## Sunday, February 7, 2016

### answer to faster than speed of light questions

By length contraction, there is a certain way in which the speed of light can be exceeded, but nothing can go faster than any specific photon of light.  In fact nothing with a rest mass can go faster than ZERO speed relative to any specific photon of light. If a physicist says "near the speed of light", then he is using an unorthodox physics terminology that would allow him to equally say "exceeding the speed of light".

Taking Carl Sagan's example from "Cosmos", if you accelerate at 1 g for 10 years and then slow down for 10 years you'll find yourself 30,000 light years away from Earth in the center of the galaxy. Dividing the distance back to Earth by your clock you will find you traveled 1500 times faster than the speed of light. Any photons that left at the same time as you will be 20 light years ahead of you, and people on Earth will think you took 30,020 years to travel that distance. Earth will be 30,020 years older while you're only 20 years older. Physicists do not use this simple division of the distance traveled by the time it took, but what's wrong with it?

Why do they not complain when someone says "near" the speed of light, when the same math that allows you to say "near" will allow you to say things can go "faster" than light?

A physicists calculates the truck driver's speed by the "mile markers on the road" and compare them to the length of "truck", thereby taking into account the fact that the galaxy got shorter in the direction of travel the faster he went, and stretched back out as he slowed down.   They will freely admit the truck driver traveled forward in time, so it is strange that they won't let him say "I traveled forward in time because I traveled faster than the speed of light".

This is why their are so many questions about "traveling faster than the speed of light" on Quora.  The common man can sense something is not right with what they are hearing about light.  The existence of a contradiction is easy to detect but harder to specifically identify. The common man is being told things can go "near" the speed of light, but nothing can go faster.  The problem is not with the common man's intuition.  The problem causing this question to constantly come up is because the physics terminology they are hearing is wrong.

Now I'll get off the beaten track: I think the underlying problem is that using the concept of speed in physics makes the equations more complicated.  "Speed" uses 2 units (time and length) that are not independent of each other.  Speed is unitless in relativity. It is a conversion factor from seconds to meters and vice versa by meters = i*c*seconds (see Einstein's "Relativity" appendix 2). "i" is the math concept "sqrt(-1)". By using this substitution, a simpler Euclidean space can be used to satisfy Occam's razor instead of having to use Minowski space. By using meters = i*c*seconds physics equations that use speed or acceleration get simpler by making plank units simpler. This is just my personal way of doing physics to remove speed from equations. This is by no means an "accepted" practice although it give the same answers, except a minus sign or "i" factor shows up sometime. For example, it gives E= -mc^2