Unless your sole reason for attacking the Earth was to keep your fighting forces in training, to justify their continued existence, or for a simple desire for combat, your time on the planet will not be spent entirely in fighting.
At some point you will have subdued or avoided all local resistance, and be free to do whatever it was that you came to Earth to do in the first place. Perhaps you will be stripping the planet of its resources, to send them back home, or to use in a war effort elsewhere. Maybe you simply need room for your expanding population, or a new home after some misfortune befell your own. Perhaps you even just want a place to visit for fun and recreation. Whatever the reasons, there are things you’ll need to think about and be prepared for.
Aside from the climate and gravity, which have already been mentioned, there are many other environmental factors that you will have to take into account when it comes to living on Earth for extended periods of time.
There are many different types of life form on the planet, some of which can prove surprisingly dangerous, whether they be tiny microbes, or large and fearsome predators. Local weather conditions and geological events must be considered when choosing sites for important facilities or landing areas.
If you are intending to stay on the Earth for a long time, for whatever reason, you will have to look at how best to take up residence, and what sort of residence will be best for you. While it is always possible to remain aboard ships in orbit, or even to land them on the surface, there is more practical value in constructing more permanent settlements.
Building cities and settlements is a complex business, as there are so many factors to consider about them, even without military concerns about security and defensibility. You must be sure the geology is stable, the temperature correct, the structure secure against landslides, earthquakes, floods, drought, and so on. The main geological and seismic issues you will face are volcanoes, earthquakes, and tsunami. There are volcanoes and seismic quakes on other planets also, so you are presumably familiar with the concept. The largest volcano in the Solar system isn’t even on Earth, actually, but on Mars. Earth, however, has many more volcanoes, some of which have been dormant or extinct for centuries, and others which are still active.
If you come from a hot and sulphurous planet, then you may feel relatively comfortable making a home away from home in one of the Earth’s volcanic areas, but otherwise they are generally best avoided when choosing locations for landing sites, planetary defensive emplacements, and large-scale military facilities. There are too many risks associated with areas prone to volcanic or seismic activity, especially near the oceans.
Many of the Earth’s volcanoes are actually to be found underwater. This is because, in general, volcanic and seismic activity is centred along the areas where the planet’s tectonic plates – the vast rafts of bedrock that form the main solid crust of the planet, floating on the more viscous lithosphere – meet. Where the edges of the plates meet, molten rock is forced upwards towards the surface, and can emerge through fissures and hollow mountains. Similarly, where these plates meet, and where other fault lines within the plates rub against each other, seismic quakes are triggered. Several of these plates meet in the middle of the Atlantic Ocean, while three of the four sides of the Pacific plate meet other plates under the Pacific Ocean. These underwater tectonic regions have formed underwater ridges of volcanoes.
Where seismic and volcanic activity takes place underwater, there is a danger of a tsunami following the original wave. This occurs when a pressure wave propagates across the ocean at high speed. When it reaches shallower coastal areas, it shortens in wavelength and vastly increases in amplitude. This will cause the water to draw back from the coast first, adding to the amplitude, i.e. the height. A massive wall of water can then hit coastal areas with enough force to smash buildings, carry ships miles inland, and kill thousands.
These areas – coastlines around the edges of the Pacific plate, are best avoided when choosing suitable locations for facilities and landing sites.
Likewise, the central plains of the United States are prone to tornadoes, while the east coast of the US, and the Caribbean islands around it, are prone to hurricanes – massive storms capable of tearing down buildings and completely changing the local geography. You will need to be careful in selecting suitable environments in which to construct settlements and facilities, which are stable and not at risk from either seismic events or extreme weather.
At the same time, you will want to build in environments that are suitable and comfortable for your species and purpose. This will be easiest if you have come from another Earth, either in the past, future, or a parallel dimension. In any of these cases you should, and no doubt will, take up residence in the same cities or regions on this Earth, as you occupy in your own Earth or time zone.
If you are adapted to a cold climate, your best option is to build in Antarctica, northern Canada or central Siberia. All of these areas are relatively stable, though areas of Canada and Siberia can warm up enough to be home to mosquitoes in the height of summer. If you want cold all year round, Antarctica is the place to go. Of the two polar caps, this southern one is more suited to the construction of cities and spaceports as it is a proper rocky continent, albeit one covered with ice. The northern cap, the Arctic, by contrast, is actually just a floating ice sheet over water, and so is less suited to large-scale building.
