For Questions That Don't Merit Their Own Thread

[wumpus]

On 2/20/2020 at 4:13 AM, K^2 said:

USA is a bit different. I'm not sure it would deter everyone, and I don't know how much impact this still has on younger generations, but the fear of nuclear war and everything associated with it that was put into people during the 70s and 80s still resonates with many. I was born in USSR, grew up in a research town next to a military base, two of my grandparents did work on uranium refinement for reactors, one served in the military, and my father's reserve training involved ICBM navigation. People I grew up around didn't have half as much respect or fear of the radiation hazard sign as I see from a lot of people a little older than me in US who had no association with any related field of work. There's also a lot of completely irrational fear of anything that has words "radiation" or "nuclear" in it, but that's a separate story.

Not USA, but you have to ask yourself why Germany turned off their nuclear plants in the face of catastrophic global warming...

In the USA I've personally made sure I selected an infra-red based smoke detector instead of a more effective radioactive-based detector.  Although that was exclusively about fear of paperwork (it was for the Marines, so lots of military regulations*) than any other reason to choose the inferior method.

* I had visions of writing "absolutely safe" over and over on a mountain of documentation...

[mikegarrison]

16 minutes ago, wumpus said:

Not USA, but you have to ask yourself why Germany turned off their nuclear plants in the face of catastrophic global warming...

I thought that seemed like a bad move. But Germany has made a huge push for solar power. When I was last there, a few years after they made that decision, I saw solar panels on the roofs of many, many private houses.

[magnemoe]

1 hour ago, wumpus said:

Not USA, but you have to ask yourself why Germany turned off their nuclear plants in the face of catastrophic global warming...

In the USA I've personally made sure I selected an infra-red based smoke detector instead of a more effective radioactive-based detector.  Although that was exclusively about fear of paperwork (it was for the Marines, so lots of military regulations*) than any other reason to choose the inferior method.

* I had visions of writing "absolutely safe" over and over on a mountain of documentation...

I was advised to shift to an  optical alarm by an fire inspector as they are better at detecting smoldering fires. The ionizing type is not dangerous unless you eat it but its something who is definite special waste. 
More expensive models are multi mode. 

[K^2]

12 hours ago, mikegarrison said:

I thought that seemed like a bad move. But Germany has made a huge push for solar power. When I was last there, a few years after they made that decision, I saw solar panels on the roofs of many, many private houses.

Solar is poor substitute for nuclear with current limitations on energy storage. The nice thing about nuclear plants is that just like coal and gas plants, they rely on a rather heavy turbine, which can store quite a bit of kinetic energy. For chemical burning plants, that energy is enough to increase/decrease power output to meet the demand. With a nuclear power plant, it doesn't quite get you there, as reactors take a good while to change the output, but it certainly helps even out the load, letting you rely on nuclear as your primary energy source. Solar doesn't have that built in. What solar does give you is peak power during peak use. So a combination of nuclear and solar can get you 90%+ of typical usage, with the remaining power coming from gas burning plants that are just above idle load, but can be throttled up to full output in a matter of minutes if you suddenly get a high usage spike.

Naturally, every one wants to go 100% renewable. That's a great goal. But it is a longer term goal and should be treated as such. Going 90% nuclear/renewable can be achieved in a matter of years on existing and proven technology if we put resources into it, and that would make a huge difference. Going 100% solar in 20-30 years might be too late if we spend most of that time burning 70% coal, and that's the trajectory the countries with renewables-only plan are on right now.

[steve_v]

23 minutes ago, K^2 said:

Going 90% nuclear/renewable can be achieved in a matter of years on existing and proven technology if we put resources into it, and that would make a huge difference. Going 100% solar in 20-30 years might be too late if we spend most of that time burning 70% coal, and that's the trajectory the countries with renewables-only plan are on right now.

Don't forget oil and gas as "transition fuels"
Other than that tiny bit of sarcasm, yeah, all of the above.

 

The irrational public fear of nuclear energy irks me no end, it's considerably safer than coal both in terms of deaths/GWH and environmental impact, and it's exactly what we need if we're going to cut greenhouse gas emissions in time to avert the worst of the coming catastrophe. Hell, it's safer than hydro in deaths/GWH, and we have the technology ready to go right now.

