cosmic evolution 04162009short
TRANSCRIPT
Dr Gary A Stilwell
Cosmic Evolution
A Six Week Course
My Cosmology course originally consisted of
two parts:
Mythological cosmology
Scientific cosmology
The outline (timeline) of only the scientific part
is shown on the next few pages
We will cover a small portion of that outline tonight,
as far as we get
Outline
Reality vs. Models
How we got the Big Bang Theory
Timelines
Big Bang Overview
Quantum Flux/Vacuum
Structure of Matter and Force
Planck Time
Matter Evolution
Inflation
Matter Creation (Atoms)
Cosmic Background Radiation
A View from the Center
Ultimate Reality
Science theory/models and religious mythology both seek to understand reality
Of which science models and religious myths may both be Platonic
cave shadows
They both use models to describe this reality
Disaster occurs when our models of reality are mistaken for reality itself
How We Got the Big Bang Theory
1920s discovered our galaxy not alone
1929 discovered other galaxies all moving away
making theories to explain expansion
1960s discovered microwave background,
proving the BB
1980s fixed problems with BB by Inflation
On-going proof
Time from Beginning
Quantum fluctuation 0 sec ?
Planck time 10-43 sec
Gravity force splits 10-43
Strong force splits (GUT) 10-36
Inflation starts 10-36
Sea of quarks 10-34
Weak force splits 10-10
Quarks combine to Hadrons 10-5
Leptons dominate energy dens. 10-4
Both annihilate immediately
Nucleosynthesis 1 min
H and He formed by ~3 min
Timeline of the Big Bang
Matter Era After Big Bang
Matter Radiation equality 60K years
Atoms form 400K years
Radiation and matter decouple 400K years
(universe becomes transparent)
Dark Ages begin 5 M years
First Stars 1 B years
Galaxies
Stars and chemistry
Planets 10 B years
Timeline cont.
Timeline cont.
Our Era
Milky Way 10 B years before present
Solar system
Sun 5 B year BP
Earth 4.6 B year BP
Life 4.2 B years BP
Biological evolution
Hominids 7 M years BP
Culture 12K years BP
The Future Eras
Death of solar system 5 B years from now
Degenerate era 1014 years
Black hole era 1046 years
Dark era 10100 years
Timelines - The Really Big Picture
The following graphics will be used to illustrate the various time periods under discussion
Time Frame - Age of Cosmos
Galaxies Formed
15 B* 10B 5B Now
* actually 13.7 B
4.6 Billion YearsEarth Formed
The ~15 Billion Year History of the Universe:
The 1st Billion years The last 5 billion years
Earth Formed Life Vertebrates
Plants Land Animals Dinosaurs Mammals Primates
5B 4B 3B 2B 1B Now
Hominids Homo Sapiens
500M 400M 300M 200M 100M Now
1M 0.8M 0.6M 0.4M 0.2M Now
500Million
Time Frame - Age of Cosmos - cont.
Human Civilization12,000 Years
Galaxies Formed
15 B 10B 5B Now
4.6 Billion YearsEarth Formed
Galaxies Form Earth Forms
15 B 10B 5B Now
Electron Capture
0 400 K 1 M
Forces separate, inflation occurs, and matter is created
0 3 minutes
Time Frame - Age of Cosmos The 1st Few Seconds
A 2-D Look at Cosmic Evolution
Here beDragons
The Birth of the Universe -Limits of Our Knowledge
time=0Temperature =infinite
increasing timeincr. expansion
Particle theories uncertain
Quantum gravity needed
Singularity!?
We can have knowledge ofthe universe's origin only after the Planck time of 10-43 sec
time = ~14 B yearsTemp = ~ 3K
}
The Progress of the New Physics
This is why weare limited toAFTER thePlanck time.
Big Bang is Not an Explosion
Big Bang - a more correct view
A More Correct View of the Big Bang Theory
Quantum Fluctuations and Particle Physics
A Review of Particle Physics is Necessary toUnderstand Early Cosmology
Quantum fluctuations are allowed by the HeisenbergUncertainty Principle
Quantum Vacuum Energy
The Standard Model of the Structure of Matter
Macroscopic object
Molecule
Atom
Nucleus
Proton and Neutron
Quarks
(Strings??)
Structure of Ordinary Matter
Standard Model of Sub-Atomic Particles all known matter and force
Ordinary matter
Forces
Exotic matter
Fermions
Planck Time, Forces Split
10-43 sec
is the smallest time that our physics works
NEED: quantum gravity theory
Planck Era
At time = 10- 43 sec
1021 times smaller
10-12 cm
Gravity
Electromagnetic
Strong
Weak
The Four Forces - Unification
Forces - breaking symmetry at cosmic origin - temperature and time
10-43 10-36 10-11
CosmicTime(sec)
Inflation
Starts ~10-36 sec.
Horizon Problem
Normal Expansion versus Inflation
Inflation
Our Observable Universe
Matter
Matter created in steps starting afterthe Planck time 10-43 sec
At ~ 60K years:
Radiation (photons, neutrinos) Energy Density becomes equal to Dark and Atomic Matter Density.
Space-time Foam
Matter Creation and Destruction
Particles Created and Annihilated
Making Quarks 10-34 sec.
Quarks toNucleiat 3 min
Making Elements at Universe = 1 Minute Old
Cosmic Background Radiation
Free Electrons and Nuclei pair up to form Atoms at~400 K years
Called Recombination
Makes Universe Transparent
Matter Evolution
The Helium Atom Model~ 400K years after Big Bang
42He
The Atomic Nucleus
The Structure of the Atom
Atom = 100,000 times Nucleus10-10 / 10-15 = 105The atom is almost EMPTY void!!
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ENDA few discussion slides follow
The Milky Way Galaxy
Universe Magnitudes
Life Cycle of Stars
Anthropic
Expanding Universe - Red Shift
ComponentApprox. SizeRelativeSize
Atom10 - 10m1,000,000,000
Nucleus10 -15 m 10,000
Neutron10 -16 m1,000
Proton10 -16 m
1,000
Electron10 -18 m10
Quark10 -19 m1