Which force in nature is believed to have formed second?

Inflation most directly explains which of the following?

What does it mean when astronomers say that we live in an expanding universe?

Explain the difference between a Doppler redshift and a cosmological redshift.

In what ways are the fate of the universe, the shape of the universe, and the average density of the universe related?

Assuming that the universe will expand forever, what will eventually become of the microwave background radiation?

What does it mean to say that the universe is dark energy–dominated? When was the universe radiation-dominated? When was it matter-dominated? How did radiation domination show itself?

Explain the difference between an electron and a positron.

Where do astronomers believe most of the photons in the cosmic microwave background originated?

Give examples of the actions or roles of each of the four basic physical forces in the universe.

What is the observational evidence for the (a) Big Bang, (b) inflationary epoch, and (c) confinement of quarks?

Explain why the detection of cosmic microwave background radiation was a major blow to the steady-state theory.

Some so-called “creation scientists” claim that the universe came into existence 6000 years ago. What is Hubble’s constant for such a cosmos? Is this a reasonable number? Explain your answers.

Discuss the implications of the fact that science cannot yet tell us what caused the Big Bang or what, if anything, existed before the Big Bang occurred.

Explain why gravitational attraction has dominated the behavior of the universe until recently and why the dark energy determines the fate of the universe.

Which of the following statements best describes the overall motion in the universe?

What is the weakest force in nature?

What do astronomers believe to be the fate of the universe?

Has the universe existed forever? If not, when did it come into existence?