Real life Sci-fi 2013

[EZO]

Re: (*) Planetesimal'fest

Jon Stewart obviously copied out the better Russian dash-cam accident scenes - a funny/sad presentation. yes, Russian society can be rather coarse - because life over there is coarse and raw. minus 20C and colder is normal. East of the Urals, roads are nearly impassable during the spring thaw. The military is well known for many shenanigans that would have US officers courtmartialed.

Ref my comment above about a US doctor wanting to drive in Russia to carry his ski equipment: After watching the video links, he upgraded his vehicle to a 7 passenger van - for two people. He figured that he needed some more crush space.... and he is considering purchasing a small dash-cam just for the trip!

moldyoldy - I can hardly disagree with your remarks. A Russian acquaintance laments that since the demise of the Soviet Union in 1991 Russian society has become more and more corrupt and dysfunctional, albeit more "open" and what corruption and dysfunction existed at the time simply came out of the woodwork.

As far as Jon Stewart's presentation is concerned, I could not imagine that I could be further astonished by any Russian dash-cam videos beyond those in my original post but several clips from the Daily Show did the trick, particularly the tractor trailer full of live cows spilling over, hence my posting it......and as sad a commentary as it is, it was indeed funny. I live in a rural area among farms where I regularly observe people transporting livestock, but with great care and caution. I mean, the average cow weighs around 700-1000 pounds and it's moving around in the back of a truck and this was literally a herd of them! You've just got to wonder how the driver could take a turn like that, at that speed in a truck full of cows. Vodka would be my guess.

I drive with a dash cam and I highly recommend them. This is partly why I am fascinated by the Russian's use of them. The media is describing the Russian's reliance on them as a "fad". I disagree. I believe they will someday be in all vehicles and perhaps may even be offered as a factory option when you buy a new car. I recommend that your doctor friend do some research before buying a dash cam as many on the market are cheap and unreliable. I pray that he has a safe journey in his 7 passenger van. I wonder if one can rent an armored vehicle in Russia?

 

[jtr1962]

Re: (*) Planetesimal'fest

You've just got to wonder how the driver could take a turn like that, at that speed in a truck full of cows. Vodka would be my guess.

I think vodka is a factor in the vast majority of those incidents caught on dash cam. From what I've read, the Russians go through the stuff like we drink Coke or Pepsi.

 

[EZO]

Re: (*) Planetesimal'fest

I think vodka is a factor in the vast majority of those incidents caught on dash cam. From what I've read, the Russians go through the stuff like we drink Coke or Pepsi.

I agree jtr1962. It makes me wonder about the scenes of the fighter jet or the helicopter gunship "strafing" the highway, or the tank cutting across the road. Hmmm......well, na zda-rov'-ye!

 

[HighlanderNorth]

Re: (*) Planetesimal'fest

Here is a video with excellent audio of the sonic booms (which caused the bulk of the damage). If you have good audio on your computer, crank it up!
https://www.youtube.com/watch?v=T8dA2A_df0w

Although the brilliant US media journalists kept referring to these blasts as sonic booms, I dont think thats what it was . I used to live near an airforce base(30 minutes away), and jets would break the sound barrier somewhat frequently, but it wasnt anywhere near that loud.

Sonic booms dont cause 50 kiloton explosion energy events. This was the asteroid exploding.

 

[StarHalo]

Re: (*) Planetesimal'fest

Although the brilliant US media journalists kept referring to these blasts as sonic booms, I dont think thats what it was . I used to live near an airforce base(30 minutes away), and jets would break the sound barrier somewhat frequently, but it wasnt anywhere near that loud.

Nope, it was indeed a sonic boom; jets don't enter the atmosphere at Mach 55 and then disintegrate from heat energy.

Sound moves through air like waves on water, throw a little pebble in the water, little waves, big rock, big waves..

 

[EZO]

Re: (*) Planetesimal'fest

Although the brilliant US media journalists kept referring to these blasts as sonic booms, I dont think thats what it was . I used to live near an airforce base(30 minutes away), and jets would break the sound barrier somewhat frequently, but it wasnt anywhere near that loud.

Sonic booms dont cause 50 kiloton explosion energy events. This was the asteroid exploding.

I would agree. The main stream media (MSM) always seems to oversimplify things or just doesn't know what it is talking about and there seems to be a lot of confusion about the difference between a sonic boom and a shock wave or detonation wave. This meteor would have made both a sonic boom and a detonation wave but the explosion was the main event here where the detonation wave was the force that broke windows and caused damage.

I witnessed a spectacular Leonid Meteor Shower some years back with numerous bright colorful flashes (mostly green) and there were indeed sonic booms happening as much as every thirty seconds to one minute apparent for a period during the event.