[Mitchz95]

Hypothetically, could a celestial body in the L2 point of a hot Jupiter be permanently shaded from its sun? If so, would this make more sense as a planet, or moon of said hot Jupiter? And what type of star would be optimal for this scenario?

Edited February 25, 2020 by Mitchz95

[magnemoe]

18 minutes ago, Mitchz95 said:

Hypothetically, could a celestial body in the L2 point of a hot Jupiter be permanently shaded from its sun? If so, would this make more sense as a planet, or moon of said hot Jupiter? And what type of star would be optimal for this scenario?

Problem is that L2 is not stable like L4 and L5. You will drift out of them and drift increases as you get longer and longer from L2, same with L1 and L3.
Not much an problem for an satellite with rcs but not an natural body 

[K^2]

There are trajectories near L1-L3 that are somewhat stable. A capture could get briefly stuck in either of these, but it wouldn't last. L3 is the most interesting case here, because that can lead to Janus/Epimetheus type orbit.

[Mitchz95]

I don't doubt the orbit would be unstable, but it's for a soft science setting, so doesn't really matter. Anyway, going by mass, would it make more sense for this world to referred to as a planet or a moon?

Edited February 26, 2020 by Mitchz95

[magnemoe]

1 hour ago, Mitchz95 said:

I don't doubt the orbit would be unstable, but it's for a soft science setting, so doesn't really matter. Anyway, going by mass, would it make more sense for this world to referred to as a planet or a moon?

Note that for an spaceship its no issues, one fun setting might be that you had to fly inn on an trajectory who kept you in shadow so you could get close and study the planet. 
It would also be an very good defensive position as an enemy had to follow that narrow trajectory to reach you, distance probably be to long for lasers and ships or missiles had to follow it. 

[Spacescifi]

 

Was wondering this for a scifi alien race I have in mind, is it chemically possible to have a race with combustible blood.?

 

The answer:  Yes, but I wonder how close the blood will be to our own? Since oxygen carrying blood like ours is preferred since it can deliver more energy for the work the creature does daily.

In the setting, the blood would become combustible when mixed with the fruit juice of a plant that is toxic to them, but animals like.

The aliens have biological retractable syringes they can poke themselves with to draw blood and then drain it with the syringe where they wish.

The toxic fruit starts to smoke with steam when the alien blood is injected into it's flesh through the rind, which lets the alien know the fruit is about to explode like a grenade.

 

How chemically plausible is this and what effect will it have on civilization and tech progress?

Aliens are humanoid.

Edited February 29, 2020 by Spacescifi

[kerbiloid]

43 minutes ago, Spacescifi said:

is it chemically possible to have a race with combustible blood.?

Yes. Our blood burns in fluorine.

43 minutes ago, Spacescifi said:

the blood would become combustible when mixed with the fruit juice of a plant that is toxic to them, but animals like.

You can't replace your blood with 70° whiskey before falling asleep.

43 minutes ago, Spacescifi said:

The aliens have biological retractable syringes they can poke themselves with to draw blood and then drain it with the syringe where they wish.

The toxic fruit starts to smoke with steam when the alien blood is injected into it's flesh through the rind, which lets the alien know the fruit is about to explode like a grenade.

Then they don't need to use their own blood. Any close species should be good.

43 minutes ago, Spacescifi said:

How chemically plausible is this and what effect will it have on civilization and tech progress?

The first drunkard will blow up the wedding.

43 minutes ago, Spacescifi said:

Aliens are humanoid.

With whiskey blood?
Never. Maybe just visually.

Edited February 29, 2020 by kerbiloid

[Spacescifi]

41 minutes ago, kerbiloid said:

Yes. Our blood burns in fluorine.

You can't replace your blood with 70° whiskey before falling asleep.

Then they don't need to use their own blood. Any close species should be good.

The first drunkard will blow up the wedding.

With whiskey blood?
Never. Maybe just visually.

 

LOL. 

True, some but not all of the wildlife have it, but none really have the bio syringes to use it like the humanoids do.

