Deck 15: Cosmology and the Universe

Question 1

Observed mall fluctuations in the temperature of the cosmic microwave background are predicted by dark energy models.

Answer 1

False

Question 2

The cosmic microwave background is the total of all the radio emissions from all the galaxies and quasars in the universe.

Answer 2

False

Question 3

An infinite universe is one of the assumptions of the cosmological principle.

Answer 3

False

Question 4

The fate or future of the universe depends only on the total number of galaxies and quasars.

Question 5

Dark matter had no effect on the distribution of matter in the early universe.

Question 6

The cosmological redshift is a direct measure of the expansion of the universe, thus independent of direction.

Question 7

Homogeneity and isotropy, taken as assumptions regarding the structure and evolution of the universe, are known as

A) Obler's Paradox.
B) Hubble's Law.
C) Wien's Law.
D) the Cosmological Principle.
E) the Grand Unified Theory.

Question 8

Primordial nucleosynthesis refers to the Big Bang making all elements up to iron.

Question 9

The cosmological redshift is actually not a velocity at all, but a measure of the expansion of space-time.

Question 10

The flatness problem is the fact that the observed density of matter is unexpectedly different from the critical density predicted by the inflationary epoch.

Question 11

The universe has been expanding at the same rate since its formation.

Question 12

At decoupling, the electrons and protons were made from neutron decay.

Question 13

The universe expanded by a factor of 10⁵⁰ during inflation, when the strong force separated from the electromagnetic and weak nuclear forces.

Question 14

The Big Bang was an expansion of matter into empty space.

Question 15

The low density universe is an open one, with expansion continuing forever.

Question 16

Not taking dark energy into account, we seem to live now in a matter dominated universe, since the observed matter density exceeds the observed energy density.

Question 17

Decoupling refers to interactions between matter and antimatter at the end of the Radiation Era.

Question 18

The Hubble constant divided into the number one gives a rough estimate for the age of the universe, or the "Hubble Time."

Question 19

Deuterium was made only in primordial nucleosynthesis, since stars destroy it.

Question 20

What is the Great Wall?

A) It is a ridge on the Moon near the crater Birt.
B) It is the distance beyond which astronomers cannot view any more galaxies or even quasars.
C) It is a large sheet of galaxies.
D) It is the time before the universe started expanding, about which we can never know anything.
E) It is an enormous intergalactic cloud of dust and gas that hides more distant galaxies.

Question 21

The concept that the direction of observation does not matter overall is

A) relativity.
B) homogeneity.
C) universality.
D) isotropy.
E) geometry.

Question 22

The redshift of the galaxies is correctly interpreted as

A) a Doppler shift due to the random motions of galaxies in space.
B) an aging of light as gravity weakens with time.
C) space itself is expanding with time, so the photons are stretched while they travel through space.
D) placing our Galaxy near the center of the Local Group.
E) the differences in temperatures and star formation in old and young galaxies.

Question 23

What does Hubble's law imply about the history of the universe?

A) The universe must be infinitely old and huge.
B) The universe had a beginning and has expanded since, giving it a finite age.
C) The Milky Way lies exactly at the center of this expansion.
D) The red shifts will lengthen with time due to dark energy.
E) The red shifts will turn to blue shifts as universe contraction follows the expansion.

Question 24

The expansion rate of the Universe is

A) increasing.
B) decreasing.
C) constant.
D) different in different directions.
E) independent of time.

Question 25

The universal accelerating force could NOT be considered

A) antigravity.
B) Einstein's cosmological constant.
C) dark energy.
D) vacuum pressure.
E) dark matter.

Question 26

What temperature has the Big Bang has cooled to by now?

A) About 3,000 K
B) 5,800 K
C) About 300 K
D) Just over 2.7K
E) 1.4 K

Question 27

The center of the universe

A) is the Milky Way.
B) is the Sun.
C) is Earth.
D) is where the Big Bang happened.
E) does not exist anywhere in space.

Question 28

What is the Big Bang?

A) An enormous explosion that organized all matter in the universe
B) The creation of matter and the universe
C) The creation of the primeval fireball
D) An explosion that spewed matter all over the universe
E) The event that started the expansion of the universe

Question 29

The Hubble time is expressed as

A) H × D.
B) D/v.
C) 1/H.
D) H × T.
E) the critical density/H.

Question 30

In which of the following models will the universe stop expanding?

A) High Density Universe
B) Low Density Universe
C) Steady State Universe
D) Critical Density Universe
E) Euclidean Universe

Question 31

The discovery of the cosmic microwave background was important because

A) it established a firm center of the Universe.
B) it was experimental verification of a prediction from the Big Bang theory.
C) it proved that astronomy at radio wavelengths was possible.
D) its detection was a major advance in microwave testing.
E) it showed the universe must be closed, with more than the critical density here.

