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Kemal
2005-Oct-23, 01:48 AM
In Dr. Plait's review of War of the Worlds he writes:


Even Cruise's character mentions that the lightning has no thunder. I don't know how'd you do that. The news scenes make it clear this is an electromagnetic phenomenon, which lightning is. Lightning is also very hot (hotter than the surface of the Sun!), and this violently heats the air around it. That creates a shockwave, which we call thunder. Lightning bolts like that without thunder don't make sense.

http://www.badastronomy.com/bad/movies/waroftheworlds.html

But a professor at the College of Environmental Sciences/Wisconsin University writes:


Mysterious lightning bolts zap the ground, not accompanied by thunder. The storm ends as abruptly as it began. Thunder is caused by the sudden expansion of superheated air around a lightning bolt. It rumbles because there are miles of bolt in the clouds and it takes a long time for sound to travel from the farthest ends of the discharge. But short discharges from directly overhead will merely produce a loud crack. I don't know whether Spielberg actually reasoned this out, but it's sensible.

http://www.uwgb.edu/dutchs/PSEUDOSC/ATMOVIEWells.HTM

So who's right?

Melusine
2005-Oct-23, 07:38 AM
Lightning always produces thunder, though if its over 10 miles away you may not hear it. If it's close to you, the sound waves don't travel far and you hear a loud thunderclap. I don't remember a thunderclap in the movie in that first "lightning" scene. Thunder rumbles as the sound waves continuously travel from the nearest part of the lightning bolt and on from the farthest part of the bolt, sometimes miles and miles long, to your ear.

That alien lightning bolt was big and it didn't just flash and disappear like normal lightning. It should have produced a very loud clap if it was close, or it should have produced a long rumbling if it was somewhere in a 10-mile vicinity, which it seemed to be. (After all, it was rejuvinating those alien ships under the city streets across the river). And as the BA said, it produced an electromagnetic pulse, plus it had it's own storm cloud, so it certainly seemed to act like lightning. How would it have not produced a shock wave, and thus sound waves? This thing had to seriously disturb the air, so the professor's last two sentences don't make sense to me.

cyswxman
2005-Oct-23, 03:00 PM
I have experienced a strike very close to me, within a few hundred feet. There was an initial, very loud, clap and I felt the concussion from it, followed by a much softer rumble, which I believe was more the result from echoing. More gentle, and longer lasting, rumbles are typical from how Melusine explained.

Sam5
2005-Oct-23, 10:10 PM
So who's right?

I’ve heard nearby short bolts and they do sound like a crack. If there is nothing for the sound to echo off of, all you will hear is the crack. A short bolt might sound like a quick “boom” if heard from a distance. Long bolts and with echoes will sound more like long rumbling thunder.

Melusine
2005-Oct-23, 11:23 PM
I’ve heard nearby short bolts and they do sound like a crack. If there is nothing for the sound to echo off of, all you will hear is the crack. A short bolt might sound like a quick “boom” if heard from a distance. Long bolts and with echoes will sound more like long rumbling thunder.
I don't understand your second sentence; I haven't read the echo factor as being a reason why one hears a loud clap from a close lightning bolt. I've understood it to be the closeness of the sound waves. Maybe Cyswxman can elaborate (he's the meterorology man). But a crack or bang sound is thunder, and the point was that in the movie this alien lightning didn't produce thunder. Maybe I'm remembering wrong and each bolt produced a bang or crack in the movie, but I didn't think so. It should have produced sound, one way or another, if it was overhead or far away. I suppose if there was some temperature inversion bending the sound waves, maybe it couldn't be heard, but I think that's stretching it, and the professor doesn't mention that above. So, what was sensible in the movie?

Sam5
2005-Oct-23, 11:50 PM
I don't understand your second sentence; I haven't read the echo factor as being a reason why one hears a loud clap from a close lightning bolt.

A single crack comes from a short lightening bolt if you are near the bolt. A multiple crack might be heard if there are some tall buildings or cliffs nearby. I've heard the crack sound from about 50-75 yards away, a short bolt hitting a telephone pole. It was a very short sharp loud crack.

Out here were I live in the West now, we have some 60-ft tall cliffs about a half mile away. We can see thunder storm clouds coming toward us. They are usually fairly small, but they are filled with lightening bolts. The further they are away, the more "booms" we hear, and echoes too. The closer the lightening is, and if it comes pretty much straight down from a cloud that is not very high, we here a sharp crack, with maybe some echo from the cliffs.

