It can be abridged to CCCL which is equivalent of 350
This is not a proper Roman Numeral. The L represents 50, the C 100, the D 500 and the M is 1000.
(((M)))(((D))) Numerals in treble brackets indicate multiplication by one hundred thousand and superscript numerals indicate multiplication by that particular numeral. Hence: (((M)))(((D))) = 500*100,000*1000*100,000 = 5,000,000,000,000,000 = 5*1015
Practically all astronomers and physicists accept the Big Bang model, and more specifically, the LCDM model. Outside of the fields of astronomy and physics, acceptance may be a bit less, but still constitutes a vast majority of the scientific community.
The cosmic background radiation refers to the faint radiation left over from the early stages of the universe, which was discovered and studied in the 1960s. It is considered a major piece of evidence supporting the Big Bang theory. This radiation is consistent with predictions made by the Big Bang theory and provides strong evidence that the universe was once in a highly dense and hot state.
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.