# The opposite to Worldbuilding: World Destruction

I am looking at different ways to destroy a planet. I am assuming the planet is of a similar size and composition to the Earth just to keep things simple.

I am starting at boiling the atmosphere to the point where it turns Earth into a dead barren rock with no vegetation, no oceans and no air left. This is as tame as I want my destruction (there's still a giant dead rock left, and I want to wreak more havoc than this!).

I am also looking into lasers powerful enough to obliterate a planet into dust, AKA the Death Star approach. At the most I am not sure if the energy required to achieve this makes this a feasible option. (Yeah, I know, I am concerned if this is feasible and then I go onto consider something else like:)

Ive been considering something that destabilizes the very structure of a planet, affecting everything from plate tectonics to the planets own gravitational pull on itself and causing a chain reaction which results in the planet flying apart. But I am not sure if I can back this up with any kind of science.

I have also considered launching another, large enough, rock in space at a planet to smash it into smithereens. I have also looked into detonating the nearby star to take out the planet and the entire system.

My problem is that I don't know which one of these (or any other crazy ideas that I have) forms of global destruction are the easiest to achieve. So my question is:

What would be the most effective or efficient way to destroy an entire planet?

I dont just want to destroy all life on the surface, I want to reduce the entire planet to rubble so that very little remains (I guess an asteroid field/belt being left behind is destruction enough, but bonus points if you can cause more destruction!).

I also want to do this in a relatively short time frame. Say, less than a day.

• qntm.org/destroy seems relevant here. – Chris Nov 27 '14 at 13:59
• @Chris A slightly less obvious method would be redefining "planet" not to include the Earth. That would indeed seem by far the easiest solution! – gerrit Nov 27 '14 at 15:59
• For lasers, note that this page claims the recoil of the Death Star would accelerate it to nearly the speed of light. This page claims only 100 km/s, which is a little faster than a space probe. I haven't compared the calculations in detail but I guess it comes from them using different masses. – David Z Nov 28 '14 at 7:24
• I felt a great disturbance in the Force, as if millions of people had just been told their planet had been reclassified as a dwarf planet. – trichoplax Dec 30 '14 at 22:46
• ... or just call the Vogons! :P – mikhailcazi Feb 19 '15 at 8:26

Countering the gravitational binding energy of a (earth-sized) planet takes roughly 2.4E32 joules. That's enough to make it come apart, but it would be a slow process; if you want it to blow apart you'll need to add more than that. It doesn't matter too much how you deliver that energy, just that it gets to that total somehow.

So what does that mean in practical terms? Well, 2.4E32J (or 240 million yottajoules) is roughly equivalent to:

The total energy output of the Sun in eight days.

The energy delivered by a rock the size of Mercury and travelling at the same speed as Earth but in the opposite direction.

A large asteroid (100km across) travelling at very, very, very close to the speed of light.

One quadrillion bombs the size of the Tsar Bomba (the largest nuke ever built).

The energy released by 1.3 trillion tonnes of antimatter hitting the same amount of regular matter.

Essentially, blowing up a planet is really, really hard. If you're staying mostly within the realms of normal physics, the most promising option is probably to hit it with another planet. If you can accelerate things effectively to light-speed, then you can use a smaller rock (for an asteroid-sized rock, the difference between 'fast enough' and actual light speed is too small to be worth calculating.)

Alternatively, you can use an ungodly amount of explosives - antimatter or conventional, the energy requirements are high enough that it more-or-less stops mattering.

Lasers are out - you'd need an energy output roughly 10 times that of the sun, and there's simply no way to build a laser that powerful without it destroying itself the moment you switch it on.

Destablising the planet, unfortunately, is going to require some form of sci-fi gadget that doesn't follow the currently understood laws of physics. (Or, at the very least, one you're pumping 2.4E32 joules into to make it work. And, as noted above, that's a lot of energy...)

Of course, if you've got the resources to pull any of these off there's another simple option: knock the planet out of orbit so it falls into the sun.

