1. 11 January 2011
1.12 How did the Universe begin?
Out of 10, how confident
are you in:
Evolution theory
The Big bang theory
What is a theory?

2. Aims
• Explore data and explanation associated with
the Big Bang

3. Galaxies

4. A spiral galaxy

5. Two nearby galaxies

6. Exotic galaxies I

7. Exotic galaxies II

8. Nazirah Jetha was
brought up in Burnley.
Now she’s studying
galaxies at Birmingham
University.

9. Galaxies, galaxies, galaxies

10. Pedro Ferreira is a
scientist at the University
of Oxford. He’s trying to
find out more about how
the Universe began.

11. Pedro Ferreira tries out his ideas by checking
predictions against observations, and also by using
computer simulations or ‘models’ like this. It shows
how galaxies are spread across the Universe.

12. Joy McKenny is an
experimental scientist.
She develops special
mirrors for observing
radiation from distant
objects in space.

14. 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

18. 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

22. 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

24. Other evidence:
• Hot big bang explains the ratio of hydrogen to
helium
• The oldest stars are younger than the Universe
(rather important!)

25. 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