The Arctic is also known to be visited by human nuclear-powered submarines from time to time, which are capable of breaking their way upwards through the ice. Obviously this is a vulnerability that you should not accept quietly. The Antarctic is as far as it is possible to get from any of the main military powers on the Earth.
If you need humidity, the most suitable rain forest areas would be those in South America. These areas have the advantage of also being stretched across the southern tropic below the equator, and the tropics are the best latitudes from which to launch vehicles into orbit. If you are adapted to dry heat, any of the North American, African, or Asian desert areas will be perfect. Again, these areas are mostly stable, as is the Spanish desert.
If you are aquatic, the oceans are very welcoming, but bear those ocean floor volcanic ridges in mind. Also bear in mind that the oceans are as filled with life as the land surfaces of the Earth. Although none of the aquatic life forms native to Earth have limbs of digits capable of manipulating tools, this does not mean that there is no intelligent or sentient life there. Given the prevalence of liquid water on the surface, and its precipitation in the atmosphere, if your species is vulnerable to harm – or dissolution – by water, you should steer well clear of the planet, no matter how suitable its crop fields are as an artistic canvas.
The range of species currently occupying the Earth is incredibly diverse, although merely the latest in a long line of life forms over the planet’s four and a half billion-year history. The main types of life you will encounter there are: plants, fungi, bacteria, virii, insects, molluscs, fish, reptiles and amphibians, birds, mammals and exotic undersea creatures. All terrestrial life forms are made up of organic cells, constructed of a nucleus surrounded by protoplasm. The number of cells varies between life forms from one only, all the way up to hundreds of trillions.
Non-mobile life forms that absorb liquid and nutrients via the soil, and use sunlight to convert carbon dioxide into oxygen – plants – are eaten by most forms of life on the planet, and also depend on other life forms – often insects – as a vector for carrying spores and thus enabling reproduction. Very few plants consume animal or insect life directly, but there are a few that deliberately entrap insects or small mammals.
Plant material is used as a food source by pretty much all life on the planet – even carnivorous predators also consume plant material for certain nutrients, or to assist with digestion. Lichens and fungi are similar immobile species, though they have a different cellular construction, and do not have the male and female genders, which true plants do.
Other plant material, called wood, especially from the larger types called trees, is also useful in construction and manufacturing, and you will probably find wood useful in many ways. It is also recycled into paper, upon which documents and even books about conquering the Earth are printed. This, if nothing else, proves that plant material is of vital importance.
Some plant material is nutritious while others are poisonous. Since you will need to arrange a food supply during your stay on Earth, and importing everything is both a resource expense and a potential vulnerability to attacks that could weaken your forces (and therefore your hold on the planet), you should be sure to test all organic materials for suitability for conversion into food. Even material which is either ineffective or actually harmful in its raw form can be processed into something useful, with the application of correct research and treatment.
Insects are the most common visible form of life on the planet. Single celled bacteria may be more numerous, but they are not visible to the naked (human) eye. Insects generally are, and there are also more insect species than any other type of life on the planet.
Some fly, some crawl, some are terrifying to humans, while others are merely repulsive. The insects are, however, essentially the unseen below-stairs staff of the Earth’s biosphere, performing vital tasks in both recycling dead and decaying materials, and ensuring the spread of plant life by pollination.
Fish are aquatic animals adapted to filtering oxygen from water by means of gills that allow oxygen molecules to be absorbed into the bloodstream by osmosis. There are many species of many sizes, not with manipulative limbs. Most species are used as a food source, particularly by humanity.
There are predator species of fish in various sizes, from small piranhas to the huge great white sharks, which are capable of consuming humans and even of damaging waterborne vehicles. These creatures should be avoided.
The oceans are also home to cephalopods, tentacled creatures with multiple brains and hearts, quite unlike anything else on the planet. Some of these cephalopods are large enough and powerful enough to – according to local legend, anyway – attack and sink surface vessels such as boats and shipping. In fact the most alien creatures, compared to the standards of the human population, live in Earth’s waters, including strange single-celled creatures that congregate around lava vents in the deepest high-pressure areas, and life forms which are neither truly animal nor vegetable, but somewhere in between. Perhaps even with a bit of mineral thrown in to complete the traditional set of organic elements.
