1. Review Quiz No. 28 :60 1.all objects and structures in the Universe (including galaxy clusters and galaxies) expanding. 2.all objects and structures in the Universe moving through a fixed fabric of space-time. 3.the fabric of space-time expanding, taking all objects and structures along with it. 4.the fabric of space-time expanding, while all objects and structures (galaxies, clusters, etc.) do not take part in this expansion. 5.None of the above. Question 1: The expansion of the Universe can be understood as

2. Question 2: If there was no solution to Olbers’ Paradox, 1.the entire night sky would appear as bright as the surface of the sun. 2.the entire night sky would appear completely black. 3.the entire night sky would appear as bright as the surface of the moon. 4.the Universe could not exist. 5.None of the above. :45

3. Question 3: The assumption of isotropy states that, on the largest scales, :45 1.the Universe should have the same temperature everywhere. 2.the Universe should have the exact same properties everywhere. 3.the laws of physics should be the same everywhere in the Universe. 4.the Universe should appear completely identical in every direction that you look. 5.objects should have the same age, no matter from what distance you observe them.

4. Question 4: The surface of a sphere can be characterized by :45 1.a positive curvature. 2.a zero curvature. 3.a negative curvature. 4.a double curvature. 5.an infinite curvature.