Who supported the big bang-theory?

Answer 1

Pretty much every astronomer and (astro)physicist today supports the LCDM model. Of course, like every scientific model, it started out with a few single sources, and went through a process of gradual scientific acceptance in the following decades. A few notable names are:

Edwin Hubble, who first observed the correlation between redshift and apparent distance of celestial objects;

Georges LeMaitre, who first came up with the notion of the observable universe expanding outward from a 'primordial atom';

Edward Milne, who proposed an oscillatory variant of the BB model;

Fred Hoyle, who initially opposed the BB model and coined the term 'Big Bang', likely as a mild pejorative;

George Gamow, Ralph Alpher and Robert Herman, who proposed nucleosynthesis as an explanation for the formation of heavier elements and predicted the existence and nature of cosmic background radiation;

For more detailed information on the history of the Big Bang model and its scientific acceptance, see links below.