Realistic Planetkillers

[gamowin]

Detonate numerous massive nuclear warheads within the mantle of the planet to cause (incredibly) violent volcanic eruptions that would rip the crust of the planet apart. A cheap and simple approach. Now where to find that much refined uranium...

[Joshington]

"The Day The Earth Stood Still" remake it. Wipe out literally everything and start fresh.

[TheDarkStar]

I like the idea of a relativistic kill weapon. However, it can be much, much stronger. Why stop at 0.8c when you can accelerate it to 0.9c, or 0.99c, or even 0.999999c? At some point, it is enough to make the planet into an asteroid belt.

[ZedNova]

Black hole gun anyone?

[The Jedi Master]

Easy, throw really big things at it. Preferably Mars size or bigger.

[Skyler4856]

a shell of uranium surrounding vacuum sealed antimatter accelerated to 80% c

[midgester222]

turn one of our stars (seeing as we have two solar systems) in to a giant hydrogen gas laser and ablate the entire surface of the planet away.

[jwenting]

Detonate numerous massive nuclear warheads within the mantle of the planet to cause (incredibly) violent volcanic eruptions that would rip the crust of the planet apart. A cheap and simple approach. Now where to find that much refined uranium...

That would not destroy the earth. It might cause havoc with the climate for a while, maybe cause some continents to change shape and some new islands to emerge, but that's it.

[Skyler4856]

Grey Goo doomsday scenario and then anti matter to destroy the planet

[Kinglet]

[RocketscientistV]

Gm microbes to consume carbon based life, from there take the excrement, everything else the body is made out of and turn it into antimatter, they wouldn't know what hit them.

[qeveren]

Realistic planet killer? Set up shop in their Oort cloud and start a momentum transfer system by flinging comets past their planet. Keep this up for a few million years and you should manage to drop their planet into the star.

[BlazingAngel665]

A large, loosely focused laser could be errected, targeted toward the planet and left on for a while. The laser wouldn't even have to melt anything, within weeks the planet would be uninhabitable due to increased atmospheric activity (assuming surface oceans), increased temperature, and a decimated biosphere with scorched ground and dead vegetation.

If you need the planet deader then that , Use your drive system to sling a couple tons of asteroid at .8c. The first one stops any antagonism from this species. The second one stops this species, and the third one stops life for a good long while. a 2km asteroid at no-relativistic velocities is quite dangerous. A 20km asteroid is a serious extinction level event. Also remember that energy scales faster with velocity then with mass. Ke=1/2MV^2 so .8c is actually quite devastating. Further add in the nonlinear acceleration energies when approaching c and you can cause quite a lot of damage with just one very fast moving rock.

[microbe999]

You could always simply introduce a super-virus into the ecosystem, wait for everyone to die, and then release massive quantities of antidote into the atmosphere.

[-Velocity-]

I don't think that destroying a life-bearing world with intelligent inhabitants is a winning strategy. It's the utter depths of evil. Also, I think we can draw from human history for how to successfully and peacefully deal with an alien threat of equal or near equal technological prowess. Look to the Cold War...

The same technologies that would allow interstellar travel might also make interstellar war too costly to wage. You might be able to destroy THEIR planet, but their relativistic weapons could not be easily intercepted, can be hidden for several light-years anywhere in three dimensional space around your planet, and all it takes is one hit on Earth to wipe it out. So it might be more like mutually assured destruction. It is much better to make peace and learn to live together than set up a track record of being a world-killer. Also, someone bigger, more advanced, and more enlightened than you might take offense to such a heinous act and decide that YOU need to be wiped out.

So, if you were unable to build trust with the alien civilization (which would probably involve cultural exchange, setting up joint colonies/ventures together, etc.) and the alien civilization truly looked like a threat, then you probably be wise to go into a Cold War-like scenario- set up some very hard to spot, automated, world-killing devices out in space around their planet, ready to launch of they act against your own civilization. In other words- the interstellar equivalent of nuclear ballistic missile submarines. Space is even bigger than the ocean, and has three dimensions... you would NEVER be able to find and destroy all the world-killers. It would be truly mutually assured destruction and it would hopefully be capable of keeping the peace until you worked your differences out.

Edited January 2, 2014 by |Velocity|

[jrphilps]

Drop some Grey Goo. Even a small amount will suffice. They'll never know what hit them.

Just make sure you don't forget where your left the kill-switch.

Open air nanotechnology is highly unlikely. A type 2 civilisation might be able to construct such swarms, but they would serve no military purpose even against a type 1 enemy. The individual probes could be destroyed by any numbers of heat based weapons, and you can also deploy chemical jamming agents. Even an air conditioning unit can be protected: By using an ionised current, you electrocute any infiltrating nanoprobe.

