How Astronomy Explores the Past, Present and Future of the Universe
The universe is a mysterious place – we know it is some 13.8 billion years old with the part we can observe being about 90 billion light years in diameter, which means that the most distant edges we can currently see are 45 billion light years away. There is essentially no knowledge about regions that are even further away; and scientists can only speculate about whether or not the Cosmos is infinite – as the Universe is on a knife-edge between being finite and without end. Modern astronomers have been able to unveil a few of the cosmic secrets – in 1929, Carnegie Institution astronomer Edwin Hubble discovered that the universe is expanding, and in 1998, two independent groups observing distant exploding stars (supernovae) found evidence that cosmic expansion is in fact picking up speed. Australian astronomer Brian Schmidt was part of the High-Z Supernova Search Team which made this unexpected discovery. In 2011, together with two of his colleagues, he was awarded the Nobel Prize in Physics. But plenty of other unsolved mysteries remain: How did the universe begin? Is there a chance that we will find life on other planets? And what is the universe made of? It is particularly this question that keeps astrophysicists awake at night. Only 5 per cent of what makes up the universe is matter we can see and measure. The remaining 95 per cent is made up of unknown substances, vaguely described as dark energy and dark matter. Scientists are getting closer to finding out about the true nature of these forces, but it is unclear whether the next decisive breakthroughs will occur during our lifetime. Discussing the key questions of cosmic past, present and future, Brian Schmidt takes us on a tour along the next walls to fall in astronomy