The Question of a New Species From Space

I have touched on this topic before but I really think I need to revisit it again as I recently heard the reason for it again.

Cheap Astronomy (a really great podcast and website) has a frequent section called Ask Cheap Astronomy, where you can ask a question and they will answer it. In their Ask Cheap Astronomy # 9 they were asked a question about humans traveling in space.

Dear Cheap Astronomy – If a human crew left Earth to explore the galaxy and their
descendants returned to Earth 100,000 years later, could they still be considered human?

I am going to provide a link to their answer rather than the whole thing since I don’t technically have permission to post it, but I can point you to their website so you can read it. So here is their answer and here is the answer in the original audio format.

I want to make 2 things perfectly clear before I go forward.

      1. Their answer is technically correct.
      2. I really like most everything cheap astronomy does and so this is not meant to detract from that but rather to add to it.

Cheap Astronomy (In short) suggests that while genetic drift would likely not be enough after only 100,000 years that we would have a new species but that maybe after floating around for 100,000 years the “human” beanbags with arms that came back would likely not want to mate with the bi-pedal monstrosities here on Earth and vise versa.

They seem to have been couching their response in such a way that the answer they gave Rene would be, “yes.” They did touch on things like genetic drift and selective evolution through “survival of the fittest,” but also mentioned that in human communities those things tend to not be a factor. See their answer for more details on why that is true. They also assumed that during this 100,000 year journey the occupants of the space ship would experience little or no gravity and so would “evolve” to adapt to that environment.

As I said, their answer is technically correct. What I think it lacks is a dose of reality.

Let’s Tackle Gravity First

Gravity is a force acting equally on two masses that lessens with distance but never really stops.

Thanks to Wiki for this explanation

Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them:
F = G \frac{m_1 m_2}{r^2}\ ,

F is the force between the masses,
G is the gravitational constant,
m1 is the first mass,
m2 is the second mass, and
r is the distance between the centers of the masses.

Understanding that the micro gravity that Astronauts encounter while orbiting the Earth is do to free fall. They are technically falling toward Earth. The same is true of people moving around in space. They are more or less falling toward something.

So as they moved away from the Earth, and the Sun and Jupiter and eventually everything in our solar system the gravity they would feel would keep getting less. But there are some other things to think about.

We have to assume (again injecting some reality into the situation) that our voyagers are going somewhere, even if that is just a grand tour of all the local interstellar space around us. (100,000 years is a pretty long time, just not genetically speaking.) if they ever hoped to make “landfall” on a planet or other body with gravity they would have to made some provisions. Even if they were just planning on such a journey and planned to come back and wanted to be able to mix with the human race again or even land on Earth, they would have had to make some plans to make that possible if for no other reason than they listened to this cautionary tale on w w w dot Cheap Astro dot com.

While things like Star Trek style gravity plating and inertial dampers have not yet been invented there are some pretty easy ways to have a space traveler experience forces that mimic gravity. Building a round space ship that spins as it travels through space. Getting the most out of your fuel and causing the least amount of stress on what would necessarily be a large ship (more on that later) by constant acceleration, also would provide for some force to be exerted on the inhabitants of this ship.

There are reasons for wanting this other than just being able to mate with humans when you get back. Without gravity, or some force that mimics it, there are no showers. Things like free flowing water would have to be severely limited if allowed at all. Foods that produce crumbs of any kind. Cooking, and baking, things that would have to happen, would have to be completely modified without gravity otherwise, everything made on this space ship would have to be microwaved. Even people who profusely sweat when they work out would cause problems with floating blobs of sweat. There are so many processes that we take for granted here in a gravity well on Earth and problems that the inhabitants of the ISS just have to deal with, because they are only there for a short time that it would be impossible to do without on such a long journey. So gravity, or a force like gravity, would be necessary to make living on such a ship for such a long time possible. Not to mention that we don’t even know if human reproduction is possible in micro gravity. There are things that millions of years of evolution have prepared our bodies for, that might not work in micro gravity, and it would be a terrible shame to have a ship go out for 100,000 years only to come back with the dusty remains of the first generation who were never able to reproduce properly.

Even if they had gravity, it would likely not be full Earth gravity so likely if nothing else the people might be very tall when they come back.

Speaking of reproduction

This is going to have to be a large ship, I mean huge. Not world sized or even moon sized but it is going to have to be big. But likely not big enough that it’s gravity would have any appreciable effect on the inhabitants. There are a couple of reasons for this. The first has to do with reproduction.

What does it have to do with reproduction you ask? Well, there are some factors that the folks who plan this trip are going to need to think about. If you are going to start a colony, any colony be that a space faring one or one on a tropical island you are going to need to make sure that your future generations don’t suffer from things like founders effect.

Founders effect is – the reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors.

What this means is that if the planners of the expedition to the stars are not trying to become another species through genetic shift, and want the best chance that in 5 or 10 generations odd mutations won’t start showing up, they will need to have a large enough population to have the genetic depth to prevent that from happening.

What about disease or mutation? We have been talking up to this point about natural genetic drift, but what if the people on the colony ship got involved with genetics. While it might be the case that they carefully screen everyone on the ship for genetic diseases and are very careful about making sure no one was sick before they got on board, there is always a chance that something got on board. Legionaries disease for example. Or what if there was some accident on the ship that wiped out a large portion of the population so that they no longer had the genetic depth to make normal breeding practices a viable option. Or there might be any number of reasons why on a colony ship that social and societal morays on genetic engineering on the human species would become acceptable. They would not even have to go as far as the gene splicing mad scientist, and simply encourage mating among individuals that had certain characteristics in order to make humans better suited to their environment.

