User blog comment:Spartian300/media biasing on a massive scale..../@comment-8615800-20141101123341/@comment-7700555-20141102143823

Guns...

Friedmann made an equation to disprove Einstein's static universe model. To begin, it's assuming the universe is spatially homogeneous and isotropic when viewed from a large enough scale. Since forces are expected to act uniformly, there should in theory be no irregularities in the structuring of the universe over the course of the evolution of the matter field.

Einstein took this and said that this evolution of this scale factor is relative to pressure and energy of the universe's matter. Friedmann then took these field equations for gravitation and created his first equation, and then created his second from Hubble's law, which in short explains Doppler shift in deep space as relative velocity from Earth, and that this is proportional to their distance from Earth (up to a few hundred megaparsecs for galaxies).

Essentially these equations deal with a few key elements: the gravitational constant from Newton's law of universal gravitation, the cosmological constant, the speed of a mass less particle in a vacuum, and the spatial curvature of the universe in any given time-slice. Anyway, these equations' have a few uses. For one, if you have an equation of state, when applied to a fluid they yield the time evolution and geometry of the universe as a function of the fluid density. It can be solved in the presence of a perfect fluid with pressure, and can be used for mixtures, etc.

Friedmann's work off Einstein's field equations were in 1922, and his equation for negative spatial curvature was given in 1924. It was this work, coupled with Hubble's measurements of nearby spiral nebulae, and other research, that led to the Big Bang Theory. Georges Lemaître had independently derived Friedmann's equations, and was the first to propose the expansion of the universe, which would explain the recession of nebulae that was previously inferred. Georges Lemaître's work would form the basis of what is today called the Big Bang Theory. All these other minds were huge contributors to science and this problem too, but don't undermine the other's accomplishments as well.

As for your comment Friedmann did not "flesh out" anything. He was dead. When Lemaître proposed the expansion of the universe he was dead, and clearly unable to expand on anything. Also not really sure where you're trying to go with the lines about saying "let there be light". "Unless you can prove it, saying something don't mean jack" is kind of ironic since you probably should have heeded that advice.

But in conclusion, let's look at what's important here. I doubt this thread's purpose was to debate the small details of twentieth century physics. To answer Toby2 plainly, it was a Catholic priest. To answer him fully, there is a vast history of physics that built up to this point. Hundreds of brilliant minds contributing to our world view of the universe. Perhaps it isn't fair to contribute just one person, but at the same time let's not belittle one man's accomplishments to science. Toby I encourage you to look into the world of physics, there are hundreds of important feats that led up to this man's conclusion, all of which important aspects of our world's thinking.