How to explain why humans weren’t encountered by alien species? [closed]

Question

So, I’ve been writing a sci-fi novel that takes place a few centuries in the future. In the novels lore, it says that there was plenty of life throughout the galaxy, but humans were just contacted infrequently. Every other pre type-1 species in the galaxy (or most) had encountered alien life. Alien life was seen as true fact, and not conspiracies. But I’m still having problems with this. How could humans become more isolated than most other species plausibly, and without to much handwaving?

• FTL Travel has been in use by many species for 700,000 years, so ancient humans were in that timeframe

Answer 1

Okay so this is the best image I can find of where we actually are in the galaxy:

If most of the life in our galaxy evolved in the core and spread to the two "main" arms of the spiral (the Scutum-Centaurus and the Perseus) then there wouldn't be a lot of point looking at the relatively few stars of the Orion Spur where we have evolved. In fact to a species-centric way of thinking there's no reason to think that life, let alone civilisation, could evolve in such an impoverished setting with neighbouring stars so few and far away.

Answer 2

The sun and the surrounding stars were explored before the raise of earth's civilization, during some ice age or during the aftermath of the Toba catastrophe, when a bottleneck in human population made us hard to find. (Update 1: by 70,000 years ago, humans already wore clothes, and had tools and fire, and possibly a language, all of which could likely grab scientist attention, that's why I find the hard to find part important.) They found lots of ice and some life, took some samples for scientific purposes and left.

Besides, the sun's neighborhood happens to be of very little interest, with few habitable planets, not worth colonizing or harvesting/exploiting due to the long distance from the relevant civilizations. You can easily have hundreds of civilizations in the Milky Way and leave some 300 light years around us devoid of advanced life forms.

This isolation would help you partly with the explanation of Fermi's paradox (from the Earth's POV) and could also be the excuse that made our neighborhood an easy target for interstellar treaties of natural reservation, pretty much like the Antarctic Treaty: Once you go galactic, you have to start caring for natural star and planet conservation too.

Update 2: You said without too much handwaving. Someone could argue this still needs some: 700,000 years is a lot of time for people from elsewhere in the galaxy to become curious. Scientists will from time to time become interested in this little-explored corner.

An argument could be made (if you need such a level of detail) that 1) political affairs have not been always too favorable to scientists, 2) there has been lots of other interesting places to explore when possible, 3) chance has made almost every visit to Earth concur with the harshest conditions of the Current Ice Age (see figure below) and/or the Toba catastrophe, 4) you say humans were contacted infrequently, maybe there were a few episodes in these 700,000 years, but only by people who chose to actively keep the existence of humans secret or at a very low profile.

1. In 700,000 years you could see the raise and fall of civilization after civilization, with periods when the Galaxy strives alternating with intermediate periods of war, local humanitarian crises (even the death of a star!) or reasons to make societies less interested in science, like some form of spiritual blossom.

2. Even in relatively normal circumstances, scientists and funding are scarce—this can possibly be true also in a scenario with swarms of robots, advanced IA and stuff—and need priorities. Intelligent beings from hundreds of civilizations from tens of thousands of stars still have hundreds of billions of stars/planetary systems to explore. Unless your lore includes a technological singularity (which is optional, and somewhat boring) the targets of the most thorough exploration will either be chosen from the closest first, or in the best case at random (if travel had absolutely no costs, which I personally think is unrealistic). FTL travel does not need to be cheap.

3. We are currently undergoing an ice age, but inside that ice age, we are in a warm sub-period. There is plenty of times during the last 400,000 years that temperatures have been 7 degrees Celsius less than today, arguably meaning less interesting climates. Most of the time it has been 4 degrees below present temperatures (see figure.) Although during this time the Earth was never completely covered by ice, a big enough ice cap could make an occasional observer with knowledge of lots of habitable worlds go "meh! Been there done that."

^{Timeline of temperature during the Current/Quaternary Ice Age. Source: NOAA/Wikipedia}

4. You can still allow for some visitors intending to protect Earth's civilization from alien influence. They can study it, know about the existence of men, but keeping it for themselves while making it low profile for others as uninteresting, or highlighting other qualitites/other nearby places (like the curious case of Janus and Epimetheus, the two satellites of Saturn that periodically exchange orbits.

Answer 3

I'm going to give you the Star Trek inspired explanation as an actual answer, perhaps you find value in it:

One ancient alien race seeded all the other races in the galaxy because they encountered no intelligent life anywhere and felt quite lonely. They since disappeared for whatever reason. Of course they didn't spread their seed equally over the galaxy but well, within their sphere of influence. This happened to be the opposite site of the galaxy from Earth, at least far away enough.

