The Factory Floor

Green

00:47

@dot_Sp0T turkey, potatoes, various casseroles, cranberries.

Shalvenay

00:59

@Green pretty much the same here, we tossed a salad into the mix, and don't forget the stuffing and/or dressing

but yeah, if you're around...how would someone with limited strength armed with a knife or a dagger avoid the "struggle over the weapon" thing if having to defend themselves from someone much physically stronger than they are?

Green

03:02

@Shalvenay I don't have an answer to that since not familiar with any martial art. @DaaHWoosh (spelling?) would have an idea since he is familiar with real sword play. @James may know something but I only know of his involvement in making weapons, not in their use.

Shalvenay

@Green ah.

I'll ask them

Worldbuilding Meta

06:09

0

Q: Clarification for new users: what is a "fishing for answers" question and why is it off-topic?

Over the last couple of months I've seen a lot of what I call "fishing for answers" questions. Questions that are either too broad or, more often, primarily opinion-based because the OP hasn't thought through their issue well enough to give us the direction participants need to answer the questi...

dot_Sp0T

08:15

@Bellerophon I just realized I actually used the term 'hard numbers' indeed: In order to get a feeling for the times involved in travelling these distances I need hard numbers for things such as constant-/max-acceleration, fuel-consumption, etc. of the propulsion system(s) in use by these spaceships.

Secespitus

@dot_Sp0T Did you add the hard-sci tag?

If they ignoring such a statement it's basically "not an answer"

dot_Sp0T

@Secespitus yeah I put the hardsci tag on it yesterday, but I'm waiting for the mod-note to be added before starting to flag

I also might do some research into chemical propulsion and ion propulsion this afternoon and then write up an answer for each if i am confident to have grasped the concept and numbers - hoping to create a good reference question there

Feeds

13:57

0

A: Sandbox for Proposed Questions

"Why is a soul required to sustain a daemonhost in a world where human bodies can be grown?" The world is at war with Carcossa, a nation that worships a powerful entity called "the king in yellow". This nation has ambitions for world domination, and uses daemonhosts to bolster their army. A dae...

Future Historian

15:51

Gentlemen?

I think I may have done a slight error.

If I deorbit rods from a 1,500 km altitude, then begin to accelerate to Mach 25 at an 80 km altitude, how much kinetic energy could that thing have on impact + would it ionise air particles around the rod?

Gryphon

How heavy is the rod?

Future Historian

It is composed of tungsten.

So..............

Gryphon

How big?

Future Historian

20 metres long and 2 metres in diameter.

Gryphon

Um... That's over a million kilos.

That's going to do some damage.

Future Historian

15:56

@Gryphon? How much damage on impact in TNT equivalent?

Especially accounting for air resistance?

And ionised particles of plasma on descent?

Gryphon

Working on it. Velocity in orbit is about 7.12 km/s

What's Mach 25 in m/s?

Just answered my own question, it's about 8.5 km/s

Future Historian

However, that Mach 25 is on approaching the target.

Gryphon

What's accelerating them when they hit 80 km? Just out of curriousity.

Future Historian

Well, I am thinking of a fusion thermal engine or something along those lines.

Definitely NOT a chemical rocket.

Gryphon

Is that inside the rod? Cause that might lower the weight a bit.

Future Historian

16:01

It is actually a separate stage.

Gryphon

OK. So, a bit over 1.2 million kilos coming through the atmosphere at 8.5 km/s.

Future Historian

But once they reach a certain altitude and the terminal velocity is at Mach 25, the stage is separated and destroyed on reentry.

I am still unsure about that altitude, though.

So, once the acceleration stage is ditched and the rod hits the target on impact, how much TNT equivalent can I expect + air resistance taken into account?

Gryphon

OK, so that's 1.02*10^10 joules of kinetic energy.

So, say we go with 10^10 after air resistance, etc.

Future Historian

@Gryphon. Let me try.

Gryphon

So, around 2.5 tons of TNT. That seems way too small.

Future Historian

16:12

I get 4.376 * 10^13 joules, actually.

No air resistance considered.

So, did you do the numbers correctly?

So, I will say about 4.374 * 10^13 with air resistance considered.

And......................................10.4541109 kt of TNT?!

@Gryphon.

Is that good?

Gryphon

Yeah, I messed up somewher.

*somewhere

I have no idea on the air resistance.

And, that's a lot of TNT

Let me try the calculations again.

Future Historian

Still, this is not accounting for ionised air particles in the atmosphere.

Gryphon

Yeah, I've got no idea how to figure out what'll happen with that.

