 Our universe is estimated to be around 93 billion light-years in width and it's constantly expanding. But then again, that's just the observable universe alone. Astronomy is an amazing field of science. But before you dive into the wonderful world of astronomy, let me share with you some basic facts that might help you later on. Let's start off with the term light-year, which is a very commonly used astronomical term. But what exactly does it mean? A light-year, simply put, is a distance light travels in one year, which is about 5.88 trillion miles. However, in astronomy we also use the word parsec, which means 3.26 light-years, but let's just try to keep things as simple as possible. So we now know that one light-year is about 5.88 trillion miles and the universe is about 93 billion light-years wide. And when we multiply those two numbers together we get this. Yup, that's the measure of the universe in miles. Anyway, our universe is governed by four forces, gravity which pulls and holds everything together, the electromagnetic force which we perceive in the form of light, the strong force which is responsible for holding together the atomic nuclei, and finally the weak force which is responsible for a radioactive decay. But forget about the four forces, let's start exploring the universe from our own solar system, which by the way is composed of 8 planets, not 9, sorry Pluto. Then we have the Oort Cloud which is a spherical collection of icy objects surrounding our solar system. This is the origin for most long period comets that have been observed. And on a larger scale we have the 100,000 light-year wide Milky Way galaxy with the massive black hole that has the mass of about 4 million suns in the center of the galaxy, 26,000 light-years away from us. However, the Milky Way is quite puny compared to some other galaxies like M87 which is an elliptical galaxy 980,000 light-years in diameter. And who could forget the lovely Andromeda galaxy which is about 2.2 million light-years away and constantly approaching our galaxy at about 670,000 miles per hour. And one day collide with our galaxy 5 billion years from now to produce Miltromeda. Oh man I've mentioned so much galaxies but how many galaxies are there in our universe or the observable universe for that matter? Well as far as we know our universe contains about 100 billion galaxies but there are only 10 billion galaxies that are estimated to be in the observable universe and all of them combined are estimated to contain about 1 billion trillion stars. And out of those 1 billion trillion stars 100 billion to 400 billion stars are estimated to be in the Milky Way alone. Our universe is so big that if I listed every fact about it this video would never end but like I said there are trillions of stars out there and there are billions of galaxies out there so if you want to keep on adventuring in astronomy your adventure will never end.