Since then, many intelligent species emerged there over the eons. However, in the unseeded part of the galaxy, on Earth, intelligent life evolved by chance, just as it did with the ancient seeding race all those millions or even billions of years ago.

So Earth is new intelligent life, randomly evolved, while the rest of the intelligent life in the galaxy is there by design.

You can also explain more things like that. For example, the other species realized what the ancient aliens did and didn't look elsewhere in the galaxy because they knew that there was nothing seeded in our part of the galaxy. Or they just encountered no life for longe distance and never bothered to search further.

Btw, you don't need one precursor species that seeded all, you could also do a chain reaction kind of thing. Newly evolved species seeded more species.

As has been pointed out via comment by Pinion Minion: This seeding I'm talking about is one specific example for uplifting. This would also work in other variants, you could have one ancient alien race uplift other creatures with other methods. The advantage of the seeding idea is that your species don't have to be aware of it and the seeder race could be long gone, it would also explain technological differences and so on, but many variations of the idea are thinkable.

Answer 4

This is going to be a bit of a grim answer, but a common justification for this in sci-fi is that humans are either the most violent species in the galaxy, or the only violent species in the galaxy.

We are generally not a peaceful species. We kill each other for money, or sport, or even just for being different. We have been this way for thousands of years, probably ever since we evolved, and our methods of killing have only gotten smarter and more brutal over time. We discover new technologies and our first thought is invariably how we can turn them into weapons (even here on WorldBuilding).

If aliens could watch our TV broadcasts, they'd see hundreds of depictions of them as evil invaders, hell-bent on destroying or subverting our civilisation. They'd see hundreds of glorifying depictions of heroic, muscle-bound warriors, slaughtering their enemies by the dozen. They'd see how we use "alien lizardmen" as some kind of scare-mongering conspiracy to disparage those we hate.

It's easy to assume that all aliens are as prone to violence as us, but it's also just as easy to assume that none of them are. It's entirely plausible that Earth is the galactic equivalent of that one neighbourhood that everyone knows not to go near, because if you do, you'll end up getting robbed or stabbed. Or both.

Answer 5

Make the aliens' thinking biased.

So there are lots of alien life in the universe. They must be sharing something, be it cultural, biological, or even religious, that humans do not have. Imagine if all of your alien species, from all their differents systems, always had two brains. From their point of view, anything with one brain (or less) isn't even considered as sentient. They may aknowledge our very existence, but tagged us as "Primitive - do not bother worry about it".

Then we develop interstellar travel and all of their minds are blowing since for them, it would be like ants having learnt to build spaceships.

Another way to put it would be how they consider a planet suitable for life: "Wow, a planet with a gravity of 9,807 m/s²? Nothing can live there! No need to lose a probe for that!". Atmosphere, temperature, gravity... anything that rings your bell for your story.

And what if humans had contact in the past?

The alien scientist who came here before may have filled reports, maybe some of them have considered us sentients enough to be a part of their... intergalactic Federation, or anything equivalent.

But these reports were dismissed. Either forgotten in the mass of administrative documents, or set aside by some neglectful alien scientist, or worse, because "Humans are not relevant".

"One brain, really? Psssh!"

Humans are f****** terrifying!

Your question reminds me of a short story I read months ago, about an abducted human who is lost in the administrative process of an intergalactic civilisation - unfortunately I can't remember the name of it. At one point, the station is attacked by an arachnid-like creature that can dismember any alien there. But the human isn't even bothered and shred the arachnid to pieces like a doll. And the others aliens are now scared that humans as a species are introduced into their universe. The story has more than that, but for your story it could be enough:

• Humans produce a combat drug when in stress,
• Humans eat organs of other species to gain strenght,
• It is said among the wise ones that if a human bites you, you can turn into a human yourself when the moon is full,

etc.

So maybe the aliens are aware of humans. They just don't want them to run everywhere like kids with scissors.

Answer 6

For one reason or another, Earth and its star have been marked as "explored and nothing is there". Since there are 100 billion more interesting, more well known places, for hundreds of thousands of years nobody has bothered to check on Earth again.

---

Remember the Nordic colonies in North America, such as New Sweden or Vinland? Have you ever tried sailing for the mythical islands of Antillia or Thule yourself? When's the last time you heard of anyone searching for the legendary cities of El Dorado or Iram of the Pillars?

Perhaps contact was briefly made with humans, but knowledge of humanity was buried under some greatly more important galactic event. Perhaps a couple exploration teams perished after searching a few stars, but their search was marked 'complete' in databases passed on throughout the ages. Perhaps fantastical tales have been told of lost planets like Earth for generations, but nobody takes such tales seriously enough to think Earth might actually have life.

