Question 1

During inflation when the universe was approximately 1 second old,its size grew by a factor of 10³⁰.

Accepted Answer

The inflationary period occurred much earlier, around 10^-36 to 10^-32 seconds after the Big Bang, not when the universe was 1 second old. During this period, the universe expanded by a factor of about 10^26 to 10^30.

Question 2

Even at its earliest moments,the universe had about as much structure in it as it has at the current time.

Accepted Answer

The earliest moments of the universe were characterized by extreme heat and density, and the structure that we see today did not form until much later as the universe cooled and expanded.

Question 3

The four fundamental forces of nature are gravity,electromagnetism,the weak force,and the strong force.

Accepted Answer

This is true.

Question 4

The three fundamental forces of nature are gravity,electromagnetism,and the strong force.

Accepted Answer

The answer of The three fundamental forces of nature are...

Question 5

The force that binds three quarks together to make up a proton or neutron is called the weak force.

Accepted Answer

The force that binds three quarks together to make up a proton or neutron is called the strong force. The weak force is responsible for certain types of radioactive decay.

Question 6

Dark energy is a force that continually decreases the expansion rate of the universe.

Accepted Answer

Dark energy is a force that accelerates the expansion rate of the universe, not decreases it.

Question 7

The fact that $\varOmega$_mass + $\varOmega$_$\wedge$ is very close to 1 means that its value has always been very close to 1.

Accepted Answer

The answer of The fact that $\varOmega$_mass + $\varOmega$_$\wedge$ is...

Question 8

The ratio of the density in luminous matter to the critical density is 0.3.

Accepted Answer

The answer of The ratio of the density in luminous...

Question 9

There are fluctuations in the CBR due to the fact that clumps of dark matter had already begun to form in the universe.

Accepted Answer

The clumps of dark matter had gravitational effects on the distribution of matter in the early universe, which in turn affected the CBR. This can be seen in the small variations in temperature observed in the CBR map.

Question 10

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 10³⁰.

Accepted Answer

The theory of inflation posits that the universe underwent rapid expansion shortly after the Big Bang, but it does not involve dark energy decaying. Instead, it involves a different mechanism, often related to a scalar field called the inflaton.

Question 11

The concept of inflation helps solve both the problems of the flatness of the universe and smoothness of the cosmic background radiation.

Accepted Answer

Inflation is a theory that proposes a very rapid expansion of the universe in the early stages, which helps to explain why the universe appears to be so flat and so evenly distributed, as seen in the cosmic background radiation.

Question 12

In the superstring theory that successfully unites gravity and quantum mechanics,the universe must have 11 dimensions (10 spatial and 1 temporal).

Accepted Answer

According to the superstring theory, the universe must have 11 dimensions, which includes 10 spatial dimensions and 1 temporal dimension.

Question 13

Observations of Type Ia supernovae in distant galaxies confirm that the expansion of the universe is decreasing over time.

Accepted Answer

Observations of Type Ia supernovae actually suggest that the expansion of the universe is accelerating over time, not decreasing. This was a surprising discovery that led to the concept of dark energy, which is thought to be driving this acceleration.

Question 14

If the sum of the mass and energy density in the universe yields $\varOmega$ < 1 then the universe will recollapse in a Big Crunch.

Accepted Answer

This statement is true. If the sum of the mass and energy density in the universe is less than the critical density needed for a flat universe, which is approximately 5.3 protons per cubic meter, then the universe will recollapse in a Big Crunch. A value of less than 1 indicates that the universe's mass and energy density are not enough to overcome the expansion of the universe and prevent a recollapse.

Question 15

The ratio of the average density in all forms of matter (luminous and dark)in our universe to the critical density is approximately 0.3.

Accepted Answer

The commonly accepted value for the density parameter, which is the ratio of the average density in the universe to the critical density, is indeed approximately 0.3. This means the universe is flat and will not collapse back on itself.

Question 16

If dark energy were to instantly cease,our universe would continue to expand forever.

Accepted Answer

This is because the expansion of the universe is not solely driven by dark energy, but also by the initial Big Bang event and the momentum acquired during the inflationary period of the universe. Dark energy just contributes to the acceleration of this expansion. Therefore, even if dark energy were to suddenly disappear, the universe would still continue to expand, albeit possibly at a slower rate.

Question 17

Current numerical models suggest that most of the universe is composed of hot dark matter.

Accepted Answer

Current numerical models suggest that most of the universe is composed of cold dark matter, not hot dark matter.

Question 18

Directly after the Big Bang,the universe was filled with a variety of charged particles,antiparticles,and photons.

