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Formation of the Universe What is the universe? Universe everything that exists, all matter and energy everywhere Why is it there and where did it come from? scientists can never answer this! How did it form? There is a theory for this... BIG BANG THEORY The Big Bang Theory is the most widely accepted scientific theory for the origin of the universe. The Big Bang Theory states that: The universe began about 14 billion years ago as an extremely hot, dense and compact state (singularity) that underwent an extremely violent expansion. The universe is still expanding today What does "singularity" mean? The singularity didn't appear in space; rather, space began inside of the singularity. Prior to the singularity, nothing existed, not space, time, matter, or energy nothing. So where and in what did the singularity appear if not in space? We don't know. We don't know where it came from, why it's here, or even where it is. All we really know is that we are inside of it and at one time it didn't exist and neither did we. 1 What is beyond the expansion? Nothing is beyond the expansion space curves and if you go the edge you will end up back at the start! How do we know that this theory is true? Evidence for the Big Bang Theory There are two main pieces of evidence for the Big Bang Theory: 1. Movement of Galaxies Galaxies are giant star/matter clusters In 1929 Edwin Hubble discovered that the galaxies that are farthest from us are moving the fastest away from us This suggests that the universe originated from a single point Diagram runners in a race as an analogy to explain galaxy movement if all runners start the race at the same point, then the faster runner would always be ahead of the slower runner. If runners started at different points (ie. a slower runner having a head start) then a slower runner could be ahead of a faster one like the runners, if the galaxies started at one point then the fastest moving galaxies should be the farthest from us which is what we see 2 2. Cosmic Microwave Background Radiation In 1965 two scientists named Penzias and Wilson discovered a Cosmic Microwave Background radiation (CMB) which is everywhere in the observable universe This radiation is thought to be the remnant of radiation from the Big Bang therefore providing evidence that it occurred The Big Bang Theory Timeline Use page 509 in Sciencepower to help you complete the following chart Temperature Substance Formed Time 1043 seconds 1032 oC ____ 104 seconds cooling cooling Protons and neutrons Helium cooling Helium STOPS 3000 oC ____ 1 billion years 3