I am curious about muons. I've been told that they appear lower in the atmosphere than they should. Ie. that they should be gone within a short distance of passing through the atmosphere, being created at a certain height and having a very short lifespan, but instead are found much lower. I think I have that right, but feel free to correct me; I have not done much physics. Now, I am told that the commonly accepted idea is that these particles somehow do some mysterious spooky time-travelling to get so low. Or perhaps some relativity stuff I'm not aware of. Why not simply consider that they travel very, very fast?