The installation of the huge 100-inch [254 cm] telescope on Mount Wilson in California made possible the acquisition of such evidence. The observations made with the use of that telescope during the 1920’s proved that the universe is expanding!

Previously, the largest telescopes could identify only individual stars within our own Milky Way galaxy. True, observers had noted fuzzy patches of light known as nebulas, but these were generally thought to be swirls of gaseous matter within our own galaxy. By using the more powerful Mount Wilson telescope, however, Edwin Hubble identified individual stars within these nebulas. These fuzzy patches of light were eventually identified as galaxies like our own Milky Way.

The Mount Wilson telescope helped to show that our universe had a beginning