square of the distance. (Remember Galileo's calculation that the distance an object travels down an inclined plane is proportional to the square of the amount of time elapsed This is the same relationship, only it's using the intensity or brightness of a star instead of the distance on the inclined plane.) In other words, Hubble could determine how far away an object was according to how bright its light was. (The calculation also factors in the star's color, absolute brightness and apparent brightness, and special types of stars called variable stars because their light intensity changes cyclically, but that's beyond the scope of our discussion.) Using this new system of measurement, Hubble concluded that the star in the Andromeda galaxy was 800,000 light years away, which is more than 10 times the distance from Earth to the farthest stars in our galaxy. (Today this figure has been updated to 2 million light years away.) So what did this mean It showed that the Andromeda Nebula was far beyond the Milky Way galaxy. In fact, it was a distant galaxy all its own. This discovery blew everyone away. It was always thought that our galaxy was the extent of the universe, and that nothing existed outside or beyond it. Hubble's discovery gave cosmologists a whole new paradigm to work with. The universe was no longer seen as finite. Instead, it appeared to be infinite. We know today that there are billions of galaxies besides our own, and more are being discovered all the time.