[Dominatus]

A fun way to do this would be to bio-engineer a super virus, designed to kill off the target species. How do we do this? Simple. First we send in a forward research team. They will grab inhabitants in rural areas, and perform autopsies and various forms of probing on them- the more humiliating, the better. They also will mutilate the livestock, in order to differentiate the physiology of animals from the guys we want to wipe out. This way we can restrict possible mutations so that it only targets the guys who we want to wipe out. Since traditional communications are at risk of interception, we will get info back home via cryptic symbols carved into fields of crops- our telescopes should be advanced enough to pick those out. Finally, we fly around rural areas, and occasionally harass any lone military aircraft for a couple minutes before abducting it. Note tht this works best in a society with kids who like to prank, and a government that isn't trusted. If "flying saucers" are considered the ravings of conspiracy-theory lunatics, all the better!

... Wait a second...

[DJEN]

Realistic planet killer? Set up shop in their Oort cloud and start a momentum transfer system by flinging comets past their planet. Keep this up for a few million years and you should manage to drop their planet into the star.

Except for the 'dropping into parent star via momentum transfer' part, this is quite a sound idea.

Although I would pick a quicker, and efficient method.

Edited January 22, 2014 by DJEN

[DJEN]

I don't think that destroying a life-bearing world with intelligent inhabitants is a winning strategy. It's the utter depths of evil. Also, I think we can draw from human history for how to successfully and peacefully deal with an alien threat of equal or near equal technological prowess. Look to the Cold War...

They were the same.

The same technologies that would allow interstellar travel might also make interstellar war too costly to wage. You might be able to destroy THEIR planet, but their relativistic weapons could not be easily intercepted, can be hidden for several light-years anywhere in three dimensional space around your planet, and all it takes is one hit on Earth to wipe it out. So it might be more like mutually assured destruction. It is much better to make peace and learn to live together than set up a track record of being a world-killer. Also, someone bigger, more advanced, and more enlightened than you might take offense to such a heinous act and decide that YOU need to be wiped out.

Agreed.

So, if you were unable to build trust with the alien civilization (which would probably involve cultural exchange, setting up joint colonies/ventures together, etc.) and the alien civilization truly looked like a threat, then you probably be wise to go into a Cold War-like scenario- set up some very hard to spot, automated, world-killing devices out in space around their planet, ready to launch of they act against your own civilization. In other words- the interstellar equivalent of nuclear ballistic missile submarines. Space is even bigger than the ocean, and has three dimensions... you would NEVER be able to find and destroy all the world-killers. It would be truly mutually assured destruction and it would hopefully be capable of keeping the peace until you worked your differences out.

Now that looks ideal.

Will we be able to understand?

Edited January 22, 2014 by DJEN
It looked like a rant of a nihilist.

[DJEN]

Except for the 'dropping into parent star via momentum transfer' part, this is quite a sound idea.

Although I would pick a quicker, and efficient method.

Lasers targeting important areas maybe?

[Champ]

I would just trick Darth Vader so that he thinks the Alliance's secret base is on that planet. Then, stop and watch. Eventually make a movie about it...

[DJEN]

I would just trick Darth Vader so that he thinks the Alliance's secret base is on that planet. Then, stop and watch. Eventually make a movie about it...

Clever idea.

[Pds314]

Actually, really screwing up the planet would be easier than that.

Step #1. Get a few square kilometers of Low-Solar-Orbit real estate just 1 million km from a sun-like star. This shouldn't be difficult, as most people don't like molten metal for their home.

Step #2. Put a few square kilometers of solar panels there. The panels MUST be made to convert 99% or more of sunlight into electricity.

Step #3. Wire the back of the panels with superconductors. If none are available that operate at the high temperatures involved, just put some radiators on the back of your panels and some liquid helium heat-exchangers to get the heat out.

Step #4. This is critical, make sure nothing painted any color but bright white or reflective and not directly connected to a re-emission laser is behind the panels. The heat there is 25000 times harsher than a hot summer's day on the equator with no clouds. The heat there is hot enough to melt the surface of tungsten and vaporize most materials very rapidly.

Step #5. After amassing something like 20 square kilometers of arrays constantly pumping out lasers of solar radiation, send several relativistically fast ships at your enemy's planet. You will need to get kind of close and need a big ship. You may need more than one to act as "relays" for the solar death ray if you can't get the initial beam tight enough. Speaking of which, a ten square kilometer circular lens would give you a focusing angle of 38.7904 arc-microseconds in green light. Which means that a ten-kilometer-wide beam would become totally homogeneously blurred at 0.002 LY. This isn't that big of an issue in terms of information loss like it is in telescopes, but the problem is the economics of putting a large station near the enemy are not good. Therefore, it makes the most sense to use multiple relays similar to the original device but larger in diameter by a factor of 2 for best economics. There would be 500 of these in a lightyear, which means your 340-terawatt ever-firing laser is gonna cost something like 20000 km^2 of solar panel sheets per lightyear (it should be noted that these could be thin and light, perhaps only 1 kg per meter squared or less. Even so, at 1 kg/m^2, this translates to 20 megatonnes per lightyear of solar repeaters.) It would also scale with the square root of the power output, so if you wanted to up this to a 34 petawatt beam, it would only take 200000 km^2 per lightyear. Basically, if you spend 10 times the effort creating your invisible galactic deathray, you get 100 times the output.

