For Questions That Don't Merit Their Own Thread

[Nightside]

3 hours ago, ARS said:

Is there any reason why submarines almost always colored black? (Or at least the portion that'll be visible when it surfaces since the bottom portion that's underwater will also almost always red) If there's no particular reason, especially that impacts it's combat performance or stealth (as long as it stays underwater), does it mean it's fine to paint the submarine with dazzle camo or for the extreme, garish color like pink?

Sure!

[kerbiloid]

And it's red from below to be invisible in tropical sunset...

Edited May 7, 2020 by kerbiloid

[TheSaint]

7 hours ago, ARS said:

Is there any reason why submarines almost always colored black? (Or at least the portion that'll be visible when it surfaces since the bottom portion that's underwater will also almost always red) If there's no particular reason, especially that impacts it's combat performance or stealth (as long as it stays underwater), does it mean it's fine to paint the submarine with dazzle camo or for the extreme, garish color like pink?

Tradition? These days the hull is painted mainly just to prevent corrosion, at least in the spots that aren't covered by anechoic coatings. I guess that black may be harder to spot when you're on the surface, but subs are only on the surface when they're transiting in and out of port. Even when you're at periscope depth you're still pretty invisible. Although, back in the day, when the old Regulus missile boats were around, the story goes that they did have to paint them with a camouflage scheme. They were diesel, not nuclear, and some of them were stationed in the Mediterranean Sea where the water is incredibly clear. Apparently they spent a lot of time operating at snorkel depth, and when they did they were visible from aircraft flying overhead. Thus, the camouflage.

And, for reference, the red paint on the bottom is also tradition. It used to be that ships hulls were painted with red lead paint to discourage barnacle growth, but that obviously doesn't fly these days. They have other compounds they use now, but the color is optional. Red is used by tradition.

[DDE]

8 hours ago, ARS said:

Is there any reason why submarines almost always colored black? (Or at least the portion that'll be visible when it surfaces since the bottom portion that's underwater will also almost always red) If there's no particular reason, especially that impacts it's combat performance or stealth (as long as it stays underwater), does it mean it's fine to paint the submarine with dazzle camo or for the extreme, garish color like pink?

It's half-symbolic, half-camo. US SEAL delivery vehicle carriers of the Vietnam war tended to have a somewhat more elaborate camouflage.

[kerbiloid]

A camouflage texture for littoral submarines.
 

Spoiler

 

[TheSaint]

21 minutes ago, kerbiloid said:

A camouflage texture for littoral submarines.
 

  Hide contents

 

Ouch

[DDE]

12 hours ago, kerbiloid said:

A camouflage texture for littoral submarines.
 

  Reveal hidden contents

 

Soviet camouflage truly was ahead of its time.

Spoiler

Also, this came up in search

 

[mikegarrison]

On the subject of pink submarines: https://en.wikipedia.org/wiki/Operation_Petticoat

[Spacescifi]

 

Regarding scifi space war VS reality again:

 

Stealth Is Overrated?

No I am not going to quote what atomic rockets says. What I will say is that there is another option besides stealth that is arguably better.

Deception.

If space nations have the resources to burn  spend on a massive war in space, then they certainly have resources to be deceptive while doing it.

In fact, given how hard it is to be stealthy in space, deception is one way that you can actually surprise your enemy.

For example consider thus scenario:

Space fleet A is coming from planet A to attack space fleet B at planet B.

Space fleet B's ships ALL look the same.

But are they?

No. They all have the same enhine nozzles, but some high different combos of propellant and reactors.

And some have missiles, while others have nothing but squishy padding and an engine. Still others are hollow and lightweight.

Really spacefleet won't even know what space fleet B can really do until it's ships start showing their hand. Kind of like playing poker.

Or Stratego.

The only thing you need to pull this off is multiple engines on each ship... or an engine that can throttle from low to high really good.

What do you think?

Edited May 11, 2020 by Spacescifi

[wumpus]

38 minutes ago, Spacescifi said:

Stealth Is Overrated?

Sun Tzu writes that "all warfare is based on deception".

I would claim logistics are most important, but deception is a close second.

The catch is that it is quite likely you can determine how much energy a ship is emitting, how much it is accelerating, and thus its mass.  Faking a high mass/high energy ship might not be worth it.

[Spacescifi]

38 minutes ago, wumpus said:

Sun Tzu writes that "all warfare is based on deception".

I would claim logistics are most important, but deception is a close second.

