And Poul Anderson. Two of the most prolific writers in SF history, and also two of the more regular Ace Double contributors. As of , though, I doubt anyone was predicting future Grand Master status for Silverberg: certainly this novel provides no support for such speculation! Anderson, to be sure, is another matter. Add caption The Planet Killers is about 43, words long. It is an expansion of "This World Must Die!
It's a very simple story -- too simple, really. I expected -- hoped -- to see a twist along the way but none really happened. The story opens with Roy Gardner, an agent of Earth, being ordered to the planet Lurion. It seems that a computer has decided that Lurion will turn warlike in 67 years, make a sneak attack on Earth, and completely destroy it. The only alternative for Earth is to destroy Lurion now, by sending 5 agents to Lurion to set off sonic generators to, I guess, shake the planet apart. The objections to this are obvious.
Most clearly, in 67 years there is no way to divert Lurion from this path? More simply, how can there be a "sneak" attack if Earth has predicted it? In One of Our Asteroids is Missing, independent miner John Storm discovers an impossible asteroid rich with fabulously valuable metals and minerals, only to find his claim stolen, along with all computer records indicating that he had ever existed! Never before reprinted since their original appearances and with a new introduction by the author, these three novels of science fiction adventure blaze back onto the scene, revealing early masterworks of one of the genre's most gifted and celebrated storytellers!
Genre: Science Fiction.
Enter the planet-killer. So what is a planet-killer? A planet-killer is something that literally "kills" an entire planet, ie- renders it dead.
This normally entails such a profound level of surface destruction that all civilization on the planet's surface is destroyed. In some cases, they go further, and completely sterilize the surface. In the most extreme cases, they actually destroy or consume the physical bulk of the planet itself, thus making them true planet destroyers. In fact, planet-killers are so common in sci-fi that a complete list would be simply overwhelming, and even the most superficial discussion would be well beyond the scope of this page. Therefore, I will restrict myself only to discussion of planet-killing objects, ships or weapons that have been seen in big-name TV or movie-based sci-fi franchises like Star Trek, Star Wars, etc.
No obscure sci-fi universes based on novels, comics, animes, computer games, etc. If you want something to be included, tell the author to convert it into a popular movie or TV show and then get back to me. And yes, I'm also excluding computer games based on TV shows and movies; such games are designed for playability and entertainment, not accuracy to the source material.
No "godlike beings". This page is about weapons, not demigods. I don't really care about how your favourite demigod could destroy a world with the power of his mind. As an aside, I have noted that people often assume a "godlike being" such as Q must be capable of destroying a planet even though we've never seen him do anything remotely approaching this.
They seem all too willing to make the unfounded leap in logic from "does things I don't understand" to "omnipotent". No great swarms or fleets of ships. Virtually anything can theoretically depopulate a planet given enough sheer numbers even buckets of water. A planet-killer singular, not plural is a single object, ship, or weapon. I'm sorry if I have excluded your favourite example by narrowing the list down like this, but without some exclusions, this page would simply be enormous.
You don't need to watch sci-fi to learn about the awesome power of a planet-killer. A sufficiently large asteroid or comet impact could theoretically devastate a planet's surface in real life, and our planet bears mute testimony to such impacts, with many large craters scarring its surface. Indeed, if it weren't for erosion and tectonic plate movement, the Earth would look like the surface of the Moon. Even the smallest asteroid impact can be extremely destructive. The destructive power of a large asteroid impact is truly horrifying.
This is a number which is so staggeringly large as to beggar the imagination; just try to imagine detonating a Hiroshima bomb every second for more than six thousand years , and then compressing all of that into a single titanic blast. Land impact destroys a large state eg- California, France, Japan and produces enough atmospheric dust loading to affect global climate, freezing crops. Ocean impact creates hemisphere-spanning tsunamis but no global climate change. Global ozone layer is heavily damaged. Both land and ocean impacts produce enough atmospheric dust to affect global climate, freezing crops.