I haven't seen the movie. Were they trying to say there were regular distant lightening bolts that had no sound? I don't think that's possible.

Melusine
2005-Oct-24, 03:39 AM
A single crack comes from a short lightening bolt if you are near the bolt. A multiple crack might be heard if there are some tall buildings or cliffs nearby. I've heard the crack sound from about 50-75 yards away, a short bolt hitting a telephone pole. It was a very short sharp loud crack.

Out here were I live in the West now, we have some 60-ft tall cliffs about a half mile away. We can see thunder storm clouds coming toward us. They are usually fairly small, but they are filled with lightening bolts. The further they are away, the more "booms" we hear, and echoes too. The closer the lightening is, and if it comes pretty much straight down from a cloud that is not very high, we here a sharp crack, with maybe some echo from the cliffs.

I haven't seen the movie. Were they trying to say there were regular distant lightening bolts that had no sound? I don't think that's possible.
Oh, I see what you were saying now. I was talking about the closeness of the soundwaves regarding a bolt close by creating single boom--nothing to do with echoes. Yeah, with mountains around I think it's harder to distinguish between what is the initial boom or rumbling and an echo. Too, forked shape lightning or spider-veined discharges will cause several booms heard at different times depending on how long each bolt is, and all those sound waves bounce around, and then maybe add to that echoing, and you get those long rumbles that seem to go on forever. I've heard successive cracks that sounded like they were on top of me, but I don't think we get much echo effect here or in Florida. Sometimes the bolts occur so continously, I've reflexively ducked in my car. Lightning is fascinating, but a scary thing. especially when stuck in a convertible.

In the movie, the bolt wasn't very distant. It was also not a flash, more of a stream, if I recall. It had to be very hot, and even if the aliens made up their own form of "lightning," they don't get a pass on what it does to the air. It's goofy, but then it's a movie, and you have to suspend your belief for a bunch of other things as well. :rolleyes:

Jason Thompson
2005-Oct-24, 09:12 AM
Two things strike me about the 'lightning' in the film.

First, it does not make a normal thunderclap, but it does make noise.

Second, when the crowd gathers round the place where it struck, Cruise's character picks up a piece of tarmac from the spot and, asked whether it is hot, replies that it is actually freezing.

This leads me to conclude that Spielberg made some attempt to address the lack of thunder by making it clear it was not ordinary lightning.

However, what everyone seems to be forgetting is that it is the product of alien technology. This is, after all, a sci-fi film. The lightning is accompanied by an electromagnetic pulse, which I am not aware is a normal effect of lightning. It also acts as a transporter beam, allowing aliens to 'beam' aboard their tripods (from goodness only knows where) and only leave a tiny hole in the ground. The absence of thunder is just one of a number of clues for the observers in the film that this is not a normal storm. Who cares why there is no thunder?

I do sometimes have to wonder why we spend so long dissecting such a minor issue when we quite happily sit back and watch alien war machines zapping people with a ray that turns people to dust and leaves their clothes intact!

Sam5
2005-Oct-24, 06:15 PM
I've heard successive cracks that sounded like they were on top of me, but I don't think we get much echo effect here or in Florida.

That's what I'm talking about. A nearby lightening bolt that sounds like a crack. I think the booming sound comes from distant lightening for different reasons.

It's like being in a big room and recording a person's voice while he is up close to the microphone. It's a nice clear sharp sound. Then you move him 30 feet away and all you get are "booming" type echoes of his voice.

baric
2006-Jan-07, 10:02 PM
Two things strike me about the 'lightning' in the film.

First, it does not make a normal thunderclap, but it does make noise.

Second, when the crowd gathers round the place where it struck, Cruise's character picks up a piece of tarmac from the spot and, asked whether it is hot, replies that it is actually freezing.

This leads me to conclude that Spielberg made some attempt to address the lack of thunder by making it clear it was not ordinary lightning.

However, what everyone seems to be forgetting is that it is the product of alien technology. This is, after all, a sci-fi film. The lightning is accompanied by an electromagnetic pulse, which I am not aware is a normal effect of lightning. It also acts as a transporter beam, allowing aliens to 'beam' aboard their tripods (from goodness only knows where) and only leave a tiny hole in the ground. The absence of thunder is just one of a number of clues for the observers in the film that this is not a normal storm. Who cares why there is no thunder?

I do sometimes have to wonder why we spend so long dissecting such a minor issue when we quite happily sit back and watch alien war machines zapping people with a ray that turns people to dust and leaves their clothes intact!


