Atlas of Astronomical Discoveries

a little more than 1° further north, and to see any real changes in the shapes of the constellations you need to wait a hundred times longer. In 400 years, the Sun completes less than a millionth of its orbit around the center of the Milky Way. That is like walking around the Place de l’Etoile in Paris and only moving 1.5 mm. Large numbers are the trademark of astronomy, but if we look at it in the right perspective, we see that the universe hardly changes in 400 years. The Sun may convert 50 quadrillion tons of hydrogen into helium in that time, but that is only a trillionth part of its total mass. And although the Andromeda galaxy has moved more than a trillion kilometers closer to the Milky Way, that only means that the light it emits takes a month less to reach us than the two and a half million years that we are used to.