Life in the Universe

6. What does the Fermi Paradox say?

a. Given all the time since the Big Bang and all the stars, why has some form of intelligent life in the Galaxy not established a network throughout the Galaxy and visited us?

12. Photosynthesis releases a particular gas as a byproduct. This gas is:

a. carbon dioxide

2. If you wanted to find a type of atom in your little finger that has been in its present form (been the same element) since the beginning of the universe, which element should you look for?

a. hydrogen

22. Photosynthesis, once it was planet-wide, changed the atmosphere of the Earth by introducing a significant amount of

a. oxygen

27. Which band of the electromagnetic spectrum do astronomers suggest is likely to be the best (cheap, little competition from nature, penetrates atmospheres) for communication between civilizations around different stars?

a. radio waves

24. Which of the following is a good summary of what most astronomers think about UFO reports in the popular media?

a. so far there is no scientific evidence that UFO's have anything to do with life outside the Earth

34. We receive a radio message from a civilization around a star about 40 lightyears from Earth? If we reply right away, how long will it be between the time THEY sent the message and the time they receive our reply?

b. 80 years

29. The first search for radio messages from extra-terrestrial civilizations was called

b. Project Ozma

19. Which of the following is, to the best of our knowledge, in the habitable zone of its star:

b. a planet about 1.05 AU from a G-type main sequence star

23. Which of the following is a biomarker that could be used from an observatory around a nearby star, with the right equipment, to identify the Earth as a planet with life:

b. free oxygen in the Earth's atmosphere

3. Chemically, the process leading to life on Earth began with lots of liquid water and

b. hydrocarbons (molecules which had hydrogen and carbon)

9. In the early 1950's, Stanley Miller and Harold Urey conducted a series of pioneering laboratory experiments involving simulations of the early Earth. What did these experiments reveal?

b. that under the conditions on the early Earth, they could synthesize some of the building blocks of life in a laboratory

15. One place that astronomers think might have had life start long ago is Mars. Which of the following is not a discovery that we have made on Mars so far?

b. the discovery of organic materials (the chemical building blocks of life, such as amino acids) by spacecraft that have landed

32. What recent series of discoveries has made astronomers more optimistic about our prospects of finding life out there?

b. the discovery of planets around thousands of stars in our Galaxy

30. The fastest speed at which we might communicate with another technological civilization among the stars (according to our present understanding of science) is

b. the speed of light

25. Which of the following spacecraft is NOT leaving the solar system?

c. Galileo

18. One reason that some scientists think that there may be life under the ice-crust of Jupiter's moon Europa is that:

c. Life has been found on Earth, at the bottom of the ocean, deriving its energy not from sun-light but from hot mineral-laden vents coming from deeper inside our planet; something similar could happen at the bottom of the ocean on Europa

26. If alien beings found one of the Voyager spacecraft in a million years, what would they find aboard?

c. an audio and video record

10. Scientists think that the life we have on Earth today originated some time between 3.5 and 3.8 billion years ago. Yet the solar system and the Earth are known to be at least 4.5 billion years old. Which of the following is one reason life as we know it had to wait until 3.5 to 3.8 billion years ago to get going?

c. before 3.8 billion years ago, the Earth was experiencing a period of heavy bombardment, when giant chunks of rock and ice left over from planet formation kept hitting our planet and making it uninhabitable

5. Which of the following is a recent (last few decades) discovery that confirms the key idea of the Copernican Principle?

c. that planets around other stars are common

31. The Drake Equation allows astronomers to estimate

c. the number of civilizations out among the stars with which we might communicate

13. For the complex biochemical reactions of life (as we know it) to happen, a solvent is required. What is that solvent for life on Earth?

c. water

1. Think for a moment about an atom of the element lead (atomic number 82) inside the radio that you listen to in the morning. In which of the following places has this atom probably NOT been during the course of its existence?

d. a cloud of gas and dust which would clump to become a star and a family of planets

21. What makes the Earth different from the other worlds that might have life in the solar system (and easier to detect from far away) is that only Earth

d. has a biosphere on its surface where photosynthesis can take place

11. Photosynthesis was a great step forward in the evolution of life on Earth, because with photosynthesis

d. life could extract chemical energy from sunlight

20. Astronomers have discovered a planet orbiting Proxima Centauri, the star closest to the Sun. This is a star of spectral type M, with 12% the mass of the Sun and 15% the size of the Sun. The habitable zone around this star would be

d. much more narrow (small) than the diameter of any planet

36. In a globular cluster, astronomers (someday) discover a star with the same mass as our Sun, but consisting entirely of hydrogen and helium. Is this star a good place to point our SETI antennas and search for radio signals from an advanced civilization?

d. no, because such a star (and any planets around it) would not have the heavier elements (carbon, nitrogen, oxygen, etc.) that we believe are necessary to start life as we know it

35. Which of the following events in cosmic history is the most recent?

d. the formation of life on Earth

4. When they talk about the Copernican principle, philosophers and astronomers mean that:

d. the idea that there is nothing special about our place in the universe

16. According to astronomers, which of the following places in the outer parts of our solar system might be a reasonable place for life to exist?

d. under the ice of Jupiter's moon Europa

28. Which of the following questions is NOT part of what astronomers call the "cosmic haystack problem" in receiving messages from other civilizations in space?

d. we don't know how to receive signals in the wavelength range that is the most likely for interstellar communications

7. From a scientific perspective, which of the following statements about life elsewhere in the universe is best supported by current evidence?

d. while we have evidence of the building blocks of life elsewhere in the universe, we have no definite evidence about life around other stars at this time

17. What discovery about Saturn's moon Enceladus has encouraged astronomers to think of that moon as a possible place where life might exist?

e. There are plumes of salty vapor coming from cracks in Enceladus' surface

14. Scientists are impressed with extremophiles, life forms that can survive under what seems to humans to be extremely unpleasant conditions. In which of the following environments have we not found life:

e. conditions resembling the photosphere of the Sun

33. What new technology has made it possible for astronomers to do "optical SETI" - searching for signals for extra-terrestrial civilization, not in the radio band of the spectrum, but in the visible-light band?

e. we have developed the ability to make laser pulses that are briefly brighter than the Sun

8. In which of the following places have astronomers NOT found evidence for the building blocks of life (organic compounds)?

e. we have found evidence for such materials in all of the above sites