Deck 11: The General Theory of Relativity and the New Cosmology

Question 1

In the theory of cosmic inflation, what is it that experiences a large rapid increase?

A) the temperature of the universe
B) the net [or total] energy of the universe
C) the mass of the universe
D) the size of the universe
E) All of the above.

Answer 1

the size of the universe

Question 2

The emergence of each of the four fundamental forces during the big bang was similar to

A) the collision of two heavy nuclei, such as two lead nuclei.
B) the gravitational collapse of matter when a new star forms.
C) a change of the "state" of a material substance, such as freezing.
D) a supernova explosion.
E) a nuclear reaction.

Answer 2

a change of the "state" of a material substance, such as freezing.

Question 3

Which chemical elements were created during the first few minutes of the "big bang" that started our universe?

A) All 92 of the naturally- occurring chemical elements.
B) Only the heaviest elements, having atomic numbers higher than that of lead.
C) Only the first three elements: hydrogen, helium, and lithium.
D) Only the elements through iron in the periodic table, i.e., only elements 1 through 26.
E) No elements were produced during the big bang-- all the normal chemical elements were produced much later.

Answer 3

Only the first three elements: hydrogen, helium, and lithium.

Question 4

One unusual aspect of dark energy is

A) its pushes outward on everything in the universe instead of pulling inward as gravity ordinarily does.
B) it's made of a material that has not yet been observed in our laboratories.
C) Both of the above.
D) it exerts a new kind of fundamental force, never observed before.
E) it exerts no gravitational force.

Question 5

What is the universe mostly made of?

A) dark energy
B) intergalactic gas
C) electromagnetic radiation
D) dark matter
E) None of the above.

Question 6

Which of the following observations lend support to the big bang theory?

A) the cosmic background radiation
B) the ripples, or variations, in the cosmic background radiation
C) Both of the above.
D) the "red shift" of the light from distant galaxies
E) All of the above.

Question 7

In an open universe, the angles of a triangle add up to

A) more than 180 degrees.
B) less than 180 degrees.
C) 180 degrees.

Question 8

According to the theory of cosmic inflation, the large- scale clumping of matter (into stars, galaxies, etc.) that we observe in the universe had its origin in

A) quantum uncertainties that were then stretched by the expansion of the universe.
B) thermal motion caused by the high temperature of the early universe.
C) quantum nonlocality, that connected bits of energy that were originally separated.
D) the creation of dark energy, that exerted an inward force and pulled things together.
E) the creation of dark matter, that exerted a repulsive force and pushed things together.

Question 9

The evidence that the universe is expanding at an accelerating rate comes from observations of

A) the redshifts of the stars in our own galaxy.
B) the rate of rotation of distant galaxies.
C) the redshifts in the light of from supernovas in other galaxies far away.
D) the center of our own galaxy, which is accelerating as it expands.
E) the redshift in the light from the cosmic background radiation.

Question 10

One line of evidence supporting the big bang theory is

A) the observed abundance of very light elements in our galaxy is just what is predicted by the big bang theory.
B) the observed abundance of very heavy elements in our galaxy is just what is predicted by the big bang theory.
C) the nuclear fission products observed in our galaxy are just what is predicted by the big bang theory.
D) the density of galaxies observed in the universe is just what is predicted by the big bang theory.
E) neutron stars have just the masses and frequencies of rotation that are predicted by the big bang theory.

Question 11

By observing gas clouds orbiting the centers of galaxies, we have learned that galaxies are made mostly of dark matter. In these observations

A) the high speeds of the gas clouds show that they are being pushed by some unseen material.
B) the high speeds of the gas clouds show that they are gravitationally attracted to the center by unseen material.
C) the low speeds of the gas clouds show that they are gravitationally attracted to the center by unseen material.
D) the light from the gas clouds is obscured by some unseen material.
E) the low speeds of the gas clouds show that they are being slowed by some unseen material.

Question 12

One experiment that informs us that gravity bends lightbeams is

A) laboratory experiments in which laser beams pass by massive amounts of iron.
B) the bending of starlight as it nears Earth.
C) the observed bending of light from stars as the light passes the sun.
D) the observed bending of sunlight in Earth's gravitational field.
E) experiments in which laser beams are shined onto the surface of the moon, and their bending is measured.

Question 13

Dark matter is made of

A) slow- moving "magnetons" that were created during the big bang.
B) fast moving "gluons" that were created during the big bang.
C) Both of the above.
D) soap bubbles.
E) an unknown material that has never been directly observed in laboratories.

Question 14

In a closed universe, the angles of a triangle add up to

A) more than 180 degrees.
B) 180 degrees.
C) less than 180 degrees.

Question 15

According to the theory of cosmic inflation, during a brief early "inflationary period," the universe

A) expanded at lightspeed.
B) quickly became far more densely filled with matter.
C) expanded at a speed that was only slightly slower than lightspeed.
D) quickly became far more densely filled with energy.
E) expanded at a speed that exceeded lightspeed.