Ship Size

As I said this would have to be a large ship to accommodate all those people, their food supply, their waste recycling systems, power systems and drive systems. Remember that solar power is not going to be an option for more than the first couple of years, until they are out beyond Jupiter, at which point the solar panels would have to be so big to collect the power needed that they would likely be bigger than the ship. A ship this size is going to require a large power system and an even larger drive system to keep it powered up and moving along. All things that would contribute to over all size of the ship, and make large typical rocket looking designs impractical. Another thing to consider this ship is going to need to be able to accommodate two to three times as many people as they started out with. The first generation is going to need to have offspring and then there is going to be the general ebb and flow of population growth that will naturally occur, unless strict rules are in place and followed.

Future Improvements or the Question of Communicating with Earth

There is the question that if a ship was going to travel out for 100,000 years would they want to keep in contact with Earth. There are a couple of reasons why they might not want to, like maybe they are fugitives or maybe they are trying to escape from all the problems of Earth and so don’t want anything to do with them for the next 100,000 years. However, I think that the benefits of staying in contact with the home world would out weight any reason for not staying in contact.

This is another topic that Cheap Astronomy has already touched on but I want to add my two cents in here but I highly encourage you to go check out their episodes. There was a discussion about if you had two species flying toward each other. One stayed static (very long lives) and didn’t contact their home world, and one that was short lived (like us) and stayed in contact despite the difficulties. (longer and longer time lag.) When they met which one would be better prepared? The answer in short is the one that stayed in contact. The reason is that even if you grouped the greatest minds on the planet on the ship in hopes that they would come up with brilliant ideas on the way, they are still only a few hundred or even a thousand people, verses a few billion here on Earth. While they might be the most brilliant minds of their time eventually they will die. While it is true that likely their offspring will be bright, there will be billions of people on Earth who will also have bright children who also come up with great ideas that they can share with the people on the ship, and there are just some things that you can’t do while traveling through space, because you don’t have the “space.” (Think the large Hadron Collider.)

Then there is technological shift. Look around you. Find all of the things that are 100 years old, 500 years old, now 1000 years old. I am willing to bet that you don’t find that many. While 100,000 years is not a long time genetically speaking it is a long time technologically and linguistically speaking. Just to give some perspective, The computers on the Apollo landers could have all been replaced (probably pretty easily) with my iPod. The computer that I am writing this on would have been considered magic only 100 years ago. Less than 500 years ago Christopher Columbus sailed across the ocean from Spain to find India. 1000 years ago was still considered the middle ages in Europe. 2000 years ago Cesar and his legions were conquering the “world.” 5000 years ago Egypt was just starting to develop as a kingdom and men were learning to use bronze instead of stone for tools. Imagine the technological progress that will be made in 100,000 years. A small colony would not have a hope of being able to keep up with what we did here on Earth. And even if they were able to keep up with it, without communication, they would very quickly diverge from what we have done and their technology would end up being extremely different than ours.

Back to the subject of looking around you. How many objects around you do you see that are more than 10 years old, how about 100? Not too many. It is very likely that within a few generations the colony ship would have to be replaced or at least modified to keep it from falling apart. They would need to update their ship. The technological updates from Earth on how to make better power supplies, stronger ships, faster engines would be invaluable. It is not too hard to imagine that in two or three generations that someone hear on Earth would come up with something like Star Trek style gravity plating or inertial dampers. Sharing those with the colony ship would allow them to build different style ships, and maybe even smaller and less power consuming ships.

Linguistically there are only a few people in the world that can understand languages from a few thousand years ago, and none of them that would be able to speak them in a way that people who used them would be able to understand. For this reason, keeping a line of communication open between Earth and our travelers would be of vast importance. Imagine them coming back to Earth and having to spend another generation trying to figure out how to speak to us. Or worse they come back to Earth. The People of Earth have forgotten about them. They can’t communicate with us and so we blow them out of the sky instead of taking the risk that they are someone here to conquer us. (This is the stuff Scifi is made of.)

Before 5000 years ago we have few records because while we believe languages abounded, written languages were just being developed, and the medium they were recorded on has not lasted all that long. Imagine the jumps in language and culture that will happen over the next 100,000 years. Even if they kept records so that they could try to communicate with Earth do you really think the floppy disk that the colonists loaded all their data on will still be around and working 100,000 years from now?

How ’bout Those Fast Engines or How Long Have They Been Gone Again?

Again while we have not developed warp engines and there is some doubt that they could ever be developed there is no doubt fast engines would give them the best chance of being able to see some of the other stars and get back in the next 100,000 years. But the nearer they traveled to light speed the more they (or we depending on your point of view) would suffer from relativistic effects. So the question becomes who is counting the 100,000 years. If they are traveling at some large fraction of the speed of light, and they are counting to 100,000 it might be very much longer for us here on Earth. If we are counting then it might be much shorter for them. It could be possible that they only travel for 1000 years in their measurement and come back what would seem to us like 100,000 years.

Summing it all up

While Rene’s question was about them being a different species there are a lot of other questions to consider when answering this one question. I have only scratched the surface. Would they be a different species? Well given a perfect environment maybe not. Would we recognize them when they came back? That is a different question entirely. And how would things have changed while they were gone? I think an even better question would be would they want to come back, or would there be an Earth for them to come back to. But those are the subject of Sci/Fi and not Cheap Astronomy.

Thank you to Cheap Astronomy for giving me such a wonderful mind stretching concept to talk about.


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