Future Historian

So, the explosion is possibly BIGGER.

laughs evilly

Gryphon

Oh, I see what I calculated wrong.

It's kinda embaressing.

I'm an idiot.

I forgot to square velocity.

Yeah, 4.378*10^13 is right.

So, what does 10.4541109 kt of TNT do to a city?

Future Historian

16:22

Enough to level entire city blocks in one go, not accounting for the ionised particles in the atmopshere.

That would be enough to level all of Brooklyn in one go, because firestorms.

Gryphon

Um, so yeah, Little Boy (the nuke dropped on Hiroshima) was about 15 kt. So this is about 2/3 of that. That's frankly terrifying.

More than 2/3 of that, because of ionization of atmosphere.

No, wait a minute. Ionization of the atmosphere won't add any energy, it has to take as much energy to ionize it (reducing the speed of the rod) as it releases on impact. So what you've calculated is kinetic energy at 80 km. Gravity will be more than countered by air resistance, so that's an upper bound. It can't release any more energy than that.

@FutureHistorian? You there?

Unless it's going fast enough to trigger some fusion. That could possibly increase the energy.

Future Historian

I am alive.

@Gryphon? You were saying?

Oh wait.

reads his comment

Oh.........................

Gryphon

16:38

Conservation of energy is annoying, isn't it.

Future Historian

@Gryphon? How much kinetic energy will that thing have on impact anyway?

Gryphon

It means smaller explosions.

Future Historian

Well, increase to 10 km/s of acceleration at an 80 km altitude.

It has to hit with Mach 25 velocity on impact somehow.

Gryphon

So, if we calculate air resistance, we can extrapolate backward to find acceleration required to hit the ground at 8.5 km/s. Which will give your calculated 10.45 kt of TNT explosion.

Future Historian

Agreed.

Gryphon

16:41

So, do you have any idea how to calculate air resistance?

Cause I sure don't.

Future Historian

F = k * velocity^2 = ((air density * drag coefficient * area)/2)* velocity^2.

So, we need to find the drag coefficient for this thing.

Gryphon

You found the equation about 3 seconds before I did.

It's a cylinder, drag coefficient should be online somewhere.

Future Historian

Well, a cylinder with a cone at the bottom.

Gryphon

OK. Still a fairly regular shape. I'll go look online.

Future Historian

0.82 for a cylinder and 0.50 for a cone.

Gryphon

16:45

So, for a shape inbetween?

Future Historian

Let us see..........

Gryphon

Can we just use the 0.50? It shouldn't be higher than that. Unless it tumbles.

Future Historian

Fair enough.

Gryphon

If it tumbles, were screwed.

Future Historian

0.50 it is.

@Gryphon? As in........?

Gryphon

16:46

As in, I have no idea how to calculate it if it tumbles.

I don't think anyone online has stats for a tumbling cylinder with a cone attached to the bottom.

Unless NASA did one of their stupid excessively detailed things.

What units is air density in?

Future Historian

And...........

I calculated a total of 2.9243 * 10^9 Newtons due to drag.

Gryphon

That's rather high.

Is that using 8.5 km/s

Or 10 km/s

Future Historian

I am using 8.5 km/s.........

As in: ON IMPACT.

Gryphon

So, yeah. I think the next step is to use calculus to back that up to how fast it needs to be going at 80 km.

And I haven't taken calculus yet.

Future Historian

When going at 11.2 km/s at that 80 km altitude, we can ignore friction until we reach a 70 km altitude.

Gryphon

16:57

OK. So we can back it up to 70 km.

Do you know calculus?

Future Historian

Since, technically, we are still in LEO altitude at about 80 km.

Yes, why? I am just still not to THAT advanced level.

Yet.

Gryphon

OK, so, maybe if we just go kilometer by kilometer.

As in, calculate it as 1, then using that calculate it at 2, etc.

That'll take a while.

Future Historian

NOTE: This is the mass while accounting for the fusion thermal acceleration stage.

1,309,513.17 kg

Gryphon

That's rather precise.

Future Historian

Well, I am going to use a 100,000 kg acceleration stage.

Let us see how much delta-v this thing has and how much thrust this thing needs.

Gryphon

17:04

Does it matter for the story exactly how much acceleration the acceleration stage produces? Can we not just say it hits the ground at Mach25

Future Historian

It is supposed to.

I just need to get the science right.

I will leave the reader to find out on his own anyway.

And besides, I will probably do a "Guide to the Visitor Series" explaining all this some day.

I will look at the Excel spreadsheet just to see what happens.

And........so far, 6,911.06 m/s of delta-v are available, assuming an exhaust velocity of up to 87 km/s.

