1. Image of the day

2. Cosmological principle
The universe is homogeneous and isotropic on sufficiently large scales. This is known as the cosmological principle. These assumptions are consistent with current observations and provide helpful guidance to our studies of the cosmos. The cosmological principle implies that there is no edge to the universe and that there is no center.

3. Big bang
Was the Big Bang an explosion? The Big Bang involved the entire universe-not just the matter and radiation within it, but the universe itself! The universe itself is expanding, which is described by Hubble’s law. There is no empty space beyond the galaxies.

4. The universe has two options:
Fate of the universe
Until the late 1990s, the prevailing view among cosmologists was that gravity would slow and ultimately reverse the current expansion.
The universe has two options:
The universe will continue to expand forever
The present expansion will someday stop and turn around into a contraction

5. Cosmic curvature
The total density of the universe includes not just the atoms and molecules that make up matter, but involves dark matter and everything that carries energy. In a high-density universe space is curved so much that it bends back on itself and closes off making this universe finite in size. (closed; positive curvature; sphere shape) A closed universe has no boundary A low-density saddle-curved universe is called an open universe. (negative curvature)

6. Origin of the universe test 4/11
Cosmology Chapter 26 pg 667: Cosmology Singularity Hubble’s Law Big Bang theory vs. Steady State Redshift Closed universe vs. open universe Cosmic Microwave Background Radiation Isotropic Homogeneous
Answer questions on page 686:
1,2,4,5,6,7,8,10,12,14
Multiple Choice questions EXCEPT 4 and 6

7. Beyond the big bang