I was reading about the 'OMG particle' and was wondering what would happen if it hit a person (before it went through the atmosphere). I did a search and most answers said you wouldn't notice. Which seems odd since it had the same energy as a baseball going 60 miles per hour, and I would definitely notice that if it hit me.

I then thought maybe I should be looking at momentum instead of energy. I did some calculations and it appears that the proton's momentum would be only 10^-7 that of the baseball. So maybe that is the preferred measure of 'noticeable?'

  • $\begingroup$ When it "hits" you, some fraction of the energy will be "deposited" in your body tissue, and the rest will be carried away by a shower of particles that exit from the other side of your body. IDK what the fraction will be, but you won't be hurt by energy that you don't absorb. $\endgroup$ Oct 17, 2023 at 1:09

1 Answer 1


That something is felt by someone is a very bad definition for 'noticeable' in physics. We, as humans, will feel something only if it struck a nerve, or a sufficient portion of one. I would argue the OMG particle is so very small that it would be impossible for you to feel the strike. If there would be consequences or not is a different thing, such as, for example, alpha radiation can strike and cause damage to the DNA molecules, but you don't 'notice' the strike. You'll certainly notice the cancer a few months or years later though. That being said, until we can know for sure what the OMG particle is/was, the potential consequences of a strike on a human are uncertain.


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