Rebound

 

Red Rubber Ball

And I think it's gonna be all right
Yeah, the worst is over now
The mornin' sun is shinin' like a red rubber ball

But how does that red rubber ball bounce?

A bounce, rebound, occurs when an object, such as a particle, encounters a discontinuity. That discontinuity can be a physical surface, or it can be merely observational, that is the ability to observe, and measure, may be the actual reason that there appears to be a  discontinuity..

If a particle is moving, and is not acted upon by a force, that particle moves in a straight line. That is Newton’s Law of Inertia. However this is only true if space is flat. It is more proper to say that a particle moves along the geodesic in its space. If the space is flat, then the geodesic is a straight line. But if that space is not flat, for instance is spherical or hyperbolic, then it is non-Euclidean, and only flat space is Euclidean.

We say that the Earth is a sphere, and we live on the Earth’s spherical surface. That is why the shortest distance between two points on earth is more properly a Great Circle Distance. While this is true, it might be only of interest to airplane pilots and others who measure vast distances. When the distances involved are far less than the radius of the Earth, then the solution for the hypotenuse of a triangle on that spherical surface is cos(c/R)=cos(a/R)*cos(b/R), where R is the radius of the Earth/spherical surface, and it is virtually identical to the solution on a classical flat Euclidean surface, cos(c)=cos(a)*cos(b), as can be verified by using the series for the trigonometric functions. Both of these are equal to Pythagoras’ Theorem, c=√(a²+b²). It is therefore customary to say that the distances on Earth  are spherical globally but are flat locally. Might this also be true for space?

The solution for the hypotenuse of a triangle on a hyperbolic surface uses hyperbolic trigonometric functions, cosh(c)=cosh(a)*cosh(b). This has a different solution than the classical solution. The classical solution relies on the circular identity, cos²+sin²=1.  In hyperbolic space the identity cosh²-sinh²=1 applies. Additionally space may not be merely what can be observed, it might be that which can not be observed, i. In this case reality having a coefficient of zero for that which can not be observed can be expressed as a complex number which is reality plus zero imagination, r+0*i. If reality is the solution of a triangle r²=(a²+b²)+0^2*i, then its solution in hyperbolic space is
ln(cosh(√(a²+b²)) ± sinh(√(a²+b²))) because cosh(0²) is 1,  where the ± indicates that there are two solutions. Because cosh is symmetrical while sin is symmetrical, and for small values of a²+b² compared to the size of the universe, sinh(√(a²+b²)), the uncertainty, is also small. This can be also expressed as a single solution, ln(cosh(√(a²+b²))-sinh(√(a²+b²))), if reality is one solution. This is no different than electrical engineering where some solutions have real and imaginary components, and the imaginary component is ignored. The single solution merely says that the real solution has the opposite sign of the imaginary solution, and that the imaginary solution is being ignored.

A rebound in flat space is symmetrical because a straight line is symmetrical about that discontinuity. Hyperbolic motions are NOT symmetrical as real numbers. They are almost linear on one side of the discontinuity and almost parabolic on the other side of the discontinuity. If there is a linear motion on one side of a discontinuity and that discontinuity is NOT a surface and the motion is parabolic on the other side of the discontinuity, this probably is an indication that the motion is hyperbolic, NOT a highly skewed parabola. A parabola requires an imaginary solution if that motion passes through, is rotated by 180º or π. It is suggested that is more reasonable to assume that this discontinuity is because the observable behavior continues as unobservable behavior than it is to assume the behavior has become imaginary.