How old is the Universe? The Universe is about 13.7 billion years old. At its beginning, it looked nothing like it does today. Yet, everything in today’s Universe did exist in some form back then. It all started with the Big Bang, a kind of explosion that would not only go on to produce all the matter in the Universe but also marked the start of time. Creation of the Universe at the start, the Universe was a bot and dense ball of radiation energy. In one-thousandth of a second, tiny radiation particles produced tiny particles of matter. These combined to form the first-ever chemical elements, hydrogen, and helium. Some regions of the young Universe contained slightly more hydrogen and helium than others. These shrank to form the first stars. Nuclear reactions inside the stars produced many other chemical elements, including carbon and oxygen. The elements in the Universe today were produced from elements created in the Big Bang. Looking back we see objects in space because of their light. Stars produce their own but others, such as the Moon and planets, shine by reflecting light. Light travels at 299,800 km per second faster than anything else. Distant stars are seen as they were in the past when the light left them. The most distant galaxies we see are about 13 billion light-years away, and as they were in the early Universe. The Universe is expanding by about 70 km every second. Planets Earth may feel big to us, but across, it is just a speck in an expanding Universe. Stars planets orbit stars-our star in the Sun. Without it, there would be no life. Galaxies Stars exist in galaxies, colossal star systems that come in a range of sizes and shapes. Earth is in the Milky Way Galaxy. Cluster-Galaxies exist in clusters-the Milky Way Galaxy is in the Local Group cluster, stretching 10 million light-years across. Supercluster-Galaxy clusters are within superclusters-we are in the Virgo Supercluster, 200 million light-years from one side to the other. Voids the largest structures in the Universe are chains of superclusters that are separated by huge empty voids.