Let me introduce you to...
In past mailings, you have met several important scientists/astronomers who made discoveries vital to our present understanding of the Universe. There were also many other scientist who also made important contributions. You should also get to know Albert Einstein, Georges Lemaitre, Harlow Shapley, and Fred Hoyle.
Einstein I'll bet you have heard of. In 1905 he was a 23 year old clerk in the Swiss patent office when he published his first paper on the Theory of Relativity. Over the next few years he expanded it to cover explanations of how the Universe works to moving and accelerating observers and how acceleration and gravity are identical for all measurements (a strange idea!). Einstein's Universe works best if it is expanding. At the time Astronomers didn't know that it was.
In 1927 the Belgian civil engineer, artillery officer, Astronomer, Cosmologist, Catholic priest, Georges Lemaitre took the Einsteinian idea of an expanding Universe and the new data of red-shifted galaxies and came up with the idea of the Universe starting from a single, huge, cosmic "egg" that exploded. It was Edwin Hubble's observations that demonstrated the basic truth to this original "Big Bang" idea.
Harlow Shapley was one of the biggest name in Astronomy in the early 20th century. It was he who figured out where the center of the Milky Way was and our solar system's position in it. He also, with Henrietta Leavitt (we've met her before), determined the brightness/period relationship of Cepheid variable stars - our "standard candle", remember?
Sir Fred Hoyle wasn't born until 1915 so he was just a kid when the idea of the Big Bang was proposed. Sir Fred grew up to become a very famous Astronomer at Cambridge University in England (and an excellent science fiction author). He also never liked the idea of the Big Bang (he was not alone) and favored a "steady state" Universe that, basically, never changes over time. In fact, Sir Fred so dislike the Einstein/Lemaitre/Hubble expanding Universe idea that he made up and insulting term for it - the Big Bang!. Yup "Big Bang" was supposed to be and insult!
Google some of these folks and read about some of the most fascinating people of the past century.