Birds are the Earth’s avian species, and in fact are direct descendants of the prior dominant species of the planet, the dinosaurs.
There are both flighted and flightless species of birds, and even a few aquatic species which ‘fly’ only underwater. This latter tendency should not be a surprise, as it is still movement in a full three dimensions, which relies on planed limbs for manoeuvring.
Birds should be no threat to an invading culture. As well as being a potential food source themselves, birds also are an egg-laying life form, rather than giving live birth, and the infertile eggs are a common food source on Earth.
Unlike the other animals on the planet, reptiles are cold-blooded, with a much lower body temperature and no internal means of regulating that temperature. They too are egg-laying creatures.
Some of the reptile species – in particular the crocodilians – have been around since the time of the dinosaurs, which had led most humans to believe that the dinosaurs were themselves reptilian. However, it has subsequently been discovered that those dinosaur species that were not made extinct at the K/T impact later evolved into birds. This suggests that the other dinosaurs were, like birds, warmblooded, and thus not reptiles. That would mean that the reptiles were always cold-blooded.
Since reptiles have been around on Earth for hundreds of millions of years in a relatively unchanged form, some believe this is a sign that aliens such as those of you now invading the Earth could quite likely be reptilian in form, if the pattern of reptile evolution is a universal norm, and there was no K/T impact on a reptile planet.
Of course, if your species is itself a form of reptilian or dinosaur life having travelled forward in time from before the K/T impact, you will already know about these species. Many humans consider reptiles to be frightening or unsettling, and this may be worth taking advantage of.
There are only 5000 mammalian species, but they are the ones that you will be most concerned with while living on Earth. The most notable mammal species is, of course, the dominant humanity, but there are many other species sharing the planet with them.
Mammals come in many different sizes, and vary between two and four-legged species. Some have been specifically husbanded by humanity as food sources – cows and pigs, for example – while others such as sheep are bred for their outer coating. There are many large predator species of mammal, but also small scavengers and rodents. Not all mammal species live on land: dolphins, seals and whales are mammals despite being aquatic.
Although the human species considers itself the dominant intelligent species on the planet, it is neither the only intelligent species nor the only one that could pose a threat to your plans for the world. Taking these issues in order, the first thing you must bear in mind is the existence of other species who may be at least as intelligent, but who simply have not evolved the physical capability to mechanically affect their environment.
On land, the apes are the closest species, genetically, to humanity, and so they naturally are close in intelligence also. There are some gorillas which have been taught to communicate with humans, and also various of the ape species are adept at using tools, and have complex social interactions, as do humans. The elephant, the largest land mammal, is also very intelligent, and has been known to display both mathematical skills and artistic talents.
In the oceans, the dolphin species is thought by local scientists to be as intelligent as humans, if not more so. They are famous for displaying empathy with not just others of their own species, but with other species that venture into the water as well. While these aquatic species are intelligent, they are unlikely to pose much of a threat to you. Even if they become hostile, they do not have the means to use weapons.
The type of threat that you will face from various other life forms on Earth is going to be in the form of attacks from predator species, and also from defensive strikes from venomous reptile and insect species.
Predator attacks are going to be the most effective, and the ones that you must guard against. The claws and fangs of the various large predators on Earth will be equally effective against any form of organic tissue, regardless of its planet of origin.
If your species is small in size – say less than one or two feet in height or length – you may find that insect and reptile species attempt to prey upon you, with the use of chemical venoms meant to paralyse or kill. If you are larger, you may still trigger defensive or territorial attacks from these kinds of creatures, even if they are not motivated by viewing you as prey.
Whether the venom from such creatures will affect you, or do so in the same way as it would affect native terrestrial creatures, is impossible to determine without study. You should certainly obtain samples for testing, and to produce antivenom if necessary.
Disease, germs, virii and bacteria are actually much more likely to be a problem if you have come from a parallel world or different time zone on the Earth itself, than if you have from a different planet elsewhere in the galaxy.
The reasons for this are due to the way that such biological agents evolve, and the way in which resistance to them works. Specifically, while some exposure to bacteria and virii can trigger the immune system to recognize them and build resistance to that strain, so the absence of exposure over generations will result in that immunity or resistance being lost, as the human DNA mutates. Also, the viral life forms themselves will also mutate in attempts to out-evolve both resistance and drug treatments.
