ASTR 123 Module 8 Quiz

The three observational pillars of cosmology are the expanding universe, big bang nucleosynthesis, and

a. the cosmic microwave background

b. the age of globular cluster stars

c. the rate of Type II supernovae

d. the number of primordial black holes

e. x-ray emission from black hole accretion disks

a. the cosmic microwave background

Which of the following did NOT happen during the first few minutes after the Big Bang?

a. temperatures throughout the universe were hotter than the cores of stars are today

b. two or three of the simplest elements fused together

c. energy was converted to matter

d. some very massive early stars formed

e. matter and antimatter collided and turned into energy

d. some very massive early stars formed

When the age of the universe was about 10 seconds, it had cooled sufficiently for neutrons and protons to bind together and form the key nuclear species which allows production of helium to proceed. This key nucleus is called

a. hydrogen

b. deuterium

c. lithium

d. a quark

e. carbon-6

b. deuterium

The reason nucleosynthesis stopped when the age of the universe was about 3

minutes was

a. because all the elements had been created at that point

b. the universe was cooling too fast to produce elements beyond helium

c. the universe was cooling too fast to produce elements beyond carbon

d. the universe began re-heating, breaking apart any new nuclei

e. it didn’t stop, but began accelerating

b. the universe was cooling too fast to produce elements beyond helium

What happened when the age of the universe was 380,000 years which allows us

to observe the cosmic microwave background?

a. ancient civilizations developed microwave ovens

b. the formation of the first stars

c. the formation of the first galaxies

d. the universe cooled sufficiently to allow neutral hydrogen to form

e. the universe cooled sufficiently to allow deuterium to form

d. the universe cooled sufficiently to allow neutral hydrogen to form

Where in space did the expansion of the universe begin?

a. at the center of the Milky Way Galaxy; that’s why all the other galaxies are moving away from us

b. near the center of the Virgo Supercluster of Galaxies

c. at a point so far away that only our largest telescopes can show us glimpses of it

d. everywhere at once

e. nowhere at all; new observations show that the universe is not expanding after all

d. everywhere at once

Protons and neutrons are composed of other more elementary particles known as

a. neutrinos

b. anti-protons and anti-neutrons

c. electrons

d. quarks

e. Higgs bosons

d. quarks

Factoring in everything we currently know about the history of the universe, our best estimate for the age of the universe is

a. 4.6 billion years

b. about 100 billion years

c. roughly 2 million years

d. about 13.8 billion years

e. the age of the universe is infinite; there was no beginning

d. about 13.8 billion years

Measurements of the cosmic microwave background provide strong evidence that the overall geometry of space is

a. trapezoidal

b. spherical, or positive curvature

c. hyperbolic, or negative curvature

d. flat, or zero curvature

e. circular

d. flat, or zero curvature

Based on cosmic microwave background (CMB) data, astronomers now conclude that the average density of the universe is

a. less than the critical density

b. exactly equal to the critical density

c. more than the critical density

d. essentially equal to zero

e. so great that the universe will experience a “big crunch” before the Sun becomes a red giant

b. exactly equal to the critical density

If the universe consisted only of matter and its density were equal to critical, the universe would

a. continue expanding, then slow down and contract, ending in a “big crunch”

b. continue expanding, eventually slowing down to zero

c. continue expanding, eventually speeding up

d. continue expanding at a reduced rate

e. not expand at all

b. continue expanding, eventually slowing down to zero

Why did Einstein introduce the cosmological constant into the equations of his General Theory of Relativity when describing the universe?

a. Einstein did not realize that black holes would exist at the centers of galaxies and pull everything into them

b. Einstein’s equations required the universe to expand or contract; he could not accept it doing either one, so he put a factor in to stop it from moving

c. Einstein talked to Hubble and learned about Hubble’s observations of the expanding universe, which made him so uncomfortable that he decided to change his equations

d. Einstein had a hunch that the universe was accelerating (speeding up its expansion) back in 1918 and so introduced the constant into his equations to describe that

b. Einstein’s equations required the universe to expand or contract; he could not accept it doing either one, so he put a factor in to stop it from moving

Recent observations indicate that the universe is expanding faster today than it

was a few billion years ago (that, in other words, the expansion of the universe is

accelerating.) What kind of observations have led astronomers to this surprising

conclusion?

a. the measurements of cepheid variables in the galaxies of the Local Group

b. the measurement of galaxy distances using Type Ia supernovae

c. the discovery of large amounts of dark matter in the halo of the Milky Way

d. the measurements of the amount of deuterium in the universe

b. the measurement of galaxy distances using Type Ia supernovae

Roughly what percent of the mass and energy contents of the universe is made

up of ordinary (atomic) matter?

a. 5 percent

b. 10 percent

c. 50 percent

d. 95 percent

e. astronomers have no way of estimating this percentage

a. 5 percent

The observed cosmic microwave background (CMB) is extremely uniform. What is the significance of the small deviations from uniformity which show up as red or blue regions in the CMB images?

a. they are known experimental errors

b. they seed the large scale structure we observe today

c. they turn into supermassive black holes

d. they became the Virgo cluster of galaxies

b. they seed the large scale structure we observe today

The model of the universe that involves an enormous increase of size during a very short time in the early universe is called:

a. the flat universe model

b. the oscillating universe model

c. the primeval atom model

d. the inflationary universe model

e. the cosmic burp model

d. the inflationary universe model

The “horizon problem” is illustrated by what observation of the cosmic microwave

background (CMB)?

a. that the microwaves should not have been able to reach us

b. that the size of the universe represented by the CMB seems to extend beyond the visible horizon

c. that the temperature of disconnected regions is almost exactly the same

d. that large scale structure doesn’t seem to be implied from the CMB

e. that the CMB is analogous to a black hole horizon

c. that the temperature of disconnected regions is almost exactly the same

Current measurements of the Hubble constant H0

a. all agree on a single value

b. disagree depending on the method used

c. all use Type Ia supernovae as standard candles

d. indicate the universe will someday contract to a single point

e. are meaningless

b. disagree depending on the method used

How does a period of extremely fast inflation very early in the history of the universe explain the observation that the geometry of the universe looks flat (not curved) to us?

a. during inflation a lot of the mass drained out of the universe, leaving its gravity much weaker

b. inflation increased the size of the universe so much that the resulting universe looks flat from any point of view

c. inflation led to the production of so much dark matter that the universe got pulled into the shape of a black hole

d. inflation caused the temperature of different parts of the universe that can’t see each other still be the same

e. The universe is actually highly curved and not flat

b. inflation increased the size of the universe so much that the resulting universe looks flat from any point of view