Out the Early Universe R. Cowen Fluctuations in the temperature of the microwave background.
Black curve is prediction for flat universe.
Intrepid explorers braved the unknown to find that the world is round. Now, a detector suspended from a balloon circling the frigid Antarctic has measured the curvature of the universe and revealed that it's perfectly flat. The balloon-borne experiment detected tiny fluctuations in the temperature of the cosmic microwave background, the whisper of radiation left over from the Big Bang. This energetic radiation cooled to microwave energies as it traveled through space for some 13 billion years. Several fundamental parameters lie hidden in the maps of the microwave background that Lange and his colleagues have constructed, researchers say.