 

If this was indeed their form of alcohol I would expect them to be more sober than humans overall, since even a cut on the to tongue could burn the mouth. Worse case scenario is the mouth is bleeding and full of juice. If they don't spit out in time or accidentally ingest it.. it's gona be a horror movie of exploding gore.

 

If the stomach processes it it's fine, but blood contact prior to that will cause a reaction.

 

They should like human wine and beer at least, given that neither of those makes them go boom. Likely be the biggest trade item. Aliens buy lots of alchohol

 

 

Edited February 29, 2020 by Spacescifi

[magnemoe]

7 hours ago, Spacescifi said:

 

Was wondering this for a scifi alien race I have in mind, is it chemically possible to have a race with combustible blood.?

 

The answer:  Yes, but I wonder how close the blood will be to our own? Since oxygen carrying blood like ours is preferred since it can deliver more energy for the work the creature does daily.

In the setting, the blood would become combustible when mixed with the fruit juice of a plant that is toxic to them, but animals like.

The aliens have biological retractable syringes they can poke themselves with to draw blood and then drain it with the syringe where they wish.

The toxic fruit starts to smoke with steam when the alien blood is injected into it's flesh through the rind, which lets the alien know the fruit is about to explode like a grenade.

 

How chemically plausible is this and what effect will it have on civilization and tech progress?

Aliens are humanoid.

Main issue might be that benefit from the explosive fruit you have to be an very smart animal. Smart as in dropping nuts on an road so cars crack them open style. 
so they need to evolve this very late like as an ape. 
Far easier with an  plant with explosive fruits in it self, an nut with an hard shell start an rapid chemical process once released from the tree create an explosion spreading the spores. 

This also discourages trying to eat or crack the fruits but make them kind of an natural grenade. 

Now for fun blood, Grendel's in https://en.wikipedia.org/wiki/The_Legacy_of_Heorot has the option to dump basically monoprop into their bloodstream allowing for some serious bursts but also overheating if run for time. 

[p1t1o]

@Spacescifi

Combustible blood? Interesting idea.

Worth noting that mammalian respiration is equivalent to combustion. Kerbo Carbohydrates are oxidised to liberate metabolic chemical energy.

The combination of oxygen with carbon, netting a release of energy (in this case a metabolite, ATP, with high bond energy that can be used to drive biological, energy consuming processes) is broadly equivalent to simply burning the carbohydrate in air. Many of the enthalpies and bond energies are the same, the same bonds are broken and formed, the same number of Joules release, just that the reaction proceeds in aqueous solution, at much lower rates than true physical combustion.

 

So to put it anther way - we dont have combustible blood, but stuff is combustible with our blood. Sort of.

Blood is not the fuel, blood is the oxidiser!

 

So you might not have a creature who bleeds, and the blood catches fire.

But you might have a creature that bleeds, and whatever its blood touches, catches fire.

 

So rather than bleeding kerosene, it bleeds strong acid or base or some other highly reactive substance.

Say...that reminds me of something...

 

**edit***

As an aside, it would seem to follow, that a creature with very reactive blood, respires something that is itself, quite UNreative.

So you could have a creature breathing nitrogen or neon or something, or it could consume gold like we consume sugar. It could consume metal oxides (rocks) and excrete pure metals.

Maybe. Depends how "hard" you want to go with the biochemistry involved, but it seems like an area quite rich with sci-fi fodder.

Edited March 2, 2020 by p1t1o

[Spacescifi]

2 hours ago, p1t1o said:

@Spacescifi

Combustible blood? Interesting idea.

Worth noting that mammalian respiration is equivalent to combustion. Kerbo Carbohydrates are oxidised to liberate metabolic chemical energy.

The combination of oxygen with carbon, netting a release of energy (in this case a metabolite, ATP, with high bond energy that can be used to drive biological, energy consuming processes) is broadly equivalent to simply burning the carbohydrate in air. Many of the enthalpies and bond energies are the same, the same bonds are broken and formed, the same number of Joules release, just that the reaction proceeds in aqueous solution, at much lower rates than true physical combustion.

