NASA photos
Do we really know anything? 
 
The more astronomers look around on the human journey to the beginning of the universe, the more they realise we really have only scratched the surface of the known universe, and we really know nothing. This is exciting, for sure, for astronomers viewing the universe, but it means space scientists are constantly reworking theories and ideas concerning the universe and the way things really work. Astronomers using NASA's Spitzer Space Telescope to vi...