For Questions That Don't Merit Their Own Thread

[JoeSchmuckatelli]

https://www.cnn.com/2021/12/17/world/juno-jupiter-ganymede-flyby-scn/index.html

 

[SunlitZelkova]

1 hour ago, kerbiloid said:

Why gather wild plants instead of burning them to use the soil as a plowland for usuak crops?

Something like 75% of the world’s crops rely on pollination. Combined with temperatures that the crops can’t withstand and high decline (or extinction) of the pollinators, I don’t think it would work.

1 hour ago, kerbiloid said:

Many people live far from sea and don't depend much on the sea food. It's just a cheap extra food, nothing more. Crops rule.

The pollinators and climate are a problem as mentioned above, and if marine ecosystems collapse as they do in this scenario, land ecosystems could likely be affected as well.

1 hour ago, kerbiloid said:

80k years ago just 10k humans had survived after the supervolcano.

This is a good point, but it should be noted that this theory is controversial and there is some evidence pointing to it being false.

Turning to the asteroid impact scenario-

The actual number of semi-long term bunkers is probably relatively low. Nuclear states obviously have a few, but most countries don’t. There are also a small number of private bunkers supposedly being commissioned by wealthy people, but these hold family and friends, not thousands of people.

[kerbiloid]

57 minutes ago, SunlitZelkova said:

Combined with temperatures that the crops can’t withstand and high decline (or extinction) of the pollinators, I don’t think it would work.

https://www.toppr.com/ask/question/in-which-of-the-countries-the-slash-and-burn-agriculture-is-known-as-roca/

They use it all the time everywhere.

[JoeSchmuckatelli]

1 hour ago, SunlitZelkova said:

Turning to the asteroid impact scenario

Could just be a regional event. 

I've seen speculation that had the Dino killing asteroid that made Chicxulub Crater not hit the Gulf it was possible that it would not have been a world killer. 

Absent a mass extinction event, humans should survive... But if you have a mass extinction - the larger life forms usually don't make it. 

[kerbiloid]

What we need about all those planetary probes-schmobes, is a good asteroid redirected into Venus just to have a look how it works.

1. Unlikely there can be found anything interesting anyway.

2. As a bonus we would get mineral examples from the upper twenty kilometers of Venus and study about it much more.

Go Venere.... Venusian Strike!

[JoeSchmuckatelli]

Pluto's polygons 

https://www.google.com/amp/s/www.space.com/amp/pluto-bizarre-polygon-science

[JoeSchmuckatelli]

More on Juno and Jupiter 

https://www.washingtonpost.com/science/2021/12/19/juno-mission-ganymede/

Quote

Surrounded by electrons, protons and ions that rapidly bounce around, Jupiter’s cloud cover has a layer of liquid metallic hydrogen

 

Edited December 19, 2021 by JoeSchmuckatelli

[JoeSchmuckatelli]

SciAm has a really nice write up about this, with some fabulous pictures and diagrams. Cover story of the Jan 22 issue.

Here's the Nature version:

https://www.nature.com/articles/s41598-021-84310-w

 

(Antikythera Mechanism) 

Astounding that they were making geared mechanisms so complex 2,000 years ago! 

 

Edit: here's the video: https://vimeo.com/518734183

 

Edited December 20, 2021 by JoeSchmuckatelli

[kerbiloid]

Finally they will realize that it was a timer for toasts.

Spoiler

 

 

And a meeting reminder.

Edited December 19, 2021 by kerbiloid

[SunlitZelkova]

1. In aerospace, has CAD made engineering more efficient, take less time to finish development [of things], or both?

2. Is the long time it takes to develop a crewed spacecraft in the 21st century inherent to all crewed spacecraft, or could a spacecraft be developed in a much shorter amount of time, albeit while sacrificing some safety?

[kerbiloid]

1 hour ago, SunlitZelkova said:

1. In aerospace, has CAD made engineering more efficient, take less time to finish development [of things], or both?

When they didn't have a CAD software, the human life was cheaper, the risks were more appropriate, the design was cheaper and easier in turn.