 

So to put it anther way - we dont have combustible blood, but stuff is combustible with our blood. Sort of.

Blood is not the fuel, blood is the oxidiser!

 

So you might not have a creature who bleeds, and the blood catches fire.

But you might have a creature that bleeds, and whatever its blood touches, catches fire.

 

So rather than bleeding kerosene, it bleeds strong acid or base or some other highly reactive substance.

Say...that reminds me of something...

 

**edit***

As an aside, it would seem to follow, that a creature with very reactive blood, respires something that is itself, quite UNreative.

So you could have a creature breathing nitrogen or neon or something, or it could consume gold like we consume sugar. It could consume metal oxides (rocks) and excrete pure metals.

Maybe. Depends how "hard" you want to go with the biochemistry involved, but it seems like an area quite rich with sci-fi fodder.

 

I like it! Thank you very much!

I like the idea of the blood reacting with stuff to catch fire, but I still wanted these aliens to be humanoid only colored differently.

 

The reason I decided to play with the blood was it's color (purple).

I decided, if it is purple why should I have it have the SAME exact traits as human blood? They are my scifi aliens after all, not ST or SW gimmick aliens.

 

So I will modify the idea slightly you that you gave me.

Their blood reacts with the wood on their planet by setting it on fire, but their blood is an oxygen carrier like our own, but different in that it reacts with wood by catching it on fire.

Don't ask me how. I am not a chemistry major.

 

You on the other hand can probably devise what the aliens should be breathing and eating given tge fact that their blood catches fire when exposed to wood.

I wanted the aliens to be able to eat what humans do, so I was also thinking, maybe the homeworld just has some strangely reactive wood that reacts with their blood? 

Interestingly, if one throws human blood on the alien wood it becomes like acid.

 

Regarding alien behavior: Humans have little in the way of instinctual behavior, behavior is very much modifiable.

These humanoid aliens behavior differ in one key way that helps them given their homeworld environment. They are inherently responsible and do not have to be taught it.

The implications of this are huge. It means that there is no such thing as an accident due to slacking off or negligence, only deliberate sabotage or misleading misinformation. Even their babies act differently, at least once they understand their responsibilities.

All of this helps prevent them from setting the honeworld ablaze, while also using fire to their advantage.

These guys likely would have harnessed technology quicker than humans thanks to the ease of producing fire.

 

The idea of their blood catching fire with any type of wood... not just the homeworld's is very tempting, but I am not sure if that will change their eating habits dramatically as humanoids.

Like I don't want humanoids eating gravel and gold.

 

EDIT: It will be as you said, the wood in contact with their blood catches fire, so they must be extra careful while working with wood.

Submerging the wood in blood won't ignite it, but the second it hits air it will go up in flames.

 

Cool. No bio syringes required. Just a knife and a bandage.

Although syringes will be used when they have tech.

 

 

Edited March 2, 2020 by Spacescifi

[DDE]

Azipods and their various relatives seem extremely common among civilian vessels.

Yet they aren't seen on warships, outside of the various retractable auxiliary thrusters.

Why?

[Spacescifi]

1 minute ago, DDE said:

Azipods and their various relatives seem extremely common among civilian vessels.

Yet they aren't seen on warships, outside of the various retractable auxiliary thrusters.

Why?

 

What's an azipod?

 

Googled the answer.

https://www.quora.com/Why-dont-aircraft-carriers-use-podded-propulsion-systems-instead-of-fixed-props

 

Short answer: More maintenence and scaling it up has some potential problems that a simple fixed propeller won't have.

 

Warships are meant to be reliable or durable above all else, which meabs complex systems more probe to maintenence are not advised.

 

Edited March 2, 2020 by Spacescifi

[DDE]

25 minutes ago, Spacescifi said:

Warships are meant to be reliable or durable above all else, which meabs complex systems more probe to maintenence are not advised.

The elimination of a mechanical link under constant mechanical loads arguably means less complexity.

[p1t1o]

43 minutes ago, Spacescifi said:

<snikt>

Like I said, a ton of fodder!

