this post was submitted on 13 Nov 2024
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[–] Etterra@lemmy.world 7 points 3 hours ago

Yeah but I thought about this I realized that whenever somebody vanished from the snap it would leave behind a slurry of gut microbes and a (different looking) dust from all of the skin mites, microbes, and stuff that just live all over the human body. Meaning the aftermath would have been even messier.

[–] lunarul@lemmy.world 34 points 10 hours ago

If surviving humans lost 50% of their gut bacteria, that means that those snapped away left 50% of their gut bacteria behind.

[–] Anticorp@lemmy.world 34 points 11 hours ago (1 children)

That's not how it worked. He killed 50% of gut bacteria by killing 50% of the hosts.

[–] Mac@mander.xyz -1 points 10 hours ago (3 children)

Source? I'm pretty sure random bacteria would still be around a while if your brain activity went to zero.

[–] Mongostein@lemmy.ca 15 points 7 hours ago

But that’s not what happened. They literally disappeared, along with the gut biome

[–] Gladaed@feddit.org 3 points 9 hours ago

Your biome is specialized to live inside of you. They are not identical to wild organisms.

[–] Anticorp@lemmy.world 4 points 10 hours ago (2 children)

The source is Thanos supposed IQ score.

[–] RecluseRamble@lemmy.dbzer0.com 5 points 10 hours ago

This is refuted by his approach to only cut out half the tumor.

[–] T156@lemmy.world 2 points 9 hours ago
[–] aesopjah@lemm.ee 39 points 14 hours ago (1 children)

or 100% of the 50% that are destroyed are the gut bacteria in the humans etc that got snapped

[–] Enkers@sh.itjust.works 33 points 14 hours ago (1 children)

The alternative is even more disturbing: snapped humans leave behind a cloud of poopy gut microbes.

[–] nieminen@lemmy.world 38 points 16 hours ago (1 children)

In reality, since it was more random, some poor soul would have their whole biomes destroyed, and just be rekd.

[–] Enkers@sh.itjust.works 28 points 14 hours ago (2 children)

That would be incredibly unlikely. Due to the huge number of gut microbes, the chance to even lose 5% off of the median, even with billions of trials, is functionally zero.

[–] yetAnotherUser@discuss.tchncs.de 4 points 9 hours ago* (last edited 5 hours ago) (1 children)

To expand a little:

For a much smaller sample size of just 1 million, the probability to lose just 1% off of the median is basically zero.

WolframAlpha doesn't even bother to calculate the exact result and just rounds it:

https://www.wolframalpha.com/input?i=P%5B490000+%3C+X+%3C+510000%5D+for+X%7EB%281000000%2C0.5%29

[–] Enkers@sh.itjust.works 4 points 8 hours ago* (last edited 8 hours ago) (1 children)

Yeah, I was trying to compute the "ballpark" of the odds, but it's actually hard to do because of how astronomically improbable it is. Even computation systems that are designed to compute rather big/small numbers (think 100,000,000^1,000,000 big) fail.

Here's another example: If a human only had 1,000 gut microbes, the chance that over 900 of them get snapped is 1 in ~10^162 [WA]. (This was roughly the biggest number I could get WA to yield a non-zero answer for a >90% snap.)

Now if you do that for every human on earth, the probability is still essentially zero. [WA]

When you consider that humans don't have 1000 gut microbes, they have over 10 trillion, it's just mind bogglingly improbable.

[–] yetAnotherUser@discuss.tchncs.de 3 points 1 hour ago* (last edited 1 hour ago) (1 children)

I've found a proper approximation after some time and some searching.

Since the binomial distribution has a very large n, we can use the central limit theorem and treat it as a normal distribution. The mean would be obviously 500 billion, the standard deviation is √(n * p * (1-p)) which results in 500,000.

You still cannot plug that into WA unfortunately so we have to use a workaround.

You would calculate it manually through:

Φ(b) - Φ(a), with
b = (510 billion - mean) / (standard deviation) = 20,000
and
a = (490 billion - mean) / (standard deviation) = -20,000
and
Φ(x) = 0.5 * (1 + erf(x/√2))

erf(x) is the error function which has the neat property: erf(-x) = -erf(x)

You could replace erf(x) with an integral but this would be illegible without LaTeX.

Therefore:

Φ(20,000) - Φ(-20,000)
= 0.5 * [ erf(20,000/√2) - erf(-20,000/√2) ]
= erf(20,000/√2)
≈ erf(14,142)

WolframAlpha will unfortunately not calculate this either.