Now, when they have gotten the CAD software, the risks had already gotten more expensive, a lot of excessive expertise is required, and most part of the space cost is not the technics and its design itself, but the salary of thousands of people who have to re-compute and re-sign everything many times on any change.

So, none of that.

1 hour ago, SunlitZelkova said:

2. Is the long time it takes to develop a crewed spacecraft in the 21st century inherent to all crewed spacecraft, or could a spacecraft be developed in a much shorter amount of time, albeit while sacrificing some safety?

See p.1.

***

In 1960s the space was a rocket engineering, now it's a social engineering.

The rockets were cheaper.

Edited December 20, 2021 by kerbiloid

[Wizard Kerbal]

Is there a method of FTL travel that won’t atomize your ship when you hit a dust particle? Other than teleporting?

[DDE]

55 minutes ago, Wizard Kerbal said:

Is there a method of FTL travel that won’t atomize your ship when you hit a dust particle? Other than teleporting?

Some descriptions of the Alcubierre drive I've passed over imply the warp pocket can be collapsed to have a frontal crossection of less than a proton.

Besides, there's always the various alternative space drives and wormholes.

[Hyperspace Industries]

Is it possible to use a rocket's upper stage (say, a falcon 9) and have at the top of the fuel tank some sort of a inflatable bag, once the top part of the tank is empty, you inflate the bag into the tank, and use the tank walls as a pressure vessel with the bag to keep out any fuel still floating around. This is sort of a variant of the wet workshop concept.

[StrandedonEarth]

49 minutes ago, Hyperspace Industries said:

Is it possible to use a rocket's upper stage (say, a falcon 9) and have at the top of the fuel tank some sort of a inflatable bag, once the top part of the tank is empty, you inflate the bag into the tank, and use the tank walls as a pressure vessel with the bag to keep out any fuel still floating around. This is sort of a variant of the wet workshop concept.

I like to think in the other direction. Don’t convert a tank into habitable space; design a habspace  that can hold propellants for the first part of its service life. A bag of sorts may (or may not) be necessary to keep fluids out of sensitive areas. 

The great thing about methalox is that it can be vaporized and vented/captured without leaving behind an oily residue. 

[DDE]

1 hour ago, Hyperspace Industries said:

Is it possible to use a rocket's upper stage (say, a falcon 9) and have at the top of the fuel tank some sort of a inflatable bag, once the top part of the tank is empty, you inflate the bag into the tank, and use the tank walls as a pressure vessel with the bag to keep out any fuel still floating around. This is sort of a variant of the wet workshop concept.

This sort of positive displacement bags and bellows are generally not used at the scale of entire upper stages. Nothing impossible physically (Vostok's retrorocket used a bellows made of nitric acid-resistant rubber) but an engineering challenge.

[kerbiloid]

1 hour ago, StrandedonEarth said:

Don’t convert a tank into habitable space; design a habspace  that can hold propellants for the first part of its service life.

Be like George Plantagenet, Duke of Clarence, fly like a duke!

https://www.historyhit.com/what-led-to-george-duke-of-clarences-execution-by-wine/

Alcohol is the original rocket fuel.

[ARS]

The days of battleship era was near its end when naval aviation becomes practical and carriers become viable weapons of war, with the main selling point being able to strike battleship far beyond its gun range. After the war, although there's still some battleships around, the doctrine then shifted more from naval gunnery to guided missiles, thus, the battleship era was totally ended when guided missile technology has matured enough to place it on nearly all types of surface vessels, from the smallest to the biggest. Now, I saw some interesting discussion on mobile warship game, basically it boils down to this:

Proponents of battleships argue that the main reason the battleship era ended was because the range of engagement gets farther and farther, far beyond their main gun range (the main selling point of a battleship). If the range disadvantage was removed, the battleship couldstand a chance to win if the modern warship is forced on close quarter combat. The battleship's heavy armor will allow it to withstand some missile hits while the main gun could blow the modern warship  apart (which is much less armored than WW2 era battlehip)

Now, what I find interesting is that the notion that battleship main gun being able to blow a modern warship apart. Now what I want to as is, if the 2 ships encountered each other, and then:

1. The battleship fired a salvo of main gun shells (let's take 9 shells, the most common number of main guns on most battleships)

2. The modern warship (let's say a destroyer), just stand still, not doing anything, except trying to intercept the 9 shells with modern CIWS

Does modern CIWS is sophisticated enough to track and destroy an object like incoming battleship shells? If it is, then yeah, the battleship has no hope at all against modern warship

[StrandedonEarth]

So if a battleship fired an AP shell at a modern destroyer, would it hit anything solid enough to trip/ignite the fuse?

