If you’ve ever heard someone tell you that there are more stars in the universe than grains of sand on all the Earth’s oceans you were probably shocked and potentially skeptical. However, according to the Sloan Digital Sky Survey’s most recent mapping of the universe you’ve likely vastly under-estimated the universe! The results of the recently updated Sloan Digital Sky Survey III (SDSS III) have mapped 200 million galaxies using data that stretches back all the way to 2001. Now think about that for a moment. 200 million galaxies, each of them averaging around 200 million stars which is considered normal for a barred spiral galaxy such as our own. There are some truly titanic galaxies out there, irregular in shape, that can host up to 10 trillion stars! Let’s just use the average number for this illustration. So just in the small patch of sky in SDSS III, which covers about 8.5% of the entire universe, there are 200 million galaxies containing 200 million stars each. In our small patch of universe there are roughly 4 x10^18, or 4,000,000,000,000,000,000 stars. That’s 4 quintillian stars just in a small 8.5% patch of sky! Estimates of the number of stars in the entire universe range up to 10 sextillion to 1 septillion!
If you’re like me, that’s probably far too large of a number for my brain to do anything with. Don’t worry, the folks over at SDSS have been kind enough to produce a video of a journey through the universe. This video give you a sense for how truly massive and complex the universe is. As Douglass Adams put it, “Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the drug store, but that’s just peanuts to space.” Despite its overwhelming hugeness, the universe has a definite order to it. All objects in the universe are governed by gravity which is the attractive force that exists between two objects that when balanced by motion creates orbits. All objects in the universe orbit something. The moon orbits Earth. The Earth orbits the sun. The sun orbits the galactic center. Gravity binds multiple galaxies together to create local groups. Several local groups are gravitationally bound to create superclusters. The universe is full of clusters and superclusters of galaxies. The entire universe can be seen as an almost infinitely large road map of galaxies. Galaxies and clusters of galaxies are attracted to each other to form strings, or “highways” and all these strings of galaxies connect with each other.
All my talking is probably not giving you a very clear image of what I’m trying to communicate. I don’t think words can adequately express the magnitude of size and wonder of the universe so just watch this video that I mentioned earlier. If you’re in the spaceship traversing the universe in the video you’re travelling faster than the speed of light and every point of light is an entire galaxy! At this speed you could travel across the Milky Way in about a couple milliseconds! Sit back, relax, and enjoy the awesome object we call, The Universe!