This is a plot point in The Accidental Time Machine: https://www.goodreads.com/book/show/21608.The_Accidental_Time_Machine; the main character
spoiler
jumps forward into the future a bunch of times, longer jumps each time, and hits a time where the human population is almost gone, and they’re like “yeah, the fucking time travelers keep showing up and bringing old diseases”:::
Also The Witcher
A similar argument could be made for making first contact with an alien species. There’s a decent chance one or both species carries some form of microscopic life that the other has no defenses against, assuming both species can even survive in the environment necessary for the other.
Not only will starship captains and crew not be able to have sex with the hot aliens they meet, “they have an nitrogen/oxygen atmosphere” won’t mean the away team can land without environmental isolation suits. Planets with oxygen in their atmospheres might be the most dangerous ones out there for us.
I personally trust humanity that we will work out a way to have sex with something we shouldn’t rather quickly. Our horniest scientiest and our brightest perverts will find a way, even if it’s at great personal cost.
Read “scientities”
Yeah, it is probably going to be one of the top 5 reasons to join a starship crew, so life will probably, ah, find a way. For all we know, NASA might even have a focus group working on this already.
BUT that doesn’t mean it won’t lead to the extinction of one or both species involved.
I think chirality is something most people overlook in those situations too. Even if you found a world of beings exactly like you, a perfect earth with plants and low CO2 concentrations, if their proteins have opposite chirality to yours, you’re probably going to die of prion disease.
“Oh look a perfectly human person on an earth like planet I’m sure I can take my helmet off”. Nope. You just inhaled spores or skin cells or pollen or viruses or literally anything that contains “misfolded proteins” and if any of those get at all digested they could cause your body to produce more misfolded proteins, a cycle that will eventually lead to your demise.
“Look this plant isn’t poisonous” chirality is harder to check than chemical makeup. So yeah it has vitamin B but is it the kind that could kill you? (We don’t have to worry about this much on earth because basically all life on this planet makes and uses proteins of similar chirality)
“Wow that alien sex was great” too bad there were skin cells in saliva you both exchanged/ingested (or proteins in other bodily fluids) so you’re both going to die now.
Worst part is that prions are really slow acting. You could all be chilling in this wonderful earth like home for months until around the same time you all suddenly get sick and die. There’s no cure, so there’s nothing you can do besides leave a warning for the next crew who might stop by.
Oh and the same dangers go for native life on the planet too. To them you’re made of misfolded proteins so any scavengers who eat you and maybe even predators who eat them have a chance of developing and spreading prion disease. Your bodies are basically bioweapons. Any earth crops or animals you brought with would be biohazards too.
Prion diseases are not as simple as coming into contact with a protein composed of D-amino acids.
While it’s still not fully known, it’s generally one specific type of protein PrP^C that gets transformed by PrP^Sc, converting the C to Sc, and so on.
D-amino acids also occur naturally on earth.
As for B vitamins, none include proteins as far as I remember, they’re all small(ish) molecules like biotin and folate. Also having a difference in stereochemistry with most of these vitamins, wouldn’t cause toxicity.
Obviously there are some cases of small stereochemical changes being toxic (thalidomide). But generally small changes won’t automatically make something toxic.
Prions wouldn’t work like that. They would have to be very similar, and the same chirality, as our own proteins, or else the misfold would not self-replicate like prion diseases do.
There’s a decent chance one or both species carries some form of microscopic life that the other has no defenses against
I’d argue there’s essentially zero change we’d be biologically similar enough for any microbes to bridge the gap. It’s a big deal when microbes jump species here on earth
That’s the result of a balance between different microbes and their own defensive measures. Entirely novel microbes and biological functions could overwhelm all of that. Hell, if they have just evolved a next level ATP, they could have access to an order of magnitude more energy than our microbes and bodies can use, in which case we’d probably have no chance unless it doesn’t recognize us as food.
It’s not guaranteed to happen, but with 0 data about alternate evolution trees, any reasoning about the odds is speculation (including my use of “decent chance”).
Edit: This would be the case for viruses. Unless they work very differently or our biochemistry has some convergent evolutions, alien viruses should be harmless to us and vice versa. Just like the hundreds of viruses we are exposed to with every breath, most don’t react to our cells any differently from how they’d react to wet rocks.
To be less hypothetical and more scary: Think about all the ancient pathogens that are dormant in the permafrost. Those could become a real problem when it starts to thaw because of global warming.
There was already an outbreak of thousand year old Anthrax from thawed animal corpses in Siberia several years ago.
The TV show Fortitude has a similar plotline. Would recommend!
Or any smallpox samples sitting in the back of an old lab, like the ones they found in 2014. Or the smallpox samples that the US and Russian governments keep
as WMDsfor research purposes.
Travelling forward in time could also kill everyone… Our adaptive immune systems are developed somatically and purifying selection is nonzero in humans.
Now that I think of it, if you can teleport or time travel and only you go but not the things on you (as is the case with pickier stories)… losing your clothes would be the least of your worries if the countless organisms didn’t also go with you on the trip.
Goodbye, gut biome!
Sounds like philosophy of identity. What is you? Is only things with your DNA you? Will a bunch of dead hair, skin cells, and nails teleport with you? Are the things inside your body you? Is only your brain you and it will get transplanted into a new body in the future?
what about water in your cells? checking out the pyramids being built and showing up as a mummy? maybe tying time travel to biology is a bad idea
The Ship of Timeus
You time travel and are suddenly both very hungry and a little more bald, haha.
The time traveler’s diarrhea
Oh shit, is that why nobody attended the 2009 Time Travelers party? No one wanted to be the person who killed the great Steven Hawking
They knew waaaay more than the rest of us did at the time, you don’t wanna get MeToo’d for a party you went to 100 years ago, do you?
Yes but NOT traveling back in time to cause the black plague results in all kinds of worse timeline shenanigans.
There’s a few of these
I think the biggest one for me is quite how much support Hitler apparently had in the Anglosphere before the wars.
Assuming he managed to grow that support without war, I have a feeling we would have potentially had a very fascist 50s across the world instead of the era of progressive politics we actually got. Then whatever inevitable revolution or nuclear winter that followed a couple of decades later, would leave the world looking very different to today.
Warp drive will really fuck up a lot of civilizations.
This is in part why we have the Prime Directive.
That thing that gets routinely ignored by every starship captain ever?
Butterfly effect is a fever dream. A world-wide epidemic and you returning back in time to a different planet is a very very likely scenario.
We’re all traveling forwards through time.
That must be the origin of Covid, it explains why they can’t find where it actually came from.
Schrodinger’s epidemic
This is addressed in The Rise And Fall of DODO. There’s a whole decontamination quarantine period for time travelers.
I’ve felt this would be similar for generation ships. If our civilizations get met up again, everyone would probably die.
Glove and Boots did a fantastic take on this very concept. https://youtu.be/75nBenOWul0?si=4lTY2at2aHtaqN-F&t=144
Miss those guys…
