ASTR101 Chapt 17

1) 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.

2) The concept that the direction of observation does not matter overall is: A) relativity. B) homogeneity. C) universality. D) isotropy. E) geometry.

3) 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.

4) The Hubble time is expressed as: A) H x D B) D / v C) 1 / H D) H x T E) the critical density / H

5) 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.

6) 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.

7) What does the Hubble 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.

8) The presently accepted value of the Hubble constant gives an age of the universe of approximately: A) 4.5 billion years. B) 8−9 billion years. C) 14 billion years. D) 18 billion years. E) 22 billion years.

9) 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.

10) The sky is dark at night A) because the stars in the Milky Way are far away. B) because the Sun is on the other side of Earth. C) because there are far fewer stars on the night side of Earth. D) because all the light from all the objects in the universe hasn't arrived here yet. E) because the quasars are too far away from Earth for their light to have arrived here.

11) 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.

12) 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.

13) In which of the following models will the universe stop expanding? A) High Density Universe B) Low Density Universe C) Critical Density Universe D) both A) and C) E) none of the above

14) In which of the following models will the universe stop expanding? A) Open Universe B) Closed Universe C) Critical Density Universe D) both A) and C) E) both B) and C)

15) What is the meaning of a "closed" universe? A) The universe is already collapsing back into another cycle. B) The universe will someday stop expanding and begin collapsing inward. C) The universe will slow down and stop expanding in an infinite amount of time. D) The universe is in a steady state, with constant replacement of matter and energy. E) The universe will expand forever.

16) If the density of the universe is greater than the critical density this means that A) the universe is expanding at a rate equal to the escape speed of the universe. B) the universe is expanding at a rate less than the escape speed of the universe. C) the universe is expanding at a rate greater than the escape speed of the universe. D) the universe is expanding at a rate equal to the speed of light. E) the universe is expanding at a rate greater than the speed of light.

17) If the density of the universe is at the critical density this means that A) the universe is expanding at a rate equal to the escape speed of the universe. B) the universe is expanding at a rate less than the escape speed of the universe. C) the universe is expanding at a rate greater than the escape speed of the universe. D) the universe is expanding at a rate equal to the speed of light. E) the universe is expanding at a rate greater than the speed of light.

18) If the density of the universe is lower than the critical density this means that A) the universe is expanding at a rate equal to the escape speed of the universe. B) the universe is expanding at a rate less than the escape speed of the universe. C) the universe is expanding at a rate greater than the escape speed of the universe. D) the universe is expanding at a rate equal to the speed of light. E) the universe is expanding at a rate greater than the speed of light.

19) According to the data from the microwave background radiation, at what speed and in what direction is Earth moving through the universe? A) 380 km/s in the direction of Leo B) 70 km/s in the direction of the Big Bang C) 300,000 km/s in the direction of Polaris D) 250 km/s in the direction of Vega E) 600 km/s North

20) If omega−naught is less than one, then A) the universe is closed, and must recycle. B) the universe will expand forever. C) no matter could have existed. D) only dark energy exists in the universe. E) there is more matter than energy in the universe.

21) 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.

22) 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.

23) The expansion rate of the Universe is A) increasing. B) decreasing. C) constant. D) different in different directions. E) independent of time.

24) The luminous matter in the universe accounts for what percent of the total mass of the universe? A) less than 4% B) about 23% C) about 27% D) about 73% E) 100%

25) 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.

26) In our best current theory, the first quasars formed about: A) 14.5 billion years ago. B) 13 billion years ago. C) 12 billion years ago. D) 11 billion years ago. E) 9 billion years ago.

27) 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

28) The discovery of the cosmic microwave background was important because A) it established a firm center of the Universe. B) it was 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.

29) 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.