• Also excellent: "The energy released by 1.3 trillion tonnes of antimatter [...]" - If you consider that no nuclear, much less chemical, reaction can yield more energy than full matter/antimatter annihilation, this figure is about the lowest bound of the mass of the energy source (reactor, bomb, or anything else) one would need. – JimmyB Nov 27 '14 at 11:56
• If you can accelerate planets at will, why not cut out the middle man and throw the earth into the sun? – overactor Nov 27 '14 at 12:01
• "A large asteroid (100km across) travelling at very, very, very close to the speed of light." or a baseball travelling even a bit faster – PlasmaHH Nov 27 '14 at 12:18
• @PlasmaHH or a proton, traveling a tad faster even... – overactor Nov 27 '14 at 12:19
• Presumably the energy required to merely melt the crust is a lot less than the binding energy? That's a step beyond "scorched dry" and would prevent repopulation any time soon. Would that be enough? – trichoplax Dec 30 '14 at 22:39

Just put humans on that rock (with or without space suits).

This animal species was observed over the course of history to destroy mostly anything it encountered in it's path, you could extrapolate to find it could be, at least theoretically, capable of destroying a whole planet.

sorry, couldn't help it :) but it might not be too off-topic, consider a human posted this question and others are thinking about it...

• Thank you Friedrich Nietzsche – user20762 Dec 19 '19 at 19:41

If you want to rip a whole planet apart then it's very hard, the amount of energy required is immense.

The simplest way would be to use tidal forces. Get something like a neutron star, black hole, or gas giant and bring that in close enough to the planet to be destroyed (inside the Roche Limit) so that tidal forces rip it apart.

Theoretically some sort of sci-fi weapon "black hole generator" could do the same job, or just drop the black hole into the planet and let it eat it. That would leave a black hole rather than rubble though.

Consider how much energy is involved in moving something like a gas giant or neutron star close to our planet and that should help you picture just how big what you are attempting here is.

• Love the concept of the Black Hole Generator to eat a planet and using a neutron star to rip a planet apart. I get that this is on a scale far beyond anything we can achieve today, but this is what I am after. – Jimmery Nov 27 '14 at 11:39
• Reminds me of the SG1 episode where they dropped of a stargate near a star, and the other end was orbiting a black hole – PlasmaHH Nov 27 '14 at 12:26
• Step 1: obtain a black hole (without it obtaining you). – corsiKa Nov 27 '14 at 20:26
• "Step 1: obtain a black hole" ... I keep checking eBay, but no luck so far – Brian Drummond Nov 28 '14 at 15:49
• I continued looking and I found the paper on building a BH generator. arxiv.org/pdf/0908.1803.pdf – Gary Walker Feb 19 '15 at 22:27

The normal physics approach got handled well in the other answers. So let me propose an alternative option: Bend the physical laws as we know it.

There are actually theories that wonder if the laws of physics and the constants used in there were always the way we experience them today. Some far future high tech weapon (or an accident involving a fridge, a smartphone and a cup of tea) might change one of a natural constant in a limited space time range. For example if you increase the gravitational constant on the planet far enough it would collapse to a small star, neutron star or even a tiny black hole. If the gravitational constant returns to normal, the remains might even explode.

How many energy would you need to blast the earth?

I'm sorry to provide this image in german language, but I think you get the point and you are able to translate the catchwords. You could use this translation site.

This graph shows how much energy specific events unleash. The Asteroidimpact 65M years ago had circa 1000 times the power of all nuclear weapons existing and only scratched the hull of our small planet (200km crater). So you might understand which massive power you need to blow a planet up. This is not possible from our technical capabilities of today.

Maybe, if you collect all explosive material mankind could gather at a single point in a little distance to the planets survace, you could change the direction in that way, that the planet "fall" into the sun within some thousands or millions of years. Just why,...

Here is a post about how much energy is needet to blow the earth.

2.24 × 10^32J or 5.34 x 10^16 Mega ton

22 400 000 000 000 000 000 000 000 000 000 Joule (!)

One nuclear warhead has an average power of 1 mega ton. 5.34 x 10^16 atomic bombs needet, 17.000 existing. Thats nothing. So now you might be able to picture the energy you need.

In the End I would say, at this point this is just impossible.

EDIT: (Moved in quotebox due its a unnecessary additional, I missunderstand one point which makes this obsolete)

I think this question is far to broad to give a specific answer, but I'll try.

