Oct 27, 2009 ... If it weren't then the Hubble law would be more complex. Hubble's law v= Ho d.
Further objects move faster away from us. We're at the center of ...
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Cosmology The study of the Universe - structure, size, characteristics
What is the Universe Like? •Big •Finite age •Fairly empty •Basic Composition – 70% hydrogen, 28% helium •Expanding (Hubble’s Law)
Age of the Universe Measuring – – – – – –
Hubble Constant Speed of light Radioactive Decay Stellar Evolution Oldest White Dwarfs
About 14 billion years old
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We see the Universe Uniformly Expanding Hubble law is simple v= Ho d
We’re at the center of the Universe!!!! No, we’re not!
No single “center” or every point is the “center” How does the Universe expand? Is it expanding into something? Will there be more parking spaces available? Back to General Relativity…..
Curvature of Space General Relativity - space is warped The Universe can have a shape = Curvature How does the expansion effect the curvature? Flat - no curvature - boring
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Positive Curvature - a sphere
Negative Curvature – hyperbolic (saddle)
More on the Expansion of the Universe Universe has Mass Universe has Gravity Gravity slows down expansion Observations show the expansion is speeding up. How’s that possible? The Universe’s expansion is ACCELERATING!!!! F=ma What is accelerating the Universe?
WL - The Cosmological Constant Einstein’s mistake - an “anti-gravity” term, L or WL How? Dark Energy Space has energy More space, more acceleration What is it exactly? Don’t know. Most likely never ending expansion…
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Since the Universe is expanding, it was smaller in the past Go back to the beginning of the expansion, to the
BIG BANG! Cosmogony - the origin of the Universe (space, energy, time).
Alexandr Friedman
Abbe George LeMaitre
Big Bang should explain observations Basic premise: Initially very small, hot How small? How hot? Expansion Bigger Cooler Complex Theory relies upon complex physics
Time = 0 Forces: Supergravity That’s all we can say
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Time = 10-43 seconds 0.0000000000000000000000000000000000000000001 Planck Era Earliest describable time Gravity is a separate force
During the first few minutes… Forces become distinct over time – First Supergravity Then Gravity, GUT Then Gravity, Strong Nuclear, Electro-Weak Then Gravity, Strong Nuclear, Weak Nuclear, Electro-magnetic Energy Matter E=mc2 Quarks, leptons protons (hydrogen), neutrons, electrons Expansion bigger, cooler, complex
Time = around 3 Minutes Nucleosynthesis Era Temperature = 109 K Hydrogen (protons) fusing into Helium nuclei End result is composition of 75% H
25% He
Trace elements formed
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Time = 380,000 Years Recombination (Decoupling) Temperature = 3000 K Radiation stops dominating the Universe Matter (Gravity) starts to dominate
Time = 500 Million Years Formation of Galaxies What came first, galaxies or clusters? Depends upon the form of dark matter.
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Robert Wilson, Arno Penzias Buzz in all directions What is it? They didn’t know They found the big bang energy!
Cosmic Background Radiation Cosmic Microwave Background radiation 3 K background radiation Cosmic radiation The radiation left over from the BB. Correct temperature (around 3 K)
WMAP Mission
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Results from WMAP (2010) The Universe appears to be Flat and Accelerating Age of Universe = 13.75 ± 0.11 Billion Years Hubble Constant = 70.4 ± 1.3 km/s/Mpc WL = 73% of Universe (drives the expansion) WM (matter) = 27% of Universe – mainly dark matter only 4.6% of Universe is made of “normal” matter
WMAP vs Planck Feature
WMAP (2012)
Planck (2013)
Shape
Close to flat
Close to flat
Motion
Accelerating
Accelerating
Age
13.75 ± 0.11
13.80 ± 0.04
Ho
70.4 ± 1.3
67.80 ± 0.77
Dark Energy
73%
68%
Matter
27%
27%
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