If the universe is expanding what exactly is expanding?

The distances between galaxies and groups of galaxies gets larger. There is too much gravity keeping galaxies together to get any expansion within them or even between tight local clusters of galaxies.

In some millions of years there will be no galaxies visible from our except the local six, the remainder having gone beyond the visible edge of the universe.

The universe is expanding at an alarming rate. The universe should have slowed down but some kind of mysterious kind oif energy dubbed "dark energy" is causing it to speed up.

We know that the galaxies are moving away by measuring the redshift in their spectrum.

Answer2.

CONSERVATION OF ENERGY MEANS THE UNIVERSE IS NOT EXPANDING!

The redshift is evidence that the Universe is NOT Expanding not the other way around. Redshift has been mis-interpreted by most physicists but not be Hubble, the "father of redshift". Hubble considered redshift an "hitherto unknown principle of nature." The redshift is and indicator of equilibrium between the centripetal force from potential energy - GmM/r and the centrifugal force from "kinetic"/vector energy, mcV.

Redshift is the cos(z)=v/c the ratio of the velocity of a object and the speed of light. This ratio gives the angle of between the velocity and the radial direction. This angle when less than 90 degrees indicates the centrifugal force, mcv/r cos(z). The centrifugal force is zero at 90 degrees and the redshift is zero.

The redshift is positive below 90 degrees and negative above 90 degrees, a blue shift.

The shift is a measure of angle not velocity. For a given velocity the angle adjusts to balance the centripetal force. This is the Conservation of energy.

Lorentz Transformation is the result of the redshift angle, Beta=v/c= cos(z)

Gamma = 1/sqrt(1 - (v/c)^2) = 1/sqrt(1- cos(z)^2) = 1/sin(z)

Relativity Theory itself needs a rework using quaternions.

Bootom line is Conservation of Energy holds and the Universe is not expanding and teh redshift is the evidence of stability..

First answer by Eric M Jones. Last edit by Yawyaw. Contributor trust: 51 [recommend contributor]. Question popularity: 14 [recommend question]