Muons on the Rails


Fred J. Schaal

This SMART website is hosted by the Illinois Institute of Technology

            This is it, this is the real thing.  I have messed around long enough.  With another week to go I am going to do what I am calling the "real thing": a short but link-laden web page about a science show that I saw on Canadian public television on the local hotel  television menu.  (I had gone from Chicago to New Orleans on the City of New Orleans, to Los Angeles on the Sunset Limited and to Seattle on the Coast Starlight.  I was resting up to return  to Chicago on the Empire Builder when I tuned in.

             Muons are part of the output of the impact of cosmic rays on the atmosphere of earth.  Cosmic rays are not rays as such but particles--high energy and charged--they strike the earth from all directions. Muons are very short lived.  They should change to the next thing in the cascade before striking the surface of the earth, but they do not.  Why?  Time dilation! 

            What is time dilation?  If  a time measuring device is on a moving device, then it will have its time units dilated or elongated or stretched compared to a similar time measuring devoice which is not moving.  A unit of moving time will equal several non-moving units of time. The link on the words "time dilation" provides a good example of both kinds of clocks.  A graph of the equation for time dilation is available at this link: graph.  Print this web site and probably the green curve will not print.  What a marvelous opportunity to graph the green curve.  You have the graph sheet and the numbers--plot away! Another web site showing multiple clocks sets one up for another explanation using mirror clocks.

            I am losing sight of the muons...their clocks  are dilated.  They are longer-lived than an earth-bound observer might suspect. Therefore they strike the earth before entering the next stage of the cosmic ray cascade. I wonder if they can decay as an earth-striking cosmic ray?  This could lead to another web page.

            If you linked yourself to the above links you found several others.  Enjoy them.


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