File talk:CMB Timeline300 no WMAP.jpg

Graphical representation of the expansion of the universe

(Extract from Talk:Expansion_of_the_universe#Graphical representation of the expansion of the universe)

A graphical representation of the expansion of the universe.

File:CMB Timeline300 no WMAP.jpg is a really misleading graphic and it has been inadvertently copied all over the internet (as of 2019). It should only ever be used in the context of explaining theoretical inflation (and I wouldn't recommend using this graphic in that context either - unless one was attempting to make a specific point about the intensity of inflationary expansion). The theoretical inflationary epoch is believed to have expanded the observable universe only up unto approximately 10-100cm^3, nothing like what is shown in the graphic (ie size of current observable universe/2). Furthermore, it is difficult to observe the approximate constant expansion of the universe in the graphic (what the graphic is typically used to demonstrate) due to;

• a) its apparent (but misleading) insignificance compared to inflationary expansion,
• b) the fact it is not uniformly expanding in the positive and negative direction of the y axis (it is nearly flat at the high end of the y axis), and;
• c) the fact the constant expansion only results in the observable universe increasing approximately 2x in size since the end of inflation (it really should be something like x10^(15+9+2=26)=x100000000000000000000000000, and so its proper visualisation requires a minimum expansion of 10x.

Note to demonstrate the concept of constant expansion (Hubble's constant), I recommend linking to a 3D simulation such as; "Simulation of the Big Bang and expanding universe" (https://www.youtube.com/watch?v=WGUBt-vNFC8).

I have created a modified version of the graphic below;

A graphical representation of the expansion of the universe from the Big Bang.