Oh, for the final layer, you want the deathray to be focused in a line going from the north rotational pole to the south on their planet. Why? because this ensures that their planet will literally catch on fire repeatedly until nothing flammable is left. It is also important to focus it more at the poles since the angle there will be shallower.

So the question then becomes, what does it take to kill a planet before it can retaliate on something at least a light-day (a day meaning the rotation period of their planet) away (critical so that their defense systems react slower than their planet scorches them alive.)

Well, based on a laser damage calculator I used, It would make the surface of an Earthlike planet reach a temperature of about 1700 C for rock or concrete. Everything else would burn very rapidly after being passed over by the beam. Equatorial areas would get little warning as the beam would be moving at supersonic speeds and only be visible for about 8 seconds, during which time, it could vaporize and melt through 15 meters of meat or half a millilmeter of concrete.

This means that the entire surface biosphere of the planet would be instantly burned and vaporized, 2 Trillion tonnes of living things carbonized in 1 day. Living things vary a lot as to energy content, but let's assume that they are basically made of wood. This means 2.736e+22 joules would be released as a result of rapid spontaneous combustion of everything on the planet. Which means that for our 2.9e+19 joule input over that day, the extra energy in all of the living things burning would outshine our death ray by 1000 times. In fact, this explosive wildfire would be a decent fraction as bright as the sun when viewed from low orbit of said planet. Rainforests would turn into expanding blobs of blue plasma engulfing portions of continents. If you built a tungsten, diamond, graphene, etc surface bunker near a forest of any kind, you would instantly find yourself in a heap of gaseous carbon. A 10-tonne tree would become equivalent to the Russian "FOAB" weapon, the largest non-nuclear bomb by yield ever detonated. A single square kilometer could have literally hundreds of thousands of tonnes of biomass in it. This means that a single square kilometer would release something on the order of a megatonne of TNT equivalent. Being near ground zero of the plants would be like sitting under a nuclear bomb as it drops. Furthermore, such densities require immense amounts of oxidizer to burn, for every tonne of biomass burned, something like a bit under 5 tonnes of air are needed to burn it.

By comparison, the atmosphere of an Earth weighs about 5 quadrillion tonnes, easily enough to burn without a second thought, though some areas would be fairly seriously starved of O2 near the ground for awhile after burning.

Final nail-in-the-coffin point. Firing this weapon costs you NOTHING.

It can ruin a planet in a day, and ruin it again the next day, and again the next one. Anything in orbit? fried. Anything on the ground? fried. Anything that comes back later to try and reclaim the surface world? fried. Even if your opponents managed to survive in their nuclear submarines or hyper-deep bunkers as the atmosphere convulsed, the crust shook, the lakes boiled and the world generally became a scorched wasteland, they would be limited to living kilometers from the surface for fear of incineration.

Also, the debris kicked into the atmosphere would be quite absurd. Most of the ashes would be blasted into a mach-1 perpetual global windblast that would cover the sky in 2 trillion tonnes of debris, but wait! what about the water vapor, the sand, the dust, the stuff that gets in the air that isn't a burn product. It would block out the sun thoroughly. This would cause rampant climate change that could make the planet become a Venus-like wreck for millennia or longer. Another point is that the atmosphere may reach a temporary peak temperature in the lower atmosphere of something close to the temperature of a B-class star (30,000 degrees C). Wind speeds would reach significant fractions of orbital velocity, and this could last quite a while. NOTHING would survive something like that near the surface. The only reason it wouldn't fry you in orbit is the fact that the air would block out most energy from escaping by radiation.

So yeah, basically, giant laser cable going through space that lights planets on fire. Perfectly workable.

[TheDarkStar]

-wall of text-

Perfectly workable.

Something about that is just hilarious. However, you say that the focusing angle is only 38.7904 arc-microseconds? Your beam's radius would increase by just over 1 mile, which is still insignificant compared to the size of a planet.

Another thing: Because the station has to orbit, it wouldn't be able to constantly fire at a planet unless it was in a polar orbit, and that would only work for part of the year anyway. However, it could be set up to fire for long enough that it doesn't matter.

Third: The main problem is that the satellite would be short-lived, unless either made of some material with an extremely high melting point or cooled with large amounts of liquid helium. The engineering would probably be the only real practical issue, other than getting it there.

[andrewas]

A) put your solar station higher and make it larger to compensate. It'll probably work out cheaper without the extra cooling needed.

you can keep it on target indefinately if it balances on the solar wind rather than orbiting

C) its more efficiet, albeit less spectacular , to use that power to fire kinetic impactors at the target, and only a little slower. The cost and power savings are more dramatic at longer ranges.

It would also be worthwhile exploring civilian uses for this. In between planet roastings, it could beam power to colonies or launch solar sail ships.