Home (earth)


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

A) Olbers's paradox.

B) Hubble's law.

C) Wien's law.

D) the cosmological principle.

E) the Grand Unified Theory.


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

A) relativity.

B) homogeneity.

C) universality.

D) isotropy.

E) geometry.


) 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.


) Because almost all galaxies show redshifted spectra, we know that

A) our understanding of redshift is wrong.

B) we must be at the center of the universe.

C) the universe is expanding.

D) the sky must be dark at night.

E) the universe is closed.



) The darkness of the night sky in an infinite universe is addressed in

A) General Relativity.

B) Special Relativity.

C) Steady State Physics.

D) Olbers's paradox.

E) the Cosmological principle.


) 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.

) 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 redshifts will lengthen with time due to dark energy.

E) The redshifts will turn to blueshifts as universe contraction follows the expansion.


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

A) open universe

B) closed universe

C) critical density universe

D) steady state universe

E) All have an ultimate collapse.



) 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.


) What is the meaning of a "closed" universe?

A) The universe will expand forever.

B) The universe will someday stop expanding and start to collapse.

C) The universe will stop expanding in an infinite amount of time.

D) The universe is in a steady-state.

E) The universe will disappear into a white hole in time.


) In the closed universe model, the geometry of spacetime in two dimensions resembles the surface of a

A) flat piece of paper.

B) saddle.

C) cylinder.

D) sphere.

E) pyramid.


) If the density of the universe is greater than critical, then

A) there is more matter than energy.

B) the universe is closed, gravity wins, and will shrink to the Big Crunch.

C) the universe is flat, and Euclid is right.

D) the universe will continue expanding forever.

E) the universe will end up as nothing but black holes.




) Studies from ________ led to the discovery of "dark energy."

A) Cepheid variables in the Virgo Cluster

B) Type II supernovae in the Large Magellanic Cloud

C) the gravitational lensing by MACHOs

D) the COBE microwave ripples

E) Type I supernovae at very large red shifts


) According to the turn-off points of the oldest globular clusters, they are about

A) 4.5 billion years old.

B) 6.8 billion years old.

C) 10 billion years old.

D) 12 billion years old.

E) 16 billion years old.


) The expansion rate of the universe is

A) increasing.

B) decreasing.

C) constant.

D) different in different directions.

E) independent of time.


) In the critical density universe now proposed, the ratio of dark energy to matter is about

A) 1 to 100.

B) 1 to 1.

C) 3 to 1.

D) 10 to 1.

E) 1 to 5.


) The major players in the discovery of the cosmic microwave background were at

A) Cal Tech and Mt. Palomar.

B) Jet Propulsion Lab and MIT.

C) Bell Labs and Princeton.

D) Kitt Peak and the University of Arizona.

E) Keck telescopes and the University of Hawaii.


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

A) about 3,000 K

B) 5,800 K

C) about 300 K

D) just over 2.7 K

E) 1.4 K






) 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.


) 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.



) Concerning dark energy, we do know

A) that it is created when matter annihilates anti-matter.

B) its density remains constant over time, so it is not important in the early universe.

C) combined with dark matter, it will ultimately produce a closed universe.

D) that it was revealed with Type II supernovae distances in the late 1990s.

E) that it makes up 90% of all the matter and energy in the whole universe.


) 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.


) The Big Bang formed

A) only hydrogen.

B) only helium.

C) hydrogen and helium, but very little else.

D) all elements up to iron.

E) all elements found in nature now.


) 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.




) Most of the deuterium 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.


) 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.


) The 3 K background radiation represents

A) the Big Bang itself.

B) the time of decoupling.

C) the formation of the first galaxies.

D) the outer edge of the universe.

E) formation of the first quasar.


) 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.


) In the Grand Unified Theory, the superforce was

A) only dark energy.

B) a union of the weak and electromagnetic forces.

C) a union of all matter and energy.

D) a union of the strong and weak nuclear, and electromagnetic forces.

E) was only in effect at low energies.