However, according to Wikipedia an approximation exists which shows that:

1 - erf(x) ≈ [(1 - e^(-Ax))e^(-x²)] / (Bx√π)

And apparently A = 1.98 and B = 1.135 give good approximations for all x≥0.

After failing to get a proper approximation from WA again and having to calculate every part by itself, the result is very roughly around 1 - 10^(-86,857,234).

So it is very safe to assume you will lose between 49% and 51% of your gut bacteria. For a more realistic 10 trillion you should replace a and b above with around ±63,200 but I don't want to bother calculating the rest and having WolframAlpha tell me my intermediary steps are equal to zero.

[–] Enkers@sh.itjust.works 1 points 18 minutes ago

Whoa, good work! I think I'm going to have to go over this a few times to grock how it works, especially the Φ(b) - Φ(a) bit. My stats textbook has a bit too much dust on it. ;)

[–] errer@lemmy.world 28 points 14 hours ago (3 children)

Maybe in your gut biome, but mine is just two or three really, really large bacteria

[–] thejml@lemm.ee 7 points 14 hours ago

So, what are their names?

[–] CrazyLikeGollum@lemmy.world 1 points 9 hours ago

That just sounds like the gut biome version of a spworm.

[–] HappycamperNZ@lemmy.world 6 points 14 hours ago

What are their names, and do they bite?

[–] marcos@lemmy.world 28 points 16 hours ago (1 children)

Losing 50% of your gut bioma will be fixed in an hour or two.

[–] Kalkaline@leminal.space 8 points 12 hours ago

Yeah, yeast doubling rate is around 90 mins in optimal conditions, I would assume the rest of the microbes in your gut would have a very similar rate and they would be well adapted to those conditions.

[–] Contramuffin@lemmy.world 12 points 14 hours ago

So will bacteriophages and viruses be snapped as well? Does it mean that scientists can utilize the Thanos snap to determine for good whether viruses are alive?

[–] ShimmeringKoi@hexbear.net 3 points 10 hours ago

50% fewer people working all critical sewer infrastructure, too

[–] Kolanaki@yiffit.net 9 points 13 hours ago* (last edited 13 hours ago) (2 children)

The snap must take intention into account, like a genie, and not the literal wording of the wish, like a monkey's paw, because otherwise everyone in the universe would have just been cut in half.

But also: what if Thanos himself got snapped out, along with the power glove (because for some reason it turned their clothes into dust, too)? The heroes would have been fucked, right? It's been a minute since I saw the movies but IIRC, they used the time stone to go back in time. But what if the stone was gone because it was part of Thanos' attire? He himself used the stones to destroy the stones, so there is probably a timeline where he got snapped away with everyone else, destroying the stones in the process.

[–] The_Decryptor@aussie.zone 2 points 10 hours ago

I imagine the stones would survive it, just fall out of the vanishing gauntlet. It's not like the stones were a part of it, they were just being held in place by it, but then there's the question of whether or not the contents of people's pockets got snapped as well, we know the pager Fury had didn't count as "part of him".

And no, they used the ant man tech to go back in time, no stones there.

[–] T156@lemmy.world 1 points 9 hours ago

But also: what if Thanos himself got snapped out, along with the power glove (because for some reason it turned their clothes into dust, too)? The heroes would have been fucked, right? It’s been a minute since I saw the movies but IIRC, they used the time stone to go back in time. But what if the stone was gone because it was part of Thanos’ attire? He himself used the stones to destroy the stones, so there is probably a timeline where he got snapped away with everyone else, destroying the stones in the process.

It might not be possible, since the stones were also performing the action, and Thanos didn't want to destroy the stones while snapping everyone in half. Otherwise, they might just self-destruct by going for the nearest target first (Thanos), and stop there, not fulfilling the desired action. You'd have to destroy/scatter them separately.

I don't think that they used the time stone to go back in time, since it was destroyed when they got there. They had to get it from the past, since a decent part of the movie surrounded that.

[–] NorthWestWind@lemmy.world 0 points 10 hours ago (1 children)

If you include bacteria, then probably no human died from the snap. There are significantly more of them

[–] ramenshaman@lemmy.world 7 points 10 hours ago (1 children)

That's not how percentages work

[–] Enkers@sh.itjust.works 4 points 7 hours ago* (last edited 7 hours ago)

Moreover, that's not how probability works in independent events.

It'd be like saying "I flipped coin A 1 billion times and got half a billion heads, so now that I'm flipping coin B 100 times, I probably won't get any more heads."

It should be fairly obvious that you can say the exact same statement about tails, and get a completely contradictory statement.