I have read a few novels that had AP shells go screaming through a lightly armoured target without exploding…

[JoeSchmuckatelli]

8 minutes ago, ARS said:

CIWS

Couple of things: ships may not be more armored, but they are better laid out and have much better fire suppression than previously.  

CIWS is good - but there are advantages to dumb bombs =very small & relatively fast. 

With a dead in the water modern ship relying on CIWS exclusively... I'd hate to be on the modern ship. 

 

 

IIRC - these novels have a modern naval task force whipped back in time to the Battle of Midway 

https://en.m.wikipedia.org/wiki/Weapons_of_Choice

Might be interesting

 

[magnemoe]

19 minutes ago, StrandedonEarth said:

So if a battleship fired an AP shell at a modern destroyer, would it hit anything solid enough to trip/ignite the fuse?

I have read a few novels that had AP shells go screaming through a lightly armoured target without exploding…

Battle of samar was the prime example of this. The Japanese with an vastly superior force assumed the US force to be cruisers and fleet carriers as it would be suicide to face them with destroyers and escort carriers, and they was the one doing suicidal last stands. 
However this mistake let the US destroyers to do better than cruisers would likely do.  https://en.wikipedia.org/wiki/Battle_off_Samar
Truly an fascinating fight.
I suspect that  the Japanese also lost their nerve then they understood how weak the US was in the area, at this time they would know the southern force was destroyed by all from battleships to torpedo boats in an night action. But this was the WW1 battleships not the Iowas and they got more and more air attacks. 
Surely tiny US force was up to something like holding them until something bad come like some Iowas supported by carrier strike groups and some subs for ganking  

Now I suspect an AP shell would fuse hitting an steel engine block or an 5" gun breach. But yes you would use high explosive unless against another battleship or heavy cruiser and probably the UK armored carriers. 

Edited December 21, 2021 by magnemoe

[StrandedonEarth]

27 minutes ago, magnemoe said:

Battle of samar was the prime example of this. The Japanese with an vastly superior force assumed the US force to be cruisers and fleet carriers as it would be suicide to face them with destroyers and escort carriers, and they was the one doing suicidal last stands. 
However this mistake let the US destroyers to do better than cruisers would likely do.  https://en.wikipedia.org/wiki/Battle_off_Samar

Thanks for that, I didn't know the name of the battle but that is definitely the battle described in the novel Space by James Michener (one of the ones I was referring to), right down to the quote "They're shooting at us in Technicolor!" Which makes me wonder if that wiki article was partly cribbed from the novel, lol, but it wouldn't surprise me if it is a real quote included in the novel..

[magnemoe]

36 minutes ago, ARS said:

The days of battleship era was near its end when naval aviation becomes practical and carriers become viable weapons of war, with the main selling point being able to strike battleship far beyond its gun range. After the war, although there's still some battleships around, the doctrine then shifted more from naval gunnery to guided missiles, thus, the battleship era was totally ended when guided missile technology has matured enough to place it on nearly all types of surface vessels, from the smallest to the biggest. Now, I saw some interesting discussion on mobile warship game, basically it boils down to this:

Proponents of battleships argue that the main reason the battleship era ended was because the range of engagement gets farther and farther, far beyond their main gun range (the main selling point of a battleship). If the range disadvantage was removed, the battleship couldstand a chance to win if the modern warship is forced on close quarter combat. The battleship's heavy armor will allow it to withstand some missile hits while the main gun could blow the modern warship  apart (which is much less armored than WW2 era battlehip)

Now, what I find interesting is that the notion that battleship main gun being able to blow a modern warship apart. Now what I want to as is, if the 2 ships encountered each other, and then:

