Nice looking underwater footage.

Those html embedding marks also seems to mess activity tab's post table.

Oliver, you don't need to post the embedding code. Just post the URL and Wreckamovie will automatically embed it. :)

Looks nice by the way!

It's fascinating really because it's a classic case of choosing between two evils. Very interesting to hear that Von Braun knew about it.

I suppose though that everything has a risk, even if it's not quite like getting a bullet through the head.

I myself learned that directly from Wernher von Braun's book Space Frontier, so I'd call that piece of information trustworthy and 'authentic'. ;)

While developing the American space program in the 1960's, they carefully studied and estimated every possible hazard to minimize the total risk for the spacecraft and crew. One of the main questions was, which will cause more risk: the known larger number of 'relatively slow' particles, which could be stopped with a strong shield, or the lower number of 'very high speed, high energy' particles, which couldn't be.

The study showed, that despite the relative rarity of very high speed particles (which may arrive from any direction with practically the same probability), the possibility of a single explosion inside the spacecraft due to such particles hitting a thick shield poses a catastrophic risk, which couldn't be tolerated. Therefore it was seen best to only build a partial shield in the direction the spacecraft was moving towards and simply let most of the high-speed 'bullets' pass though the spacecraft, if encountered. A pointed partial shield could considerably reduce the risk caused by the 'slow' particles without increasing the possibility for a catastrophe too much. Occasional single 'bullet holes' in the hull, on the other hand, could be relatively easily fixed, if necessary.

So, the astronauts are basically playing some Russian roulette all the time up there. They know well, that there's always a certain risk of 'getting a bullet through one's head' without a warning at any given time. Although the possibility is low, it's real.

"One single bullet occasionally crossing easily through the lab is much less of a risk than what thick walls causing hundreds of bullets potentially spreading out at a time would be."

I didn't know that, interesting post!

Thinking about it though, I suppose that's like people who survive being shot: the bullet goes straight through without hitting anything important.

Jussi: A projectile hitting anything thick in a spacecraft at very high speed causes pretty much similar effects as an anti-tank missile hitting a tank. The kinetic energy heats up the material on its way, ultimately vaporizing it instantly and explodes material out of the wall on the other side, if it can get through. Pieces of the wall will spread out in a cone depending on the speed of the projectile, its total energy, as well as the thickness and material of the wall. Pieces ripped off the wall act like a swarm of high-speed bullets within the cone and may cause serious damage.

If the wall is relatively thin and the speed of the projectile high, the projectile may simply make a hole and practically pass through the interior to the next wall before it gets decomposed. Therefore spacelabs etc. actually have very thin walls, so any high energy particle hitting the lab will simply pass though it and not explode inside. One single bullet occasionally crossing easily through the lab is much less of a risk than what thick walls causing hundreds of bullets potentially spreading out at a time would be.

I used a bit more time thinking through this yesterday and here's what I found out how it could look "natural" and how it could be made.

Scientifically thought, such an the effect might be possible in theory even in reality, if the explosion created a very dense plasma bubble at its outskirts, and this plasma would only gradually let the radiation pass in a similar fashion to what happened in the Big Bang.