And to deorbit, I need 6.2197 km/s of delta-v.

So, that is 691.36 m/s of delta-v left to work with, which will be expended to accelerate the bloody thing or make course corrections, if necessary.

Actually, I need to only expend 2.9458 km/s of delta-v to deorbit.

And to make it easier, I am dumbing down the exhaust velocity to 40 km/s.

That gives me 3.1775 km/s of delta-v, and since I only need to expend 2.9458 km/s of delta-v, I have 231.7 m/s left of delta-v.

However, with an 87 km/s exhaust velocity, I get 3.96526 km/s of delta-v left to work with.

And to give those engines an 80% efficiency rate, I will give them.............203.1 kN of thrust.

What?!

Fine. Increase to 85% efficiency and let us see what happens.

@Gryphon? Is a 15 TW fusion reactor unrealistic?

Or not?

Gryphon

17:27

Well, right now any fusion reaction that gains power is unrealistic.

Shalvenay

@Gryphon this makes me wonder "how close to break-even are we anyhow?"

Gryphon

I have no idea. I'm looking up fusion reactors. What are the size constraints? Mass has to be less than 100,000 kg, right.

Future Historian

@Gryphon. Well, fusion reactors on Earth are still new.

These bastards have been using them since their equivalent of the mid-21st Century technologically and they are still a late K1 - early K2 civilisation, depending on whether you think a partially finished Dyson Swarm makes them early K2 or still late K1.

Gryphon

So, maximum energy output (assuming the entire 100,000 kg is hydrogen to be fused) is 2.5*10^19 Joules. So that's an upper bound.

If, say, we get 50% efficiency, and our fusion rig is 80,000 kg, we get 2.5*10^18 Joules of energy.

With 20,000 kg of hydrogen.

Where are they getting that much hydrogen? There's a lot of kinetic rods.

Future Historian

17:43

Well, they are a late K1 civilisation - early K2 civilisation.

They probably had to scoop out ENTIRE gas giants just to get that much hydrogen or should I say......deuterium/helium-3.

Gryphon

True

Future Historian

Depending on what triggers the reaction, though I had a helium-3-deuterium reactor in mind lately, albeit originally I was thinking of a deuterium-tritium reactor.

And this is just a scout force, remember?

Gryphon

Oh, the calculations above are Deuterium-Deuterium reactions. I'll recalculate for helium-3

Future Historian

They still have other similar-sized spacecraft in their overall self-sustaining military force.

So, any one of them should have had scooped out an entire gas giant over time just to get the required hydrogen for this stuff.

dot_Sp0T

17:56

what?

Future Historian

@Gryphon? Any estimates?

Shalvenay

hey there @Bellerophon

Future Historian

18:23

@Gryphon? One more thing: would it be a good idea to install an additional stage to serve to store four additional, smaller rods capable of functioning like MIRVs?

@Shalvenay?

Shalvenay

dunno, might be useful in the same way a cluster munition is...

Future Historian

If each of the strategic rods has 11 kt of TNT equivalent packed onto them, would you say 40,000 of them dropped across the globe is overkill?

And that is not counting the MIRV rods.

@Shalvenay? 40,000 rods * 11 kt per rod = climate change-inducing?

Shalvenay

@FutureHistorian it's going to be rather different than actual nuclear warheads -- I suspect you'd get less soot in the atmosphere than the equivalent kilotonnage of nuclear strikes

Future Historian

Still, would that be enough to cause climate change-inducing problems, though?

Shalvenay

not sure

Future Historian

18:31

Well, you are talking about 440 Mt of TNT equivalent being detonated.

Shalvenay

it's only 440MT of TNT equivalent anyhow

Future Historian

Is it THAT bad?

Shalvenay

probably not

Future Historian

@Shalvenay. Anything for a nuclear fall (at best)?

Shalvenay

I doubt that it'd have much impact on the climate at all even

Future Historian

18:34

@Shalvenay. Well, a 2014 nuclear war simulation for the Indian subcontinent with 100 Hiroshima bombs predicted that climate could be affected for the next 30 years before it begins to recover.

So...............is that bad?

At least they had to worry about fallout and firestorms the size of Afghanistan.

On the other hand, these are kinetic rods.

Not the same, are they?

A few months of freezing temperatures or mass extinction event?

Shalvenay

aye, not the same

Future Historian

Oh.

So, no expecting a few months of freezing temperatures, or a mass extinction event?

Shalvenay

I'd expect a bit of a chill at worst

Future Historian

For how long, though?

Shalvenay

hard to tell

Future Historian

18:40

Well, is three months good?

