a populated area, it would have been devastating, but nothing like the event that ended the dinosaurs.
