Astronomy Test 7 - Cosmology & ET Life 5/5/03 ctr

Please put your name on the back of the last sheet only. Answer all. Good luck!


___The cosmic background radiation was discovered by
1-television sets tuned to static.
2-the Hubble Space Telescope.
3-Bell lab's antenna experts.
4-NASA's Cosmic Background Explorer (COBE).

___ Current spacecraft can travel at about 1/10,000 the speed of light. At that speed, how long would it take to get to the next Sun like star, Alpha Centauri, more than 4 light-years away?
1-40,0000 years
2-40 years
3-4 years
4-1/40,0000 of a year

___ Radio communication is the currently preferred way to find other civilizations because
1-most people have radios in their homes or automobiles.
2-there is less chance of alien invasion.
3-we can do it easily and inexpensively
4-interstellar asteroids make human travel dangerous.

___ Besides those planets orbiting our Sun, astronomers have found
1-fossils on all planets more distant than Jupiter.
2-no evidence of habitable zones around other stars.
3-no planets orbiting other stars.
4-many planets orbiting other stars.

___ One of the most difficult variables to estimate is the number of civilizations that exist at the present time because it is possible for advanced civilizations, like ours, to
1-destroy themselves with their own technology.
2-decide not to communicate with other civilizations.
3-decide not to leave the home world.
4-all of these choices.

___ The force that binds galaxies together is the
1-gravitational force.
2-weak force.
3-electromagnetic force.
4-strong force.

___ NASA's Cosmic Background Explorer (COBE) satellite showed
1-that fluctuations in the cosmic background formed present day galaxies and galaxy clusters.
2-that the cosmic background is not perfectly uniform.
3-that the cosmic background is perfectly uniform.
4-that the global curvature of the universe is flat.

___ One of the principal predictions of the Big Bang theory is that astronomers should observe
1-quickly rotating galaxies.
2-cosmic background radiation.
3-white dwarf supernovae.
4-high temperatures between galaxies.

___ The first observation suggesting a Big Bang theory was
1-gravitational lensing.
2-detection of the microwave background.
3-that spiral nebulae contained stars.
4-the observation of galactic red shifts.

___ Grand unified theories suggest that, at high temperatures,
1-the gravitational force is stronger than the weak force.
2-the weak force is stronger than the strong force.
3-all fundamental forces were the same at one time.
4-the gravitational force is stronger than the electromagnetic force.

___ If astronomers had discovered that the microwave background was perfectly smooth (to better than 1 part in 10 billion, say) except for the expected variations because the Earth is moving with respect to the background, they would have a difficult time explaining:
1-the relationship between the strong and the weak force.
2-the expanding universe.
3-the size of the NASA budget.
4-why galaxies formed at all.

___ Based on our current understanding of physics, astrophysicists agree we probably understand the basic physical laws governing the universe from the time it was
1-1 sec old to the present.
2-10-35 seconds old to the present.
3-300,000 years old to the present.
4-3 minutes old to the present.

___ Einstein’s theory of relativity suggests that travelers in a high-velocity spacecraft will experience time
1-more quickly than those on Earth.
2-more slowly than those on Earth.
3-at the same rate as those on Earth.
4-in suspended animation.

___ Besides those planets orbiting our Sun, astronomers have found
1-fossils on all planets more distant than Jupiter.
2-no planets orbiting other stars.
3-no evidence of habitable zones around other stars.
4-many planets orbiting other stars.

___ Microbial life has probably existed on Earth for about
1-400,000 years.
2-4,000,000,000 years.
3-4,000 years.
4-4,000,000 years.

___ One of the most difficult variables to estimate is the number of civilizations that exist at the present time because it is possible for advanced civilizations, like ours, to
1-decide not to leave the home world.
2-destroy themselves with their own technology.
3-decide not to communicate with other civilizations.
4-all of these choices.

___ The most difficult part of interstellar travel is
1-waiting for a time-travel breakthrough.
2-waiting for a fuel-source breakthrough.
3-the enormous distances involved.
4-waiting for a propulsion breakthrough.

___ The number of civilizations in the galaxy depends on all of the following EXCEPT the number of 1-globular clusters.
2-planets in habitable zones.
3-years a technological civilization can exist.
4-Sun-like stars.

___ The distances between planets are such that sending a manned mission to Mars with current technology would require a trip that is
1-2 weeks long.
2-2 months long.
3-2 decades long.
4-2 years long.

1. What two pieces of evidence do we have that support the big bang theory?




2. Why is the theory that the universe may someday collapse back upon itself in a "big crunch" no longer accepted?




3. Other than effects involving time, what serious danger would space travelers face if they traveled at 99% the speed of light?




4. Why should we be cautious about believing UFO's are extraterrestrial space craft?




5. (a) What is Olber's paradox?




(b) How is the big bang theory a solution to Olber's paradox?




6. What is meant by the term "inflationary cosmology?"