The Universe

1
The Universe

• Characteristics
• Expanding (Hubbles Law)
• Finite age
• Cool now, hotter long ago
• Composition
• 70 H, 28 He, 2 the rest Why?
• Most matter is dark (unseen)
• Most content is dark energy gt gravity
• Accelerates the Universes expansion

2
Universe Content

• Matter
• Composed of elementary particles
• QED quantum electrodynamic theory
• Quarks, leptons, lions, tigers, and bears, oh my!
• These particles interact via force carriers
• 3 out of 4 forces covered gravity not
• How did this stuff form?
• How does it behave under extreme conditions?

3
Quarks u up 2/3 c charm Mass gt s t top Heaviest g photon E-M
Quarks d down -1/3 s strange Mass gt d,u b bottom Massgtc g gluon Strong Nuclear
Leptons ne electron neutrino nm mu neutrino nt tau neutrino Z z boson Weak Nuclear
Leptons e electron -1 muon Massgte tau Massgtm W w boson Weak Nuclear
Proton uud Neutron udd
4
Universes Energy

• Total Energy Energy of motion Energy of
  gravity
• Combined with other laws to get the Friedmann
  Equation -
• H Hubbles constant H, r, R are
• r density of the Universe time dependent
• k curvature measure
• R scale of the Universe

5
k gt 0

• Positive curvature, hyperbolic shape
• Kinetic Energy rules
• Open Universe
• Eventually.
• 1012 1014 years - Star formation ends
• 1020 years Galaxy mergers end
• 1030 years Galaxy death (massive black hole)
• 1030 1035 years proton decay
• 10100 years black hole evaporation
• Eventually heat death

6
k lt 0

• Negative curvature, spherical shape
• Gravity rules
• Closed Universe
• Eventually
• Galaxy redshifts become blueshifts
• Universes temperature increases
• Cluster collisions
• Black hole growth, matter evaporation
• Total collapse

7
k 0

• No curvature, Flat
• Perfect balance between gravity, energy
• Marginally Open
• Eventually
• Like the kgt0 case, but slower
• Which is it?
• Define critical density

8
(No Transcript)
9
Other options?

• Einsteins Idea
• Static Universe
• No motion requires anti-gravity effect
• Change the formulae
• The Field Equations
• Cosmological Constant
• An anti-gravity term
• That cant really exist, can it?

10
1997

• West Coast Supernova Cosmology Project
• East Coast High-z Supernova Team
• Type I SN best for great distances
• Testing expansion rate of the Universe
• How much is gravity slowing the expansion?
• How fast was the expansion in the past?
• Current expansion rate? (Hubble constant)

11
Low redshifts
12
(No Transcript)
13
Where is the SN?
14
Higher redshifts
Best result is case Where L?0! Also find k0
15
L gt 0 Universe

• L gt 0 Accelerating Universe
• k 0 implies a Flat Universe
• Density of the Universe Critical Density?
• What is the density
• Matter
• Dark and regular
• Energy (remember Emc2)
• Energy of light, radiation
• Energy of motion - gravity
• Energy of motion anti-gravity!

16

• Continual acceleration?
• No, varies with z (distance)
• Initial deceleration for zgt1
• Acceleration took over later, zlt1

17
Confusing terms

• kcurvature (0 Flat, lt0 Closed, gt0 Open)
• Define W (1 Flat, lt1 Open, gt1 Closed)
• Lcosmological constant
• Also written as WL
• M matter density (regular and dark)
• Also written as WM
• General rule - W WL WM

18
Universal Light - CMBR

• Cosmic Microwave Background Radiation
• Everywhere
• Black body temperature 2.725 K
• First detected in 1963 by Penzias, Wilson

19
WMAP Results

• Launched 2001
• First results 2003
• Flat (k0, W1)
• Age 13.7 billion years
• Hubble Constant 72 km/s/Mpc
• Most of the Universe Dark Energy
• WM .27
• WL.73

20
(No Transcript)
21
(No Transcript)
22
Same results - Supernova projects CMBR
projects Galaxy Cluster projects
23
Options for the Universe?
24
Big Rip

• WL should increase with expansion
• Lead to a tearing apart of all matter?
• When?
• 22 Billion years from now
• Galaxy cluster dissolve (1 Gyr before end)
• Galaxies dissolve (60 Myr before end)
• Solar systems dissolve (3 months before end)
• Planets dissolve (1/2 hour before end)
• Atoms dissolve (10-19 seconds before end)