An Ancient Universe: How Astronomers Know the Vast Scale of Cosmic Time . ... The Sun is one of hundreds of billions of stars that make up a magnificent grouping of stars we call the Milky Way galaxy. ... The other stars are so far away, however, that even at this speed, light from the next nearest star takes 4.3 years to reach us. ... The Ancient Universe - The Age of the Expanding Universe - The Age of the Oldest Stars - The Age of Light From Distant Galaxies - The Age of the Chemical Elements | ...