 

[EZO]

I found a reference to what I was trying to explain in the wikipedia entry on shock wave:

"When the 2013 meteor entered into the Earth's atmosphere with an energy release equivalent to hundred or more kilotons of TNT, dozens of times more powerful than the atomic bomb dropped on Hiroshima, the meteor's shock wave produced damages as in a supersonic jet's flyby (directly underneath the meteor's path) and as a detonation wave, with the circular shock wave centered at the meteor explosion, causing multiple instances of broken glass in the city of Chelyabinsk and neighboring areas."

So, according to this explanation both the shock and detonation waves caused damage. However, as best I understand the explosive detonation wave was the more powerful.

 

[StarHalo]

It's the same thing - movement of air caused by some sort of energy transfer. When the meteor broke, it released more energy at that point, but all of it came from the movement through the atmosphere, and all the damage was done by a "sonic boom" shockwave.

 

[EZO]

It's the same thing - movement of air caused by some sort of energy transfer. When the meteor broke, it released more energy at that point, but all of it came from the movement through the atmosphere, and all the damage was done by a "sonic boom" shockwave.

There is a distinction; shock waves are not sound waves; a shock wave takes the form of a very sharp change in the gas properties. Shock waves in "air" are heard as a loud "crack" or "snap" noise.
Over time a shock wave can change from a nonlinear wave into a linear wave, degenerating into a conventional sound wave as it heats the air and loses energy. The sound wave is heard as the familiar "thud" or "thump" of a sonic boom, commonly created by the supersonic flight of aircraft. A detonation wave follows different rules to a shock wave since it is driven by chemical reactions occurring inside the wave itself, and so the speed of the wave depends on the nature of the chemical reaction occurring. So a "sonic boom" is a "relative" of a shock wave but is a different animal. A shock wave can cause a sonic boom if it happens in air. I am by no means an expert on this stuff and NASA has a whole department full of physicists whose job it is to analyze and theorize about this subject but as I understand it a shock wave or detonation wave can exist in a vacuum, like outer space but a "sonic boom" can't.

 

[LEDAdd1ct]

I don't have knowledge in this field to contribute to the discussion, but here is a page distinguishing shock waves from sonic booms:

Page

And Another

 

[HighlanderNorth]

It's the same thing - movement of air caused by some sort of energy transfer. When the meteor broke, it released more energy at that point, but all of it came from the movement through the atmosphere, and all the damage was done by a "sonic boom" shockwave.

I think the point that we are making is that the explosion was essentially a separate event from the sonic boom, and it was the explosion that caused the vast majority of the energy that caused damage. The explosion was caused by, as you stated, the asteroid entering the atmosphere at mach-???, and the sudden friction caused by the asteroid hitting the air at such a high speed caused extreme heat and the eventual explosion. It didnt explode because of the sonic boom, and the sonic boom wasnt the main contributor to the shock wave that caused the damage. look at the many videos, and you'll see a blinding white light at the very moment of the explosion. That was proof of the massive amount of energy and heat released by the explosion.

But our main point was that the US media were initially blaming the damage on the sonic boom, with no mention of an explosion, as if the entire incident was caused by the noise created by the sonic boom.

Its like back in 2004 after the pacific tsunami, I watched at least 2 journalists speculate that global warming played a role in the tsunami. I dont doubt global warming, but the fact is global warming has absolutely nothing to do with plate tectonics!

 

[moldyoldy]

just some reference data for pressure waves;

The military grade explosive Octol has a flame front of ~8000 ft/sec depending on the specific formulation. Octol is used in certain bombs. View the various videos of B-52s running Arclight missions over Vietnam and watch the _mostly_ spherical expansion of the shock wave compressing the air from each bomb exploding. or watch any video from Iraq of a VBIED detonating, like the one from that dump truck. You can see the air compression effects as the wave travels towards the camera and the dust/dirt kicked up by the pressure wave as well as people being knocked down. The point is that exploding gases themselves also exceed the speed of sound. and most explosive devices are at least somewhat shaped to focus the energy in specific directions. ie: not the usual flash-powder-based aerial bomb in fireworks, the effects of which are spherical. At some point the gases from the explosion slow down and dissipate, but the air pressure wave propagates further.

Back to the Chelyabinsk meteor: As far as I have read in Russian or German press, the wall(s) of that Zinc factory were knocked down or heaviily damaged by a localized pressure wave, not by a large extra-terrestrial object that was "found". Overpressure above 5 psi on a building will cause collapse, some buildings sooner, some later. In Hiroshima, the overpressure from the nuclear bomb was estimated above 12 psi on the ground. IOW, in the case of the Chelyabinsk meteor exploding from intense heat, the shock wave was not symmetrical.

Dash-cams typically have a max of 30 frames per sec, same as the double-scan effect on CRT TV with a dual-scan interlace which raises the effective rate up to the supposed flicker free of 60hz. Although it is visible from the dash-cam videos that there seemed to be more than one explosion, the progression of the main explosion was difficult to ascertain except for the blinding light which seemed to last a bit longer than the detonation from an explosive. However the image retention of the CCD in a dash cam is unknown. It takes a while before the charge on individual elements in a CCD dissipates.