The way you can destroy a planet depends on many factors and I'll go over some of them. While doing this I sometimes take comparisons like "small vs big". Doing this I always assume that both (small and big, far and close,...) have everything in common, except the state I'm talking about.

Size

A large planet is more resistant against impact and explosions. Also, a large planet is not pushed out of it's orbit with ease.

Material

Do not underestimate this point(!) How would you try to destroy a gas giant like Jupiter? An Impact must be huge due the massive atmosphere. (Sidenote: gas giant doesn't mean the Planet is entirely of gas, but light elements. Hydrogen for example has a liquid state, this would still be a gas planet.)

Have you ever thrown a ball into water with full strenght? It's hard to penetrate the water very deep. The Liquid will absorb the power of the impact to a big point, same for explosions. So I assume that an impact of any kind is not very effective against a gas planet like Jupiter or Neptun.

Beside of this an Explosion can wreak massive havok on solid matter like rock.

Distance to the sun

The sun could be a tool to destroy your planet, if the distance is not to high, you might just push the planet toward the sun. This would take less energy than blasting the planet.

• Great answer thanks! But I think you missed the bit where I said "I am assuming the planet is of a similar size and composition to the Earth just to keep things simple." – Jimmery Nov 27 '14 at 10:55
• Oh yea I missed that, sorry. But the point of my answer stays same. – jawo Nov 27 '14 at 10:56
• Your answer is great! Perhaps I should ask instead: What is the easiest way to generate the 5.34 x 10^16 Mega tons required to destroy a planet? – Jimmery Nov 27 '14 at 11:41
• 70 km/s even relative speed is awfully fast. – user Nov 27 '14 at 12:41
• The ice comet energy is presumably its kinetic energy. What happens if it penetrates below the crust (lucky hit on a weak point) and 10^9 tons of shattered ice flash to steam in a geologically active area? – Brian Drummond Nov 28 '14 at 15:53

How FAST do want to destroy it? If you have sufficient resources, try a fleet of World Devastators from Star Wars to eat the planet (very efficient, saves resources!) or, if you're really ambitious, try and make a Sun Crusher, which does what it says, by making any star go supernova, but that may be a bit much! ... or just enough.

Some are proposing you slam things into the planet in question, but I want to propose the opposite: move the planet into the star. It might take a really long time, or maybe it wouldn't, but with the right technology (and a little bit of crazy) we can move a planet. Our current ideas are painfully slow (and dangerous) but if you have some sort of massive gravity generator, you could destabilize the orbit of the planet enough that, just maybe, it could fall into the star. Or just get a giant wormhole between the planet and its star and boom, same effect. Stargate, anyone?

How about using advanced quantum computers to understand (and thus exploit) chaos? Use a reasonable amount of energy to divert a small asteroid. It crashes into another larger asteroid and diverts that. Through picking on successively laeger objects in eccentric orbits and a few gravitational sligshots around the gas giants, eventually you get the Earth's orbit destabilized or a dwarf planet to collide with it. I call it celestial judo.

• Interesting. It might not even take all that much calculation, given the convenient fact that there are a number of large asteroids that are already on near collision course with the Earth. – trichoplax Dec 30 '14 at 22:31

I am surprised I didn't see this before (only saw it now because of a link in chat) but I'm even more surprised no-one mentioned my solution, especially in the era of fidget-spinners...

Simply add a couple of large engines - I'm thinking Ringworld attitude adjustment engines - on pylons high enough to get them above the majority of the atmosphere, pointed in such a direction as to increase the rotation speed of the earth.

Then keep adding fuel/energy (the equivalent of the annoying child who just won't stop spinning that fidget spinner thing!) until the planet gets close to breaking up.

Along the way, you'll lose water, atmosphere, people (at about 17xfaster than current rotation) most stuff, to be honest.

Of additional benefit, if you can build the engines to run on any matter, you can use the planet's matter as fuel - and if you start using the surface layer round the equator, this will help by increasing the spin speed in the same way ice skaters do by pulling in their arms.

Once close to break up, position yourself above one of the poles, set your GoPro to record and wait for the catastrophe in all its technicolour goodness.

Read this question for more details.

