Solution for the muon riddle

Day 4,772, 05:19 • Published in Austria Austria • by Mayamoto

Of course you get some smooth background music also for this article.

If you haven't read yet, here is the muon riddle itself.


Solution


Most of you do know a little bit more about Einstein than that he was a pretty clever guy. Many did hear about his theory of relativity, but only a few really manage to understand it really. This riddle I asked you is one proof of said theory.


For an observer in an resting frame (us on earth), time for a fast moving object (muon) goes by slower. This effect is called time dilation.
Yes, from their point of view muons only exist for 2.2 microseconds. But moving with nearly speed of light, time goes by for them a lot slower by our observation. In fact 15 times slower, so from our point of view they exist for more than 33 microseconds. And this is enough time for the muons to move through our whole atmosphere.

To look at it from another angle, namely the point of view of the muon:
The opposite effect of time dilatation is the relativistic length contraction. When moving with relativistic speed, lengths of a resting reference system (earth) are shortened. So for the very fast moving muon the earth’s atmosphere is not like a few kilometres thick, but only a few hundred meters. And that’s a distance they easily manage to travel before dissolving after 2.2 microseconds into electrons and some other fancy stuff.

If you’re speaking German, you’ll find a way better explanation here.
(Explanation for muons starting at 2:52. If you’re not used to time dilation, you might want to start the video at the very beginning though. For a deeper understanding I recommend to watch the whole playlist: https://youtube.com/playlist?list=PLmDf0YliVUvGGAE-3CbIEoJM3DJHAaRzj )

Trivia

Fun fact: For light itself, moving with (you got it! 🙂 ) speed of light, lengths are reduced to zero. So from the point of view of a photon, the universe is … not more than a dot!

Speaking of it: Have you ever seen light moving through the air? No?
Then you must watch this video!
Yes, it really is a video of photons moving. Its captured at 10 trillion frames per second, so you can literally watch the light moving!


This riddle was to heavy stuff?
Then I recommend to you this channel (english): Kurzgesagt – In a Nutshell

It’s a very cool channel with pretty simple explanations for many interesting topics throughout all kinds of science

Winner

As expected paricipation wasn't that heavy, but luckily we got at least some answers. 🙂

So the first price (5g) goes to RodderickJames.

Though you didn’t explain why, your answer (“Is 12 correct? I mean, 15! I say 15. Yes, I'm sure.“) is correct. 15 is the Gamma factor or Lorentz factor, by which the length of the earth’s atmosphere has to be divided in order to get its length in the reference system of the muon.




And second price (2g) goes to Luis Grindl for making an educated guess.


That's all for now, so enjoy your Sunday.
Yours, Mayamoto