I agree completely. The lack of thunder was clearly done to show that the lightning was not of natural origin and nothing else. Not sure exactly what the big hangup about this is when there are worse science clunkers made every year. War of the Worlds was intended to be fantastic, not realistic.

HenrikOlsen
2006-Jan-08, 04:33 PM
The lightning is accompanied by an electromagnetic pulse, which I am not aware is a normal effect of lightning.
Lightning IS accompanied with an electromagnetic pulse, that's why you can hear it crackle on the radio, and that is how lightning is registered by meteorologists.

Jason Thompson
2006-Jan-11, 01:11 PM
Yes, but it doesn't frazzle every electrical system within a mile or so. Again, this is obviously NOT normal lightning, therefore the absence of thunder is hardly anomalous.

Gillianren
2006-Jan-11, 08:04 PM
Yes, but it doesn't frazzle every electrical system within a mile or so. Again, this is obviously NOT normal lightning, therefore the absence of thunder is hardly anomalous.

I have to disagree, there. I think the fact that it has stronger effects only makes it more likely that it should have thunder. If it doesn't, that's some pretty fancy laws-of-physics violating it's doing, there.

HenrikOlsen
2006-Jan-11, 11:16 PM
I think I see the problem.
Being aliens, they obviously didn't know that on earth you have to subcontract Thor to get thunder, the others only make the lightningbolts.

Gillianren
2006-Jan-11, 11:30 PM
I think I see the problem.
Being aliens, they obviously didn't know that on earth you have to subcontract Thor to get thunder, the others only make the lightningbolts.

Hey, I read that book . . . .

Jason Thompson
2006-Jan-12, 09:36 AM
I have to disagree, there. I think the fact that it has stronger effects only makes it more likely that it should have thunder. If it doesn't, that's some pretty fancy laws-of-physics violating it's doing, there.

But that's precisely my point! It already violates known laws of physics by acting as a matter transporter across unspecified reaches of space. Aliens made this lightning. [/i]Aliens[/i] used it to transport themselves across space. Aliens used it to travel down into their machines leaving a very small hole that they could not have normally crawled through. The ground that was repeatedly struck by the alien generated lightning was freezing cold.

This is already fictional and fantastic. I can hardly believe people are quibbling over the fact that this stuff that resembles lightning but clearly is not lightning as we understand it is not behaving like normal lightning in one respect when it does all these other things as well!

For anyone who may have missed my point again: normal lightning does not freeze the ground it strikes; normal lightning will not strike the ground in preference to other, taller, better conducting objects like metal streetlamps, and certainly not twenty-seven times in a row; normal lightning does not fry every electrical system within a mile or two when it strikes; and normal lightning does not transport aliens into buried war machines. This is not normal lightning! It already violates several known laws of physics from our point of view, so why single out one example and make it such a big deal?

Gillianren
2006-Jan-12, 06:11 PM
. . . so why single out one example and make it such a big deal?

For one, it's pretty easy to explain what's wrong about it. For another, given that none of the lightning stuff, as far as I know, anyway, appears in the book, it's yet another example of our intelligence being insulted by a Hollywood blockbuster. I'm not saying the scriptwriter sat down and thought, "You know, the American public is dumb as a brick and won't know that lightning without thunder violates the laws of physics," but that's what I come away from these things feeling. Besides, I'm sure there are vital plot reasons for the other stupid things the lightning does, whereas the only conceivable reason for the lightning without thunder is to make it weird and alien. I think actually having aliens accomplishes that rather nicely.

Jason Thompson
2006-Jan-12, 10:56 PM
For one, it's pretty easy to explain what's wrong about it.

But only if you start from the assumption that it is something it is clearly explained it is not, namely lightning or some related phenomenon.

For another, given that none of the lightning stuff, as far as I know, anyway, appears in the book, it's yet another example of our intelligence being insulted by a Hollywood blockbuster.

No, none of the lightning stuff appears in the book (the invaders come from Mars in space capsules, plain and simple), but I still don't see why putting in an alien transporter beam that superficially resembles lightning, then drawing attention to every way in which it is clearly not lightning, is an insult to the intelligence. Insulting the intelligence would be including lightning with no thunder and then not having any character notice that it is weird.

I'm not saying the scriptwriter sat down and thought, "You know, the American public is dumb as a brick and won't know that lightning without thunder violates the laws of physics," but that's what I come away from these things feeling.

