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Invisible <voi### [at] dev null> wrote:
> > goes off, you can clearly see the shockwave propagate as a glassy shell.
>
> Yeah, Invisible Worlds did this. They detonated a big stack of
> gunpowder, and you actually can see a visible shockwave. It's vaguely
> visible even at normal speed, but in super slo mo it's very clear.
>
> It looks Photoshopped.
Do you think it only *looks* 'shopped, or do think it actually *is* 'shopped?
I thought it looked as one would expect it to, personally.
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>> Yeah, Invisible Worlds did this. They detonated a big stack of
>> gunpowder, and you actually can see a visible shockwave. It's vaguely
>> visible even at normal speed, but in super slo mo it's very clear.
>>
>> It looks Photoshopped.
>
> Do you think it only *looks* 'shopped, or do think it actually *is* 'shopped?
> I thought it looked as one would expect it to, personally.
I'm rather surprised that it's a real effect. I thought it only happens
in Hollywood action films. But, apparently, it's real. Even if it does
look hard to believe...
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>> Thermal IR cameras are pretty well established as equipment for e.g.
>> police helicopters to search for or track people (particularly at night).
>
> I'll bet they're damned expensive though. ;-)
Not *that* expensive, we use one in the lab to see the hot-spots on LCDs. I
don't think it was more than a few times the cost of a good visible-light
camera (ie about 3-4K).
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Invisible <voi### [at] dev null> wrote:
> >> Yeah, Invisible Worlds did this. They detonated a big stack of
> >> gunpowder, and you actually can see a visible shockwave. It's vaguely
> >> visible even at normal speed, but in super slo mo it's very clear.
> >>
> >> It looks Photoshopped.
> >
> > Do you think it only *looks* 'shopped, or do think it actually *is* 'shopped?
> > I thought it looked as one would expect it to, personally.
>
> I'm rather surprised that it's a real effect. I thought it only happens
> in Hollywood action films. But, apparently, it's real. Even if it does
> look hard to believe...
Nah, hollywood only tends to do it in 2 dimensions, a ring-shaped wave (which I
believe you can get on water surfaces etc, but that's not what I've seen in
movies!). They also make it too prominent and slow-moving. I'm more inclined to
believe the slo-mo because it is spherical, very fast, and fades very rapidly.
Although of course it might be 'shopped!
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scott wrote:
>>> Thermal IR cameras are pretty well established as equipment for e.g.
>>> police helicopters to search for or track people (particularly at
>>> night).
>>
>> I'll bet they're damned expensive though. ;-)
>
> Not *that* expensive, we use one in the lab to see the hot-spots on
> LCDs. I don't think it was more than a few times the cost of a good
> visible-light camera (ie about 3-4K).
Sure, it's not expensive for suitably large definition of "expensive". ;-)
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>>>> It looks Photoshopped.
>>> Do you think it only *looks* 'shopped, or do think it actually *is* 'shopped?
>>> I thought it looked as one would expect it to, personally.
>> I'm rather surprised that it's a real effect. I thought it only happens
>> in Hollywood action films. But, apparently, it's real. Even if it does
>> look hard to believe...
>
> Nah, hollywood only tends to do it in 2 dimensions, a ring-shaped wave (which I
> believe you can get on water surfaces etc, but that's not what I've seen in
> movies!). They also make it too prominent and slow-moving. I'm more inclined to
> believe the slo-mo because it is spherical, very fast, and fades very rapidly.
> Although of course it might be 'shopped!
Well, on the example I say, it wasn't spherical at all. The shockwave
seemed to propogate more quickly along the ground (presumably because
it's a hard surface?), and was vaguely cylindrical like the tower they
detonated.
Then there was the smoke cloud reigniting briefly as it escaped the
shockwave area, "due to the extra oxygen"...
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Invisible <voi### [at] dev null> wrote:
> Well, on the example I say, it wasn't spherical at all. The shockwave
> seemed to propogate more quickly along the ground (presumably because
> it's a hard surface?), and was vaguely cylindrical like the tower they
> detonated.
Ah, I've not seen this one. Sounds about right, tho.
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Bill Pragnell wrote:
> Nah, hollywood only tends to do it in 2 dimensions,
There was a video showing the real-time shockwaves going thru the Iceland
volcano ash as it was coming out of the cone.
--
Darren New, San Diego CA, USA (PST)
Linux: Now bringing the quality and usability of
open source desktop apps to your personal electronics.
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On 4/29/2010 8:13 AM, clipka wrote:
> It's being done, not only for IR, but also for radio/microwave.
I'm supposing that's what the radio telescope images some from....
> Thermal IR cameras are pretty well established as equipment for e.g.
> police helicopters to search for or track people (particularly at night).
Yep. But those cameras are very expensive pieces of equipment, and have
to be specially cooled in order to work properly.
> Sound "images" are common for sonar systems. And ultrasound imaging
> devices, for that matter.
Well, that and Doppler radar (used for weather) also shows an image of a
radio wave of sorts. (A very similar concept, actually)
I was thinking more along the lines of a "CCD" for radio type device,
though. I think the radio telescopes generally examine a small are of
the sky for a certain frequency, then composite the information to build
a picture.
--
~Mike
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On 4/29/2010 9:27 AM, Bill Pragnell wrote:
>
> Do you think it only *looks* 'shopped, or do think it actually *is* 'shopped?
> I thought it looked as one would expect it to, personally.
>
Watch Mythbusters enough and you'll see one ...
--
~Mike
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