This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Chapter two study guide BANG Scientific theory- a theory is a proposed description , explanation , or model of some natural phenomenon or process; the theory must be capable of predicting future occurrences or observations of the phenomenon/phenomena being studied, as well as being capable of being tested through experiment.- The scientific study of the large-scale properties of the Universe as a whole is called cosmology the big bang- The Big Bang did not occur somewhere in space; it occupied the whole of space. In fact, it created all space. We have a name for that space: we call it the Universe . The Big Bang Theory At some moment of the past there was a singularity. All of the future Universe resided in that singularity, which would have had the dimensions of a single atomic nucleus. In the next moment, time and space were created in a gigantic explosion, and the Universe was born. The pillars of proof of the Big Bang are the following three main pieces of evidence: microwave background and its slight irregularity recession of the galaxies abundance of light elements Microwave Background It had been predicted in 1948 that if the Big Bang theory was right, there should still be a detectable cosmic background radiation (i.e. we should still see the remnants of the huge energy); so, like any good scientific theory, it can be tested, and theres a tool to do it with. It was discovered, almost by chance, in 1965 by a group of scientists building a very sensitive radio microwave receiver ( In fact, at first they thought the slight noise they detected was from pigeons nesting in the antenna! ). After much study, in all of the parts of space readily viewed from Earth, measurement of that background radiation has produced a nearly uniform background temperature of 2.725oK (Kelvin) above absolute zero ( 0o on the Kelvin scale = -273o on the Celsius scale) every temperature determination is almost exactly the same! This uniformity is one compelling reason to interpret the radiation as remnant heat energy from the Big Bang . Many scientists have tried to devise alternate explanations but none have succeeded. We said the background radiation was nearly uniform everywhere but its not quite. The way matter clumps together in stars and galaxies leads to the prediction that the intensity of the microwave background has tiny irregularities. The theory predicts that the background radiation has a blotchy pattern, with a characteristic size of half a degree (about the angular size of Moon) or less. The irregularities should be only about one part out of one hundred thousand, but sure enough - they have in fact been observed (Fig. 2- 3)! I guess you could say that this but sure enough - they have in fact been observed (Fig....
View Full Document
This note was uploaded on 11/01/2010 for the course EARTH SCIE 2010 taught by Professor Neil during the Fall '10 term at UWO.
- Fall '10