No, they probably thought 'the viewers will know that lightning with no thunder is out of the ordinary, so let's make a little play on that, since this is not actual lightning.' So what? It's called building tension and suspense, prior to the Tripod emerging, and it is standard in film and television. It gives the viewer a hook, something odd that requires explanation. Subsequent events provide that explanation. Here's the way I reasoned it:

'Lightning with no thunder is weird.'... 'Hmm, the frozen ground at the spot struck twenty-odd times is also weird. Wonder what that's all about then.' ... 'Ah, this is actually an alien transporter beam. OK, that explains the lack of thunder, since it actually was not lightning.'

I really, really cannot see why this is such an issue.

Besides, I'm sure there are vital plot reasons for the other stupid things the lightning does, whereas the only conceivable reason for the lightning without thunder is to make it weird and alien.

Yes, and in terms of the plot that is the whole point. It's precisely because it is so weird that the viewer gets drawn into the plot, and that such a crowd gathers at the spot the lightning struck to witness the emergence of the Tripod. If the lightning had not been so weird, or there at all, Ray would not have gone to check it out, so would not have been there to see the Tripod emerge and start killing people, and therefore the film would have ended shortly thereafter as his first sight of the Tripod comes when it flattens his street and his house with him still in it.

grewwalk
2006-Jan-13, 06:40 AM
In the newsvan video, you can see that the pulses are not traveling all that fast. Maybe 2-3 frames (if I remember correctly) to complete a pulse that is traveling downward. I don't think it would make a thunderclap. It's still going very fast and maybe should make a ripping sound instead.

Chris Pemberton
2006-Mar-01, 04:16 PM
Cold Plasma. Everyone is under the assumption that the lightning in this movie is hot, like regular lightning. The movie clearly tells us this is in fact NOT regular lightning. So, what if we change the properties of it a little bit? If the lightning were a form of cold plasma (rather than the superheated plasma we are accustomed to), then there would be no superheated air to violently radiate out from the bolt.

Just a thought.

Cheers.

Kullat Nunu
2006-Mar-02, 06:22 AM
If you can break air molecules and make the atoms to lose some of their electrons without heating it, you might have cool plasma. But how would that be possible?

shadowwalker
2006-Apr-09, 04:20 AM
The key to this is alien lightning.What makes us so sure it was an Earthly induced weather action?If it was alien then everything about it may be Alien also.The point is there are so many variables to Alien phenomena then Alien induced lightning, or what we percieve as such may be something else all together, and that "something else" adds to the beauty of the imagination.What proof do I have of this? Well just look at the number of posts here on this thread.We are thinking arent we?:think:

Zamise
2006-Apr-14, 03:23 PM
If you get too too close to lightning, or rather it gets too close to you, your ears might just start ringing instead, no thunder, no crack, and then its hard to hear anything for a little while. Thats from my personal experience. And, I don't think it was suppsed to be lightning as we are familar with in the real world that was portrayed in that movie either. It was acceptable to me, but seeing cruize getting eatin by a giant orifice of the rear end type did bother me a bit which I cant explain exactly why that would be.

furtim
2006-Jun-04, 09:24 PM
For one, it's pretty easy to explain what's wrong about it.

Jason, it seems to me this is at the heart of the BA's original discussion in his review of War of the Worlds. The point isn't to argue that the movie is bad because it goofed on a scientific point (because, clearly, it's fiction, and therefore judged on different criteria entirely) but rather to use the movie as an springboard to discuss the real physics of lightning. Nothing more, nothing less.

Melusine
2006-Jun-05, 12:42 PM
Jason, it seems to me this is at the heart of the BA's original discussion in his review of War of the Worlds. The point isn't to argue that the movie is bad because it goofed on a scientific point (because, clearly, it's fiction, and therefore judged on different criteria entirely) but rather to use the movie as an springboard to discuss the real physics of lightning. Nothing more, nothing less.

Here, here! This thread began, because of the OP's question regarding contradicting statements regarding lightning. (read the OP) The BA would would think every SF movie was bad if he used scientific reality as a sole standard of the film's value--that would eliminate any movie with aliens alone! He does not. I know that many high school science teachers use movies for examples of what is not possible, or maybe even possible, as it's a good way to engage students' attention. (Hey, and quibbling can be fun...sometimes.) ;)

billbeebe
2006-Jun-07, 02:40 PM
A couple years ago I was standing in my yard when felt a gravity release. My hair stood straight up and I felt very light. A moment latter the strike was so close that I felt part of it.

Bill