
Nearby stellar explosions could have killed off large animals - hhs
https://www.quantamagazine.org/did-supernovas-kill-off-the-monster-shark-megalodon-20190115/
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basicplus2
And passing through a local galaxy spiral arm...

[http://curious.astro.cornell.edu/physics/55-our-solar-
system...](http://curious.astro.cornell.edu/physics/55-our-solar-system/the-
sun/the-sun-in-the-milky-way/207-how-often-does-the-sun-pass-through-a-spiral-
arm-in-the-milky-way-intermediate)

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astazangasta
Ok, so they're saying[1] 1 Sv every 30 years. That's 33 mSv a year. Meanwhile,
according to [2], "160 mSv: chronic dose to lungs over one year smoking 1.5
packs of cigarettes per day, mostly due to inhalation of Polonium-210 and
Lead-210". I'm pretty sure heavy smokers are still reproducing successfully.

Even if the muon-dose theory is true, it doesn't amount to an extinction-level
event for a single species. Cancer takes time to develop; sometimes it
doesn't. When the muon flux goes away, life would resume as normal. It might
contribute to an extinction event already in progress, but that is not the
same thing. And there is a lot of if, if, if in this hyopthetical.

[1]
[https://arxiv.org/pdf/1712.09367.pdf](https://arxiv.org/pdf/1712.09367.pdf)

[2]
[https://en.wikipedia.org/wiki/Sievert#Dose_examples](https://en.wikipedia.org/wiki/Sievert#Dose_examples)

~~~
Retric
“Larger and longer-lived organisms will experience a greater relative increase
in radiation dose” 30 mSv does not have that high of a risk to a human, but
with 50+ times as much tissue the cancer risks would be vastly higher for
whales. A 1% risk in humans might be a 50% risk in a whale species.

Further, specific tissues receiving radiation only increases the risk to those
tissues. A sunburn does not increase your risk of lung cancer. Making a x mSv
exposure to your lungs less risky than that same exposure to your entire body.

PS: Heavy smokers also don’t start in infancy. If they did they would be dying
~20 years sooner.

~~~
astazangasta
If your conjectures were true elephants would be dying of cancer all the time.
In fact elephants are much more cancer resistant than humans due to differing
biology. The whole "more tissue, more disease" part of this is bunkum.

~~~
Retric
I don’t disagree, but we lack direct evidence for how resident these animals
where to radiation.

Water is a great shield vs most kinds of radiation as is their bulk which
means these animals may have significantly lower resistance. Worse they would
still be getting ~1SV over 30 years at ~1km below the oceans let alone the few
feet of their bodies. Which is vastly above background radiation levels.

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pvaldes
> mutations killed megalodon and other big animals

Well, first of all sharks are famous for being extra-resistent to developping
cancer. They are superconservative in its structure and did not changed
practically its shape in the last 100 millions of years. If there are a
creature that is practically un-mutable are sharks.

Second, the theory claims that big sharks where killed by muons but whales
where somehow respected. Why the animals able to find refuge in deep waters
(that stop muons) were wiped, but the animals that need to remain in the ocean
surface are alive?

Third, trees are also huge organisms, for some reason weren't wiped. Why?

and fourth, big animals trive in Chernobill even with radiation.

I think that as hypothese is interesting but it has a lot of loose ends to
explain.