1. The battleship fired a salvo of main gun shells (let's take 9 shells, the most common number of main guns on most battleships)

2. The modern warship (let's say a destroyer), just stand still, not doing anything, except trying to intercept the 9 shells with modern CIWS

Does modern CIWS is sophisticated enough to track and destroy an object like incoming battleship shells? If it is, then yeah, the battleship has no hope at all against modern warship

Problem for battleships was that the huge as in small fighter plane missiles designed to kill capital ships pretty much defeated armor. It was also an strong belief back in the 1950 that nuclear bombs would be used fallout style, now battleships survived close nukes surprisingly well but they lost the superstructure with radars, rangefinders and bridge  
Also they require an huge crew as they was build for WW2 conscription so no need to automate something we can have an sailor do and he is also damage control and other useful stuff.  And outside the Iowas was getting worn out during the war, and at Y2K the Iowas engines was worn out and the USN did not use steam turbines anymore outside of nuclear powered ships. Yes it was ideas to upgrade them, remove rear turret and magazine to replace engines then put an hangar deck and an missile launcher in the rear barbet.  
Too expensive for the time and they was ugly   

CIWS is an failback system, now an battleship opening up on an US carrier group at 20 km the AA destroyers would deal with the shells with the CIWS dealing with stranglers. 
Now during an exercise back in the 90's an US carrier group got intermingled with an Iowa and its escorts, both was under radio including radar silence. 
Unfortunately they was on the same side as they would be inside of comfortable 5" range or the secondary on an Iowa. Probably to short for many missiles to work.

Now US fleet carrier has an armored belt but its mostly against splinter or idiots shooting stupid stuff like anti tank missiles at them. 
In that case it makes sense but armor is kind of pointless in an blue water navy, now for brown water it start making sense again as tanks and other stuff will do potshot at you. 
Bit its better to get into an sniper duel with an battleship.  Texas has an legacy here. 

[SunlitZelkova]

3 hours ago, ARS said:

Does modern CIWS is sophisticated enough to track and destroy an object like incoming battleship shells? If it is, then yeah, the battleship has no hope at all against modern warship

Yes, most definitely. CIWS, at least the Phalanx, are already capable of handling 122mm and higher caliber artillery shells- certainly they can handle 356mm battleship shells. One would assume Russian and Chinese systems have similar performance.

2 hours ago, StrandedonEarth said:

So if a battleship fired an AP shell at a modern destroyer, would it hit anything solid enough to trip/ignite the fuse?

Even if it does not detonate, it would be probably be able to disable it anyways by punching holes in critical systems, namely the engines. Just Google “Arleigh Burke class cutaway” (I would post an image here but I am on my phone).

1 hour ago, magnemoe said:

Problem for battleships was that the huge as in small fighter plane missiles designed to kill capital ships pretty much defeated armor. It was also an strong belief back in the 1950 that nuclear bombs would be used fallout style, now battleships survived close nukes surprisingly well but they lost the superstructure with radars, rangefinders and bridge  
Also they require an huge crew as they was build for WW2 conscription so no need to automate something we can have an sailor do and he is also damage control and other useful stuff.  And outside the Iowas was getting worn out during the war, and at Y2K the Iowas engines was worn out and the USN did not use steam turbines anymore outside of nuclear powered ships. Yes it was ideas to upgrade them, remove rear turret and magazine to replace engines then put an hangar deck and an missile launcher in the rear barbet.  
Too expensive for the time and they was ugly

Even without anti-ship missiles, battleships were basically useless in a great power conflict post-1945. Just look at what happened to Yamato, which was attacked by dumb bombs and torpedoes.

I think the USN just kept them around for naval gunfire support in the various proxy wars they expected to fight.

[kerbiloid]

https://en.wikipedia.org/wiki/Piasecki_H-21

Was using the https://en.wikipedia.org/wiki/Wright_R-1820_Cyclone , which was using 

Quote

• Fuel type: 87 octane rating gasoline

Do I get it right that this helichopper was fueled with gasoline (not kerosene), so can be credibly treated as a realistic craft for Kerbals, using the petrol synthesized from algae by the Fischer-Tropsch process?

(As well as other Wright R-1820 powered crafts)