Impact ejecta are globally distributed, causing widespread fires. Land impact destroys a large nation Mexico, India. Probable mass extinction event. Global climate changes last for weeks or months. Direct destruction occurs on continental scale Australia, United States. Massive global firestorms.
The K-T extinction event 65 million years ago fell into the upper end of this category. One of the most common misconceptions regarding asteroid impacts is that they do all of their damage through stratospheric dust loading. This is not true; asteroid impacts can damage or exterminate a biosystem through a variety of mechanisms:. Wake radiation. A large asteroid or comet will create an enormous "bow wave" of superheated, ionized gas in front of it as it passes through the atmosphere, and it will leave a "wake" of superheated, expanding gas behind it.
The wake can be modelled as a cylindrical explosion, with the effects of a conventional nuclear fireball: shockwaves, intense thermal radiation, etc. Moreover, the height of the elongated fireball column means that much of this radiation will propagate through upper-atmosphere layers which are essentially transparent to thermal radiation, so it will have much more widespread effects than a surface-level nuclear explosion of equivalent yield. In fact, it is theorized that massive casualties on a continental scale may be caused by wake radiation alone , even before a massive impactor hits the ground.
Impact groundquake. Like a hammer-blow, an asteroid impact will produce powerful seismic shockwaves that propagate directly through ground matter. Impact fireball. In addition to the columnar fireball produced by the impactor's hypervelocity passage through the air, there is a huge fireball produced by the violent release of kinetic energy upon impact. This fireball is similar to that created by a nuclear explosion, with powerful atmospheric shockwave or underwater shockwaves for ocean impacts, although these don't travel as far and thermal radiation effects.
The fireball tends to be drawn up into the ionized wake, so it takes on more of an elongated vertical shape than a spherical nuclear fireball. It should be noted that these effects scale according to the inverse square law for radiation and the inverse cube law for shockwaves, so the radiation effects easily outstrip the shockwave effects for large-magnitude impacts.
A large-body ocean impact vapourizes a column of water, thus producing a "hole" in the ocean. A column of vapourized water is hurled into the stratosphere, and an enormous water wave is created. This water wave moves outward from the impact site until it reaches the shore, whereupon it loses speed and gains height, thus causing a height increase of 10 to 20 times.
Unlike atmospheric shockwaves, tsunamis scale according to the inverse square law rather than the inverse cube law, so ocean impacts are actually more destructive than land impacts, particularly since human civilization tends to concentrate at shorelines rather than inland regions. Ballistic impact ejecta. A large asteroid impact tends to produce more melted and vapourized particulate debris than a nuclear explosion, and much of this debris is hurled upwards as a hypervelocity plume.
Like any other hypervelocity atmospheric entry object, the condensed and coalesced debris particles will ablate from air friction, thus re-heating them and the atmosphere. These processes have the effect of converting the kinetic and thermal energy of ejecta into globally distributed thermal radiation and elevated upper-atmospheric temperatures, thus igniting global firestorms and altering the climate.
Extremely large impacts tens of billions of megatons can produce so much high-energy ballistic ejecta that the entire atmosphere will be radiatively heated beyond K, in which case all other damage mechanisms essentially become irrelevant because the planet is completely sterilized. Acid rain. Hypervelocity shockwaves produce NO nitrogen oxide because of chemical reactions in the energetic "shocked air".
Such shockwaves are produced three times: once by the impactor's passage through the atmosphere, again by the movement of its ejecta plume up into space, and yet again by the re-entering ballistic hypervelocity ejecta. NO can also be produced if the impact happens to strike a sulfate or carbonate-rich area of the surface. The result would be ozone layer destruction much more than for nuclear explosions and a global increase in acidity of surface waters, which would provide yet another environmental damage mechanism. It would take many years for the NO loading of a large impact to be removed from the atmosphere.
