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Comment by swinglock | Hacker News Reader

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

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.

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.

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

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

You are correct, the cosmic rays you see in a cloud chamber are typically muons (and its pretty easy to make one with stuff you can get at the drug store (or apothecary if you're outside the US :-)). If you want to see the higher energy ones then shielding helps.

On a more positive note, cosmic ray flux and the ensuing daughter products are used by geologists to date how long a particular rock has been buried or exposed.

https://en.m.wikipedia.org/wiki/Surface_exposure_dating

More or less, how often is “occasionally”? Can this be used as a source of randomness, like for example time as a Poisson?

> More or less, how often is “occasionally”? Cosmic ray fluxes vary depending on the energy of the photon you're talking about, but the number of events is, on a human scale, surprisingly large.

> Can this be used as a source of randomness, like for example time as a Poisson?

Yes. Although from an electronics point of view, lower energy photons are _much_ easier to deal with. That's how random.org started -- https://www.random.org/history/

A good example of "bad things" happening would be Quantas Flight 72 [1], an event in 2008 in which an Airbus A320 made a series of uncommanded movements, because of a particularly strange design bug in one of its flight computers, the air reference data unit one. Despite being repeated in triplicate, a timing bug occasionally resulted in pitch down movements being voted on as the 'correct' thing to do. Unlike MCAS in the 737, these were _not_ repeated and ultimately the pilots were able to fly in 'alternate law', and land safely.

Subsequent investigations believe that a cosmic ray induced bit flip is the most likely explanation.

[1] https://en.wikipedia.org/wiki/Qantas_Flight_72

I’m pretty sure I have seen a cosmic ray flash a couple of times over the past 20 years, lying in bed with eyes closed. It’s a sudden, bright flash caused by a cosmic ray hitting the optic nerve. I read that Astronauts get them frequently, causing sleep difficulties.

Citation https://en.wikipedia.org/wiki/Cosmic_ray_visual_phenomena

We've evolved with this rate of radiation and are adapted to it. It's even possible that we need it for something.

Yes. Both.

My son was most likely hit by a cosmic ray in the early stages of development in the womb. It will have effected only a small number of cells (maybe even a single one) but the error replicated and caused a malformation in his heart.

Try looking it up in search engines first:

https://en.wikipedia.org/wiki/Cosmic_ray#Effect_on_electroni...

https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays...

Please don't be a jerk on this site. The threads are supposed to be conversations, and that question was just the sort of thing one asks in conversation.

https://news.ycombinator.com/newsguidelines.html

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