On another web site (forgot which), there was an analysis of the depth of atmospheric penetrations of increasing sizes of meteors. The Tunguska meteor was about as large as it could be to still explode in the atmosphere and not create a significant crater in the Earth's crust. rather fascinating to read how close the Earth has routinely avoided disaster because of a thick atmosphere.

Going off topic just a bit regarding air pressure waves: on 30 Oktober 1961, a Tupolew-Tu-95W-Bomber dropped the Soviet Царь-бомба (Tsar-Bomb) (AN602) (hydrogen bomb) that detonated at about 4000 meters altitude over Novaya Semlya north of the Soviet mainland. I watched the blips of the air pressure wave from that detonation as it traveled around the world twice - as they were recorded live on a recording barograph in an open window at the high-school that I was attending. The first blip was much higher than the second blip. The actual megaton numbers from that H-bomb vary around 60 megatons, but evidently the yield was higher than Soviet scientists had calculated (to be 50 megatons). A 10 megaton nuclear weapon was considered to be a city-buster. At that time, I did not fully understand the physics implications, but I understood the pressure blips on the barometric chart - because since grade school I had to routinely participate in Civil Defense exercises in schools, such as ducking under desks and always away from windows. and it was glass shards from broken windows in/around Chelyabinsk that caused most of the human damage.

 

[EZO]

I know, I know, we've had enough videos of the Russian meteor event already!

Maybe not? This is clever, well done and contains some footage most of us haven't seen previously.

Russian Meteorite: The Movie!! (trailer)

 

[LEDAdd1ct]

Quite melodramatic, but including the sound really amplifies the "I'm there" effect.

The tinkling glass and reactions on people's faces going about their daily business really emphasizes the sudden nature of the event.

 

[moldyoldy]

this is one of those rare cases where Chicken Little and Henny Penny are able to legitimately agree that "the sky is falling".....

 

[orbital]

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I know this has nothing to do w/ the OP,, but check this out

http://www.youtube.com/watch?v=2jvLalY6ubc&feature=player_embedded


___________ ^ not sure if I should be scared or not!!! ^ oo:__________________

 

[moldyoldy]

+

I know this has nothing to do w/ the OP,, but check this out

http://www.youtube.com/watch?v=2jvLalY6ubc&feature=player_embedded


___________ ^ not sure if I should be scared or not!!! ^ oo:__________________

the mechanical mule is not new, including walking up a hill or across uneven ground with a serious load, but the ability to throw a concrete block is new for me. Should you be scared? Not until the power pack has shrunk from that power cable leading up/across the ceiling to a compact autonomous size w/in the device. Then be very scared - Star Wars will not be long in coming...

To my observation, CPF itself is one of the better Internet sites to routinely visit to understand the problems and opportunities with increasing energy density in a battery, or more generally, in a easily portable power source. At my former job in various design meetings it was repeated and clear that electric drives had sufficient power to replace all hydraulics in vehicles/weapon systems, but dissipating the heat w/o a high I/R signature represented a major problem. Hydraulics are considered a major fire threat.

 

[EZO]

Should you be scared? Not until the power pack has shrunk from that power cable leading up/across the ceiling to a compact autonomous size w/in the device. Then be very scared - Star Wars will not be long in coming...

I've been watching the creepy robots Bostons Dynamics has been developing with keen interest and I had the same thought about what happens when they cut the cables on these things as they become more and more autonomous. Then I remembered that they've already done that! Scared? Not yet, but we are certainly getting closer to that day. Terminator can't be too far off!

 

[EZO]

March 9 - "An asteroid as big as a city block shot relatively close by the Earth on Saturday, the latest in a series of visiting celestial objects including an asteroid the size of a bus that exploded over Russia last month, injuring 1,500. Discovered just six days ago, the 460-foot long (140-meter) Asteroid 2013 ET passed about 600,000 miles from Earth at 3:30 p.m. EST. That's about 2-1/2 times as far as the moon, fairly close on a cosmic yardstick.

"The scary part of this one is that it's something we didn't even know about," Patrick Paolucci, president of Slooh Space Camera, said during a webcast featuring live images of the asteroid from a telescope in the Canary Islands."

Four asteroid flybys occurred between March 4 and today (March 10). The asteroids were also all discovered this month, some just days ago.

http://www.space.com/20149-asteroids-buzz-earth-week.html

 

[jtr1962]

Scary yes, but putting things into perspective in the worst case something small enough to not notice until it's nearly on top of us will take out a city. Granted, that's not a pleasant prospect, but it's not an extinction level event either. And chances are good the impacts will either be in the ocean, or in remote areas. Large, dense cities with the potential for the most casualties are a very small percentage of Earth's land area. Anything large enough to do serious damage to the planet we'll probably know about decades in advance, giving us plenty of time to deflect it. I think deflecting these space rocks to crash on the moon is a good strategy as it puts them out of commission for good as potential Earth impactors.