Implode the Sun, thus creating a very dense object that's close (?) to Earth. Eventually, the rapidly intensifying radiation from the Sun would scorch Earth into a barren rock - as stars become smaller, they burn more fiercely.

• I like this idea - however, if you have the capability to implode the sun, surely you have the capability to directly destroy a planet without affecting the star it orbits? – Jimmery Nov 23 '15 at 11:38
• Not necessarily - Earth is denser/more solid than the Sun, and thus requires more energy to implode. – Wick Nov 28 '15 at 1:52

A superdense piece of neutron star hitting the earth would accelerate down to the core and then out the other side. If it were not going too fast to escape back into space it would turn around under gravitational attraction and then come back through. This oscillation would go on and on. Stuff would get smashed up as these things went thru. A large number of these things would be more like destroying a building with sledgehammers than with dynamite. It would be dramatic but not immediate and so time for events to take place on earth. I can imagine the sequence where a building sized chunk of neutronium exits the earth near the protagonists, who survive ensuing badness but then realize chunk is going to come back down.

Roaches would probably still survive. After superdense chunks come to rest in the core you would need to spray.

Greg Bear had something like this in Forge of God. The chunks, not the roaches.

https://en.wikipedia.org/wiki/The_Forge_of_God

but the oscillations were a side benefit; his things were going to destroy Earth in a matter / antimatter explosion.

A couple of posts mentioned knocking an asteroid into the Earth's path, effectively killing all life on Earth but leaving the planet itself still relatively intact.

I'm surprised no one thought of just repetitively knocking asteroids into the Earth's path. (Btw I read that somewhere else) I mean there are over 1 million asteroids over a km. large in the asteroid belt alone. I don't know if it would be enough but I'm pretty sure having asteroids ramming into the planet over and over again would damage it a lot more than a bunch of nukes.

I suppose it wouldn't be too long before the atmosphere would start tripping, and once that's gone every impact will just hurt even more.

• How does an atmosphere trip? – Serban Tanasa Mar 28 '15 at 0:59
• Going all crazy and s... I was lazy, apologies. I meant all the dust sprung into the atmosphere, the heating, and any other changes brought in the aftermath of a large asteroid colliding with the earth. I don't know to what extend, but it would definitely damage/change it, perhaps weakening it (or maybe quite the opposite). – Spacemonkey Mar 29 '15 at 4:12

I think I may fail at the timeline being under one day with this approach, but this would work with your lasers approach. The energy involved likely isn't enough to fully counteract the gravitational binding of Earth, but it'll turn the planet into a few chunks and require significantly less energy than simply trying to vaporize the earth. A bit of a combination move of throwing an asteroid at the earth, except we're going to use lasers to do it.

Have your death star approach the moon and fire its laser as a large spread heating the side of the moon facing away from Earth as much as possible (not to destroy the moon, but to heat the surface to as extreme heat as possible). This heat vaporizes the moons surface, propelling this material away from the moon, functionally turning that side of the moon into a rocket propelling it into earth. This collision between the moon and the earth won't actually provide enough energy to fully counteract the Earth's binding energy, however it'll definitely tear the two bodies apart and not leave much beyond a barren rock. And all for a significantly less amount of energy than outright destroying the Earth with a laser. Unfortunately I'm not enough of a physicist to calculate exactly how much energy you would need to turn the moon into a self propelled rocket straight into the planet and what angle of impact would cause the best destruction rate for you.

The area of the moon that is vaporized needs to both halt the moons orbit around Earth and propel it into the Earth to get the best impact angle.

• You would actually want to fire the laser at the "front" of the moon, not the far side. Far side pushes it in which accelerates it and moves it out. Push on the front and it decelerates and falls in. – Tim B Nov 28 '14 at 9:20
• @TimB - good point! it almost sounds counter intuitive, but you basically want to halt the moons orbit and have it fall into earth instead of trying to push it into the earth. I kinda mentioned it in my last line, but you have it right here – Twelfth Nov 28 '14 at 20:32

construct a large solar reflector that orbits the planet outside of it's moon's orbit. The reflectors centrivical spin is such that it always focuses light from the sun, onto the far side of the moon. This pushes the moon closer to the planet, gradually changing its trajectory until it falls out of orbit.