The practical upshot of this is that if you come back in time from a future Earth, you will find that biological threats in the target era are adapted to affect humans of that era, but any such bio-agents which have been eliminated between the target era and your own will be more dangerous. With those bio-agents no longer a threat in your era, you will almost certainly have lost your resistance to them, which local humans will have due to exposure. The bio-agents, however, will more likely still be perfectly adapted to you, being human, and thus their effect will be more devastating upon your forces than upon the more resistant humans native to the target era.
Conversely, new diseases and bacteria will have evolved in your era, which are capable of affecting the people of the target era. You must be careful not to carry these back in time to the target era, as not only will they be effective against a population which has no resistance to them yet, but you will risk causing a paradox in which a pathogen from your era wipes out your own ancestors.
There is a similar danger of cross-contamination for those invaders coming from parallel worlds, though at least in their case there is no need to worry about the potential for temporal paradox.
Those of you coming to Earth from other planets will doubtless also bring assorted bacteria with you. It is believed that bacteria are capable of surviving in dormant form in space, living on asteroids and surviving meteoric impact with the Earth’s surface. In fact, the theory of panspermia suggests that microbial life is capable of originating from base chemical compounds and amino acids almost anywhere, and that comet and meteor impacts may have brought it – or at least some forms of microbial life – to Earth in both the past and the present.
This means there is already good reason to believe that alien bacteria could thrive on Earth, building its way up into life from the simplest chemical compounds. But what about the other way round?
Most people on Earth believe that the Martian invaders of whom H. G. Wells did such a good job of reporting in War of the Worlds were wiped out by native virii – specifically the common cold (a viral infection affecting the respiratory system and eyes). The popular belief is that the Martians are killed by their lack of immunity to this virus, and that therefore germ warfare would be a practical option for defending against future invasions. However, this is not actually the case.
Examining the original text shows that what attacks the Martians are in fact necrotic bacteria – the bacteria that decompose the flesh of deceased organisms. This occurs because the Martians are not recognized by terrestrial bacteria as alive, and therefore are treated as dead, and disassembled on a cellular level. They are in fact decomposed to death.
Thankfully, this is actually an unlikely event to happen to you, though it does happen even to humans, in the form of necrotizing fasciitis.
The good news is that you will probably not – if you come through space from a different planet – have to worry too much about virii, because they have spent millions of years evolving and adapting to affect terrestrial species. This is, after all, how they best survive. In fact, humanity – and the other species living on Earth – would have more to worry about from the bacteria you bring, as those bacteria are more likely to be robust basic bacteria, ready to adapt themselves to new environments and life forms, as happens in the previously-mentioned panspermia theory.
When it comes to food, it is said that there cannot be a creature on the planet that the humans do not cook and eat. If any of the foodstuffs on the planet are suitable for you, then that is an excellent advantage. If you are trying to pass as human, though, take care not to be seen eating anything that the local culture considers repulsive – such as live rodents – as this will arouse suspicion.
Discovering a food source on Earth is a task not to be undertaken lightly. It will be of vital importance, and it will also bring with it certain implications that are not at first obvious.
It is utterly vital that you test every type of organism on the planet – from the smallest bacterium to the largest cetacean – with which you are likely to come into contact. You will need to know whether any of them are pathogenic to you, and you will need to know which, if any, of them are capable of providing your species with nourishment. You will also need to know if any organism is likely to have an unexpected non-fatal effect on your forces, such as causing allergic reactions, dizziness, sensory interference, neurochemical imbalances, drunkenness, or whatever.
If your tests identify any organic material as being digestible by your species, and that your bodies will absorb nutrients from, this is not all good news. On the one hand, it does mean you do not need to import all your food supplies from home, but the cloud to that silver lining is that it means bacteria which can affect those organisms can be absorbed by you, and could kill you.
There is no reason not to use other life forms – native terrestrial ones or extraterrestrial – as helpers, or even as weapons. The concept is older even than sentient life on Earth, as mutually co-operative arrangements have lasted a long time. Obviously humans have domesticated many creatures, such as horses for transport, dogs as guards, etc, but other creatures across the planet have done it too. For example there are birds that certain large predators such as crocodilians allow to clean their teeth for them; there are remoras, which protect sharks from parasites; and many other such relationships.
