professor martin hendry university of glasgow
TRANSCRIPT
Professor Martin HendryUniversity of Glasgow
A long time ago,
in a galaxy far, far away…
State of the Universe: Feb 2013
The nature of the nebulae?…
Early 20th Century
Gas clouds within the Milky Way, or Island Universes?….
10x
1000W
10W
1000W
Galaxy
Laboratory
Hubble’s Law
Einstein’s RelativityEinstein’s Relativity
Matter causes space Matter causes space to to curvecurve or or warpwarp
“Space tells matter how to move, and matter tells space
how to curve”
Gravity in Einstein’s Universe
Will the Universe expand forever?...
It depends how much matter there is
Weighing the Solar System
Johannes Kepler
Isaac Newton
More than meets the eye?...
Fritz Zwicky
1933: finds evidence for dark
matter in the Coma galaxy
cluster
Vera Rubin
1970s: studies the rotation of
spiral galaxies.
Weighing galaxies
Galaxies were spinning faster than they should be!
What we seeWhat we see
What we think is really there….
10 times as much as the luminous matter in the visible galaxy
So, is the expansion slowing down?...
redshift
‘Speeding up’ model
‘Slowing down’ model
Hubble’s law for nearby supernovae
Hubble diagram of distant supernovaem
easu
re o
f di
stan
ce
redshift
Latest results: still speeding up...m
easu
re o
f di
stan
ce
Early Universe too hot for neutral atoms to exist
Free electrons scatter light (as in a fog)
Early Universe too hot for neutral atoms to exist
Free electrons scatter light (as in a fog)
After ~380,000 years, Universe cool enough for neutral hydrogen to form: the fog clears!
Background radiation predicted in 1950s and 1960s by Gamov, Dicke, Peebles.
Discovered in 1965 by Penzias and Wilson
Arno Penzias and Robert Wilson
Robert Dicke
Jim Peebles
COBE map of temperature across the sky
CMBR ‘ripples’ are the seeds of today’s galaxies
Galaxy formation is highly sensitive to the pattern of CMBR temperature
???