I think everyone has dealt with the real world physics as we currently know it. So what about invented physics?

Turn the planet into strange matter via a nuclear autocatalytic reaction. It takes a tiny bit of strange matter to start the process. More than nature has ever generated accidentally via cosmic rays etc. But not so much that it can't be done with advanced nuclear/particle tech.

Or destabilise it's foundations in the 4th or higher spatial dimension. string theory says there are seven more spatial dimensions that we don't perceive because they are sort of rolled up. The theory is incomplete. They can be unrolled. The planet then rolls out of our known universe.

Or have someone put the cosmic censorship theorem to the test. This says that if you try to build a time machine the universe will prevent you from succeeding. So the sun goes nova just like that. (This story has already been written but I've forgotten author and title)

Or my favorite: the universe is in fact a virtual reality. Have someone find a bug in its hypervisor and try to exploit it. Even better, succeed in exploiting it, until it's too late to stop the unanticipated consequences.

• "So what about invented physics?" They have a tendency to fail the science-based criteria of the question. – user Nov 23 '15 at 22:27
• Well, I was trying to stick with "Unlikely, but not actually contrary to anything known with a high degree of certainty". I mean, if you'd written a story including a substance that conducted electricity with zero resistance back in 1900, many would have said not just unlikely but impossible. And today, we have superconductors. – nigel222 Nov 24 '15 at 13:37

I'm surprised that no one mentioned nanobots.

There's no big boom but if you have nanobots that simply make copies of themselves using available resources, you could end up with a grey goo scenario.

the planet is still there but anything that lands on it corrodes into the nanobot swarm.

I have the idea of time travel, if your planet or your enemy's planet's inhabitants have the tech advanced enough for time travel then you could create a hybrid of some animal (e.g. King Kong) whose genes are wonderfully powerful and set it loose and watch the destruction.

Another way is to destroy historical objects sixty, seventy, or one hundred years in the future and do that multiple times and then the time changes in that whole time-line and world happen so fast that the world's physics is broken. Then everything from the planet's evolution to their oxygen supply so that would kill the inhabitants easily. Somewhat destroying and jumbling the world into pieces.

• destroying the historical objects (like Big Ben or Mount Rushmore) change the world physics... interesting! How can it work? – L.Dutch - Reinstate Monica Aug 21 '17 at 5:09
• time paradoxes would be a good way to completely eliminate a world - thanks for the answer :) – Jimmery Aug 21 '17 at 10:23

## Antimatter

Now, a lot of antimatter would be required to destroy Earth. Around 6 septillion kilograms. In other words, in order to destroy Earth with antimatter you would need an anti-Earth to do it. Now if you were to launch that at Earth you would completely annihilate* it. But though, you would also destroy a good piece of the solar system as well. considering the fact that around a quarter of a gram of it could level a city. The only problem is though that producing antimatter is expensive. But if you built anti-Earth on the outskirts of the solar system and then contained it in a vacuum, and launched it at 50% of the speed of light it would hit Earth in about 8 hours. There would not be a remainder of Earth after this happened.

*Annihilation- The result of matter reacting with antimatter. It produces a lot of energy.

• It's perfectly true that to annihilate the Earth (in the sense that you're talking about) would require the exact same amount of antimatter, but is there a smaller amount of antimatter that would impart enough energy to blow the Earth up without 'annihilating' it in that sense? – Mithrandir24601 Aug 21 '17 at 22:20

I'm surprised that nobody has mentioned the recent scare stories surrounding experimental physics. In October 2008, when the Large Hadron Collider was switched on near Geneva, there was some concern that the device was capable of unintentionally creating a small black hole.

The scenario goes that the black hold would then sink to the centre of the earth, furiously consuming matter as it went. The earth's core would then be consumed in a few hours. The earth would then suddenly flatten out into the shape of a large frisbee ( the accretion disc ) before collapsing in on itself while being consumed.

Here is an article on the scare from the NASA website.

• The article states: "There never really was a danger from the accelerator." – Jimmery Feb 19 '15 at 10:16
• @Jimmery That's right. Any potential black hole would quickly evaporate. The idea was more to think of experimental physics in the future, when larger and larger amounts of energy are employed in more and more exotic ways. – User2178 Feb 19 '15 at 17:06

Well, if you are on a budget, you might prefer to make the planet unusable for humans via the route of poisons that are persistent and difficult to mitigate. Dimethylmercury would have to be one of the candidates for such.

