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Old 01-24-2019, 07:31 AM   #81
Flyndaran
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Default Re: Orbital Lasers

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Originally Posted by Rupert View Post
Because they don't have neural links, don't have or don't trust AIs, and have found (like we have) that manual controls are faster and can give feedback than voice activated?
It would be easier if all these setting dials were mentioned in a single post.
But I forgot that Alexander Howl was the one that started the thread when I responded to him.
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Old 01-24-2019, 11:51 PM   #82
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Default Re: Orbital Lasers

Wouldn't the entire earths nuclear arsenal simultaneously fired at and subsequently shot down by the aliens catastrophiclly damage our biosphere?

Seems pyrrhic at best, and an extra spiteful forum of mass suicide at worst.
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Old 01-25-2019, 01:39 AM   #83
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Wouldn't the entire earths nuclear arsenal simultaneously fired at and subsequently shot down by the aliens catastrophiclly damage our biosphere?

Seems pyrrhic at best, and an extra spiteful forum of mass suicide at worst.
That depends on where the warheads are when they are hit. If almost all of them are halfway up to 35,000 kms, or even closer to that target altitude, then the effect will be negligible.

Note that if we assume the firepower constraints mentioned above, it will be against the interests of the aliens to aim at missiles when they still are in the atmosphere, where the damage to Earth would be the worst, because air makes for a worse environment than vacuum for the laser.
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Old 01-25-2019, 06:35 AM   #84
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Default Re: Orbital Lasers

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That depends on where the warheads are when they are hit. If almost all of them are halfway up to 35,000 kms, or even closer to that target altitude, then the effect will be negligible.

Note that if we assume the firepower constraints mentioned above, it will be against the interests of the aliens to aim at missiles when they still are in the atmosphere, where the damage to Earth would be the worst, because air makes for a worse environment than vacuum for the laser.
Well if these lasers can preform groundside bunkerbustings then they could start destroying our ICBMs immediately, if they're holding fire to provent collateral damgage then that's something to be factored in, possibly even exploited.
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Old 01-25-2019, 06:45 AM   #85
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Default Re: Orbital Lasers

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Wouldn't the entire earths nuclear arsenal simultaneously fired at and subsequently shot down by the aliens catastrophiclly damage our biosphere?

Seems pyrrhic at best, and an extra spiteful forum of mass suicide at worst.
No. Even if they were shot down before they finished boosting, and thus ended up back on Earth the contamination would be relatively local. They'd not be exploding or even fizzling - it's hard to make a modern nuke go off unintentionally.
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Old 01-25-2019, 08:51 AM   #86
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Well, there may be an unintentional detonations because the vaporized casing would heat and compress the fissile material of the bomb. When you are talking about 100 GJ of energy every blast, there are going to be a lot of weird physics involved (that is more than the energy equivalence of 1 mg of matter). For example, a one ton warhead would, briefly, reach temperatures of over 100,000 K, which would cause the warhead to explode. The only question would be whether the primary explosion also causes a secondary fission/fusion explosion.
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Old 01-25-2019, 09:05 AM   #87
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Even if the warheads all exploded, it wouldn't destroy the biosphere. We have about 15,000 warheads; a 1 MT warhead has a blast radius (1 psi) covering about 1200 km^2; the earth has a surface area of 510M km^2. Even with optimal placement of every warhead to avoid overlap, it's less than 4% of the Earth's surface. (Feel free to say "land", and it's still less than 12%.) That's about the same as the past 25-40 years of intentional forest loss, for instance.

We're proud of the technological terror that we've constructed, but once you get to the scale of planets, nukes really aren't all that powerful. Our own current modern civilization, we might be able to wreck. Catastrophically destroy the biosphere, leaving the planet entirely lifeless? No.
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Old 01-25-2019, 12:43 PM   #88
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You do not need that many nukes to cause a nuclear winter that would kill a lot more humans that the warheads did directly. 400-500 warheads under the right circumstances will cause enough fires that would drop global temperatures for a decade (or the EMP blasts would fry all electronics within 1000 km of each detonation). Nuclear weapons are great for space based combat but pretty horrible for anything ground based.
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Old 01-25-2019, 12:48 PM   #89
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You do not need that many nukes to cause a nuclear winter that would kill a lot more humans that the warheads did directly.
You do, however, need the warheads to actually go off (in areas with flammable stuff). Missiles being shot down won't result in a nuclear explosion.
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Old 01-25-2019, 01:42 PM   #90
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Default Re: Orbital Lasers

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When you are talking about 100 GJ of energy every blast, there are going to be a lot of weird physics involved (that is more than the energy equivalence of 1 mg of matter).
There will be physicists keen to start experiments on this. There's a lot to be learned about how these lasers work and what can be done about them, and methods of fighting the aliens may develop from that.

There's also the question of what they're using for sensors. Radar-stealthy warheads definitely exist already, as the French use them on their SLBMs, and I'd expect other powers to have them but keep quiet about them. And if your warheads don't have to go through re-entry, that opens up a lot more scope for stealth. There's also attacking the aliens' sensors, by using expendable mirrors to reflect the lasers back, as well as chaff, bomb-pumped lasers, and so on.

What's the aliens' long-term objective? Leaving this example of high technology somewhere that an entire planet full of people only one TL lower can observe it and experiment on it isn't a stable situation. They'll find a way to disable or destroy it eventually, unless you use the lasers to destroy technological civilization and keep it from recovering.
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