Science plotholes in a book I am writing

[ChrisShield]

Hi all,

I'm new here. I was looking for a science-related forum as I have some questions I want to raise regarding plot holes in a fantasy/sci-fi novel I am writing.

I wasn't certain which sub-forum to post in but since the questions most important to me are biological in nature, I thought here was a good place to start.

I have a planet colonised by humans in my novel. There is also a human outpost on the planet's moon, but due to a galaxy-wide cataclysm (not decided on the specifics) civilisation almost collapsed, and now the two colonies have not made contact for around 5000 years.

Fast forward time in the book and those on the planet eventually have the capacity to visit those on the moon. This is where I get stuck:

 

1) Would the inhabitants of both worlds be incredibly susceptible to diseases/bacteria etc that the other brings along? Such as when European colonisers came into contact with American natives. Would things like the common cold on one world kill people on the other as they have no immunity?

2) How much would change in 5000 years in terms of evolution and human behaviour? I'm presuming the answer to this one is not much as I'm not sure if 5000 years is enough for any real anatomical change, but I'm by no means an expert.

3) My novel is set something like 10,000 years in the future of our world time. This question I guess is similar to question two: In 10,000 years will we have changed much as a species?

 

This one isn't as 'biological' as the others but I've put it here anyway as I had four questions, apologies if this isn't allowed!

4) How much would language have changed? Both colonies spoke the same language (we will say English for arguments sake). Would they be able to communicate with one another after 5000 years? Looking at old English from the middle ages, I'm gonna say not without a sci-fi related translator machine for this one.

 

Thankyou!

[swansont]

21 minutes ago, ChrisShield said:

 

I have a planet colonised by humans in my novel. There is also a human outpost on the planet's moon, but due to a galaxy-wide cataclysm (not decided on the specifics) civilisation almost collapsed, and now the two colonies have not made contact for around 5000 years.

Fast forward time in the book and those on the planet eventually have the capacity to visit those on the moon. This is where I get stuck:

 

1) Would the inhabitants of both worlds be incredibly susceptible to diseases/bacteria etc that the other brings along? Such as when European colonisers came into contact with American natives. Would things like the common cold on one world kill people on the other as they have no immunity?

2) How much would change in 5000 years in terms of evolution and human behaviour? I'm presuming the answer to this one is not much as I'm not sure if 5000 years is enough for any real anatomical change, but I'm by no means an expert.

3) My novel is set something like 10,000 years in the future of our world time. This question I guess is similar to question two: In 10,000 years will we have changed much as a species?

 

This one isn't as 'biological' as the others but I've put it here anyway as I had four questions, apologies if this isn't allowed!

4) How much would language have changed? Both colonies spoke the same language (we will say English for arguments sake). Would they be able to communicate with one another after 5000 years? Looking at old English from the middle ages, I'm gonna say not without a sci-fi related translator machine for this one.

 

Thankyou!

All of these can probably be looked at with an historical lens. Humans from 5k years ago and isolated from other populations show, at most, minor physical differences. They were around different animal species, and so different diseases, so they would likely be susceptible to each others’ diseases. Just like “old world” and “new world” populations. Language would also have diverged. 

[Phi for All]

If they haven't been able to communicate at all in 5000 years, they probably wouldn't be able to understand each other now. This could be an interesting plot point, because now they both have to go back through their records to find a common tongue (circa, I don't know, early 21st century Earth?).

The power of evolution in fiction is creating some kind of pressure that would cause a certain trait to be selected for that you, as the author, want the humans to have. One group has webbed fingers and toes because the cataclysm forced the population into the oceans hundreds of generations ago, for instance. 

Behavior, again, is something you can influence as the writer. Have something occur that causes a population to behave predominantly in a certain way, and you can "imagineer" the kind of society you need for your story. 

Even for hard science-fiction, if you give us a reasonable scenario to explain why people are the way they are, several hundred generations of changes in allele frequency and some cataclysmic selective pressures can create a not-insignificantly changed population.

[Area54]

32 minutes ago, ChrisShield said:

2) How much would change in 5000 years in terms of evolution and human behaviour? I'm presuming the answer to this one is not much as I'm not sure if 5000 years is enough for any real anatomical change, but I'm by no means an expert.

Given that you have specified a planet and its moon, rather than a double planet system, there is likely to be a significant difference in the gravity between the two. Presumably your moon is considerably larger than ours, else no atmosphere would have been retained (not to mention plate tectonics and geodynamos either having shut down or never started). Even so one would expect adaptation to a lower gravity. That will place the moonites (for want of a better name) at a distinct physical disadvantage if they are on the planet.

 Although as @swansonthas pointed out there are unlikely to be gross physical changes, there may still be significant ones. Thus the natives of Tibet and of the high Andes have both evolved characteristics that make it easier for them to tolerate the low oxygen pressure at those altitudes. Or consider the sickle cell anemia of some Africans that can cause debilitating disease, yet provides major protection against malaria. Expect something of the kind to have occurred in 5000 years.

However, even larger changes may occur if either sets of natives employ gene modification. Then the field is wide open. (If that provides an unecessary side issue just have the technology lost during whatever disaster led to the separation.)

In terms of changes in human behaviour just take a look at the diversity of lifestyle, attitudes, beliefs etc across the planet today. Does 5000 years bring an increase in diversity, or do we all wind up working at Mcdonalds?

[studiot]

Just now, Area54 said:

Given that you have specified a planet and its moon, rather than a double planet system, there is likely to be a significant difference in the gravity between the two.

Oi! I was just about to write that  +1

@ChrisShield

FYI our moon's gravity is only 16.6% of Earths.

I would think that 5k years would be enough for lunar inhabitants to have diverged biologically in the lower gravity.

Also our moon keeps one side towards the Earth so its day and night are 14 earth days/nights long.

 

Plenty of scope in the imagination in variations of those two facts to play with.

[ChrisShield]

I should have added that the moon settlement will have Earth-like gravity like the planet does (sci-fi reasons, probably an artificial grav field like ships in star wars). But the other points added are very helpful!

The main reason for this post is that I want to have as little difference between the two groups as possible (as I'm more interesting in the story than trying to explain to the reader that they aren't speaking the same language, or have to recieve loads of immunisation jabs etc). The less divergence within the (sort of) realms of science, the better.

 

Edited March 26, 2021 by ChrisShield