One drop is more than fatal. It can be absorbed through gloves and has a high vapor pressure to boot. Very nasty stuff. One of the strongest neurotoxins, it is also easily synthesized, so it is not very expensive.

Disperse a million tons of this over the planet and no-one is ever going to call it home. In theory you could clean it the mess, but the cost would make it very unlikely -- plenty of cheaper rocks to inhabit.

I know this does not really answer your question as stated (planet is not left in rubble or dust), but it would otherwise be quite effective and it was too long for a comment.

Reading some of the other answers made me put my geology hat back on. As noted, the energy required to kill a planet from an external source is huge. However, there are natural processes that could be harnessed to destroy the planet. The key to destroying Earth would be to direct the tectonic energy towards destruction. Triggering massive earthquakes along the Ring of Fire could sufficiently damage the atmosphere to make the planet unlivable.

Another possibility came from Greg Bear, I think. He postulated the destruction of Earth by destroying or stopping the core. This would stop the magnetic shield around the planet and result in massive ecologic devastation. In his case, the enemy release high density devices that were able to slow and stop the core. The devices also triggered massive tectonic movement and destroyed the continents. I suspect a 1 kg release of antimatter at the core or the introduction of an artificial singularity to the core would suffice.

Though I'm unsure of the amounts needed, introducing lots of additional radioactive matter into the deep mantle could, over time, render the Earth too hot to be inhabited. Likewise, an overall increase of surface radiation will render Earth uninhabitable by humans and most other lifeforms.

If I were to be writing such a story, I would do something to strip away the magnetic protection we enjoy. All we have to do is look one planet out to see the results of that.

"I am starting at boiling the atmosphere to the point where it turns Earth into a dead barren rock with no vegetation, no oceans and no air left. This is as tame as I want my destruction (there's still a giant dead rock left, and I want to wreak more havoc than this!)."

Nice! I think most plausible option is:

1. CRASH THE MOON ON EARTH.

Since moon is tidaly locked to earth, put a huge autonomous helium3 harvesting facility on its surface, and burn this fuel through an enormous rocket engine, which pushes the moon prograde until it gets a very high apoapsis. Then make plenty of retrograde burns at apoapsis until it crashes on earth's surface.

2. CRASH THE EARTH ON THE SUN.

Wait until earth + moon newly formed "earthmoon" planet gets cold enough in order to have a solid crust. Build other facilities and rocket engines at the equator, and burn counter-rotational until you get an earthmoon tidal locking relative to the sun.

Repeat deorbit manoeuvre ( burn prograde at periapsis plenty of times, to get a highly eccentric orbit, with an apoapsis at about pluto's distance or further away, and then burn retrograde at apoapsis, until final ultimate doomsday.

Almost 3 years and I find one that's been missed:

Drop a device into the sun that will explode, causing a shock wave through the photosphere. The idea is runaway nuclear fusion--create an enormous flare that will fry the biosphere.

I have seen an estimate that puts the energy needed within the range of h-bombs. Protecting it until it's deep enough would be a challenge, though!

• I was after the world being completely destroyed, not just burning off the biosphere. – Jimmery Aug 22 '17 at 8:19

Most other responses focus on a single approach, but what about a scenario involving more than one concept?

There was that fear back in 2008, 2009 that LHC would produce black holes. If your story passes on the future, the complete annihilation of Earth could be the result of the first run of an immensely powerful particle accelerator. Something so big and so powerful that it would make LHC look like a Kinder surprise.

This humongous particle accelerator could have being built by megalomaniac physicists, who wanted the most powerful accelerator they could possibly build to get data they could not even imagine.

The problem lies precisely there. Maybe the accelerator was so powerful that it tears the very fabric of the space-time continuum on its first run, and matter and energy begin oozing out of our universe through this tear, effectively destroying Earth because it's on the center of this hole. Slowly, then, the tear would "heal itself", because the laws of physics would force the Universe to be a closed space, but enough time would have passed for our planet to be crushed and expelled from this cosmos. It's not just destruction, we're talking about total obliteration here!

