The Off Topic Topic

[Razgovory]

If you throw a big enough rock at a planet you could turn the whole surface into a lava field for millions of years.

[The Brain]

Good input all.

@TheBrain, I'm thinking population and production centers, not just mining operations. They would exist on those planets, but the majority would come from mining outposts/smaller colonies that are more easily taken out. And even having the resources means little if your infrastructure for converting them into weaponry is disrupted. Still going underground is something I've considered and not sure how to get around it (except that such facilities might be limited since it was not expected that war would lead to such levels of destrcution; but that feels like a weak excuse).

@TheLarch, that's what I'm currently sitting on. It's not a hard sci-fi setting, so I'm fine with having a "magic" chemical that has that effect.

@Barrister The races would be "adjacent" - genetically somewhat distinct but compatible (in setting, one faction actually uses such a virus as last ditch defense against an ancient enemy, but the virus spreads to another. The joint retaliation leads to the (almost) complete extermination of the the ones who created the virus.

Yeah when I talk of going underground I mean everything, population centers, food production, manufacturing, etc. If the planet's main resource is surface farming then underground farming is likely to be a lot more expensive, and therefore the use of the planet has been restricted compared to before the attack. But if the main resource is mining then that's hardly affected by disruption of the surface environment.

If enough underground stuff doesn't exist at the time of the attack then the population will effectively be toast by a big asteroid. But my impression is that you don't want the enemy to be able to sneak back into the system when your fleet has moved on and reestablish themselves?

[Syt]

But my impression is that you don't want the enemy to be able to sneak back into the system when your fleet has moved on and reestablish themselves?

That's correct, the proverbial salting the Earth.

[Josquius]

It's weird how different phone companies work.

One phone I have is free to use anywhere in Europe.
Another is free in the EU but not ch.

[The Brain]

One thing about nukes is that you need a LOT of them to make a planet useless through radiation. Earth has suffered 2,000 nuclear detonations, and even if radiation from those is measurable it has no global impact on health or the environment. And radiation levels drop off fairly quickly if you look at a decades-long interstellar conflict.

[Barrister]

One thing about nukes is that you need a LOT of them to make a planet useless through radiation. Earth has suffered 2,000 nuclear detonations, and even if radiation from those is measurable it has no global impact on health or the environment. And radiation levels drop off fairly quickly if you look at a decades-long interstellar conflict.

3/4 of those

What about my idea of trying to seed the atmosphere with, I dunno, Cesium-137?  30 year half life should render the planet habitable again in oh couple hundred years?

[The Brain]

One thing about nukes is that you need a LOT of them to make a planet useless through radiation. Earth has suffered 2,000 nuclear detonations, and even if radiation from those is measurable it has no global impact on health or the environment. And radiation levels drop off fairly quickly if you look at a decades-long interstellar conflict.

3/4 of those

What about my idea of trying to seed the atmosphere with, I dunno, Cesium-137?  30 year half life should render the planet habitable again in oh couple hundred years?

"...were underground", I assume. Yes.

You'd need to produce it. It is produced by nuclear bombs as well as reactors, so you'd have to look at what's quickest and simplest, bombs or reactors. But you need a LOT of Cs-137 to have decisive global effects. A basic problem both for terrorists and Ming Lites is that radiation isn't that dangerous compared to many other things. Compared to say a virus you simply need a LOT of it to kill people.

[Zanza]

You could do stuff like destroying the ozone layer in the atmosphere fairly easily. Humans almost did it by accident. Also greenhouse gas emissions seems straightforward. Use some kind of weapon to free the methane bound in ocans and permafrost and you have a runaway greenhouse effect that might render the planet too hot to live on it.

[Barrister]

You could do stuff like destroying the ozone layer in the atmosphere fairly easily. Humans almost did it by accident. Also greenhouse gas emissions seems straightforward. Use some kind of weapon to free the methane bound in ocans and permafrost and you have a runaway greenhouse effect that might render the planet too hot to live on it.

Ozone layer took decades of earth's full industrial production capabilities.  Same thing for greenhouse gasses.

[The Brain]

One more thing about radiation (I'll shut up I promise): it seems reasonably likely that an interstellar civilization has solved cancer, and it's no longer a dangerous illness. In that case you need to kill people through acute radiation sickness, which requires even higher levels of radiation.

[grumbler]

I'm leaning towards dropping asteroids in the planet's oceans.  Enough water vapor high in the atmosphere will drop the planet's temperature below that of liquid water, and only the most energy-rich underground shelters will even survive long term.  Underground dudes will need to spend a lot just heating hair they take in (or treating the air if the shelter is closed-cycle).

[Eddie Teach]

Underground dudes will need to spend a lot just heating hair

They could forego the luxurious curls...

[Josquius]

How do such mind numbingly stupid people become professors?

Jordan Peterson is long established. Just saw a video from a guy called John Mearsheimer talking about the US trying to force Ukraine into NATO and such...

[Syt]

One thing about nukes is that you need a LOT of them to make a planet useless through radiation. Earth has suffered 2,000 nuclear detonations, and even if radiation from those is measurable it has no global impact on health or the environment. And radiation levels drop off fairly quickly if you look at a decades-long interstellar conflict.

What about devices in the gigaton range? I understand that they're (technically) possible, though they would likely weigh in at hundreds of tons. Also, with spherical blasts, more of the energy would not be directed at the ground, and a planet's curvature isn't helping either (unless you can detonate it at a sweet spot below surface where it can apply most of its energy to the surrounding area, I guess?).

[Syt]

I'm leaning towards dropping asteroids in the planet's oceans.  Enough water vapor high in the atmosphere will drop the planet's temperature below that of liquid water, and only the most energy-rich underground shelters will even survive long term.  Underground dudes will need to spend a lot just heating hair they take in (or treating the air if the shelter is closed-cycle).

That makes a lot of sense.