Without creating a complete viable biochemistry from scratch - and thus becoming a god - one can at least say that there is great scope for variation and strange metabolisms in the "phase-space" that is biochemistry.

For example, catalysts (and their biological, protein-based counterparts, enxymes) can enhance reaction rates by many orders of magnitude (easily 100,000-1M times) and can be extremely specific. Like a lock and key, molecules of the wrong shape wont react - but molecules of a similar shape can.

Quote

Their blood reacts with the wood on their planet by setting it on fire, but their blood is an oxygen carrier like our own, but different in that it reacts with wood by catching it on fire.

So for example, alien blood could be an oxygen carrier like our own.

And like our own, does not exactly react with much when exposed.

Except that this alien blood contains certain enzymes or catalytic compounds that have a biological role to react with a certain type of compound as a part of its normal metabolism.

This compound could just happen to share certain reactants, proteins etc. with some innocuous material, meaning that if it came into contact with this material, there would be a vigorous reaction, but not so with other materials.

The choice of wood is a good one, being a biological material itself, it isnt ridiculous that it shares various molecular active sites with whatever your alien might eat.

 

Quote

I wanted the aliens to be able to eat what humans do

"Be able" to eat human food, or "naturally eat the same thing as humans" ?

It would be strange - and harder to reconsile biochemically - for a species to have the exact same diet, but strange biochemistries.

Not impossible mind, but it might jump off the page as a red flag if it goes entirely unexplained - unless its only a minor plot point, that is.

It'd be a little easier to explain an alien that normally eats different types of food, but can tolerate human food as well.

Like, a human can actually derive metabiolic energy from hydrocarbons. You can drink petrol and metabolise calories out of it - this is because many of the biological pathways that metabolise fats, are tailored to deal with chains of carbon molecules, similar to hydrocarbons like petrol. Now petrol is toxic for other reasons, but yes, you can technically be fuelled with petrol.

But it doesnt have to be so severe, there could easily be alien carbohydrates (sugars) that do not naturally occur on earth, that a human might find tasty and nutritious without any toxicity.

 

Spoiler

I took it as a given but since you thanked me, and since it sounds like you might actually be writing something - feel free to use/not-use/abuse, modify/copy/udpate/change entirely any/all of the suggested concepts/ideas in your writing with no credit whatsoever.

 

Edited March 2, 2020 by p1t1o

[Spacescifi]

7 minutes ago, p1t1o said:

Like I said, a ton of fodder!

Without creating a complete viable biochemistry from scratch - and thus becoming a god - one can at least say that there is great scope for variation and strange metabolisms in the "phase-space" that is biochemistry.

For example, catalysts (and their biological, protein-based counterparts, enxymes) can enhance reaction rates by many orders of magnitude (easily 100,000-1M times) and can be extremely specific. Like a lock and key, molecules of the wrong shape wont react - but molecules of a similar shape can.

So for example, alien blood could be an oxygen carrier like our own.

And like our own, does not exactly react with much when exposed.

Except that this alien blood contains certain enzymes or catalytic compounds that have a biological role to react with a certain type of compound as a part of its normal metabolism.

This compound could just happen to share certain reactants, proteins etc. with some innocuous material, meaning that if it came into contact with this material, there would be a vigorous reaction, but not so with other materials.

The choice of wood is a good one, being a biological material itself, it isnt ridiculous that it shares various molecular active sites with whatever your alien might eat.

 

"Be able" to eat human food, or "naturally eat the same thing as humans" ?

It would be strange - and harder to reconsile biochemically - for a species to have the exact same diet, but strange biochemistries.

Not impossible mind, but it might jump off the page as a red flag if it goes entirely unexplained - unless its only a minor plot point, that is.

It'd be a little easier to explain an alien that normally eats different types of food, but can tolerate human food as well.

Like, a human can actually derive metabiolic energy from hydrocarbons. You can drink petrol and metabolise calories out of it - this is because many of the biological pathways that metabolise fats, are tailored to deal with chains of carbon molecules, similar to hydrocarbons like petrol. Now petrol is toxic for other reasons, but yes, you can technically be fuelled with petrol.