Or, maybe the accelerator was so incredibly useful that it produced strangelets, or a new kind of particle that's responsible for transforming matter in antimatter. Both would involve chain reactions: Strangelets transforming any other particle in more strangelets, which in turn would convert even more particles in strangelets and so on. In the other scenario you would have to propose a new fundamental force, responsible for maintaining matter, antimatter and dark matter stable, and a mediating boson for this force that can convert one kind of matter into another. This chain reaction would convert matter to anti- or dark matter, with each conversion producing more and more of these conversion bosons. In a few time, the entirety of our planet's mass would had been converted to sterile matter.

• Sorry but I tagged this question as science-based - firstly the fear that the LHC could produce black holes was a combination of pseudo science and bad reporting, no actual basis in science at all - secondly, do you have any scientific evidence to back up an "accelerator being so powerful it tears the very fabric of the space-time continuum"? Great ideas, don't get me wrong, but I was looking for something that was backed by hard science. – Jimmery Sep 1 '17 at 11:38
• @Jimmery - Sorry, I left my imagination to run a bit too wild on this. I cannot back up these concepts with hard science, I just thought they were cool ideas. – Eduardo W. Sep 1 '17 at 17:06

Well, there are a few approaches you can go.

If you want to stay in the realm of hard sci-fi, I suggest a nuclear war. It has been estimated that at the cold war's height there were enough A-bombs to make Earth uninhabitable. Plus, even if there are not enough nukes to destroy the crust, the nuclear winter will still kill most everything.

If you are wanting a natural phenomenon, plant a field of Slaver Sunflowers from Larry Niven's Known Space series. They will gradually expand, incinerating everything in their wake. Plant them in a remote region with lots of sunlight, so that they can reach undefeatable population levels. This does not qualify for the 1-day limit, but it is nevertheless a good option.

Since you clarified that the world in question is earth-like, not earth itself, it probably does not have a sizable moon. As a result, "de-orbit the moon" is not a good option.

If you are willing to allow slightly softer science, make a Stargate-style wormhole connecting point A (somewhere in the general vicinity of a quasar) to point B (somewhere in the general vicinity of your planet). The energy, plasma, and hard radiation that go through the wormhole will instantly reduce your hypothetical planet to a Hitchiker's Guide to the Galaxy-style "puff of ozone". It has everything you could ever want; its efficient, it gets the job done, you don't have to deal with any angry natives, and best of all it gives you the opportunity to say that they should have checked the sector planning office!

Large hydrogen bomb being very deep - aka the Armageddon approach, but instead going to the asteroind you stay home, dig deep, even deeper ... basically as deep as possible to the Earth core and place huge bomb here.

Imagine having there several Tsar Bomba exploding at the same time.

The plausibility of destroying a whole planet to the pieces is very high.

And even if you do not succeed, not even the Jedi would feel it ;)

• Actually I disagree, a nuclear explosion that deep wouldn't even be felt on the surface. See worldbuilding.stackexchange.com/q/2965/49 – Tim B Nov 27 '14 at 10:49
• In theory it's possible, but the amount of energy involved is incredible. You'd need a substantial amount of antimatter injected directly into the core or something similar to get the amount of energy needed. Even then you'd tend to vaporize things rather than shatter them. – Tim B Nov 27 '14 at 10:51
• No it is not plausible. The gravitational binding of the earth is 2.24 × 10^32J. Even 1 million Tsar Bombs (there is not enaugh material for that) would only provide 2.092E+24 J – jawo Nov 27 '14 at 10:55
• To save on the energy bill -we're all considerate about the climate, right?- one could try to use several smaller detonations at the core, so as to cause shockwaves at the right frequency to resonate. The peak forces of those waves are larger than those of a steady force of the same energy. I imagine it would be a nice show if pieces of the surface the size of a country got blown into space when the wave hits a spot, followed by a giant blob of magma. Repeated over, this could cause the almost hollow planet to collapse and travel on surrounded by a field of contry-sized asteroids. – JimmyB Nov 27 '14 at 12:12
• The power of nuclear weapons is often grossly overestimated. – mic_e Nov 28 '14 at 15:02