(Subtitled: Ooops! I forgot one) 😉

There is yet another reason why Time Travel is ( probably) impossible, specifically involving the method of light/hyper light speed.

I did not make it clear ( because it makes it even more complicated and confusing to those who don’t like maths) but there is a reason why Time seems to slow down at near light speed. And it is the same principle that creates this latest nail in Time Travel’s coffin so i better give you the lowdown before i come to the clincher.

Around the end of the 19th century Hendrik Lorenz and others were considering the implications of the recently discovered electron and came up with a formula known as the Lorentz Transformation (later refined and corrected by mathematician Henri Poincare in 1905 and which helped Einstein produce his special theory of relativity).

Basically this formula describes how physical equations that describe some events in our ‘normal’ reference frame here on earth have to be modified when their speed relative to someone doing the observing of events is considered.

Forgive the math but it simply (?) says:

γ = 1/√(1-v²/c²)

Anyone who remembers their high school maths knows that as the denominator of a number gets smaller, the resultant gets bigger, and that you can never divide 1 by zero since the answer is something infinitely large.

Looking again at the equation above we see that as our velocity = v starts to get very close to c – the speed of light – v²/c² gets very very close to one, so 1 minus something very, very close to one becomes very, very close to zero! The square root of that number is even closer to zero and so γ becomes massively large.

Using the Lorentz Transformation as it applies to Time between two observers moving apart at speed = v

To = γTv tells us that for the person who sees themselves as ‘stationary’ (To), Tv( time to the moving person in the spaceship) appears to be Tv = To/γ or, our ‘time’ divided by a huge number if v ~ c meaning their time appears very much slower,

Similarly, for the moving observer (although to him he sees us as moving away from him while he is ‘stationary’ in the spaceship with his clock) To = γTv so he sees time as moving very fast on Earth compared to his clock back on board.

The same transformation applies to the momentum of any object travelling at speed.

This says that the momentum of the moving object appears to have γ times the momentum of a ‘stationary’ object (a stationary object actually has zero momentum relative to the stationary reference frame since momentum = mass times velocity p= mv, if v=0 then p=0)

But p=mv is true only for ‘low’ values of v at light speed we have to use p= γp so an object has ‘infinite’ momentum if v = c

The energy require to increase an object’s momentum to infinite would also be infinite.

In other words it would take more energy than we can ever accumulate to travel fast as or faster than light speed.