Question 16

Does a high- speed bullet's path bend more than a light beam bends as it passes near Earth?

A) Yes, because the light beam has a greater acceleration that the bullet.
B) Yes, because the bullet is heavier than the light beam.
C) Yes, because the bullet moves slower than the light beam.
D) No, because all falling objects accelerate at the same rate.
E) No, because of Einstein's equivalence principle.

Question 17

As evidence for the cosmic inflation hypothesis, this hypothesis explains

A) the observed "flatness" of the overall three- dimensional universe.
B) the origin of the "clumping" of matter and energy that we see today in such aggregations as stars and galaxies.
C) Both of the above.
D) the force of gravity.
E) All of the above.

Question 18

Recent evidence from very distant supernova explosions indicates that the universe is expanding

A) at a decreasing rate, and this will eventually come to a halt with no further expansion or contraction.
B) at an unchanging rate.
C) at a decreasing rate, but without ever coming to a halt (so that it will expand forever).
D) at a decreasing rate, and this will eventually turn into an overall contraction.
E) at an increasing rate.

Question 19

The universe is made mostly of

A) dark energy.
B) ordinary matter.
C) dark matter.
D) pizza.
E) neutrinos.

Question 20

How do we know the shape of the universe?

A) By observing distant stars during eclipses of the sun.
B) By triangulation measurements involving the distances to the sun and to the moon.
C) From the comparison between the pulsations coming from distant neutron stars.
D) By observation of the angular size of a typical wavelike disturbance in the cosmic microwave background.
E) By observing the light from distant stars and one star passes in front of another star.

Question 21

Evidence for the big bang comes from

A) observations of the pulsations of distant neutron stars.
B) the observation that the galaxies are all receding from each other.
C) observation of the cluster of stars near the center of the Milky Way galaxy.
D) All of the above.
E) None of the above.

Question 22

If you were in a rocket ship in distant space, far from all gravitational influences, and accelerating at 2g, you would feel

A) your normal weight.
B) twice your normal weight.
C) weightless.
D) This cannot be answered without knowing your speed.

Question 23

The big bang created

A) space and time.
B) matter and energy.
C) Both of the above.
D) None of the above.

Question 24

The big bang is thought to have occurred about

A) a million years ago.
B) 14 million years ago.
C) 14 trillion years ago.
D) 14 billion years ago.
E) 5000 years ago.

Question 25

According to the principle of equivalence, gravity is equivalent to

A) velocity.
B) energy.
C) net force.
D) acceleration.
E) the state of free- fall.

Question 26

Galaxies seem to be made mostly of dark matter. One type of evidence for this comes from observations of

A) the redshift in the light from the explosions of distant supernovas.
B) the redshift in the light from the earliest galaxies in the universe.
C) Both of the above.
D) the speeds at which gas clouds orbit the centers of galaxies.
E) distant quasars.

Question 27

The evidence favors a universe whose overall geometry is

A) open.
B) circular.
C) closed.
D) cylindrical.
E) flat.

Question 28

Since accelerations are equivalent to gravity, a person could cancel the effects of Earth's gravity by

A) going into orbit around Earth.
B) falling from a high place.
C) Both of the above.
D) accelerating straight upward at an acceleration of 1g.
E) Nonsense-- you can't cancel the effects of gravity.

Question 29

Dark energy

A) has never been directly observed in the laboratory.
B) pushes on space.
C) has mass.
D) All of the above.
E) None of the above.

Question 30

According to the theory of cosmic inflation, at what time in the history of the universe did inflation occur?

A) at the time that the cosmic background radiation formed
B) at a tiny fraction of the first second, but not quite at the very beginning of the big bang
C) at the very beginning of the big bang
D) around the third or fourth second
E) around the third or fourth minute

Question 31

In the equivalence principle,

A) all forces are equivalent.
B) acceleration is equivalent to force.
C) all velocities are equivalent.
D) velocity is equivalent to the gravitational force.
E) acceleration is equivalent to the gravitational force.

Question 32

The cosmic microwave background is

A) caused by the world's microwave ovens.
B) the now- cooled X-ray radiation emitted by very distant supernova explosions.
C) the faint glow from the most distant galaxies.
D) the faint radiation that comes from the hydrogen atoms that fill the universe.
E) the now- cooled radiation that was released by the big bang.

Question 33

One piece of evidence supporting the theory of cosmic inflation is

A) the observed fact that the temperature of the cosmic background radiation is now about 4 Kelvin.
B) the fact that neutrinos are now known to have no rest mass.
C) the observed fact that the geometry of the universe is "flat.".
D) the observed fact that the geometry of the universe is "open."
E) the fact that neutrinos have been found to have rest mass.

Question 34

Dark energy is made of

A) invisible electromagnetic fields.
B) an unknown material that has never been directly observed in laboratories.
C) fast moving "gluons" that were created during the big bang.
D) weak force fields that were created during the big bang.
E) slow- moving "magnetons" that were created during the big bang.

