# Chapter 22

Topics: Universe, Big Bang, Cosmic microwave background radiation Pages: 20 (8112 words) Published: February 26, 2015
﻿The Cosmic Perspective, 7e (Bennett et al.)
Chapter 22 The Birth of the Universe

22.1 Multiple-Choice Questions

1) To date, physicists have investigated the behavior of matter and energy at temperatures as high as those that existed in the universe as far back as ________ after the Big Bang. A) 1 million years

B) 300,000 years
C) 300 years
D) 3 minutes
E) 10-10 second

2) How long after the Big Bang was the Planck time, before which our current theories are completely unable to describe conditions in the universe? A) 10-10 second
B) 10-35 second
C) 10-43 second
D) 3 minutes
E) 300,000 years

3) The Planck era refers to the time period
A) before the Big Bang.
B) before the Planck time.
C) after the Planck time.
D) after inflation.
E) after the GUT era.

4) Why can't current theories describe what happened during the Planck era? A) We do not yet have a theory that links quantum mechanics and general relativity. B) We do not understand the properties of antimatter.

C) We do not know how much energy existed during that time. D) It was a time period from which we cannot receive radiation. E) The Planck era was the time before the Big Bang, and we cannot describe what happened before that instant. Answer: A

5) A GUT (grand unified theory) refers to theories that
A) unify all four forces.
B) unify gravity and the electromagnetic and weak forces.
C) unify gravity and the strong and weak forces.
D) unify the strong force and the electromagnetic and weak forces. E) unify the electromagnetic and weak forces.
6) When we say that the electromagnetic and weak forces "freeze out" from the electroweak force at 10-10 seconds after the Big Bang, we mean that A) these forces are important only at temperatures below the freezing point of water–a temperature that the universe reached at an age of about 10-10 second. B) "freezing out" was a term coined by particle physicists who think that the Big Bang theory is really cool. C) prior to this time the electromagnetic and weak forces maintained a single identity, but they possessed separate identities following this time. D) following this time neither the electromagnetic nor the weak force was ever important in the universe again. E) quantum fluctuations by high-speed, relativistic particles in a state of false vacuum cause disturbances in the spacetime continuum, leading to the process described in the question this answer refers to. Answer: C

7) How many forces operated in the universe during the GUT era? A) one, what we call the "super force"
B) two, gravity and the GUT force
C) two, gravity and the electroweak force
D) three, gravity, the strong force, and the electroweak force E) all of the above forces

8) Which forces have physicists shown to be the same force under conditions of very high temperature or energy, as confirmed by experiments in particle accelerators? A) gravity and the weak force

B) gravity and the strong force
C) the strong and weak forces
D) the strong and electromagnetic forces
E) the electromagnetic and weak forces

9) What do we mean by inflation?
A) what happened the instant after the Big Bang
B) a sudden expansion of the universe after the strong force froze out from the GUT force C) the expansion of the universe that we still observe today D) the sudden release of photons when a particle and antiparticle annihilate each other E) the separation that occurs after two photons collide and create a particle and an antiparticle Answer: B

10) (From a science quiz that appeared in the weekly magazine The Economist.) Economic history is easier to write than the history of the universe. Nevertheless, most cosmologists now think that when the universe was formed, A) first there was a Big Bang, then inflation (of space) caused recession (of all matter, away from the Big Bang). B) first there...