You may find, therefore, that it is useful to either recruit certain humans to perform menial duties, or, if humans are simply too rebellious and unreliable, you can always train other creatures for certain duties. Aggressive predators, for example, can be trained to patrol important exclusion zones and attack intruders. Other territorial animals can be conditioned likewise, or equipped with cameras and sensors to increase security without requiring the use of more of your forces.
Longer-term but forgettable assistance from other life forms can come in the form of plants, or similar in-place life forms. Anything that has thorns or poison harmful to humans can be used as a living barrier, to help keep humans out of important areas.
In the eastern hemisphere, the preference is for alien invaders to make use of the availability of large saurian and other life forms, possibly survivors from the dinosaur era or mutations created by unwise use of nuclear power, and to use them as weapons.
Unlike the early 20th century practice of using flocks of sheep to clear paths through minefields and other booby-trapped areas, the use of these so-called kaiju is more like unleashing a weapon – the kaiju in question can be used to destroy large areas of cities, either by controlling their brains remotely, or simply relying on their tendency to do so when on land anyway. If you can find examples of such beasts, they are most useful for distracting human military forces, prior to your main attack.
Given the interstellar distances involved, and therefore the time and expenditure of resources necessary to transport troops and officials, it actually makes more sense under certain circumstances for you to set up a client state on Earth, than to rule it by force of numbers.
Under the client state model, you would offer the local populace self-determination and the freedom to carry on as they have done, subject to your approval of leaders and of policies that would affect your objectives. For example, you would appoint a planetary governor from your forces, with suitable enforcement units and military backup, who would oversee that the correct local leaders were chosen, and that the resources you require are shipped back home. This approach has worked for thousands of years on Earth.
Alternatively, you can consider making alliances with existing Earth authorities. This is an especially useful approach if you have a preference for hands-off rule, have difficulty understanding humanity and life on Earth, or do not have the military power available to be projected effectively on Earth. Since you will doubtless have technology, if nothing else, that is desired by humans, you can forge an alliance for mutual benefit, or at least the appearance of such, by exchanging a few such technological trinkets for the kind of co-operation you require.
Such alliances can be genuine, or you can use them as delaying tactics while you conduct reconnaissance of the planet and study its defences or move your forces into position. You can use an alliance with humans to lull them into a false sense of security by pretending to be friendly visitors, and thus sow the groundwork for confusion that will inhibit the effectiveness of resistance later. For example, you can do this by offering medical advances, or enfolding certain preferred groups within your alliance while shunning others; divide and conquer is classic strategy for a reason.
Why did you come to Earth? Nobody embarks on a distant military campaign for no reason at all. Just because you have conquered the Earth doesn’t mean your work is over. Quite the opposite, in fact.
If you came to mine the Earth’s resources, you will need to be able to make use of them once you have mined them. At the very least you will need to be able to ship those resources back to your homeworld, or to wherever they are going to be put to use.
If you came by wormhole, dimensional portal, matter transmission, or time portal, you shouldn’t have any difficulty in transporting you booty back home. Just as the planet’s current owners transport their resources by ship and ground vehicle, you should be able to do the same, and simply pass containers on through the wormhole, or beam them to wherever they need to go.
Sending the materials to a different planet through space is a different matter. You can bring in ships to carry it off, but the more material you try to launch, the more fuel your ships will require, which makes them heavier still, and every load is another chance for something to go wrong with a valuable ship. Therefore you would be better off using a mass driver capable of accelerating cargo to the Earth’s escape velocity. Rather than repeat the mistake of the Centauri, who wasted such devices on bombarding a planet, you would use it for its intended purpose, launching compacted raw materials of whatever kind into space.
You wouldn’t be able to shoot the materials all the way home, because the payloads wouldn’t be able to be accelerated to faster-than-light velocities – and even if you did, that’d just mean you’d essentially fired a giant gun at your home – but you could certainly put shipments of cargo easily into orbit. There, your transport ships can scoop them up and take them to whichever planet they need to go to, or indeed just process the materials in the microgravity of space and make whatever products from them that are required, without any deformations caused by a planetary gravity.
The same principle applies to anything you want to launch from Earth – foodstuffs, plant material, anything.
The best place to construct such a mass driver would be on the western slope of Mount Chimborazo in Ecuador, at the north end of the Andes mountain range. This is not the highest mountain on Earth – that would be Everest in the Himalayas, of course – but because the planet bulges slightly in the middle, Chimborazo is about a mile and a half closer to orbit. The western slope should be chosen because the Earth spins west-to-east, and so launching towards the east always imparts an extra flick of velocity.
