Origins : Part 3 - Where are the Aliens? (A NOVA Miniseries)                               Name ___________________________

Study Guide  (Answer the following questions as you watch the video tape or DVD)

1.  Most aliens depicted in the movies:
a. Use DNA as a code for life
b. have faces
c. are friendly
d. are much smarter than us

2. This suggests:
a. humans were brought to Earth by other aliens
b. all aliens must have morals
c. they have a common ancestry with life on Earth
d. intelligence is normal in the universe

3. How have we been announcing our presence to nearby stars:
a. we are broadcasting radio signals inadvertently
b. we use laser beams to flash a form of Morse code to other star systems
c. we have sent spacecrafts to other star systems
d. we have done nothing to announce our presence, fearing they might be hostile

4. SETI is:
a. an attempt to open the records concerning area 51
b. an attempt to send a spacecraft to the nearest star
c. an attempt to broadcast a "we are here" signal to other worlds
d. an attempt to detect radio signals from other worlds

5. The Drake Equation is an attempt to estimate:
a. the number of ways we can contact other alien civilizations
b. the number of intelligent civilizations in the Milky Way Galaxy
c. how long it took life to evolve on Earth
d. when life on Earth started

(You can find more information about the Drake Equation at http://www.pbs.org/wgbh/nova/origins/drake.html if interested)

6. Frank Drake's estimate for his equations is:
a. 1
b. 1,000,000
c. 10
d. 10,000

7. The answer to this equation is:
a. highly speculative because the value for each variable is basically unknown
b. definitely between 1 - 100 because computers have worked out the details
c. something geologists will be able to find once we examine all the rocks in the crust
d. not important because nobody really cares

8. In this equation, f_p represents:
a. the probability that life will become intelligent
b. the length of time an intelligent civilization will exist on a planet
c. the percent of stars with planets around them
d. the number of stars in the Milky Way

9. Marcy & Butler used this technique to find extrasolar planets:
a. they watch for a planet to cross in front of the star on a regular pattern
b. they block out the light of the star so they can concentrate on the much fainter planets
c. they look for infrared signals coming from the planets themselves
d. they observe a wobble in the star as the planet goes around it

10. When Marcy & Butler examined the data of 51 Pegasi, they:
a. found exactly the same thing a team of Swiss astronomers claimed to have found
b. detected nothing special about data
c. were the first team of astronomers to find a planet around another star
d. found evidence of life outside our solar system

11. The odd thing about their discovery was:
a. most all stars showed evidence of life but we were too dumb to interpret the data correctly
b. 51 Pegasi has an Earth like planet orbiting at the same distance as we do around the sun
c. the 51 Pegasi system is not at all like our solar system
d. it proved that life in the universe is highly unlikely

12. Jupiter is important to us because:
a. Jupiter deflects asteroids and comets which would normally collide with Earth instead
b. Earth received most of its organic molecules from Jupiter
c. without Jupiter, none of the other planets would have formed at all
d. Jupiter's magnetic field protects Earth from harmful UV radiation

13. Marcy estimates that ___ of all stars might harbor "Earth like" planets.
a. 1%
b. 5%
c. 10%
d. 50%

14. Which is a false statement regarding early life on Earth:
a. life was abundant on Earth 3.8 billion years ago
b. the first life was tiny, single-celled creatures
c.  scientists are quite sure they understand how it got started
d. if the chemistry of life is easy, then life would develop quickly

15. The element ___ seems to be the most essential for the chemistry of life.
a. sulfur
b. carbon
c. magnesium
d. helium

16. Life on Earth:
a. can exist in all kinds of extreme conditions
b. is only found at the surface of the ocean and on land
c. has never been detected at the bottom of the ocean
d. has been purposely transported to other planets in the probes we sent to explore them

17. Liquid water seems to be an essential molecule for life because:
a. water helps bond simple DNA molecules together to make more complex DNA molecules
b. it is an ideal solvent
c. it allows other molecules to move and react
d. both a & b
e. both a & c
f. both b & c

18. If water is essential for life, then ___ is the best place to begin the search in our solar system, ... with ___ as a backup.
a. Venus / IO
b. Mercury / Pluto
c. Mars / Europa
d. Jupiter / Saturn

19. During the entire history of life on Earth, intelligent life:
a. dominated most of the entire time
b. is used by most species as a survival trait
c. was present for about 1/3 of the entire time span
d. is an extremely recent event

20. Biologists explain the diversity of life on Earth by:
a. interbreeding between species
b. occasional mistakes in the replication of DNA
c. viruses are able to alter one species into another
d. bacteria are able to alter the chromosomes in such a way that new species arise

21. One major key to the development of intelligent life may be:
a. whether the planet orbits in a nearly circular shape around the sun
b. lots of time may be required
c. if the sun produces sufficient cosmic rays
d. where we are located in the Milky Way

22. What event allowed mammals to rise to dominance on Earth?
a. mammals became more resistant to infection
b. mammals' brains were much larger than all other life forms
c. Earth went through a long period of glaciation and mammals had fur
d. an asteroid collided with Earth, .. killing off 2/3 of all species, including the dinosaurs

23.  Cephalopods, including octopus, squid and cuttlefish may suggest to biologists:
a.  there may be several paths to intelligence
b. life started in the sea
c. humans may not be the dominant life form on Earth for very long
d. all species go extinct

24. In 1997, SETI observers were excited to find:
a. the first proof of alien intelligence
b. we are definitely alone in the universe
c. humans have already populated space
d. a false alarm, .... they detected signals from one of our own satellites

25. The search for life in the universe is:
a. almost completed
b. a total failure
c. still in its infancy
d. a fruitless effort