The catch is that it is quite likely you can determine how much energy a ship is emitting, how much it is accelerating, and thus its mass.  Faking a high mass/high energy ship might not be worth it.

 

Logistics?

You mean how efficiently they can transport supplies for tge war effort?

I suppose.

The only real counter to that is pure numbers, which because of the high orbital plus speeds involved, usually means that all out offense is both the best defense and offense. 

The closest thing to a defense is faking high value targets with hollow ships with engines and padding only.

Or even better... shield ships. Ships full of water that can take a beating and even reseal the hull breaches with ice spray.

 

EDIT: Full quote by Tzu:

"All warfare is based on deception. Hence, when we are able to attack, we must seem unable; when using our forces, we must appear inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near."

Sun tzu, The Art of War

Tags: deception, strategy, tactics

Too bad scifi villains are idiots too often. Never read Tzu.

Edited May 11, 2020 by Spacescifi

[K^2]

4 hours ago, wumpus said:

I would claim logistics are most important, but deception is a close second.

Art of War has lengthy passages on logistics. Also, deception around logistics.

[YNM]

1 hour ago, K^2 said:

deception around logistics.

What most of war effort sums up to IMO. Hiding in plain sight until the last possible minute (or even beyond).

Best kind of war is wars that doesn't even look like one - physical warfare is overrated, just make the ruling structure collapse and install your puppet.

[Spacescifi]

32 minutes ago, YNM said:

What most of war effort sums up to IMO. Hiding in plain sight until the last possible minute (or even beyond).

Best kind of war is wars that doesn't even look like one - physical warfare is overrated, just make the ruling structure collapse and install your puppet.

Casualties in space should also be low or none, given that robot ships can do most of the fighting.

All crew are to an enemy is hostages. And the whole objective of the war, if merely to take territory, whether a space station or a resource outpost on a planet, involves not blasting whar you want to bits.

If you do that, it's just a button pushing affair and sooner or later the bombs will be coming for ya.

To be honest I find wars of annihilation to be... kind of cliche.

Like IRL wars of annihilation are often because religions or ethnic hatred, which is rarely the case in popular scifi since religion is like supposed to not be around or is ignored or something (B5 is an exception even though they scified by saying it was aliens all along).

What I am saying is that going on extermination mode simply fir territory is a rather extreme act to take, and should be far less popular than it is in scifi, at least if going for realism.

Ignore or have zero rules of engagement and sooner or later everyone will take you down.

Don't believe me?

Look what happened to the Assyrians.

After a costly civil war they were ganked by their many enemies. End of empire.

Edited May 12, 2020 by Spacescifi

[kerbiloid]

The deception is a short-term bells-and-whistes to the long-term logistics. The wars are running between economics and industries.

And Napoleon with logistics occupied much more than Sun Tzu with deception, though wasn't executing palace concubines after failing their military training, and was rather poor in philosophy.
Macedonian Alex and his dad Phil, too.

When the army doesn't have food and ammo, it may hide as much as it wants.

Edited May 12, 2020 by kerbiloid

[DDE]

We don't have a thread for this launch vehicle.

 

[magnemoe]

15 hours ago, YNM said:

What most of war effort sums up to IMO. Hiding in plain sight until the last possible minute (or even beyond).

Best kind of war is wars that doesn't even look like one - physical warfare is overrated, just make the ruling structure collapse and install your puppet.

This, note that having others take the bill is also an major point in peacekeeping, Yes we can do recon and air strikes but we don't want to put serious boots on the ground. Russia says we want to do that in Syria. Nice can you not take Lebanon too, you can make it an Russian province as long as you keep the crazy Iranians out. In short they are solving an problem, Russia having an fleet base in the Mediterranean is not an serious problem.
Yes they need to crack some eggs pacifying the place but that is their problem and Russia is an way better place to live than Syria who again beat ISIL or other alphabet soup radical groups holdings. 
Exception is stuff like Sweden join their first international combat alliance in probably 100 years to combat prove their fighter jet to boost sales. 

[YNM]

9 hours ago, magnemoe said:

Yes we can do recon and air strikes but we don't want to put serious boots on the ground.

Pretty sure they would rather not have anyone else on their dirt, be it "east" or "west". (I'm not from the US or Russia.)

9 hours ago, magnemoe said:

Russia having an fleet base in the Mediterranean is not an serious problem.

That depends on how one wants to see it honestly. How long is the other superpower going to pretend that they are concerned ?