Of course, major mining operations will require more than one mass driver, but this should set the pattern: building them on the western slopes of mountains in the equatorial band bordered above and below by the tropics.
Oddly enough, this is one of those situations in which completely destroying the Earth is actually feasible. It just would take a very long time. In fact, removing a million tons from the Earth every second would completely remove the Earth from existence in 186,015,123 years, if the effect of having a large percentage of its mass didn’t result in the force of its rotation tearing the rest apart in half that time. Interestingly, humanity itself already has the technology to do this if they really wanted to, so it would be a far simpler matter for a more advanced invader.
Removing the Earth’s core while retaining the rest of the planet’s surface, as seen attempted twice by the Daleks, is, sadly, not physically possible. This means that it won’t be possible for you to remove the core and replace it with a power unit in order to drive the planet around, no matter how attractive the idea is.
One issue with it would be how big an engine you would need to pilot the Earth, and what type of engine – where would the exhaust for the thrust emerge, and what would it do to the atmosphere in the process. Not to mention the fact that the core of the Earth is nearly three thousand miles across, which is a lot of space to be filled.
The bigger problem with any attempt to eject ‘the molten core of the Earth’ through any sort of mineshaft or excavation is that the actual inner core, at the very centre of the planet, isn’t molten. Instead it is a ball of solid nickel-iron some 1,560 miles across. The molten core is a layer 1,400 miles thick wrapped around that. Even if you could draw out this magma, you’d still be left with the solid inner core rattling around inside.
There’s really no excuse for the Daleks to have not known this, as the solid core was originally discovered by humanity in 1936, when seismologist Inge Lehmann calculated it from the propagation of seismic waves recorded during earthquakes. That said, study of the temperatures of the Earth has shown that the inner core has been cooling to its current temperature of 5430C since the planet formed four and a half billion years ago. At some point in the past the entire core of the Earth has been molten, but as it has cooled from the inside out, the solid inner core has been growing.
This may show the value of remembering that if you are studying the Earth from a great distance away, the conditions there will have changed by the time you arrive.
There are many ways of ruling a conquered territory, whether directly, by taking up residence and being in charge on a permanent basis, or more remotely, by issuing orders from a central throneworld and leaving it up to individual planetary governors to decide how to get the best out of their charge. As with so many other things, how you rule the Earth will depend on your motives for conquering it, your numbers in the vicinity, and your attitudes to your own culture and society in comparison to others.
Regardless of these factors, some things are going to be necessary no matter what. One is that you must establish that you are in charge. You do not have to rule by fear and terror, but even if you are magnanimous in victory and magnificent in your benevolence and granting of freedoms, you must ensure that the population understands that it is your decision to make it so.
If you choose to rule the Earth by fear, holding it in an iron fist (or claw, or tentacle, etc), you must be sure that the population fear and respect you. If you threaten violence for transgressions, you must follow through on that threat, or you will be perceived as weak. Your decisions must be understood to be decisions, not suggestions or requests. The disadvantage to ruling by fear is that it will tend to provoke resentment, and that will lead to resistance and rebellion.
Conversely, if you allow the Earth to carry on as it did before, with a self-determining population, you may run the risk of that populace returning to conflict among themselves, which will get in the way of your plans.
The golden rule for ruling however is this: don’t flip-flop. If you want to rule by fear, rule by fear. If you want to rule benevolently, rule benevolently. However else you wish to rule, rule that way, but most of all be consistent. Consistency will carry you further than wisdom or military power on Earth, simply because human societies prefer the maintenance of a status quo.
One important information resource with which you must familiarize yourself, of course, is the legendary ‘Evil Overlord List’, which contains many practical tips for being the evil (or otherwise) overlord of a planet.
Did you come to expand your empire or replace your homeworld? If so, then bringing your own population to the Earth is a necessity. Whether or not to do something about the native population is up to you. If there are very many of you, or you have slightly different environmental or climate requirements which will necessitate changes to the Earth, then you will have to look at eliminating or moving humanity.
If you are happy to share the planet, then you will probably have to make sure that the local population know who’s in charge, and accepts that the superior newcomers have the edge. Note that even if you have no intention of declaring superiority, or have laws about not interfering with the natural development of native species, this will occur anyway. Historically, no contact between a technologically superior society and a technologically inferior one has resulted in anything other than the inferior society being absorbed into the superior one, and changed by it.
