Greetings and welcome back to Mind Blown. I’m going to go out on a limb today and assume that if you are reading an obscure blog about mind-blowing scientific concepts, that you have at least a passing familiarity with The Big Bang Theory (not the television show, the actual Big Bang Theory). What you may not know is that following the creation and the rapid expansion of the universe as we know it, things kept expanding!
To explain that a little bit more clearly we need to go back to Einstein and his Theory of General Relativity (I mean don’t we always?). Einstein realized that if his theories were accurate they would result in the universe collapsing in on itself under the weight of its own gravity. Since that wasn’t happening (as far as Einstein knew the size of the universe was static) then there must be some other outside force working against gravity keeping everything in place.
“Mystery Force” never looks good in a published scientific theory, so it got a few people thinking. One of those people was Alexander Friedmann, who in 1922 published a set of papers that proposed the idea of a universe that was expanding at a constant speed. Seven years later working off an article published by Georges Lemaître and data collected by Vesto Slipher; Edwin Hubble announced that he had discovered the value of the rate of expansion and proven that the universe was indeed expanding. The clincher? The light from the stars Hubble was observing were shifting towards the red end of the spectrum as a result of the Doppler Effect. This change in light known is cosmology as “redshift” was a measurable phenomenon from which Hubble could infer a change in distance. This rate of movement away from the earth is a measure of universal expansion. Referred to today by the scientific community as Hubble’s Constant.
From that name you might infer that the rate of expansion is uniform throughout the universe, you would be incorrect. The further away a star is from the earth the faster it is moving away. This implies that the outward edges of the universe are expanding at a faster rate than the interior of the universe. Where are we on that sliding scale? Who knows? But we are definitely flying further away from the origin point of the universe with each passing second and that is kind of fun to think about. Mind blown?