Water injection. A large hypervelocity impactor can produce a towering column of water and steam which reaches up over km in altitude, and which contains 10 to 30 times the mass of the impactor. This has the effect of literally humidifying the entire upper atmosphere, but the effects of such humidification are not known. Cloud particles can produce a runaway greenhouse effect or they can reflect sunlight, but these particles can produce heating or cooling effects depending on their size.
Electrodynamic interactions. The ionized wake, ionized hypervelocity ballistic ejecta plume, and consequent atmospheric shockwaves of a large impactor will all contain ions obviously. The ionized jet will interact with the Earth's magnetic field to create a giant magneto-hydrodynamic generator which alters the shape of the magnetosphere and converts the jet's kinetic energy into thermal energy in the ionosphere.
This will destroy the ozone layer and disrupt the Van Allen belts, with unknown but probably detrimental effects upon the biosystem. Atmospheric dust loading. This is the most famous consequence of an asteroid impact. Much of the ballistic ejecta plume condenses into tiny droplets which are small enough to remain suspended in the upper atmosphere for months, blocking sunlight and cooling the Earth, as well as disrupting plant photosynthesis.
It should be noted that nothing in our direct experience could prepare us for such phenomena, because some of them are a direct result of the sheer size and concentration of the effects. This limitation is due largely to their relatively insignificant yields, since many of these effects are dependent upon an extremely large release of energy in one concentrated place at one time. The cobalt bomb is an idea which dates back to the early Cold War, and which was made famous in science fiction films such as the Planet of the Apes movies.
The basic principle is that if a nuclear weapon is encased in cobalt, it will produce significant quantities of the Cobalt radioisotope, which is radioactive enough to pose a serious threat, but long-lived enough to render territory effectively uninhabitable. This was extrapolated to the "planet-killer cobalt bomb", which would supposedly render the entire Earth uninhabitable. However, the threat of the cobalt bomb is seriously exaggerated. There are limits to how much Co a single bomb can be expected to produce, and even a large number of bombs cannot produce enough cobalt to kill the world's population.
In other words, a very large number of Co bombs might render large portions of the Earth's surface uninhabitable, but that only means there would be an elevated cancer risk in those areas for many years; it does not mean that the entire population would die. A cobalt bomb does not really qualify as a planet-killer at all, but it is included here simply for the sake of discussion, and because it is so widely known.
The Shadow planet-killer is a giant spaceborn MLRS multiple-launch rocket system concealed within an energy-draining cloud. Some Babylon 5 fans claim that this cloud is composed of nano-bots, but that seems absurd. Nano-scale constructs either mechanical or biological have an extremely low "thermal capacitance", which is an engineering short-hand way of saying that their ratio of mass to surface area is extremely low, so they heat up very quickly in the presence of radiation yes, size matters.
In other words, thermal radiation which would be harmless to a conventional vehicle or even human skin would rapidly heat nanobots to the point of destruction this is why microbial life forms must encase themselves in spores or they won't even survive sunlight. The radiative output of a single megaton-class nuclear weapon would destroy all of the nanobots in a volume of space encompassing at least many tens of thousands of cubic kilometres.
Only a lunatic or a fool would build a superweapon out of a cloud of nanobots. The size of this network is unknown, but when it approaches Earth, it does not appear to be of planetary scale. However, it is widely claimed that it completely envelops an entire planet. If true, it means that the cloud must be very widely spread out in the process, since it was mostly empty space on its approach to Earth, and it had not even fully deployed yet. This would imply that there is a lot of empty space between each active missile-firing web-node when it is fully deployed.
An enveloping mesh would scale according to the inverse square law.
Therefore, if the cloud is km wide before deploying and 15, km wide afterwards, the amount of empty space between nodes should increase by a factor of 22, In other words, there should be many tens of thousands of kilometres between active missile-firing nodes in the cloud. As is all too common in science fiction, this weapon has an Achilles Heel. One of the nodes is a "control centre", and its destruction causes the destruction of the entire cloud along with all of its associated nodes.
