Dorky Poll: The Speed of Light

The speed of light is such that you can just detect the effects of its finiteness in the space surrounding Earth. You see electron cyclotron frequencies that are a little lower than they should be (because that pesky gamma factor comes in), and you actually have to worry about displacement current in magnetohydrodynamic waves. So I voted "just right".

However, there are some modelers in my field who, in practice, act like it's too high. There is something called the "Boris correction", in which modelers will artificially lower the speed of light. The reason for doing this is a cheap shortcut for making your code satisfy the Courant condition: any waves in your system cannot propagate more than one grid point per time step, or your code becomes numerically unstable. Sometimes, the right way of dealing with this problem (i.e., making your time steps small enough) becomes too expensive in CPU time, especially when you need to get a publication before your grant expires.

Of course it's just right! It's exactly equal to 1. What crazy value do you people use?

Evan: Well, 1 is too small! We should use c = 2.

2?! That's a silly answer. c = 3.8.

Scharnhorst efect - get any excess lightspeed you like, admittedly through a sub-atomic gap with some minor boundary conditions imposed,

http://www.npl.washington.edu/AV/altvw43.html

Too low. Seems I'm with the majority. You forgot it could be energy dependent though. Presently hotly discussed in some corners of your community ;-)

I voted too high.

It would get a lot more kids into physics if you could get relativistic running downhill with a good tailwind!

And it would slow the flow of emails into my inbox if they took a couple of weeks to cross the Atlantic, which would encourage old fashioned letter writing skill.

Ahem...

According to the bible, Pi = 3

and, according to Mr. Wise Old Owl it takes 3 licks to get to the center of a tootsie pop;

Therefore,

c = 3.

c = 1 foot/nanosecond. Works for me.

1 is too low, even for very large values of 1.

If it was much slower, the delay when watching a football game over satellite would be very annoying.

I prefer the current value of 30 Miles/hour. Watching Lorentz contraction of passing bicycles is a very pleasant way of spending an afternoon.