You should spend about 20 minutes on Question 14-26 which are based on Reading Passage below. You can also download this practice (pdf file)
The Search for Extraterrestrial Intelligence (SETI) is conducted by dedicated scientists every day. In the movie Contact, Jodie Foster’s character, Ellie Arroway, searches the heavens with several large radio telescopes. When she receives a radio message from a distant star, there are profound implications for humanity. Modern SETI efforts began with a paper written by physicists Giuseppe Cocconi and Philip Morrison and published in the science press in 1959. Since then, SETI has been an extremely controversial scientific endeavor. Some scientists believe that it is a complete waste of time and money, while others believe that detection of a signal from ET would forever change our view of the universe.
The idea that life, especially life with intelligence, might exist in other parts of the universe is a very old one. Early ideas were based on an intuitive belief in the enormity of the universe and in what is now called the mediocrity principle, namely that there is nothing special about the Sun, the Earth, and the human race. Present ideas are also based on the mediocrity principle supported by the universality of the laws of physics and chemistry, and by the enormity of the universe. The chemical evolution, that is, the natural formation of complex organic compounds that led to the origin of life on Earth is quite common in the universe.
SETI is not generally viewed by scientists as a trivial task. Our galaxy, the Milky Way, is 100,000 light years across and contains approximately a hundred billion stars. Searching the entire sky for some far-away and faint signal is an exhausting exercise. A number of assumptions are needed for SETI to be feasible. A basic assumption of SETI is that of “mediocrity”: the idea that humanity is not privileged in the cosmos but in a sense “typical” or “medium” when compared with other intelligent species. This would mean that the humanity has sufficient similarities with other intelligent beings and that communications would be mutually desirable and understandable. If this basic assumption of mediocrity is correct, and other intelligent species are present in any number in the galaxy at our technological level or above, then communications between the two worlds should be inevitable.
Another assumption is to focus on sun-like stars. Very big stars have relatively short lifetimes, meaning that intelligent life would likely not have time to evolve on planets orbiting them. Very small stars provide so little heat and warmth that only planets in very close orbits around them would not be frozen solid, and in such close orbits these planets would be tidally locked to the star, with one side of the planet perpetually baked and the other perpetually frozen. About 10% of the stars in the Milky Way galaxy are sun-like, and there are about a thousand such stars within 100 light-years of the Sun. these stars would be useful primary targets for interstellar listening. However, we know of only one planet where life exists, our own. There is no way to know if any of the simplifying assumptions are correct, and so as a second priority the entire sky must be searched.
The search for extraterrestrial intelligence was initiated only after the development of radio astronomy and large radio telescopes. Visiting another civilization on a distant world is presently beyond human capabilities. Distances between the stars are unimaginable vast, and our most advanced ideas for space rockets, such as light propulsion, nuclear from becoming reality. However, it is currently technologically feasible to develop a communications system which uses a powerful transmitter and a sensitive receiver to search the sky for extraterrestrial worlds whose citizens have a similar inclination as terrestrials.
In order to find an electromagnetic transmission form an alien civilization we also have to search through most of the useful radio spectrum, as there is no way to know what frequencies aliens might be using. Trying to transmit a powerful signal over a wide range of wavelengths is impractical, and so it is likely that such a signal would be transmitted on a relatively narrow band. Cocconi and Morison suggested that the microwave frequencies between 1 and 10 gigahertz would be best suited for interstellar communications. Below 1 gigahertz, galactic magnetic fields tend to drown out other radio sources. Above 10 gigahertz, radio noise from water and oxygen atoms in our atmosphere tends to also become a source of interference. The low end of this “microwave window” is particularly attractive for communications, because it is in general easier to generate and receive signals at lower frequencies. The lower frequencies are also desirable because of the Doppler shifting of narrow-band signal due to planetary motions.
In 1960, Cornell University astronomer Frank Drake performed the first modern SETI experiment, named “Project Ozma”. Drake used a 25-meter-diameter radio telescope at Green 99Bank, West Virginia, to examine the stars Tau Ceti and Epsilon Eridani near the 1.420 gigahertz marker frequency. In 1971, the U.S. National Aeronautics and Space Administration (NASA) funded a SETI study that involved Drake, Bernard Oliver of Hewlett-Packard Corporation, and others. The report that resulted proposed the construction of an Earth-based radio telescope array with 1,500 dishes, known as “Project Cyclops”. The OSU SETI program gained fame on August 15, 1977 when Jerry Ehman, a project volunteer, witnessed a startlingly strong signal received by the telescope. He quickly circled the indication an a printout and scribbled the phrase “Wow!” in the margin. This signal, dubbed the “Wow!” signal, is extraterrestrial source ever discovered, but it has not been detected again in several additional searches.
At least 60 radio searches have been carried out, and three radio observatories search continuously for radio signals. The results continue to be negative, however, it appears that the public is greatly interested in SETI research, and the future of SETI looks bright. We are currently at a time when our technology has advanced enough for us to detect signals from ET and even broadcast our own signals to the stars. With the advancements in technology and the increasing interest in SETI, we may be close to finding the answer to that age-old question:”Are we alone in the universe, or are there ETs out there?”
Which part of the passage contains the following information?
Write the appropriate letters i-iv in boxes 14-17 on your answer sheet.
- Widespread public interest and a promising future.
- Technological prerequisites for its implementation
- Basic assumptions underlying SETI research
- Former and current ideas about a controversial scientific endeavor
14. Part A
15. Part B
16. Part C
17. Part D
Answer the following questions USING NO MORE THAN THREE WORDS from the passage.
18. How do modern scientists conduct SETI?
19. What are previous beliefs in the enormity of the universe presently known as?
20. How many stars are would-be major targets for the SETI search?
In boxes 35-40 on your answer sheet write
TRUE if the statement is true
FALSE if the statement is false
NOT GIVEN if the information is not given in the passage.
21. Communication with intelligent alien beings is desired only by humanity.
22. Modern SETI interests and efforts spurred the invention of radio telescopes.
23. It is unfeasible to send radio signals at various wavelengths.
24. The report by Drake and Oliver resulted in the construction of “Project Cyclops”, a radio telescope array.
25. The “Wow!” signal is the only case of communication from an extraterrestrial source.
26. Sixty radio searches have been carried out to broadcast our own signals to the stars.
18. with radio telescopes
19. mediocrity principle
24. NOT GIVEN
26. NOT GIVEN