Exam 15: Observing the Evolution of the Universe

Why does Olbers's paradox suggest that the night sky should be light instead of dark?

The era of combination occurred about 3 minutes after the Big Bang,and the era of recombination occurred about 3000 years after the Big Bang.

How do we know that matter in the early universe was extremely smooth (i.e. ,not really lumpy)?

Strong evidence for an original Big Bang,which "created" our universe,comes from

At an age of 380,000 years,the temperature of the universe had fallen to 3000 K,and electrons could then combine with protons to produce hydrogen gas instead of roaming freely through space.What major transition occurred as a consequence of this change in the universe at this time?

The four physical forces at work in the universe are gravitation,electromagnetic,strong nuclear,and weak nuclear forces.Which two of these are very short-ranged,extending over distances of only about 10-15 m?

After carefully removing all potential sources of electronic "noise," including bird droppings inside the microwave horn antenna,Penzias and Wilson realized that they were actually detecting radiation from space.

The wavelengths of light from very distant galaxies are shifted to the blue part of the spectrum,indicating that the universe is contracting.

Opposite sides of the universe have the same temperature,yet according to the standard Big Bang theory,these points are too far apart for light to have traveled from one side to the other in the age of the universe;that is,they cannot have exchanged heat to even out their temperature.Why,then,do they have the same temperature?

Which of the following statements correctly describes the universe for the entire first 380,000 years of its life?

Immediately after the cosmological singularity,the four forces were indistinguishable.Then they began to "branch off" and become separate.Which was the first of the four to branch off?

How is the Hubble constant measured?

Describe how the universe changed in the first second after the Big Bang.

The two fundamental forces that act over infinite distances are

If space has an open geometry what will happen to two initially parallel flashlight beams as they traverse billions of light-years of space?

In which order did the fundamental forces of nature "freeze out" of the initial phase of the Big Bang at the beginning of the universe?

The resolution of Olber's paradox (i.e. ,the reason why the sky is dark at night)is that

The theory of everything (TOE)would provide one equation to describe all of the processes in the universe,and there would be no differences among the gravitational,electromagnetic,and strong and weak nuclear forces.

In our description of the universe,what does the word "isotropic" mean?

The physical force that controls the structure of the nucleus and binds together protons and neutrons is the