This was how the allied fleet was able to destroy the Shadow planet-killer in "A Call to Arms". However, it had a lot of heavy guns to destroy even the heaviest warships before they could hit this point and they proved effective , so a smarter method would have been to send vast swarms of fighters into the cloud ie- overrun the defenses with sheer speed and numbers in an effort to locate the vulnerable node, and then have them act as forward artillery spotters, to relay its co-ordinates to high-powered long-range weapon platforms sitting outside the cloud.
There is some question as to the intelligence of the designers; why build a weapon which must disperse itself over such a huge area in order to accomplish the mundane task of firing missiles at it, when you could simply fire a swarm of guided missiles from a conventional starship?
To prevent escape? That seems a ridiculously convoluted way to prevent escape; why can't a fleet of ships simply blockade the world?
Why is the entire cloud controlled from a single control centre, with no redundancy? Amazingly enough, it actually has a second control centre, but it is a non-functional decoy!
Why go to the bother of constructing a second control node which looks exactly like the first one, and not give it the ability to take over in the event the first one is destroyed? The intelligence of the Shadows is questionable for other reasons as well; for example, they have been aware of a telepath vulnerability in their basic warship design for more than a thousand years telepaths can jam their warships, thus stopping them cold , yet they have done nothing whatsoever to remedy this crippling design defect.
A Whitestar under the command of a Ranger named Ericsson sent back video of a Shadow planet-killer attack, in which we could see clusters of missiles being fired from one of the misile-firing nodes. A transcript of Ericsson's report follows:.
Note the erroneous terminology; the missiles burrow ten miles below the surface, then twenty, and they're already near the "molten core? I guess they don't teach geology in Ranger school. Worse yet, he claimed that the core was "breaking up". What does it mean for a molten substance to "break up"? In any case, his sensors are probably more reliable than his interpretations of geological events, and he registers huge thermonuclear explosions of "thousands of megatons", seismic disturbances, and atmospheric ejecta, all of which are consistent with sub-surface explosions which are close enough to the surface to cause cratering and injection of matter into the atmosphere.
The electromagnetic pulse so powerful that it affected a starship in high orbit is consistent with surface breakthrough; a completely buried subsurface explosion will produce a weak electromagnetic pulse, and the pulse from a blast deep inside the mantle of the planet would be muffled by the huge quantities of ferrous material between the blast and the surface. The burrowing action of the missiles is probably intended only to increase the cratering and seismic effect of the bombardment, perhaps for the purpose of destroying underground facilities such as mines and bunkers. Sheridan observed large craters from orbit around Daltron 7, another planet victimized by the Shadow planet-killer at right, image poached from Babtech on the Net.
This is consistent with the mechanism described above. The need for cratering and surface break-through is probably why the missiles stopped short; if they continued to go deeper ie- if they had continued deep into the molten mantle , they would not produce surface cratering.
In order to keep him working at his project, a psychologist is brought in to keep him in a delusional state, thinking that she is still alive This is many times the yield of the infamous K-T extinction asteroid, which seems excessive in light of the fact that Sheridan could walk around comfortably and see without night-vision goggles on Daltron-7's surface mere days after an attack ie- sunlight was not blocked out by atmospheric dust and atmospheric heating was negligible. Added by 1 of our members. September Learn how and when to remove this template message. Could you add a 3. Ramp up the scale to 1, times the yield of Tsar Bomba , the most powerful fusion weapon ever detonated on Earth, and there's your planet killer. From: William R.
A 20 mile 32 km deep crater in surface silicates assuming hard granite requires roughly 50 gigatons , so this implies that each missile has 50, megatons of yield. This is a bit large for "thousands of megatons", but perhaps we shouldn't read too much into Ericsson's choice of words, given his confusion of geology terms.