The Expanding Universe
The twentieth century was changed by the discovery of the expanding universe. This discovery changed our view of the Universe and out place within it. Before the telescope was invented by Galileo in 1610, astronomers believed the universe consisted of only a few thousand stars and a few dozen nebulae. Telescopes and optics improved substantially over the nineteenth century allowing better and deeper visualization of the cosmos. By the end of the century, the universe seemed endless with billions of stars and millions of nebulae. There seemed to be no end in sight – there seemed to be no boundary… Read More »