We Will Destroy Your Planet (5 page)

The most well known (to the dominant native life form) extinction event is the so-called K/T impact at the changeover between the Cretaceous and Tertiary geological eras, 65 million years ago. (No, Cretaceous doesn't start with a K, despite the acronym.) This event wiped out around 70% of all species, of all types and forms of life, extant at the time. The most destructive extinction event in the planetary history was 251 million years ago, when the Permian–Triassic extinction eliminated a massive 95% of the species on the planet.

The K/T impact is thought by many of Earth's scientists to have been caused by an 8-mile wide (some say 6 miles, others 9) asteroid 65 million years ago, and left a crater 110 miles wide at what is Chicxulub, in the Yucatan Peninsula. Other scientists believe a structure called the Shiva crater, off the east coast of India, indicates a much larger impact, which could have caused this mass extinction. (The Shiva crater is 370 miles by 250, suggesting an impactor 25 miles wide. It's possible that both impacts could have resulted from the break-up of a single larger body.)

Not all Earth's scientists agree that either of these was responsible for the extinction of the dinosaurs. Some believe that other factors, such as volcanic activity, climate change, or simple overpopulation leading to an inadequacy of food supplies were as much responsible. There is also much debate over whether the Shiva crater is in fact an impact crater, or a product of natural geomorphology.

In any case, the use of such large impactors proves not to be as reliable as one might expect, when it comes to genocide. Altogether, 25% of species did survive (including the likes of sharks, crocodilians, Coelacanths, and so on), and none of them had constructed reinforced underground bunkers, which some humans have done over the years as protection in the event of nuclear war.

If the goal is to wipe out all terrestrial species, it would be more effective to alter the chemical makeup of the atmosphere and oceans, rendering them inimical to carbon-based life. This too may leave a certain amount of survivors, however, as there are various smaller single-cell life forms the likes of which are capable of surviving even in such altered circumstances. For example, there are water bears, and organisms that live around the vents of so-called ‘black smokers' deep under the ocean, at crushing pressures and high temperatures.

No such creatures are sophisticated or likely to offer resistance to invasion, of course, but there is always the theoretical chance that they could evolve to threaten you at some future date. And it's frustrating to be unable to complete a set.

To put this into perspective, 99.9% of all the species that have ever existed in Earth's history are now extinct, and yet there are still literally millions of species, from sentient space travellers to single-celled virii, and from avian species that soar in the skies, to strange multi-cellular creatures that can only live in the areas around ocean-bottom vents that leak heat from the Earth's core. Life on the planet is tenacious in the extreme, and some of it always survives somewhere, no matter what the extinction event.

It would, therefore, be something of a challenge to destroy absolutely all life on the planet, as anything guaranteed to do so – and this would have to be on the order of a massive solar event, such as the Sun swelling into a red giant, and burning the planet to the extent of the sea and atmosphere burning off into space – would be likely to render the structure of the planet unsuitable for the acquisition of resources. If such a planet was ideal for your purposes, you perhaps would have been better off finding a world in such a position to begin with, rather than expending the energy required to have the Earth reach such a state.

Biological warfare would be a much better option, especially if the goal is merely to wipe out humanity and leave the rest of the biosphere intact for use and exploitation. A biological pathogen could be engineered to be inimical to the human species, and other species you want rid of, without harming yourself. Pathogens that would affect humanity are unlikely to affect any invading species, and vice-versa. Humanity has, of course, made it easier to spread a suitably lethal pandemic globally, by instituting a global transport network of pressurized aerial vehicles.

There would undoubtedly be survivors in isolated areas – even with a long-lasting airborne pathogen, the weather patterns of the winds could allow areas of the planet to remain uncontaminated – so you would then have to hunt down and eliminate them, by whatever means.

It is theoretically possible that a virus genetically engineered to be inimical to all carbon-based life forms could eventually accomplish the task, but the likelihood of those pockets of life existing out of contact with each other make it unlikely that true 100% infection could ever be achieved.

The extent of life remaining might well be reduced to something as simple as single-celled organisms, or non-sentient creatures existing in the depths of the oceans, but they would still be there as a symbol of your failure, and may have the potential to evolve into something more threatening later. They would also, of course, be far harder to track down, and detect and eliminate, than groups of large mammals. That being said, it would still be your best way of trying for the complete extinction of life.

If wiping out the dominant species, humanity, will suffice for your purposes, then matters become far more practicable. There are many good reasons for taking out the dominant species on Earth before you invade, but the most important one is to prevent the danger of active resistance. There is a simple way of almost certainly wiping out humanity and so guaranteeing total lack of resistance while you carry out your chosen operations on the planet.

That way has already been touched upon in earlier sections: the use of large natural impactors against the planetary surface. Or, to put it another way, asteroid bombardment. The use of asteroid bombardment will guarantee not just large-scale elimination of population centres, but also changes to the climate of the planet, rendering it uninhabitable by humans. Changing the atmosphere and climate can also be achieved by planetary engineering, or terraforming, as it's called on Earth, but that is a technique more useful for long-term planning than as warfare, and will be addressed in the chapter on ‘
Living On Earth
'.

Having mentioned asteroid impacts, it's time to look at meteor bombardment as a general tactic in assaulting the planet. Bear in mind that even if you don't intend to destroy the Earth or to wipe out humanity, it is still necessary to eliminate local surface defences prior to invasion, and meteor bombardment is an excellent tactic for this.

The golden rule with this form of warfare is to make sure not to use unnecessary excess energy in delivering these natural warheads to their targets. Such adaptation of natural weaponry has been used in a few dramas over the years.