Question 32

The critical evidence for cosmic acceleration in 1998 came from two teams of astronomers, both observing

A) hypernovae.
B) gamma ray bursts.
C) type I supernovae.
D) type II supernovae.
E) ages of globular clusters.

Question 33

Recent work with type I supernovae at great distances suggests the universe may in fact be accelerating its expansion, a discovery attributed to a newly found

A) repulsive charge on dark matter.
B) polarization and a universal spinning magnetic field.
C) dark energy.
D) magnetic field associated with antimatter.
E) mass determined for the neutrinos.

Question 34

The luminous matter in the universe accounts for what percent of the total mass of the universe?

A) About 5%
B) About 23%
C) About 27%
D) About 73%
E) 100%

Question 35

What was there just after the Big Bang?

A) Nothing
B) The primeval fireball
C) A singularity
D) A black hole
E) Everything was inside Earth.

Question 36

The presently accepted value of the Hubble constant gives an age of

A) 4.5 billion years.
B) 8-9 billion years.
C) 14 billion years.
D) 18 billion years.
E) 22 billion years.

Question 37

From the 1970s to the present, the accepted value of H has almost doubled, so

A) the age of the universe is twice as old as we originally believed.
B) the age of the Universe is half what we believed.
C) the Copernican principle is not valid beyond our solar system.
D) the ages of the oldest globular clusters are invalid.
E) the critical density must also be halved.

Question 38

While a variety of factors can produce red shifts in the spectrum, the one associated with the expansion of the universe is called

A) universal.
B) cosmological.
C) olberian.
D) relativistic.
E) the Zeeman Effect.

Question 39

Astronomers know the universe is expanding because

A) everything is moving away from us.
B) all stars are moving away from us.
C) most galaxies are moving away from us.
D) galaxies farther away are moving away from us faster.
E) there is a cosmic microwave background.

Question 40

The concept that on the grandest of scales, the universe is similar in appearance everywhere is

A) special relativity.
B) general relativity.
C) homogeneity.
D) isotropy.
E) universality.

Question 41

Why didn't elements heavier than helium form in the first minutes of creation?

A) The first generation of stars used them up too quickly to observe them.
B) There was not enough matter in the universe at that time.
C) When He-4 was formed, the expansion cooled the cosmos below 100 million K.
D) The electrons slowed down enough to be captured into orbits by protons.
E) Only Type I supernovae can produce iron and heavier elements.

Question 42

The best answer to both the flatness and horizon problems is

A) the Steady State Theory.
B) the GUT theory.
C) the inflationary epoch.
D) dark energy.
E) decoupling.

Question 43

Before about 4 billion years ago the universe was

A) radiation dominated.
B) quark dominated.
C) lepton dominated.
D) matter dominated.
E) dark energy dominated.

Question 44

How does the energy of the cosmic microwave background compare to the energy radiated by all the stars and galaxies that ever existed?

A) They are very close to being equal.
B) 73% cosmic background, 27% starlight
C) About ten times more from the Big Bang than from stars and galaxies
D) The starlight now dominates the background, as your eyes show clearly.
E) We have no way of comparing matter and energy this way.

Question 45

Which of these substances must be primordial?

A) Helium
B) Lithium
C) Deuterium
D) Beryllium
E) Tritium

Question 46

About how hot was the Big Bang when matter and energy "decoupled"?

A) 900 million K
B) 15 million K
C) 3,000 K
D) 300 K
E) 2.73 K

Question 47

Of the normal elements around us, the Big Bang produced

A) none, only energy.
B) only hydrogen.
C) hydrogen and helium.
D) all elements up to iron.
E) all elements in much their present proportions.

Question 48

Before about 50,000 years after the Big Bang the universe was

A) radiation dominated.
B) quark dominated.
C) lepton dominated.
D) matter dominated.
E) dark energy dominated.

Question 49

Which of these seems the best present answer to the flatness problem?

A) The superforce rules creation.
B) Dark Energy speeds the universe on out to infinity.
C) Symmetry in creation of particles and antiparticles
D) The inflationary epoch
E) The GUT theory

Question 50

The Big Bang formed

A) only hydrogen.
B) only helium.
C) hydrogen and helium, but nothing else.
D) all elements up to iron.
E) all elements found in nature now.

Question 51

Before the decoupling

A) the Universe was transparent to radiation.
B) the Universe was opaque to radiation.
C) protons and electrons combined to form atoms.
D) there was more helium than hydrogen.
E) deuterium produced electrons and positrons.

Question 52

What key event happened during the decoupling epoch?