The "natural" looks would then be in slow motion:
1. Of course, the first part of radiation can always escape and particles from the very outskirts will be thrusted out at close to light speed. So, seen from a distance the first flash should always be extremely intense white light practically in just a single point. The near light speed first wave of plasma may reach the observer and objects nearby almost simultaneously with light, so it will create a physical shockwave resembling earthquake and "wind" of particles immediately after the initial flash light passes. However, the particles will gain a spectrum of velocities, so it won't create but a partial shockwave followed by a windy "rumble", which will fade out before the following spectrum of radiation.
2. Once the plasma sphere were formed, only the most intensive radiation could escape at first and gradually less intensive spectrum would follow, i.e. starting from gamma- and X-rays and ending to radio waves as described. X-rays, microwaves and ultraviolet being invisible to naked eye, the explosion would actually black out for a moment after the initial flash while only those most intensive frequencies were reaching the observer. Only the "relatively slowly" expanding surface of the plasma sphere would be glowing bright white rapidly and fractionally degreasing in brightness from the initial flash. Remember, from a distance it would still appear almost as a single spot, although still extremely bright.
3. During the "blackout" for naked eye, the most intensive radiation would be hitting all objects in the vicinity as it expands. This would cause all matter and especially all metals extremely "heating up" (getting ionized or even radioactive). Ionization as such isn't visible, but this state is temporary and the matter returning swiftly back to less elevated states may cause it glow in extremely bright colors specific to each matter (fluorescence). Thus objects could be fluorescent against black sky for a moment! (The brightness of this fluorescence shouldn't be exaggerated, however, as only a portion of the energy of all the radiation is this intensive. Think of it as the edge of a continuous distribution or as the top of a pyramid, and the rest will be following gradually later..)
4. More of the radiation gradually reaching objects (less intensive frequencies adding up to the previous effects) the general brightness of the ionized objects would keep increasing due cumutatively more energy having caused ionization.
5. Once also visible light gets through to the objects, they will start reflecting colors as normal, gradually starting from violet to red - on top of the fluorescence generated earlier, which would continue its afterglow wherever it started. (Long lag! Remember, those fluorescent colors each object emitted earlier will keep showing up and shall be added together with whatever else will light up the object later.) However, visible light doesn't cause ionization like X-rays or ultraviolet, so no afterglow would remain from it and the visible colors could be following each other relatively separately as in spectrum, very close to just one frequency at a time. Theoretically the colors wouldn't be quite as intensive as in lasers, but close. (In principle some fluorescence should start dimming now, but objects are heating up and getting much hotter and brighter due more energy hitting them in general. So, as the time passes we may well forget that.)
6. Some absorbant (dark) objects may get heated enough to start glowing reddish, yellowish or even white just like hot objects normally do by the bright visible light alone. This is, again, specific to the material of the object and the amount of energy of the light absorbed. A black object would absorb more light than a white one (which would reflect colors away more efficiently), so it would start glowing hot more easily. (A stealth plane might burn hot due to this... Of course, the pilots got X-rayed already earlier, which would make two nice views of skeletons flying the plane in the cockpit - first as in an X-ray picture, then bones literally in flames before the plane gets vaporized off...)
7. The expanding plasmaball will keep glowing in the distance as a single bright white spot for a long time, although its brightness is decreasing gradually. However, depending on the distance of the observer, the plasmaball will sooner or later reach the observer and starts rapidly growing visually in size before it hits him. When the plasma sphere finally reaches the observer (finally filling all vision), it may still be completely white and shocking bright, or it may have started cooling down thus changing color towards red already. Either way, the edge of the sphere will hit the observer as a shockwave like a catastrohic earthquake or as in a nuclear blast, if the explosion was near enough. The strength of the shock will depend on the distance from the explosion, from catastrophic to neglicient.
8. As all the spectrum has passed, only the afterglow will remain. I.e. ionized and hot objects will slowly start cooling down. For ionization this means dimming out exponentially, but keeping the single bright color specific to each material. For pure heat also the color will change slowly towards dim reddish color as hot iron does while cooling down.

Well, such a glittering blast is only one possibility of this idea. I believe the looks would very much depend on the settings, for which there are practically infinitely many different possible choices.

For instance, the effect might as well pass in a split of a second to create a possibly strong new visual experience still or last for several seconds in slow motion. I have no actual knowledge of how such might look like, but it might be worth testing. Running an explosion simulation through a filter slightly separating the timing of different colors shouldn't be impossible, I think. I trust Samuli's team is able to test such relatively easily.

Interesting idea, but don't you think, that space battles will look a bit like a 80' disco? :)

LOL! Brilliant... absolutely brilliant...