Regardless of why, after a hundred billion stars were explored, one was bound to slip through the cracks. Earth is just a tiny island in a vast sea, and everyone thinks somebody else already landed on it.

Answer 7

Do we really want to make contact with meat?

According to a 1990 Omni article, Aliens don't attempt to make contact with humans because "They're made out of meat". The short story is a great read.

Similarly, due to our location, the galactic version of Google Maps routes everything around us. The lack of traffic also causes limited (or no) review on the galactic version of "Yelp!". (We also have a Bermuda Triangle reputation thanks to Area 51, etc).

The extinction of Dinosaurs has also caused the galactic version of "Field & Stream" to cease the series "Big Game on Planet Earth".

The galatic version of Wikipedia might have a decent write up. But, the more popular cousin, "The Hitchhiker's Guide to the Galaxy", only has the simplistic entry of "harmless" or "mostly harmless" (depending on updated revision).

If there was a Prime Directive, that galactic government would probably have a "no contact" ban on us until we get pulled over by the FTL Highway Patrol for not obeying local traffic laws.

Finally, according to Ancient Aliens, we are a genetic experiment. Most likely, we are an experiment that went wrong and was sanitized with a world wide flood. The area is still considered to be contaminated. The cops will bust us hard for claiming we are from a contaminated region of space.

As far as aliens detecting our radio signals from SETI, those are ignored. Citizens of the galaxy don't use light based communications to send an email to their grandmother on Omicron-Persi-8

Answer 8

Lets go Uplift for a moment.

Every sentient race in the known Five Galaxies was raised (uplifted) to sentience by another race. The most prestigious and well respected intelligences in the Five Galaxies can trace their lineage back to the Progenetors (and of course, the fewest generations between your race and the Progenetors, the better). This process has been going on for two billion years. A species raised to intelligence by its parent species serves a period of servitude, usually a few hundred thousand years, not that long, really.

Then Earth and Humans come along, having uplifted themselves. And not only that, they've already uplifted chimps and dolphins! Why do they get the status that comes with being an patron race without serving a period as an client race first!? The scandal!

Of course, how did Earth go without notice? Everyone wants to know...

Well, as every species in the Five Galaxies knows, inhabiting a planet and harvesting its resources and building cities there causes ecological harm to the planet, reducing its biodiversity. But in order to continue the chain of Uplift and having new and wonderous species to find, raise, Uplift and nurture...planets have to go fallow for a while, let the planet recover. Destroy all the buildings, toss it all in the ocean trenches for recycling...Come back in a few hundred million years and open it up for settlement again.

And it's a crime of the highest order to cause a species to go extinct intentionally. Surely you've heard about the Bururalli. They were given their first planet, which they proceeded to exterminate every last higher lifeform on the surface and went feral. Their parent species, the Nahalli, were made clients again for having failed to teach their client species properly.

How did Earth go without notice?

Well, it was fallow.

There was not supposed to be any contact to avoid violating the intergalactic rules regarding a planet's fallow status!

Answer 9

There's a lot of great answers here, but I'd like to offer one which is so subtle it might not even be interesting: random chance.

Consider the case where contact with aliens is not something that is organized in some galactic consul which makes sure all planets are accessed equally. Make it be more random. Perhaps planets get visited when it was convenient, such as when a shipping run brings you close by.

There's a fascinating story about such statistics. A teacher was teaching about statistical distributions. He gave the students a homework assignment: flip a coin 500 times, and record H or T for each one. The next day, he gathered the assignments in class, and to everyone's surprise, he graded them immediately. He started announcing whether each student cheated (by writing random letters without flipping the coin) or did the exercise properly, within a few seconds of looking at the paper. When he was done, he had divided the classes papers into two neat piles. He then asked them if anyone felt they had been graded improperly. Nobody raised their hands. He then asked if anyone knew how he did it.

When nobody raised their hands again, he explained his technique. He simply looked for 7 H in a row or 7 T in a row. If that was there, he assumed the student did it properly. If there were not, he assumed that the student cheated. We, as people, tend to assume highly unlikely events actually occur less often than they should. Sever heads or tails in a row should occur once every 128 draws, so between the two, you should expect it to occur in 500 draws at least once in the majority of cases. However, seven in a row feels "too lucky" to the human mind. We think it starts to look suspicious. Thus, none of the students who cheated let such long strings appear in their paper. They injected a H or a T to break up the streak, to make it look more random.

We could simply be nothing more than the statistically unlucky draw. We could be the one civilization that just didn't happen to get visited all that much.

