1.12 how did the universe beginPresentation Transcript
11 January 20111.12 How did the Universe begin? Out of 10, how confident are you in: Evolution theory The Big bang theory What is a theory?
Aims• Explore data and explanation associated with the Big Bang
A spiral galaxy
Two nearby galaxies
Exotic galaxies I
Exotic galaxies II
Nazirah Jetha wasbrought up in Burnley.Now she’s studyinggalaxies at BirminghamUniversity.
Galaxies, galaxies, galaxies
Pedro Ferreira is ascientist at the Universityof Oxford. He’s trying tofind out more about howthe Universe began.
Pedro Ferreira tries out his ideas by checkingpredictions against observations, and also by usingcomputer simulations or ‘models’ like this. It showshow galaxies are spread across the Universe.
Joy McKenny is anexperimental scientist.She develops specialmirrors for observingradiation from distantobjects in space.
A big bang• Until the 20th century most people thought the Universe was eternal and unchanging• Big telescopes changed everything, light from distant galaxies showed the Universe was getting bigger• Space itself is actually expanding• It is now imagined that the Universe was once incredibly dense, hot and small – the Big Bang theory
The bigger bang• The theory passed a major test in 1965. A group of scientists predicted that the afterglow of the Big Bang should still fill the whole universe• Penzias and Wilson found an annoying background hiss on their radio antennae – they found the microwave background radiation• Whenever you see the snow on an untuned tv channel, some of the signal is this afterglow
The age of the Universe• Fifty years ago scientists used the speed and distance of galaxies to estimate how long ago all galaxies were in the same place• They made lots of assumption meaning the age of the Universe was between 10 – 20 billions years• Later observations (2003) clarifies this date to 13.7 billion years +/- 0.2 by
Other evidence:• Hot big bang explains the ratio of hydrogen to helium• The oldest stars are younger than the Universe (rather important!)
Models of the Universe• Cosmology is the study of the cosmos or universe• Cosmologists often use mathematics to help their thinking• Computer models use maths to stimulate the formation of galaxies• Topology models physical properties