Or too long?

Then again, by month #2, the Invasion is already over and Earth is practically under Visitor occupation.

So..............

@Shalvenay. And..........a Discord server is telling me that the climate change-inducing effects would be equivalent to a runaway Mars or Venus.

I am confused.

Shalvenay

hrm...I think the first thing that needs to be accounted for is how much soot the rods loft compared to an equivalent sized nuke

Future Historian

Well, we are talking about 11 kt of TNT + the 4 MIRVs inside the rods for bonus points.

Which detonate 118 tonnes of TNT each.

Wait a second.

calculates how much TNT equivalent he can expect from four MIRV-like rods

BLOODY HELL!!!!!!!!

216,591.360 Mt of TNT!?

@Shalvenay? How much climate-induced trouble could that cause compared to the 440 Mt of TNT minus the MIRV rods?

Shalvenay

@FutureHistorian a lot more

although I'm a bit suspicious of that number

Future Historian

18:56

Well, I just calculated 118 tonnes of TNT * 4, followed by multiplying the result of 40,000, then multiplied 11 kt of TNT by the result of the first equation, then multiplied the overall result by the result of the second equation.

And I got that much TNT.

Future Historian

19:10

@Shalvenay? How much in terms of climate-induced effects could that have?

Shalvenay

@FutureHistorian much, much more indeed -- I suspect that'd be a serious nuclear winter if that was a correct number

Future Historian

How long would that last, though?

Shalvenay

months to years?

Future Historian

@Shalvenay? About the rods...........turns out we have to worry about the shockwave and heat flash when it comes to both nuclear weapons AND kinetic rods.

I think.........

Shalvenay

19:57

hey there @Mithrandir24601

Mithrandir24601

@Shalvenay Rytsas! How's life? I'm just eating some lovely chocolate :)

Shalvenay

alright here

Future Historian

And developing the outline timeline further............

I destroyed Hong Kong and New Orleans with 3 90 kt nuclear detonations and a 170 kt nuclear detonation respectively.

Three from a JL-2 SLBM and one from a B61 tactical nuclear device.

Well, what is left of them anyway.

@Shalvenay? Is it a bad idea to stop some of the Invasion force's initial landing with tactical nuclear weapons?

Or with SLBMs?

Shalvenay

@FutureHistorian I'd say that it'd be a "go for broke" scenario

Future Historian

As in........?

@Shalvenay? How bad is it?

Shalvenay

20:06

@FutureHistorian there's just not a whole lot left to lose at that point

Future Historian

Because I am thinking the Battles of Hong Kong and New Orleans respectively end in nuclear obliteration.

@Shalvenay. Just how many more cities have to get nuked in the process anyway?

Especially after Hong Kong and New Orleans are nuked?

@FerretCivilization? If Hong Kong and New Orleans are nuked during the Invasion, which other cities do you expect to get nuked?

And this is using our remaining nuclear arsenals.

Even though the kinetic rods alone causing a total of 440 Mt of TNT to be detonated would be a climate change-inducing nightmare, depending on how you view things.

Ferret Civilization

Just reading over the past conversation, did you think that the rod had extra kinetic energy somewhere or just looking at the plasma sheath.
Also the rods would not put up near the amount of soot an explosive fireball like a nuclear missile does, you can drop as many as you want without getting the same climate change as a nuclear explosion causes.
As for the which cities get nuked, that is up to you.

Future Historian

Oh.

Well, in that case, 40,000 rods deployed on the planet it is, then.

:D

@FerretCivilization? What about the 4 additional MIRV rods per rod?

Multiply 4 118 tonne rods by 40,000 of the main rods that they are supposed to be released by.

Ferret Civilization

How are you achieving that, by bundling rods together?

Future Historian

Well, it is a three-stage rod.

One stage is for orbital manouevres and final acceleration once at the 80 km altitude, the second stage holds four 6.1 m long and 0.30 metre in diameter rods, which basically work like MIRVs to spread out the damage at an altitude of 2 km from the target, followed by the main rod doing most of the damage.

Ferret Civilization

20:22

That way of doing it would be no different than just saying they were all individually fired rods.

Future Historian

@FerretCivilization, explain.

And this is just a proposal.

Nothing final unless it is seen as useful.

So, is that MIRV rod second stage useful?

Or should I just stick to my original two-stage rod plan?

Ferret Civilization

Spread out the damage. Firing individual rods spreads out the damage in the same way. Just changing how the rods get from point A to B. You could use the MIRV to hit the same area, or you could fire many individual rods into the same area for a little more effective bunker busting. Depends on what you are trying to do.

