1. Lectures on galaxies and cosmology
Astronomy II, Fall 2005
Lectures on galaxies and cosmology
Dr Martin Hendry
University of Glasgow, UK
(Basler Chair, 2005)
Tel: 94252
Brown Hall, Room 373
Office Hrs: Mon – 11.30
Tue – 15.30

2. Cornerstones of the Hot Big Bang Model1.
Expansion of the Universe 2.
Background Radiation 3.
Light Element Abundances

3. Present Day
Big Bang

4. Present Day
Big Bang

7. Present Day
Big Bang

8. Present Day
Big Bang

9. From Lineweaver (1998)

10. Value of
Scale factor of the Universe
Present-day
If the Concordance Model is right, we live close to a special epoch. Why?…

11. The Big Bang
1920s - Georges Lemaitre proposes idea of a ‘primeval atom’
Einstein not impressed!
“your calculations are correct, but your physics is abominable”

12. The Big Bang
1920s - Alexander Friedmann develops non-static universe models
Einstein not impressed!
“The results concerning the non-stationary world…appear to me suspicious”

13. The Big Bang
Late 1940s – 1950s:
George Gamow proposes hot early Universe…
…with Alpher and Bethe predicts existence of ‘smoking gun’ – relic radiation from the primordial Universe…

14. …discovered in 1965 by Penzias and Wilson
…predicted in more detail by Gamov, Dicke, Peebles, in the 1950s and early 1960s…
…discovered in 1965 by Penzias and Wilson
Robert Dicke
Arno Penzias and Robert Wilson
Jim Peebles

15. Cosmic Background Explorer (CoBE), launched 1989

16. T ~ 3K

17. T ~ 3K
Strong support for the Cosmological Principle:
“The Universe is homogeneous and isotropic on large scales”

18. Early Universe too hot for neutral atoms
Free electrons scattered light (as in a fog)
After 380,000 years, cool enough for atoms; fog clears!

19. CoBE map of temperature across the sky

21. CMBR ‘ripples’ are the
seeds of today’s galaxies
Galaxy formation is highly sensitive to the pattern, of CMBR temperature ripples

22. Microwave Anisotropy Probe

23. First year WMAP results published 2003
From Bennett et al (2003)
First year WMAP results published 2003

24. + Isotopes of hydrogen Deuterium Tritium Hydrogen
Another Big Bang prediction is that the lightest elements were ‘cooked’ during the first few minutes. Their relative abundance today depends on how much matter there was back then…
Isotopes of hydrogen +
Deuterium
(1 proton + 1 neutron)
Tritium
(1 proton + 2 neutrons)
Hydrogen
(1 proton)

25. Another Big Bang prediction is that the lightest elements were ‘cooked’ during the first few minutes. Their relative abundance today depends on how many baryons were around back then…
There is excellent agreement between the predicted and observed abundances of the lightest elements

26. Another Big Bang prediction is that the lightest elements were ‘cooked’ during the first few minutes. Their relative abundance today depends on how many baryons were around back then…
There is excellent agreement between the predicted and observed abundances, but only if the present-day numbers of atoms is about 1/7th of the total matter density.
But why dark energy?...

27. The future of the Universe:-No
Big Crunch!!!