It's just amazing to me how many new basic things we are learning every day about the universe that we live in:
The Milky Way is twice the size we thought it was
"It took just a couple of hours using data available on the internet for University of Sydney scientists to discover that the Milky Way is twice as wide as previously thought. Astrophysicist Professor Bryan Gaensler led a team that has found that our galaxy - a flattened spiral about 100,000 light years across - is 12,000 light years thick, not the 6,000 light years that had been previously thought."