23 hours ago, kerbiloid said:

And Napoleon with logistics occupied much more than Sun Tzu with deception

Not sure about that now - Sri Lanka's Hambantota was done with no single ammunition utilized, meanwhile the rooster has become old and senile. It wasn't entirely secluded and in secret, but they definitely have a lot of such moves being played across the world. Also they've definitely dominated the marketplace, so much so that the whole world was crippled when they gone awry. Their immediate neighbors do generally keep them in check, but we don't know for how much longer.

[mikegarrison]

On 5/11/2020 at 4:09 PM, wumpus said:

Sun Tzu writes that "all warfare is based on deception".

I would claim logistics are most important, but deception is a close second.

Sun Tzu also wrote quite a bit about logistics. And many other things. I would argue that you are taking this out of context.

Sun Tzu basically agreed with Nathan Bedford Forrest that the best thing was to get there first with the most men. But if you couldn't do that, he had many other suggestions about how to overcome a force disadvantage if you have to.

Edited May 14, 2020 by mikegarrison

[DDE]

Alright, who's having fun with the time machine again?

Quote

Cosmism may have been inspired by the discovery of the Biela Comet, first recorded in 1772 and then, mistakenly, charted on a collision course with earth. In 1826, Wilhelm von Biela confirmed the comet as periodical; it was predicted to collide with the planet within the 1830s. The impending end of the world produced a worldwide panic (and several more thereafter throughout the nineteenth century), similar to the Y2K computer scare at the turn of the twenty-first century.

Awareness of Biela’s Comet and the planet’s impending collapse inspired several literary works written around 1830. One of these was an unfinished sci-fi novel by the Russian writer, philosopher, and music critic Prince Vladimir Odoevsky (1803–69). Originally published in fragments between 1835 and 1840, The Year 4338 describes a futuristic society in the year before a comet emerges from the depths of cosmic space to destroy earth. The protagonist of the novel, a young man from Beijing, travels to St. Petersburg to meet with scientists who he thinks can prevent this impending cataclysm before doomsday in 4339. He travels on a high-speed electrical train under the Caspian Sea, through a futuristic Russia where all households are connected by telegraphs, and where people read newspapers made of liquid-crystal screens, have personal flying devices in the form of hot air balloons, eat synthetic foods, inhale special gas for recreation, and wear electric clothes that change colors and patterns. A moneyless economy has also been achieved.

 

[ARS]

19 minutes ago, DDE said:

Alright, who's having fun with the time machine again?

That's awfully close to what we have now, with the exception of:

1. Hot air balloon as a personal flying device. We commonly use cars now

2. Electric clothes concept exists, but not for changing colors but for heating (although it does change color, if you see it from thermal imaging camera)

3. LCD is actually starting to get replaced with LED (but still, pretty close approximation of what 20th century tech looks like)

4. We still use money, and it's still driving the economy

Edited May 14, 2020 by ARS

[kerbiloid]

1 hour ago, DDE said:

 The Year 4338 describes a futuristic society

"The overlapping concurrent temporal threads merged. Please, ignore possible artifacts. Matrix."

1 hour ago, ARS said:

Electric clothes concept exists, but not for changing colors but for heating

Just wait for a couple of decades when e-paper becomes e-cloth and e-cover for furniture.

Btw, this gives us a hint when did the Odoevsky's informant came from.

(I would add, 1830s are a rather sick choice of the destination point (kinda he'd even better jump into 1930s, lol), so probably the chronojump was unexpected. See "resonance cascade".)

1 hour ago, ARS said:

3. LCD is actually starting to get replaced with LED (but still, pretty close approximation of what 20th century tech looks like)

Now we can see that the covid will have slowed the electronics replacement for two decades.

1 hour ago, ARS said:

4. We still use money, and it's still driving the economy

Long-term effects of the same. First the physical money will be exterminated for safety, then toilet paper gets socially available for free.

P.S.
I have a feeling, the first half of XIX was a time of mass descent from the future.
Downloading Odoevsky.

Edited May 14, 2020 by kerbiloid

[Mitchz95]

We often refer to stars as being red, yellow, blue, etc. But the sun, a "yellow" star, actually looks white when viewed from outside the atmosphere. So what color would the other star types be in unfiltered light?

[kerbiloid]

They so bright that all look white.

[K^2]

7 hours ago, Mitchz95 said:

We often refer to stars as being red, yellow, blue, etc. But the sun, a "yellow" star, actually looks white when viewed from outside the atmosphere. So what color would the other star types be in unfiltered light?