Future Historian

Well, I am trying to fire the MIRVs to hit the same area.

And this is SPECIFICALLY for the ones designed to hit major cities, NOT the ones hitting military air bases with fighters or nuclear silos.

Actually, come to think of it.

Ferret Civilization

By same area I mean the exact same point on the map.

Future Historian

Oh.

I suppose I can remain with my original plan for the rods.

So...........now, what cities do you recommend I obliterate as the Visitors advance on the planet?

With nuclear weapons.

Ferret Civilization

20:31

The ones that have the perfect mix of being lost and has an overwhelming enemy force in it.

Future Historian

That makes sense.

Pick your targets, President @FerretCivilization. We are awaiting the order to launch.

awaits for launch codes

Mr. President? We are awaiting the order to launch at any minute.

hears the sound of morse code

Alpha-Echo-One-Three-Niner-Foxtrot-Niner. We are go! I repeat: launch is a go!

begins to launch SLBM towards the last remaining city in the Western US: Seattle.

Ferret Civilization

Well 10 cities have just been obliterated. 6 cities to the Canadians. Where were the aliens landing?

Future Historian

Well, they are landing in the same cities that got bombed all over the world.

They are just finishing off anyone left alive.

And of the bombed cities, 50% of their infrastructure has been completely demolished.

So, the Visitors are just destroying the 50% of the infrastructure still standing, mainly as collateral damage in the subsequent fighting.

Ferret Civilization

Then why is New Orleans getting nuked?

Future Historian

Oh, right.

How many inhabitants does New Orleans have + the surrounding urban area?

New Orleans metropolitan area

New Orleans–Metairie Metropolitan Statistical Area, or the Greater New Orleans Region (as it is often called by the Louisiana Tourism Commission) is a metropolitan area designated by the United States Census encompassing eight parishes (the Louisiana equivalent of other states' counties) in the state of Louisiana, centering on the city of New Orleans. As of the April 1, 2012, estimate, the metropolitan statistical area (MSA) had a population of 1,227,096. The New Orleans-Metairie-Hammond Combined Statistical Area (CSA), a nine-parish area, had a population of 1,452,502. The metropolitan area was...

You were saying?

looks into the data

Oh.......................................

Nevermind, then.

Ferret Civilization

20:43

Metropolitan area made up of 3 separate cities

Future Historian

Oh.

Well, what about the urban area, then?

Ferret Civilization

That is why I asked before when dealing with South Africa are you working with greater area populations or city boundary populations.

Future Historian

I am working with Greater Area populations mostly.

Sorry about that.

:P

So, @FerretCivilization? Given that, which are the cities worldwide that get nuked over the course of two months?

Ferret Civilization

That raises US bombed cities from 10 to 36. And probably the ones of those 36 that are written off as a lost cause.

Future Historian

Oh.

So, @FerretCivilization? San Diego is probably one of those cities, hmmmmm?

Along with Los Angeles, New York, New Orleans and Miami?

Or is Miami spared?

Ferret Civilization

20:49

San Diego's large Naval base would probably spare it.

Future Historian

Why? It is already demolished in the kinetic bombardment (per the coordinates).

Remember?

Even though it was a total accident.

On my part.

Oh well. More for me.

Ferret Civilization

Just because it was destroyed does not remove the value of the location to go ahead and make it radioactive. Especially since it is kind of an important port. Also means there would be more service members in the greater area to not write the city off as lost.

Future Historian

@FerretCivilization? And since SAC no longer exists, who fires the ICBMs now?

As in: even before the Invasion?

@FerretCivilization? Global Strike Command and NORAD are both gone, correct?

They are basically located here: en.wikipedia.org/wiki/Barksdale_Air_Force_Base and here: en.wikipedia.org/wiki/Peterson_Air_Force_Base respectively.

Peterson AFB and Barksdale AFB are both destroyed, correct?

Even though NORAD's alternate command is still Cheyenne Mountain.

So, are both of these bases gone?

Or are they still standing post-bombardment?

Ferret Civilization

The military would take it over from there and probably use it to nuke lost locations. Also NORAD would move to it's alternate command as soon as there was an extraterrestrial threat. Which as soon as they are known about existing.

Future Historian

@FerretCivilization? What about Global Strike Command?

Because Global Strike Command is part of the US Air Force and US STRATCOM so...........

Ferret Civilization

20:57

The base would probably be destroyed but the command itself would have probably moved along with everyone else

Future Historian

Where, though?

Cheyenne Mountain? Raven Rock? Mount Weather?

Ferret Civilization

Probably one of the closer bunkers, those are just the famous big ones.

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