Accepted Answer

According to the Big Bang theory, after the initial explosion, the universe was filled with a hot, dense plasma of charged particles, antiparticles, and photons. This is also known as the "primordial soup." As the universe expanded and cooled, the particles and antiparticles annihilated each other, leaving behind a small excess of matter particles that eventually formed galaxies and stars.

Question 19

As structure formed in the universe,galaxy-sized objects formed before cluster-sized objects.

Accepted Answer

According to the hierarchical model of structure formation in the universe, galaxy-sized objects formed first and merged together to form cluster-sized objects later on.

Question 20

The weak force mediates the beta decay of neutrons into protons,electrons,and antineutrinos.

Accepted Answer

The weak force is responsible for the beta decay of neutrons in which an electron and an antineutrino are emitted along with the conversion of a neutron into a proton.

Quiz 17: Modern Cosmology and the Origin of Structure

During inflation when the universe was approximately 1 second old,its size grew by a factor of 10³⁰.

Even at its earliest moments,the universe had about as much structure in it as it has at the current time.

The four fundamental forces of nature are gravity,electromagnetism,the weak force,and the strong force.

The three fundamental forces of nature are gravity,electromagnetism,and the strong force.

The force that binds three quarks together to make up a proton or neutron is called the weak force.

Dark energy is a force that continually decreases the expansion rate of the universe.

The fact that $\varOmega$ _mass + $\varOmega$ _$\wedge$ is very close to 1 means that its value has always been very close to 1.

The ratio of the density in luminous matter to the critical density is 0.3.

There are fluctuations in the CBR due to the fact that clumps of dark matter had already begun to form in the universe.

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 10³⁰.

The concept of inflation helps solve both the problems of the flatness of the universe and smoothness of the cosmic background radiation.

In the superstring theory that successfully unites gravity and quantum mechanics,the universe must have 11 dimensions (10 spatial and 1 temporal).

Observations of Type Ia supernovae in distant galaxies confirm that the expansion of the universe is decreasing over time.

If the sum of the mass and energy density in the universe yields $\varOmega$ < 1 then the universe will recollapse in a Big Crunch.

The ratio of the average density in all forms of matter (luminous and dark)in our universe to the critical density is approximately 0.3.

If dark energy were to instantly cease,our universe would continue to expand forever.

Current numerical models suggest that most of the universe is composed of hot dark matter.

Directly after the Big Bang,the universe was filled with a variety of charged particles,antiparticles,and photons.

As structure formed in the universe,galaxy-sized objects formed before cluster-sized objects.

The weak force mediates the beta decay of neutrons into protons,electrons,and antineutrinos.

Quiz 17: Modern Cosmology and the Origin of Structure

During inflation when the universe was approximately 1 second old,its size grew by a factor of 1030.

Even at its earliest moments,the universe had about as much structure in it as it has at the current time.

The four fundamental forces of nature are gravity,electromagnetism,the weak force,and the strong force.

The three fundamental forces of nature are gravity,electromagnetism,and the strong force.

The force that binds three quarks together to make up a proton or neutron is called the weak force.

Dark energy is a force that continually decreases the expansion rate of the universe.

The fact that Ω\varOmegaΩ mass + Ω\varOmegaΩ ∧\wedge∧ is very close to 1 means that its value has always been very close to 1.

The ratio of the density in luminous matter to the critical density is 0.3.

There are fluctuations in the CBR due to the fact that clumps of dark matter had already begun to form in the universe.

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 1030.

The concept of inflation helps solve both the problems of the flatness of the universe and smoothness of the cosmic background radiation.

In the superstring theory that successfully unites gravity and quantum mechanics,the universe must have 11 dimensions (10 spatial and 1 temporal).

Observations of Type Ia supernovae in distant galaxies confirm that the expansion of the universe is decreasing over time.

If the sum of the mass and energy density in the universe yields Ω\varOmegaΩ < 1 then the universe will recollapse in a Big Crunch.

The ratio of the average density in all forms of matter (luminous and dark)in our universe to the critical density is approximately 0.3.

If dark energy were to instantly cease,our universe would continue to expand forever.

Current numerical models suggest that most of the universe is composed of hot dark matter.

Directly after the Big Bang,the universe was filled with a variety of charged particles,antiparticles,and photons.

As structure formed in the universe,galaxy-sized objects formed before cluster-sized objects.

The weak force mediates the beta decay of neutrons into protons,electrons,and antineutrinos.

During inflation when the universe was approximately 1 second old,its size grew by a factor of 10³⁰.

The fact that $\varOmega$ _mass + $\varOmega$ _$\wedge$ is very close to 1 means that its value has always been very close to 1.

The theory of inflation assumes that at some point in time dark energy will decay and the universe will expand rapidly by a factor of 10³⁰.

If the sum of the mass and energy density in the universe yields $\varOmega$ < 1 then the universe will recollapse in a Big Crunch.