# Cosmological Principle

### Short Topical Videos[edit]

- From the Big Bang to First Light --- the History of Our Universe (Aaron Parsons, UC Berkeley)
- The Illustris Simulation: Most detailed simulation of our Universe (Mark Vogelsberger, MIT)
- Cosmology, Homogeneous, Isotropic, Cosmological Principle, Curvature (Clements)

### Reference Material[edit]

- The Cosmological Principle (Wikipedia)
- The Observable Universe (Wikipedia)
- The Cosmological Principle (James Schombert, U. Oregon)

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\begin{document} \section*{ The Cosmological Principle}

\begin{figure} \centering \includegraphics[width=6.5in]{universe.png} \caption{A cartoon map of the scales of structures in our universe.} \end{figure}

The {\bf Cosmological Principle} states that the universe is spatially {\it isotropic} (looks the same in all directions) and {\it homogeneous} (has constant density everywhere) on large scales. The {\bf Perfect Cosmological Principle} states that the universe is also {\it temporally} isotropic and homogeneous (a steady state universe). This is unlikely because it doesn't describe the Cosmic Microwave Background (CMB). The CMB and Hubble's Law are both provide evidence for isotropy and homogeneity.

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