But it doesnt have to be so severe, there could easily be alien carbohydrates (sugars) that do not naturally occur on earth, that a human might find tasty and nutritious without any toxicity.

 

  Hide contents

I took it as a given but since you thanked me, and since it sounds like you might actually be writing something - feel free to use/not-use/abuse, modify/copy/udpate/change entirely any/all of the suggested concepts/ideas in your writing with no credit whatsoever.

 

 

 

Good points again. I was wondering what they might eat, and having it be toxic to humans but sweet or tasty to them would be great.

Animals for example, do not taste everything we do, for example cats have no sweetness taste I read, they eat ice cream and cheese because they taste and enjoy th fat.

 

Just curious, I am thinking I xan't allow native wildlife to have this blood or their will be fires often, so just the intelligents.

 

And I imagine much of their food woukd be toxic to us with some exceptions, namely some fruits and veggies. Likely most meats too.

[HaplessBystander]

Been thinking about nuclear pulse propulsion rockets lately. Wanted to know, is the mass flow rate the mass of all bombs detonated per second or is it just the mass of the tungsten propellant (as per the Project Orion design) in all the bombs detonated per second? As I understand, the mass flow rate times the exhaust velocity equals the force exerted by the engine, so I want make sure I'm using the right value for the mass flow rate. 

Also, if you're aware of any valuable equations specific to nuclear pulse propulsion rockets (that aren't too complicated for a layman) please do share. 

Edited March 7, 2020 by HaplessBystander

[kerbiloid]

Orion is not a rocket. (As it's specially noticed in the Dyson's book.) 
It's a cannonball throwing back single-use cannons to be shot by them again and again.
It's isn't propelled by throwing back the fuel. It is propelled by external kicks.

The only propellant is the tungsten (maybe some other material could be used, but they use tungsten).
Any other part of the charge is a heater or director of the tungsten.

So, it actually doesn't have an exhaust and exhaust velocity.
The rocketry equations and analogies are limited in its case, and can be used only as an in-game replacement.

I would guess that actually the equation is just the momentum conservation law:
acceleration =
(
tungsten mass per charge (several kilograms up to first tens of kilograms for the multi-kiloton range, as the charge masses several hundred)
*
tungsten speed (~150 km/s)
*
blasts per second (2..4)
/
current ship mass
)

[wumpus]

18 hours ago, kerbiloid said:

Orion is not a rocket. (As it's specially noticed in the Dyson's book.)

I'll have to read it again.  I was going to make a comment about obeying the rocket equation, but I'm not sure it has to (it gets its momentum a bit differently).

PS: the book is by George Dyson, the late Freeman's son.  Highly recommended. https://www.goodreads.com/book/show/21243.Project_Orion

[kerbiloid]

(the pages may vary due to editions)

A datasheet with numbers is in Ch.6 Critical Mass, p.55

Ch.10 Columbus, p.90 - a pic of Mars-landed Orion (later it's used as long-term base and never leaves)

Also see  Ch.11 Noah's Ark, pp.105+, the propellant speed varies from 30 to 60 km/s for different design. (Somewhere in the text therei was also 150, so take any).
Orion never was an option for inyerstellar flights, its delta-V limit is 10 000 km/s (1/30 c).  (Though, in KSP distances are 11 times shorter).

Ch. 12 Free Expansion of the Gas, p.113 - a charge pic with numbers, and the rest of the chapter is a description of the propulsion principle.

Also the next, 13 chapter Hotter than the Sun, Cooler than a Bomb. (Also about the ablation and how to defeat it).
p.127 - a pic with nums.
p.130 - about a 6 mil thick layer of heavy oil for anti-ablation in later designs, "No pusher material is ablated."

Ch 16 Engineers' Dreams, pp. 162 and below - data
Also data - Ch 17 Coca-Cola, pp.176+.
pp.179+ a descriptive description describes the work process from inside.

Ch.18 Enceladus is all about nums.

Ch.20 Jackass Flats, pp.210+ and especially 220+ - nums.

Ch21 Fallout, p. 234 - a very interesting picture of a failed shot. Pay attention to the charge shape.

Ch.22 Huntsville - more details about interplanetary variants.