Astronomy Chapter 26

From the 1970s to the present, the accepted value of H has almost doubled, so: Select one: A. the critical density must also be halved. B. the Copernican principle is not valid beyond our solar system. C. the age of the universe is twice as old as we originally believed. D. the age of the Universe is half what we believed. E. the ages of the oldest globular clusters are invalid.

The center of the universe: Select one: A. is the Milky Way. B. is where the Big Bang happened. C. is the Sun. D. does not exist anywhere in space. E. is Earth.

What is the Big Bang? Select one: A. The creation of the primeval fireball. B. An explosion that spewed matter all over the universe. C. An enormous explosion that organized all matter in the universe. D. The event that started the expansion of the universe. E. The creation of matter and the universe.

Astronomers know the universe is expanding because: Select one: A. all stars are moving away from us. B. everything is moving away from us. C. galaxies farther away are moving away from us faster. D. there is a cosmic microwave background. E. most galaxies are moving away from us.

In which of the following models will the universe stop expanding? Select one: A. Open Universe B. Closed Universe C. Steady State Universe D. Critical Density Universe E. All have an ultimate collapse.

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

If the density of the universe is greater than the critical density, this means that: Select one: 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 greater than the speed of light. E. the universe is expanding at a rate equal to the speed of light.

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

If the density of the universe is lower than the critical density, this means that: Select one: A. the universe is expanding at a rate equal to the speed of light. 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 speed of light. D. the universe is expanding at a rate greater than the escape speed of the universe. E. the universe is expanding at a rate equal to the escape speed of the universe.

If the density of the universe is greater than critical, then: Select one: A. the Universe will continue expanding forever. 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 end up as nothing but black holes. E. there is more matter than energy.

What is the meaning of a "closed" universe? Select one: A. The universe will expand forever. B. The universe is in a steady-state. C. The universe will disappear into a white hole in time. D. The universe will someday stop expanding and start to collapse. E. The universe will stop expanding in an infinite amount of time.

In an open universe two parallel beams of light will: Select one: A. remain parallel. B. converge. C. circle back on themselves. D. continue on forever. E. diverge.

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

The universal accelerating force could NOT be considered: Select one: A. Einstein's cosmological constant. B. vacuum pressure. C. antigravity. D. dark energy. E. dark matter.

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

In the critical density universe now proposed, the ratio of dark energy to matter is about: Select one: A. 1 to 1. B. 1 to 5. C. 3 to 1. D. 10 to 1. E. 1 to 100.

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: Select one: A. magnetic field associated with antimatter. B. mass determined for the neutrinos. C. dark energy. D. polarization and a universal spinning magnetic field. E. repulsive charge on dark matter.

What temperature has the Big Bang has cooled to by now? Select one: A. 1.4 K B. About 300 K C. About 3,000 K D. 5,800 K E. Just over 2.7K

The discovery of the cosmic microwave background was important because: Select one: A. it proved that astronomy at radio wavelengths was possible. B. its detection was a major advance in microwave testing. C. it established a firm center of the Universe. D. it was experimental verification of a prediction from the Big Bang theory. E. it showed the universe must be closed, with more than the critical density here.

The presently accepted value of the Hubble constant gives an age of: Select one: A. 14 billion years. B. 8-9 billion years. C. 4.5 billion years. D. 22 billion years. E. 18 billion years.