Ch. 19 Reading Quiz – Flashcards
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Where have scientists begun a concerted search for life outside of Earth?
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Mars
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The only place outside of Earth where there is irrefutable evidence for (ancient, microbial) life is a) the Moon. b) Mars. c) Europa. d) Titan. e) None of the above - there is no irrefutable evidence for life beyond Earth.
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e) None of the above - there is no irrefutable evidence for life beyond Earth
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The analysis of Martian rocks on Earth show that they contain
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tantalizing hints of life
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After Mars, the next most likely candidates for life in the solar system are a) Oort-cloud comets. b) the jovian planets. c) asteroids. d) the large moons of the jovian planets. e) Kuiper-belt comets.
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d) the large moons of the jovian planets
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Which of the following is the best candidate to search for planets that might harbor extraterrestrial life?
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Solar mass stars because they have both a large habitable zone and a long stellar lifetime
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How does the Kepler mission plan to detect Earth-like planets around other stars?
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By observing the slight dip in brightness of the central star as the planet transits
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Which of the following gases, which we might be able to detect in infrared spectra, would be a strong indicator of life on another planet?
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ozone
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Why do some scientists think that Jupiter's existence may have been critical for life to evolve on Earth?
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It kicked out many comets from the inner solar system through gravitational encounters, thus ending the heavy bombardment phase of the solar system
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Which of the following is the most important for maintaining a stable climate on Earth over the time it took for large organisms to evolve?
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plate tectonics
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Why do some scientists say that the Moon may have been important for the evolution of human life?
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It stabilized the earth's axis tilt, preventing large climate changes
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What defines the habitable zone around a star?
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the region around a star where liquid water can exist on planetary surfaces
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Which of the following statements best reflects our current knowledge about the term f life in the equation Number of Civilizations = Np x f life x f civilization x fnow?
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The value of f life must be either 0 percent and 100 percent
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At present, what is the primary way that the search for extraterrestrial intelligence (SETI) is carried out?
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By using radio telescopes to search for signals from extraterrestrial civilizations
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In 1974, a radio message was sent out from the Arecibo observatory in Puerto Rico. How far has it gotten, approximately?
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just a miniscule fraction of the distance across the Milky Way
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SETI (the Search for Extraterrestrial Intelligence) searches for communications from life in planets and moons
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around nearby stars
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The Voyager I and II spacecraft visited the jovian planets in the 1980s. When will they reach the nearest stars?
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tens of thousands of years from now
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Which of the following describes a major danger of interstellar travel at near light speed?
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Atoms and ions in interstellar space will hit a fast-moving spacecraft like a flood of dangerous cosmic rays
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Which of the following statements about matter-antimatter engines is NOT true?
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Matter-antimatter engines would be great in theory, but to sate we have no evidence that antimatter even exists
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Which of the following best explains why an interstellar ramjet could, in theory, achieve continuous acceleration?
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it collects its fuel as it goes, rather than having to carry the weight of fuel along with it
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If we develop spacecraft that can take humans to nearby solar systems at a few percent of the speed of light, how long would it be before we could conceivably populate all habitable planets in the entire Milky Way?
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a few million years
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Which of the following is NOT considered a likely solution to the question of why we are not currently aware of a galactic civilization?
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the galactic civilization probably is undetectable to us because it makes use of technologies that do not obey the known laws of physics
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T/F We have already launched four spacecraft that are bound for interstellar space.
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True
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T/F The two Voyager spacecraft carry a message from Earth, just in case an alien civilization ever runs across them.
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True
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T/F Although antimatter is an interesting theoretical idea, there is no evidence that it actually exists.
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False
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T/F If they existed, and if they were watching, a civilization at the center of the Milky Way could have detected our first TV signals by now.
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False