Such an answer is amusing to me because that story of the teacher could appear in the novel itself, teaching people something about statistics. It also means that, when we do finally have contact (and I presume we do), the greater galactic civilization is going to have reason to treat us as an oddity. We're the statistical oddity that just got left out, and is now running to catch up.

It all depends on what story you want to write, but I find the story of humans trying to catch up to fluke accidents says a great deal about the human condition.

Answer 10

The aliens are water creatures, they looked for intelligent life forms in the depth of the oceans. Clearly they didn't find many humans, there. Not alive, at least.

They sometimes found rests of ships, which they took as remnants of a lost civilization.

Answer 11

700,000 years is not very long. It may very well be that other life forms just hasn't gotten around visiting Earth yet. And for that, there can be many reasons.

For instance, other lifeforms just may not have that much interest in visiting other worlds. They may not go exploring for the sake of exploring -- perhaps they only venture out to other worlds when they need to.

Or they have have the interest, but find it way too expensive. Or they find Earth just too far away (if you go many times the speed of light, in space, things are just very, very far away).

On the other hand, while on a galactic scale, 700,000 years isn't that long, it is long for humans. If aliens had visited Earth 20,000 years ago, how would we know? Even if they had had contact with humans; writing wasn't invented, and it may easily have gotten lost in oral tradition (after all, who would believe the person who says (s)he's visited by green men coming from a flying saucer, specially before saucers were invented?).

Answer 12

Multiple causes

TIME: Specifically the time where we as humans could be contacted and could record such contact. The universe is a very big place and civilizations rise and fall. In Billions of years of the existence of the universe, we have only been able to even reliably record history for about 2,000 years. Any race to contact us would have to be capable of contacting us during this windown, which compared to the age of the universe is a very tiny one. Some alien civilizations visited when the earth was still a molten ball, not even begun to cool, They come back a billion years later, then find nothing worth noting. But now their civilization is beginning to ebb, either through disease or playing with forces they did not fully understand, they go extinct.

INTEREST Some alien races are just not interested in exploring as humanity is, and are content to look no further than their own immediate interests. Perhaps they also think that they are alone, or are so advanced that all other species are of no concern. To them it would be like us trying to communicate with bacteria. Nobody would bother which brings me to:

INABILITY The life could be so alien to us that we may not even be able to perceive them. They may exist only partially in our universe, or be energy based. Their methods of communication are not only incomprehensible, but unperceivable to us.

BAD PAST EXPERIENCES WITH OTHER RACES Perhaps they had been in a long, drawn out war with a brutal race. This alien species, while having won the war and exterminated their enemy did at great cost. They do not want to go through anything like that again, so they have become xenophobic and cloak their existence from the rest of the universe.

BAD PAST EXPERIENCES WITH US It could be that initial scouts were sent to earth and were brutally murdered or just didn't like what they saw. They have quarantined this planet as dangerous and stand just outside our detection, waiting to act if we get too far out of line.

Answer 13

The planet was found by an alien civilization, however this civilization does not have radio signals invented, leaving their only method of communication as direct physical transfers.

However this civilization's technology, for one reason or another, does not have the capacity to enter an atmosphere this rough. (Maybe they're a civilization that has always existed on a planet without an atmosphere, or a very weak one)

So in short, they know it's there, but they can't talk to it.

Answer 14

TLDR: They don't want to influence our evolution

What does two civilization that encounter themselves do? they interact. By trading technologies or doing war, by studying the opposite culture...

We would make a huge technology leap, our culture would change a lot, in short, our society would evovle and enter a new era.

Even if they didn't offer us technologies, we would know space travel and alien are a thing.

However, if aliens have some advantages to contact us (yeah, more people will by our insert random alien thing to sell), they also have an advantage to not contact us: see how a society evolve without any help.

Yep, we are more or less an anthropological experiment. We where not put on earth by alien on purpose, but they deliberately avoid any contact to analyse how fast we evolve, and if we will be able to contact them by ourself.

Answer 15

This answer depends on what aliens you use, but they could use a finicky classification system when it comes to intelligent life. For example, if the dominant species are eusocial (have multiple sexes) or reproduce asexually, maybe they simply wouldn't consider humans anymore sapient than we consider tool-using birds sapient. Its very arrogant, but it would mean they have no reason to socialize with us as long as we stay on Earth.

Alternatively, you could so say that Earth and the local group has already be claimed by a very territorial alien species. This species wouldn't be interested in interfering with humans either because Earth doesn't have any resources you couldn't get elsewhere for cheaper. Maybe they don't want any interaction with Earthlings because they are worried it would forces changes in their culture, so they ignore the human problem until humans leave Earth themselves. In the meantime, the territorial species discourages all the other aliens from going to Earth. Maybe once humans make first contact, the whole galaxy gets pissed at the humans "landlords" for never doing anything. Could make for a fun backstory, I don't know.

