Can someone tell me why people age our universe at about 13.7 billion years? I know this is done with WMAP, but I can't seem to make much of that. Is there a measurement that aims to explain the age of our universe with just the help of our solar system? I know there are some methods of trying to find out it's age, with the following: globular clusters, radioactive elements, and Cosmic microwave background radiation (CMB) which is done by the Wilkinson Microwave Anisotropy Probe (WMAP) and tempature measurements. The only star we can measure that is not light years away is our sun. The sun is supposed to be 4.5 billion years old measured through stellar evolution, and nucleocosmochronology. Do other techniques give us the same answer? Can we prove that any of these techniques are truly true?