Depending on how rough the conditions on Earth are, there is a chance that your own forces or population might feel disinclined to remain there, especially if there is an easy way to return home. You may consider disabling your own ships to ensure that your colonists have to remain and make the colony work. Make no mistake; however superior your technology, setting up a viable colony on Earth will be hard work, requiring the building of suitable cities, systems put in place to ensure that edible food is available for your species, and so on.
‘Terraforming’ may be necessary in order to make the Earth completely suitable for your population, but please note that if you came to radically change the place, you’d have been better off consulting the chapter on destroying all humans, since keeping them around will cause you endless trouble later.
Strictly speaking, you can’t actually ‘terraform’ the Earth, since the word means to make something like the Earth. Which the Earth, of course, already is. You can still alter the planet’s environment and geology, but the phrase for doing this to the Earth itself is ‘Geoengineering’, or you could call it planetary environmental engineering. Of course your forces will be more likely to refer to the process as ‘forming’.
The concept is known on Earth, having been originated by the astronomer Carl Sagan, in 1961, though he originally called the process ‘planetary engineering’. His original suggestion was that Venus be seeded with blue algae, to facilitate the conversion of water, carbon dioxide and nitrogen into organic compounds. (Do not be tempted to try this on your way to Earth – Sagan had the idea before it was discovered that the clouds of Venus are mostly composed of sulphuric acid, which would destroy such algae. In 1973 he revised his suggestion to engineer Mars instead, and the space agency NASA held a study on this, though they called it ‘planetary ecosynthesis’.)
The word ‘terraforming’ itself was coined in 1982 by Christopher McKay of the British Interplanetary Society, in a paper discussing, again, Mars.
Note that if your requirements for a planetary colony require a mostly carbon dioxide atmosphere, with either acid rain and much greater surface temperatures than on Earth, or a thinner and colder atmosphere, you would be better off simply colonizing Venus or Mars, respectively. Those planets would be more suited to your needs for less resource expenditure, and have the advantage of not being occupied by a species who will resist you. As far as anyone knows, anyway.
Likewise, if you are going to terraform the Earth, you should have wiped out the surface life with an asteroid bombardment first. If you’re making major changes to the biosphere, the native life will be killed in the process anyway, and this way you can start with a clean slate, without having to worry about sabotage or interference.
Believe it or not, there are several contexts in which it is possible to take up a necessary or desired position on Earth without having to expend the time, effort, or energy in conquering it.
In most of these cases, making alliances with native factions will be perfectly serviceable, and you can always betray them by launching a proper attack later if you so desire. In some other cases, conquest would simply be non-applicable, or even counter-productive.
As well as making alliances, it may be less resource-intensive to trade with the native humans for what you want, or even to actually make friends with them.
Establishing a military garrison on the planet may be necessary, if you’re looking to prevent activity by other civilizations in the vicinity. It may not, however, be necessary to conquer the Earth in order to establish a garrison there. In fact, it may not even be desirable to do so. This is one of those situations in which simply making peaceful overtures to terrestrial authorities may well achieve the result you want: permission to establish a garrison.
This is because, since humans are already quite preconditioned to accept the idea of hostile forces among the stars, it should be a relatively simple matter to establish that your enemies are bent on the conquest of the Earth. With careful manipulation of the collective psyche it should even be possible to persuade human forces to form the bulk of your garrison, risking their lives under your guidance so that your forces don’t have to. Aside from negating the need to conquer the Earth, this also has the advantage of sparing your forces for more important duties elsewhere.
It’s always possible that you came to Earth in order to escape some persecution, warfare, or other threat elsewhere. In this instance, you may find it more useful to simply ask the local populace for help, or at least to manipulate them into getting what you want, rather than causing yourself more trouble. This is especially the case if you have no means of returning home or moving on, or if your equipment is limited by your situation. Also, if you’re looking to hide, then conquest is very conspicuous, and so likely counterproductive.
Think instead about setting up an Alien Nation in the US, or living in District 9 in South Africa…
On second thought, don’t do either of those things. You didn’t come to Earth to be viewed as inferior either. Your best course of action if you are seeking sanctuary or political asylum on Earth is to work with some appropriate shadowy government cabal or agency – or better still, several, in different nations, so that you can spread your population over a wider area, and move on as and when one agency betrays you – who will make sure you are covertly re-homed on Earth, usually in return for technology or scientific and mathematical formulae.