It's not just filtering. Sun's spectrum is yellowish. But because peak of the Sun's output is right around the middle of our visible spectrum, which certainly isn't a coincidence, it's pretty close to white*. So if you were to look at the Sun directly through a filter that cuts out most of the light, but uniformly across spectrum, you'd see a disk that's white with a tinge of yellow. All G-type stars are yellowish to white, and F-type stars are white to blueish. So particularly hot G stars and particularly cool F stars can look almost perfectly white. I don't honestly know if there is a spectral type that's indistinguishable from white to human eye, or if it'd all look just a touch off, but at any rate, there are certainly stars closer to white than Sun.

But there are also stars a lot colder than Sun and these that are way, way hotter. Cooler stars are often called red, but they're actually closer to orange, ranging from orange-red to orange-yellow. It's actually really easy to see what a light of red giant looks like, because light from an incandescent light bulb is very close in temperature to a typical red giant. And this is why talking about colors is a bit complicated. If you are sitting in a room lit by incandescent light bulb, you'd notice that it's a bit yellowish, but you'd think it's not far from white. While if you could actually compare it side-by side with daylight, you'd see how deeply orange incandescent light is. So if you ever want to picture what a world illuminated by a red giant looks like, you can just picture it illuminated by incandescent lights. If that's all you're getting, it actually wouldn't look all that alien.

Likewise, there's a good example for what a blue giant light looks like down here on earth. A lightning generates plasma that's pretty close to the temperature of the typical blue giant's photosphere. The problem is that it's too bright and too brief for the color to register, and the gases involved typically shift the spectrum quite a bit. A bit easier to watch, perhaps, though certainly not directly, is an arc of an electric welder (always use eye protection!). Their temperatures are a bit cooler, but still, typically, in the ranges of blue stars. Unfortunately, most welding goggles distort colors quite a bit, but if you can find a set that doesn't, you could look at what the world illuminated by a blue giant would be like. Again, it doesn't register to our brain as particularly blue, and you'd call it bluish white, most likely. And if you're looking around a room illuminated by an arc welder (still through some sort of UV filter, always!), you might not even see it as particularly blue, because your eyes and your brain are going to compensate quite a bit. The blue tint of the arc will only really be visible in side-to-side comparison with a source of white light.

And, of course, there are factors that play when light is too bright or too weak for our eyes to register correctly. Pretty much anything sufficiently dim will look yellowish and anything sufficiently bright can go from white to basically anything as it overwhelms your retina. So in all of the above, we're assuming that you're getting enough light to activate all the cones in the retina, but not so much as to overwhelm that, and that will necessarily involve looking through some sort of filter when looking at a star from up-close, or a telescope to amplify the light if you're looking from far away. Both of these can be achieved with minimal color distortion.

 

* Ok, it's actually worth discussing what "white" means. Perception of color is a complicated thing. The most convenient definition of white is color you perceive when looking at so-called white noise. A spectrum that has equal power at all wavelengths. If you were to look at an artificially created white spectrum and compare it to sunlight, you'd perceive sunlight as slightly yellowish.

 

Edit: I've actually found some code I used a while ago to try and display night sky from various places in our stellar neighborhood as precisely as possible. One of the things I tried to do is approximate the spectral color of each star. And the very first step was matching RGB output to be as close to what the eye would perceive. This involves figuring out the approximate spectrum of the star, and for this I just used black body radiation, ignoring chemical composition, then computing relative stimulus to the L, M, and S cones in the human eyes by that light, and finally, finding best RGB match that would produce the same stimulus. I found some papers that did most of the hard work, and was able to produce the following spectrum. It starts at 1700K, which is about as cold as a star can get and still be a star, and goes up to 25,000K, which isn't the hottest that stars get, but up there.

To be clear, this is not what the stars at these temperatures actually would look like. It's the closest that the RGB display can produce, with pretty big error for the white-balance of your particular display, which I have no way of accounting for. (There are "correct" ways of tuning your screen to match this better, but they are not even possible on all displays, and pretty involved one ones that do support it.) So take this with a pretty big grain of salt. Nonetheless, it has the right features. The "red" it starts with is rather orange. The "white" area is pretty narrow, and not all that white. Clearly, most stars are going to be either yellowish or blueish. And the bluest it gets is kind of pale light blue.

Edited May 18, 2020 by K^2