viscount aero wrote: About the sound--I think it is no different a mechanism behind that than what is observed in severe lightning strikes and thunder. In my opinion, this event, although initiated differently, involves the same mechanisms. Moreover, I think, too, that the sounds were not just from one thing but at least a couple things. One source for some of the cracks were sonic booms, another being the super-heating of the air instantly.
It's funny you mentioned the lightning. I believe the sound from lightning is mainly due to the pinch effect. I had posted some stuff in another thread in case you're interested, also has some links to youtube plasma speaker videos. The speakers are nothing but two wires with air in between (the arc makes the sound!).
dahlenaz
Re: Feb 15 Meteorite(s) hit Russia - Analysis
viscount aero wrote:
Beata-at-home wrote: viscount aero, If you don't mind, please explain your answer. ("Highly unlikely.")
I think they are hiding the evidence, that is why they "can't find" any pieces. Also, why would the Syrian video be banned from Youtube?
They have been finding pieces. And do you mean the meteor was a missile, or it was shot down by a missile? Regardless, I find the missile theory highly far-fetched at best.
Although the event is shorter as the object is smaller and enters at a sharper angle, you can see the same entry pattern with the 3 major points of interest: it descends, brightens, flares up (#1), dims, flares up again (#2)--leaving a fat bulging first part, a pinched area of dimming, then the #2 portion with the remaining bolide (#3) emerging and glowing dimmer compared to the residual plasma trail structure.
Was this shot down, too? I don't think so.
The pinch area that you speak of is very possibly only a lens anomoly and i've obtained a photo to shows how a digital camera (very similar to the dash cam) reacts to overly bright areas before it makes its electronic adjustment. The image below is from a video taken as the camera rotated toward the sun while keeping the ground as a significant part of the photo.. The bright cone didn't diminish until the sun was the domonant subject for the CCD to adjust to, then a large round area was captured.
I've run further tests with dashcam type cameras to determine if using video evidence to build specualtion about the occurrance of an electrical discharge during the russian event has risks, and i will say that optics and other factors has led some people down a path of erroneous speculation about an hour glass shape in the video being evidence of an electrical discharge,,, it is likely to be only an anomoly of digital cameras that can tolerate direct sun-like light... I have several videos which replicate the lower side of the bright cone as they adjust to the bright light coming into frame. The speed at which the russian anomoly disappears is very close to the time it takes for these cameras to adjust,, or so it seems, from my non-expert experiments with cheepo dashcams cams.
So,, i hope all you mirage chasers come back to rethink and re-open the discussion of the notions about what happened in russia.
I would put these videos up on the web but thats become too much of a chore now that google is ruining youtube. d...z
...
CharlesChandler
Re: Feb 15 Meteorite(s) hit Russia - Analysis
dahlenaz wrote: I would put these videos up on the web but...
I'll take your word for it. I agree that there wasn't a bolide-to-ground discharge. I think that the flashes and the glowing trails were evidence of ionization and charge recombination having to do just with the bolide's movement through the air (i.e., the so-called "frictional charging", or what others loosely refer to as triboelectrics). The bolide broke up due to the failed covalent bonding, and due to electrostatic repulsion, both of which resulted from the core becoming positively charged (with a negative double-layer around the outside). So EM is still central to an accurate description of the event. But it wasn't EU-style megalightning from the bolide down to the ground.
seasmith
Re: Feb 15 Meteorite(s) hit Russia - Analysis
A Coulomb Explosion is a "cold" alternative to the dominant laser etching technique of thermal ablation, which depends on local heating, melting, and vaporization of molecules and atoms using less-intense beams. Pulse brevity down only to the nanosecond regime is sufficient to localize thermal ablation – before the heat is conducted far, the energy input (pulse) has ended.
CC,
It's probably a bit more than simple "electrostatic repulsion", as described here:
I agree that there wasn't a bolide-to-ground discharge.
But Charles, I want an arc to ground...
(Which smilie indicates "whining" ?)
CharlesChandler
Re: Feb 15 Meteorite(s) hit Russia - Analysis
Sparky wrote: But Charles, I want an arc to ground...
I know — at first, that's definitely what it looked like.
If you absolutely need an arc to ground, and you need it right now, and you're handy with house wiring, I could explain some things that I've tried over the years that didn't end well, but definitely fall squarely in the "arc-to-ground" category...
Sparky
Re: Feb 15 Meteorite(s) hit Russia - Analysis
I am going to try to fit a resistive meteor as an overloaded circuit component for a possible explanation. I suggested before that the meteor's travel through the ionosphere made a plasma connection from there toward earth. There may have been current flow from ionosphere, through the meteor, and diffuse , by glow discharge , to ground. The large flashes may have been ohmic heating of the shorting out meteor, and as a resistor explodes, so too the meteor. Smaller pieces of the meteor would still be electrically connected between the ionosphere and earth and the current dissipated into the atmosphere.
justcurious
Re: Feb 15 Meteorite(s) hit Russia - Analysis
Sparky wrote: I am going to try to fit a resistive meteor as an overloaded circuit component for a possible explanation. I suggested before that the meteor's travel through the ionosphere made a plasma connection from there toward earth. There may have been current flow from ionosphere, through the meteor, and diffuse , by glow discharge , to ground. The large flashes may have been ohmic heating of the shorting out meteor, and as a resistor explodes, so too the meteor. Smaller pieces of the meteor would still be electrically connected between the ionosphere and earth and the current dissipated into the atmosphere.