A) Pairs of neutrons and protons were created.
B) Electrons and positrons were created.
C) Expansion cooled the universe enough that protons could capture electrons in orbit.
D) Dark energy accelerated the cosmos on to infinity.
E) The universe underwent a brief period of very rapid expansion.

Question 53

The crossover point from radiation to matter domination occurred

A) when the strong force separated from the other two forces.
B) with the emission of the cosmic background radiation.
C) about 50,000 years after the Big Bang, at a temperature of about 16,000 K.
D) with the creation of neutrons and protons, at about 10¹³ K.
E) with the creation of electrons and positrons at about 6 × 10⁹ K.

Question 54

The one theory of the early universe before the Recombination Epoch and after the Planck Epoch that was developed to resolve a conflict between observation and theory is

A) the Grand Unified Theory.
B) the theory of inflation.
C) the theory of nucleosynthesis.
D) the theory of recombination.
E) the quantum quark theory.

Question 55

At the end of the first fifteen minutes, the mass ratio of H/He created was about

A) 50/50.
B) 75/25.
C) 27/73.
D) 90/10.
E) 1/4.

Question 56

The "flatness" problem arises because the curvature of space seems remarkably close to

A) zero curvature, favoring a spherical cosmos.
B) exactly one.
C) 0.5, suggesting we are split between open and closed universes.
D) 2.73 K, in spite of the eddies and turbulence that led to galaxy formation.
E) infinity, suggesting an open universe is the only possible cosmology.

Question 57

At this time, the universe is

A) radiation dominated.
B) quark dominated.
C) lepton dominated.
D) matter dominated.
E) dark energy dominated.

Question 58

Currently, most of the mass of the matter of the universe is believed to consist of

A) baryonic matter, made up of protons and neutrons.
B) tachyonic matter, travelling only faster than the speed of light.
C) dark matter not made of protons and neutrons.
D) dark energy.
E) tiny but very numerous black holes.

Question 59

Which of these did NOT occur at decoupling?

A) The cosmic microwave radiation was released from matter.
B) Neutral atoms were formed.
C) Matter dominated radiation.
D) Electrons began to orbit protons.
E) The universe became transparent.

Question 60

Most of the deuterium that formed right after the Big Bang

A) is still around today.
B) broke down into electrons and neutrons.
C) turned into dark matter.
D) quickly burned into helium nuclei.
E) was found in the globular clusters.

Question 61

Observed temperature fluctuations in the Cosmic Microwave Background Radiation are

A) millions of kelvins.
B) hundreds of kelvins.
C) a few kelvins.
D) tens of millionths of a kelvin.
E) immeasurably small.

Question 62

The extended sheet of galaxies that spans 70 Mpc × 200 Mpc and includes about 24,000 galaxies is called the ________.

Question 63

The ________ background radiation in fact far exceeds all the energy radiated by all the stars and galaxies that formed since then.

Question 64

Ripples in the Cosmic Microwave Background correspond to

A) matter density fluctuations.
B) temperature fluctuations.
C) energy fluctuations.
D) fluctuations in both matter and radiation.
E) imperfections in measurement techniques or equipment.

Question 65

The first structures in the universe appear to have formed within

A) the newly formed helium.
B) the normal matter.
C) the electromagnetic radiation.
D) the dark matter.
E) the dark energy.

Question 66

How does dark energy affect the expansion of the Universe?

Question 67

The cosmological principle is the ultimate extension of the ________ principle; we are note at the center of the solar system, the galaxy, or the universe.

Question 68

Is the Hubble Constant really constant?

Question 69

Contrast dark matter and dark energy with respect to their roles in the future of the universe.

Question 70

The universe was two minutes old when ________ started to form from deuterium fusion.

Question 71

The huge, dark, almost spherical regions between the superclusters of galaxies are called ________.

Question 72

When dark matter first became popular, many astronomers thought that was greater than one from the extra gravity, favoring what type of Universe?

Question 73

The ________ is the observational evidence that the whole universe was once extremely hot and dense, as called for in the Big Bang, but has now expanded and redshifted this energy to much longer wavelengths.

Question 74

________ is the concept that all large samples of the universe are alike in appearance anywhere in the universe.

Question 75

All of the ________ now observed must be primordial.

Question 76

Most astronomers agree to interpret ________ Law to mean that the present day universe is expanding.

Question 77

Discounting the newly discovered role of dark energy, the universe we live in now is said to be ________ dominated.

Question 78

With the exception of a few nearby objects, every galaxy in the universe is rapidly moving away from ours; therefore, ________.

Question 79

Computer simulations and the huge structures observed in the universe support the ________ model of the universe.

Question 80

________ is the concept that the universe looks the same in all directions.