Be warned, though, that some such agencies have been reported as willing to abduct and conduct medical experiments on aliens, rather than waiting for you to do it to them.
Those of you who have parental interest in Earth may decide to make yourselves known in order to avert disaster or improve humanity’s attitudes and morals. In many ways this is just as arrogant as the invaders who feel themselves superior to non-spacefaring civilizations, as it implies that you have a right to judge other species, and determine their worth.
Deciding that unworthy species should be improved and uplifted rather than destroyed is certainly a more reassuring option, but it still smacks of what humans call the ‘nanny state’.
Though arrogant, this can be achieved by negotiation as well as direct conquest. The benevolent nanny state society can still invade and conquer the Earth for its own good, but you will find that humanity is more receptive to your teachings if you instead offer rewards for learning the right lessons. This approach also works for slavers and military recruiters, of course.
You do not need to be entirely selfless to take this approach, of course. You could well be concerned about turning humanity away from an aggressive expansionist path before it gets too much of a foothold in space.
Another far more practical reason for uplifting humanity is if you have become stranded, and require a superior level of technology to be attained in order for you to repair your ship or otherwise complete preparations for your return home.
It is possible that you are a non-sentient creature of some kind, and that your arrival on Earth was by pure chance, perhaps carried by an unsuspecting sentient traveller. If this is the case, your whole objective in life will be to survive and possibly reproduce.
Since if you’re not sentient you won’t be reading this, there is very little advice that can be given, other than to watch out for hunters, either human or otherwise. Certainly you will have no need to conquer the Earth in order to roam wildly, and nor would you ever conceive of doing so anyway.
For what it’s worth, general advice for such a species would be to make sure to find a suitable location in which to create a nest or den, because hunting is a popular pastime in most regions of Earth.
On Earth, the human race often refers to itself as the most dangerous game, in the context of big game hunting, or hunting animals for sport. If such hunting is a part of your society’s life, then it may be worth considering using the Earth for this purpose.
The wide range of terrain and environments make for a good choice of types of chase. Although human bodies are relatively flimsy, you may always find, or even breed and train, specimens who will give the most satisfying chase, or prove to be worthy opponents in physical combat to test their mettle.
If you are going to engage in blood sports on Earth, you will not necessarily need to conquer the planet in order to do so. There are enough remote areas of all kinds for you to conduct hunts without being disturbed by human authorities in most cases, though you will have to ensure that your prey do not bring others into the game. You may even be able to gain permission for such hunts with the collusion of terrestrial governments, who may be willing to give you their enemies or criminals for the purpose.
You also will not need to conquer the Earth if you simply want to blow off some steam by having some raucous fun, blowing stuff up, recreational fighting (Glasgow has been good for this sort of weekend off for aliens since Victorian times), and so on.
So long as the native authorities and militaries do not have the ability to seriously harm your holidaymakers and their activities, it doesn’t matter whether they know about you or not. You can simply carry on enjoying yourself in whatever way takes your fancy.
There is so much to see and do on Earth that you could simply enjoy yourself for years, with every whim catered for, and nothing to stop you. Visiting the Earth simply to see the sights, insult the natives, play pranks on them by strutting up and down making ‘beep beep’ noises, or destroy things that don’t matter to you for the sheer joy of it, are all perfectly valid reasons for going.
Why shouldn’t the Earth be a vacation spot? It has many beautiful sights. If you want to sample the sights, the food, the sports, or just to have whatever your society considers to be a good time, there really is no need to mount an expensive and complex military campaign.
Well, it does happen from time to time that visitors to the planet are either so taken with the lifestyle of humanity that they decide to join in, or are stuck for so long that they assimilate into a human lifestyle by exposure over time becoming habit-forming.
This is far more likely to happen to visitors who have crashed, been exiled, or otherwise ended up living on Earth for extended periods not by choice. This, logically, will happen to individuals rather than societies. And so conquering the Earth would be neither practical nor desirable. By doing so, the adopted native will be denying their preferred status.
If you find yourself in this situation, probably by trying to blend in at first, you can try seeking help from government agents with suburban families or interested amateurs.