Question 35

According to the principle of equivalence, acceleration is equivalent to

A) energy.
B) gravity.
C) net force.
D) velocity.
E) the state of free- fall.

Question 36

In the general theory of relativity, we assume the observer to be

A) moving with constant velocity.
B) moving at a significant fraction of lightspeed.
C) moving slowly compared to lightspeed.
D) at rest.
E) None of the above.

Question 37

Cosmic inflation caused the universe to expand, for a brief period, at faster than lightspeed. But special relativity says that nothing can move faster than lightspeed. How can this contradiction be resolved?

A) We now realize that special relativity does not apply to dark energy.
B) The laws of specially relativity were not valid during the inflationary period, but the other laws (such as conservation of energy) were valid.
C) Special relativity says nothing can move through space at faster than lightspeed, but doesn't restrict the speed at which space can expand.
D) It hasn't yet been resolved, but scientists are working on resolving it.
E) The laws of physics (conservation of energy, special relativity, etc.) as we presently know them were not valid during the "inflationary period" that existed for a fraction of a second into the big bang.

Question 38

Is everything in the universe expanding?

A) No, the distances between the galaxies are not expanding.
B) No, the Milky Way galaxy is not expanding.
C) Both of the above are correct.
D) Yes.

Question 39

According to Einstein, gravity is

A) the bending of space that is caused by masses.
B) the force that masses exert on each other.
C) caused by the electromagnetic force.
D) due only to velocity.
E) due only to acceleration.

Question 40

In coming to the conclusion that lightbeams are bent by gravity, Einstein reasoned that

A) accelerated observers would find that lightbeams bend, so gravity must also bend lightbeams.
B) increased mass at higher velocities causes increased gravitational effects, so lightbeams moving at lightspeed should have gravitational effects.
C) since all observers experience the same laws of physics, Newton's theory of gravity must apply to lightbeams.
D) fast- moving observers would find that lightbeams bend, so gravity must also bend lightbeams.
E) since lightspeed is the same for all observers, moving observers would observe that lightbeams bend.

Question 41

The amount of dark matter in the universe is

A) many times more than the amount of visible matter.
B) entirely unknown at the present time.
C) about the same as the amount of visible matter.
D) many times less than the amount of visible matter.
E) about twice as much as the amount of visible matter.

Question 42

One unusual aspect of dark matter is

A) its gravitational force pushes (or repels) instead of pulling.
B) it does not interact with electromagnetic radiation.
C) it exerts a new kind of fundamental force, never observed before.
D) it exerts no gravitational force.
E) it moves faster than lightspeed.

Question 43

The expansion of the universe seems to be accelerating. The evidence for this is based on observations of

A) the cosmic background radiation.
B) gas clouds orbiting the centers of galaxies.
C) the slowing down in the pulsation rate of distant neutron stars.
D) the redshift in the light from the explosions of distant supernovas.
E) the manner in which the stars are distributed in our own galaxy.

Question 44

According to the theory of cosmic inflation, the universe

A) began from a powerful electromagnetic effect in vacuum.
B) had no beginning but instead has always existed.
C) began as the result of the "big crunch" collapse of some pre- existing universe.
D) began when two very massive pre- existing particles collided and annihilated with each other.
E) began as a tiny fragment of space and time.

Question 45

The evidence favors a universe whose overall geometry is flat. That evidence comes from observations of

A) the force of gravity acting on laboratory objects.
B) distant quasars.
C) the earliest galaxies in the universe.
D) the cosmic background radiation.
E) the center of our galaxy.

Question 46

Galaxies seem to be made mostly of dark matter. One type of evidence for this comes from observations of the

A) energy emitted by distant quasars, which is far larger than can be explained by the visible matter in the quasars.
B) gravitational bending of light from distant galaxies as it passes other galaxies on its way to Earth.
C) redshift in the light from the earliest galaxies in the universe.
D) redshift in the light from the explosions of distant supernovas.
E) force of gravity acting on laboratory objects.

Question 47

What is the universe mostly made of?

A) dark matter
B) electromagnetic radiation
C) ordinary matter, including intergalactic gas
D) neutrinos
E) None of the above.

Question 48

If you were in a spaceship in outer space and accelerating at 0.5 g, how heavy would you feel?

A) Weightless
B) 1.5 times your normal weight
C) Your normal weight
D) Half your normal weight
E) The answer depends on how fast your spaceship is moving.

Question 49

Can anything go faster than light?

A) No, special relativity forbids it.
B) No, general relativity forbids it.
C) Yes, space can expand at faster then lightspeed.
D) Yes, certain subatomic particles can move through space at faster than lightspeed.
E) Superman can.

Question 50

Space and time

A) have always existed.
B) were created at some time before the big bang.
C) were created by the big bang.
D) were created at some time after the big bang.

Question 51

One unusual aspect of dark matter is

A) it exerts no gravitational force.
B) it moves faster than lightspeed.
C) it's made of a material that has not yet been observed in our laboratories.
D) its gravitational force pushes (or repels) instead of pulling.
E) it exerts a new kind of fundamental force, never observed before.