Where the forces depicted in these dramas have tended to go wrong is in using technology such as mass drivers – using arrays of magnetic linear accelerators to accelerate a metallic mass such as an iron-dense asteroid – to launch chunks of space rock at target planets. For example, in the TV series
Babylon 5
, the Centauri use mass drivers built into their capital warships to pummel the planet Narn with meteors, turning the whole globe into a ruined dustbowl.

This proved three things: 1) space superiority is effective in besieging a planet from orbit; 2) bombardment with meteors really will do plenty of damage to a planet's biosphere, and 3) the Centauri are idiots with more money (or resources) than sense.

Why are they idiots? Because they had no need to build ships that use a (probably quite high) percentage of their power to accelerate lumps of rock, so long as the target planet has a gravity well. As all planets do.

The mass driver isn't that new an idea; they were first thought of as a weapon by Robert A. Heinlein in his 1966 novel
The Moon is a Harsh Mistress
. In the book, the population of a Lunar mining colony wants to secede from being ruled by the authorities on Earth, and, as part of their campaign, use a linear accelerate built in the vicinity of the Mare Undarum to launch rocks at cities on Earth.

What seems to have been forgotten by later thinkers on the matter of meteoric bombardment is that the Loonies (as the rebels are referred to in the book) need to accelerate their rocky payloads to the Moon's escape velocity (5,400 miles per hour) in order to get them off the Moon and heading towards Earth. A rock already placed into the gravity well may need a nudge to get it on course to impact with a particular point on the surface, but it won't need anything like the amount of energy required to impart an escape velocity from a decent-sized body.

From the Centauri point of view in
Babylon 5
, conducting a general bombardment of the surface as a whole, giving the rock a good shove out the airlock, would have done the job.

Also, because of the simple fact of Newtonian physics – every reaction has an equal but opposite reaction – a spacecraft-mounted mass driver would actually function better as an engine than as a weapon. It is, after all, exactly how rockets work. There's a gorgeous visual image used in the title sequences of the later
Babylon 5
seasons showing one of the main characters standing at a window, in which is reflected the image of rocks being launched from his ship's mass drivers. Sadly, it does not show the ship suddenly tumbling backwards away from us, which is what should actually have happened next.

In short, do not try using ship-mounted mass drivers to launch your asteroid bombardment. Let gravity do the work; it's cheaper, easier, and more effective.

This approach is more rarely seen in drama and literature, but is not entirely unknown. Oddly, one of the best examples is in the otherwise comedic film
Iron Sky
, which is about a group of escaped Nazis who have been hiding out in a Lunar base for decades, who then return to try conquering the Earth. At one point their flying saucers are seen to tow big rocks to release into the Earth's gravity well while the ships themselves peel away. This is, in fact, the far more sensible and energy-efficient way to do it.

If merely thinning out the surviving populace will suffice for your purposes, you should take note that disease will be rife among most of the animal species after the asteroid bombardment, whether you help it along by introducing suitable pathogens or not.

The large numbers of unburied dead and lack of food and clean water resulting after such a disaster will mean harmful bacteria will spread like wildfire through the surviving population. This is well worth exploiting, so long as you have no need of strong captives, as it will further lessen the likelihood and ability of any resistance to your arrival and your plans. Alternatively, you can always pose as benefactors, curing the pandemic, in the hope of gaining human trust. This may be a worthwhile tactic if you are relatively few in number and require an amount of goodwill and help from the population.

It goes without saying, of course, that if you are coming to Earth by means other than starships, then asteroid bombardment will not be an available option. Also, if you are coming from a parallel Earth or from a different period in the planet's history, and are human yourself, then using a global pandemic as an option is definitely not a wise course of action, due to the risk of some of your forces carrying the pathogen back to your time/dimension and wiping out that population also. At the very least, you will have to make sure all your own populace is inoculated against the chosen disease.

In that instance, your best option for wiping out the native population may simply be to gain access to the Earth's national nuclear launch codes, and trigger a global nuclear war. You will have to wait some considerable time afterwards, however, for the radiation levels to settle to a point at which you can safely move in and begin full operations or settlement.

Most hostile extraterrestrial interest in the Earth will be in the form of planned invasion and takeover, though the base motive behind that intention will, of course, vary. Whether it's a desire for living space, the planet's chemical resources, strategic position, livestock, or just because it's fun to conquer a planet and gives your military something to do, there are a number of things you must do correctly.

Before embarking on any military campaign, you must gather information. The successful interplanetary conqueror will always be the one who has gathered every possible piece of knowledge and calculated every possible eventuality. Conquests are made in the research and planning stage, not in the running around screaming ‘it's game over, man,' stage. It's admittedly a truism that no battle plan ever survives first contact with the enemy, but this is why you must be prepared with alternate plans in advance.

Even on Earth, the wisdom holds true that the warrior who knows both the enemy and themselves will always win; the warrior who knows themselves but not the enemy will win and lose equally; and the warrior who knows neither really ought to give up and get a civilian day job.

So, knowing your enemy – in this case human society – is an absolute must. If you are coming from a parallel world, you may already know much of what you need, but not everything; there will always be differences, and even if not, you'll still be dealing with other nations, whose strategy and tactics are secret to you even in your own identical world. If you're coming from the past, you will have records and histories, but these are written by the victors, and usually with a political slant, so may be unreliable. It will always be better to infiltrate and investigate yourself – and at least you will have the advantage of being able to pass for a local with authority.

If you're an extraterrestrial coming by a means – such as a wormhole or matter-transmission beam – that will have you arrive directly on the surface, you will also have to do your research by means of either electronic intelligence gathering (tapping data and communications) or infiltration. If you are unable to infiltrate by stealth, you can always try controlling authorized humans by means of telepathy or even simple bribery. Use of robots and drones is also advised, especially if they can be camouflaged as humans or as other acceptable Earth species that will not arouse suspicion.