Answer 16

We are in the waiting line to be contacted, you could always assume the galaxy is extremely populated, but only one or two species have got so far as to be able to travel faster than light. The ships are rare and there are millions of planets calling out for a visit and each one needs scanning and observing and processing before being allowed into the club.

we are just waiting for our turn without even knowing

Answer 17

Simple: Humans are just a backwards species that is far more violent and short-sighted than their alien brothers. A culture that puts people in giant stadiums and makes them fight to the death? Too violent, let's wait a bit before contact... A culture of xenophobia that murders entire groups of people and calls it their "final solution"? Too dangerous. A culture that treats their entire planet as a waste disposal plant? I guess the humans really don't improve. Let's see what the future holds!

Answer 18

Man (AKA Homo Sapiens) is the most violent animal on this planet. I suspect that the dark side of the moon has a large warning sign (or transmission device) to warn intelligent species that there is nothing of value on the adjacent planet.

Perhaps a few thousand years in the future, assuming mankind has not eliminated itself and that the radioactive debris reaches acceptable levels, something might get curious as to what was here.

In fact, I am quite surprised that I am alive today as I never expected to live past middle age due to what would have been called World War III. I worked in industry in some interesting places, including within the program office for the development of the Poseidon submarine launched ballistic missile. I reported directly to the Chief of Weapon Systems Effectiveness.

It is fortunate that Russia was sufficiently intelligent to recognize that World War III would not be of benefit. I do not have that degree of confidence when I look at some countries that currently exist in the Middle East and Asia.

Answer 19

Only about 0.0000000000000000000042 percent of the universe contains any matter. We are only a very, very small fraction of that and on top of that, we are also in a fairly sparse region albeit the Milky Way and Andromeda are beacons seen many light years away.

So, it is as it happens that we were just not stumbled upon. Our inhabited planet was not marked on any galactic maps. We are lonely of visitors.

Answer 20

Faster-than-light doesn't work here

For some reason, the usual faster-than-light travel devices don't work in (and some light-years around) our solar system. Due to this, none of the spacefaring species discover us here.

In Beyond the Impossible, this is caused by a device from some ancient civilization (older than the current rulers of the Galaxy) hidden on Earth, but it could also be some natural anomaly.

Answer 21

They did

They did. Millennias ago an ancient species, the First, discovered the solar system and built bases on Earth, Mars and Phaeton.

Proof

Some architectural wonders like the pyramids of Giza or Machu Picchu are remnants of their presence. Look it up, there are many sceptics around the current explanations of the construction and use of these ancient sites. I can recommend YouTube channel Bright Insight, whose host questions a lot but does not throw in wild theories like others do. Should provide a lot of inspiration that fits nicely into our storyline. Why the bases on other planets? Earth itself proved to be inhospitable to the species itself because of temperature, atmosphere or seasonal climate changes - make something up, I'm not going into the Firsts' physiology and biology - so they settled on Mars to provide food and shelter for the scientists and collected minerals and metals from the resource rich Phaeton.

The Homo Sapiens project

Discovering various primitive Homo species they started genetic alterations of the most promising species trying to create a simple, yet effective race to act as soldiers, which resulted in the creation of Homo Sapiens. There were many issues of the soldiers' obstinacy, denying orders, going rampant killing other soldiers, birth issues (humans are pretty much the only species with such a high stillbirth rate and danger of the mother dying in the process) and various other health problems. An explanation to our hostility.

Galactic war

The Homo Sapiens project has still been in the process when another rivalling species, the Second, declared war on the First and in the process drove the solar system into a battlefield, destroying Phaeton altogether ripping it apart into small chunks forming the asteroid belt between Jupiter and Mars, stripping Mars of its atmosphere casting it into the lifeless planet it is today and causing destruction to the bases on Earth.

Forgotten history

Few humans were able to evade the destruction and remained undetected by the galactic fleets that were busy fighting each other and over millenias the history of the First cast them into gods, changing the actual events into our current religions. The biblical myth of the great flood - one of the Seconds' superweapons - still lives on today (other religions have told this story before in different ways, like the ancient Sumerian belief) that was part of the devastating destruction.

Neither the First nor the Second ever returned, with the destruction of Mars and Phaeton driving the Solar System due to its distance and empty neighbourhood into irrelevance and the Homo Sapiens project being cancelled due to the high amount of investment with highly problematic and seemingly unsolvable physical and mental issues. There was no reason to return.