== Build a Universe! (enable the FlashPlayer) ==
https://wmap.gsfc.nasa.gov/resources/camb_tool/index.html

1. Find the parameters that match the data points

2. Record the behaviour of the power spectrum, when you vary a parameter
	* For example: What happens when you reduce the “Spectral Index”? What happens when you increase  “Atoms”?
	* Tip: Where to start? Start by varying one parameter away from the best-fitting parameter you found in (1)
	* Explore the behaviours of as many parameters as you have time to explore

3. Document your findings in the shared note.
	* I have not yet taught you how the power spectrum depends on the parameters. So, collect data yourself now; it helps you understand physics later.

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1. What are the best-fitting parameters?
- Omega_B ["Atom"] = 4%
- Omega_D ["Cold Dark Matter"] = 22% 
- Omega_Lambda ["Dark Energy"] = 74%
- Hubble Constant = 73
- Reionization Redshift = 11
- Spectral Index = 0.95


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2. What happens when you vary:
    
    1. Omega_B ["Atom"]
    - higher Omega_B leads to higher power fluctuations shortward of ~0.5 deg and lower longward
    - changes relative height of the peaks
    - higher OmegaB means more baryons, so photons oscillate in deeper potentail wells, which means bigger difference between peak heights (?)
    - 3rd peak is higher than 2nd when atom content increases. --> odd/even peaks different
    
    2. Omega_D ["Cold Dark Matter"] 
    - higher Omega_D, higher the second peak compared to the first one 
    - changes relative sizes of the peaks
    - changes amplitude of the power spectrum
    - changes amplitud: higher Omega_D, weaker fluctuations
    -Peak location shifts to the left when Omega_D increases
    
    3. Omega_Lambda ["Dark Energy"]
    - shift on the angle across the sky (so shifts the whole spectrum in x direction)
    - changes frequency of the peaks
    - does not affect photon-baryon physics, so it does not affect ratios between the peaks, but simply shifts the C(l) 
    - Lower Omega_Lambda, lower the angle across the sky of the power spectrum.
    
    4. Hubble Constant
    - changes power fluctuations for the same angle across the sky while maintaining the overall shape
    - for angles < 2 degree the increase / decrease is less severe
    - peaks become shifted in x direction
    
    5. Reionization Redshift
    - shifts the power spectrum in the y direction while maintaining the shape
    - higher reionization redshift leads to overall damping of the power
    - peaks does not become shifted in x direction
    
    6. Spectral Index (n=1 is the scale invariant; see Lecture 4, page 37)
    - Changing the spectral index changes the intensity of first peak only.
    - Changes the tilt of the power spectrum
    - Impacts features on scales > 0.5deg
    - Changes the intensities of all the peaks, being the change in the first peak more dominant