A few people who contribute to the development of humanity in terms of ideas, were in existence on the planet Earth. Carl Sagan is one of them. My advice, read his books, give his books to your friends, they read also. And discuss. Thus, you will be one step closer to understanding the universe and own planet.
By the way, my favorite his book is “The Demon-Haunted World/Science as a Candle in the Dark”
photo via der-kommunist.tumblr.com