Well... the electric connection to the next atmospheric layer (ionosphere?) certainly seems plausible to me. Even if there is no arc to the ground, there is a corona, which means that there is a discharge between the meteor and surrounding environment/air, so no need to necessarily close the circuit with an electric arc directly to ground IMO. So... I suggest that there can be ohmic heating even if there is no direct visible arc to the ground (as in lightning). Personaly, I'm not sold on the ohmic heating thing (based mostly on my own intuition), but I also don't buy the "because we can't see a lightning bolt to the ground there is no current flowing through the meteor".
meemoe_uk
Re: Feb 15 Meteorite(s) hit Russia - Analysis
> But it wasn't EU-style megalightning from the bolide down to the ground.
Why not? For months I haven't seen a speck of evidence or reason to suggest anything other than this most simple and intuitive explaination.
CharlesChandler
Re: Feb 15 Meteorite(s) hit Russia - Analysis
meemoe_uk wrote: > But it wasn't EU-style megalightning from the bolide down to the ground.
Why not? For months I haven't seen a speck of evidence or reason to suggest anything other than this most simple and intuitive explanation.
Analysis of fragments that fell to the Earth indicate that the bolide was an ordinary chondrite, made up of iron and olivine, making it at least a good (if not excellent) conductor. In a good conductor, any net electric charge will always be found at the surface. If there was enough potential for lightning, it would have discharged only the surface potentials — it wouldn't have drilled through the bolide. Hence the disintegration of the bolide cannot be attributed to bolide-to-ground lightning, which at best would have been just a surface flare.
In the more general sense, a lot of bolides have been captured on film, but none of the film shows any lightning strikes. The apparent flare-up between the bolide and the ground in the Chelyabinsk video was demonstrated to be an artifact of the digital camera that was used.
So the physics isn't there, and the observational evidence isn't there.
That doesn't mean that the bolide wasn't electromagnetically active. It is well-known that bolides separate charges. But the charge separation is entirely within the context of the bolide and its coma, not between the bolide and the atmosphere above it, below it, or the Earth below it.
justcurious
Re: Feb 15 Meteorite(s) hit Russia - Analysis
The fact that there is no lighting does not mean that there is no current through the meteor. As the footage shows, there is corona/glow discharge hence the circuit completes in the surrounding air, as opposed to a filament-like lightning structure. In other words, the lack of lightning does not prove that there is not a circuit forming from the ionosphere (or whatever atmospheric layer marked the beginning of the plasma tail) to the air surrounding the meteor.
CharlesChandler
Re: Feb 15 Meteorite(s) hit Russia - Analysis
justcurious wrote: The fact that there is no lighting does not mean that there is no current through the meteor. As the footage shows, there is corona/glow discharge hence the circuit completes in the surrounding air, as opposed to a filament-like lightning structure. In other words, the lack of lightning does not prove that there is not a circuit forming from the ionosphere (or whatever atmospheric layer marked the beginning of the plasma tail) to the air surrounding the meteor.
It's true that the high-temp plasma in the coma could serve as a conduit for a current, and that there is a fair weather field of 100 V/m through the ionosphere, mesosphere, and stratosphere (where the bolide finally disintegrated). But what effect would a discharge from the ionosphere to the stratosphere have on the bolide? It sounds like you're suggesting that the bolide simply got in the way of an atmospheric discharge. But I don't see why that would cause the disintegration of the bolide. When a conductor in the air (such as an airplane) gets struck by lightning, the current doesn't go through the conductor — it goes around the outside, generally having little effect on the conductor itself. This is why airplanes keep flying after getting struck. It's also why many people have survived getting struck by lightning — the current traveled across the surface of the skin, instead of taking the more direct path through the excellent conductivity of the human body, resulting in skin burns, but not bodily disintegration. This is because the valence electrons on the surface of an object are freer to move than electrons in the same band in the interior of the object. So we can say with confidence that an atmospheric discharge going past a bolide would not have had a significant effect on the bolide itself.
Sparky
Re: Feb 15 Meteorite(s) hit Russia - Analysis
So we can say with confidence that an atmospheric discharge going past a bolide would not have had a significant effect on the bolide itself.
I like the way you analyse these things....
What if the current was continuous from the ionosphere to flash points? Could the explosion have been the culmination of stress charge? There may have been an induced charge before the bolide went through the ionosphere.
GaryN
Re: Feb 15 Meteorite(s) hit Russia - Analysis
But what effect would a discharge from the ionosphere to the stratosphere have on the bolide? It sounds like you're suggesting that the bolide simply got in the way of an atmospheric discharge. But I don't see why that would cause the disintegration of the bolide.
Micro-second scale electric field pulses are recorded in lightning discharges, and as pulsed electric fields are used commercially to shatter rock, that would seem to account for the shards that were found on the ground. The hole in the ice was never really explained, and no large pieces were ever found, though there were lots of fragments found in the area, suggesting the object was 'in the way' of an atmosphere to ground discharge.
