HANDOUT D
THE UNIVERSE
We have found some incredible sizes and distances from our Sun, to the farthest planet Pluto, to the next star, to the edge of the Milky Way Galaxy and to the next galaxy of similar size and shape, the Andromeda. But all these sizes pale in comparison to what we are to discuss next, the entire universe. The Universe encompasses everything known to man. Everything visible to the unaided eye is in our own galaxy except for the two Magellanic clouds and the Andromeda Galaxy. Just after the invention of the telescope in the seventeenth century have we had the capacity to view further into space. And only in the past 40 years have we been able to estimate the outside edge of the universe to be 15,000,000,000 light years away. To get an idea of how far this is, let us reduce the Milky Way of the size of a tiny ant head, then the edge of the Universe would be about 500 feet away or the size of 1 1/2 football fields! In this huge space would be billions and billions of other galaxies with the largest ones no bigger than a pencil eraser.
At the edge of the Universe we would find some of the most amazing things ever examined by science. It just so happens that at this edge are some of the very first galaxies created at the beginning of the Universe. Inside some of these galaxies are the most mysterious sources of light called ‘quasars’. We are still not completely sure what these quasars are but we can tell that they are giving off the largest amount of light of anything in the Universe. Let us imagine for a moment one of these galaxies being reduced to the size of Los Angeles County. If we could fly over L.A. at night we would probably see a billion lights between all the cars, houses, streets, etc. We could compare this to a typical galaxy with all it’s stars. The quasar would be a tiny light source about a centimeter in size and putting out more than a thousand times all the other lights combined!
It is hoped that by this point you should be very much amazed at the size of the Universe and by some of it’s unusual features. The Universe is so remarkably complex and large that there will always be something out there to search for and explore for a very, very long time.