
Cosmic Ray Update: New Results from the Moon - throwaway3627
https://spaceweatherarchive.com/2019/07/16/cosmic-ray-update-new-results-from-the-moon/
======
mustntmumble
As a layperson, I found this article about protecting spaceships from cosmic
rays, from many years ago, to be very informative. I had seen the interview
with Eugene Parker from the BBC "The Planets" not long before finding this
article, so I was quite excited to find something written by him!

[https://www.dartmouth.edu/~sshepherd/research/Shielding/docs...](https://www.dartmouth.edu/~sshepherd/research/Shielding/docs/Parker_06.pdf)

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nisten
“We can’t stop the highest energy cosmic rays, however. They penetrate the
walls of any spacecraft.”

I was gonna say, we better bring spare parts with us, but imagine you just
installed a new eyeball in your skull and it was full of dead pixels when you
fired it up.

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bawana
again, radiation absorbed dose from cosmic rays is different from that
radiation of solar flares and coronal mass ejections. Cosmic radiation has
been decreasing over time. Even a Mars mission at solar minimum would not
expose the astronauts to significantly more radiation than they would have in
orbit

[http://www.srl.caltech.edu/ACE/ASC/DATA/bibliography/ICRC200...](http://www.srl.caltech.edu/ACE/ASC/DATA/bibliography/ICRC2005/usa-
mewaldt-RA-abs1-sh35-oral.pdf)

Solar flare activity can be as hazardous to commercial air passengers

[https://eos.org/research-spotlights/solar-flares-increase-
ra...](https://eos.org/research-spotlights/solar-flares-increase-radiation-
risk-on-commercial-aircraft)

In any event, we truly live in the goldilocks zone where a balance of cosmic
factors enable us to enjoy life. Yet we continue to do our best to screw it
all up because we can only think of one thing at a time. We should do more to
increase the earth's ability to tolerate us.

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yummypaint
Something not mentioned in the article: more shielding isn't always better
when it comes to high energy cosmic rays. A single cosmic may pass straight
through a person without interacting at all, but if you add shielding, that
particle can create a shower of less energetic particles which can be
ultimately more harmful.

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swinglock
Does it effect us on earth? Could it increase DNA and computer errors?

~~~
ChuckMcM
Cosmic rays do reach earth, and they can cause bit flips in memory. Generally
any damage to human cells is repaired by cell reproduction. Cosmic rays are
primarily protons so they get generally channeled by the magnetic field to one
of the poles, and the air provides some shielding as well, but even with all
of that you can build a cosmic ray detector[1] and get the occasional ping.

Generally it isn't something to worry about. Should we have a star nearby go
super nova on us, or if a gamma ray burst occurred nearby (from a black hole
eating a big chunk of matter for example) it would be more problematic.

[1] Cosmic rays are distinguished from "regular" solar flux by the energy of
their particles (not all of them have higher energy, but the ones that do are
much more likely to be of cosmic rather than solar origin). A simple cosmic
ray detector can be constructed by shielding a cloud chamber such that
shielding blocks any events below your desired cut off level. Detection events
are then most likely cosmic rays.

~~~
beezle
IIRC most turn into muons or electron/positiron showers, depending on the
incident angle. Recall a physics lab long ago playing with NaI scintillators
and photomultipliers at 10kV to detect the muons from the showers.

~~~
oliveshell
Yeah, rather than reaching earth’s surface directly, it’s far more likely that
a given cosmic ray will collide with molecules in the atmosphere, creating a
particle shower [1].

Extremely high-energy cosmic rays are sometimes detected, however. The so-
called “Oh-My-God particle“, detected in 1991, apparently carried as much
energy as a baseball moving at 58 mph [2].

[1]:
[https://en.wikipedia.org/wiki/Particle_shower](https://en.wikipedia.org/wiki/Particle_shower)

[2]: [https://en.m.wikipedia.org/wiki/Oh-My-
God_particle](https://en.m.wikipedia.org/wiki/Oh-My-God_particle)

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Causality1
Ok, so cosmic rays represent 20x the radiation dose of solar flares. That data
is meaningless without relating the values to actual health impacts on human
beings, which the authors don't even attempt to do. Would a year in space
represent a 10% lifetime increase in the risk of cancer? I have no idea and
neither do these authors. This is childish alarmism.

~~~
ChuckMcM
Perhaps the authors of the paper made the assumption that the reader would
already be familiar with the effects of ionizing radiation on humans?

For example, this presentation by NASA
([https://ccmc.gsfc.nasa.gov/RoR_WWW/SWREDI/2013/Evans-
SWREDIB...](https://ccmc.gsfc.nasa.gov/RoR_WWW/SWREDI/2013/Evans-
SWREDIBootCamp2013-SEPLecture-FINAL.pdf)) on Solar Energetic Particles (or
SEPs) relates how one can translate from pfu (proton flux units which are used
in the article linked) and biological effects as part of the solar storm
intensity scale (slide 15).

Perhaps if someone was already familiar with the NASA research into SEPs, they
would read this paper/article and say "Hmm, here is some evidence that Cosmic
rays are not something that can be assumed to be negligible when evaluating
radiation exposure risk."

