The size and age of our Universe is not only a critically important issue in cosmology, but is also among the most controversial and delicate of the cosmological questions. Infrared observations made using NASA's Spitzer Space Telescope have now given us the most precise estimate yet of the rate at which our Universe is expanding. The key was not the discovery of a new method for measuring distance. Rather, astronomers discovered how to measure brightness more accurately. The new value for the Hubble constant, good to within three percent, is 74.3 kilometers per second per megaparsec (km/s/Mpc).
Read the full article: Spitzer space telescope observations reveal expansion rate of the Universe