Group Activity: Time to Move On. A common theme in science fic-tion is “leaving home” to find a new planet for humans to live on. Now that we know about thousands of planets, we can start imag-ining how to choose. Note: You may wish to do this activity using the same four roles described in Chapter 1, Exercise 39.
a. Make a list of characteristics that you would look for in a planet that might make a good home.
b. Examine the planets in Figure 10.13. Does this graph give enough information to determine which planets might make good homes, or poor ones? If not, what’s missing?
c. Suppose you also knew the orbital distance for each of the plan-ets in Figure 10.13. Would that make it easier to find potential good homes? Why or why not?
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Essential Cosmic Perspective
- Kepler-444 is one of many stars with terrestrial planets that is over 10 billion a) What do you think the spectral type of Kepler-444 might be? b) How do stars of this spectral type end their lives? c) If evolution followed a similar course on a habitable pranet around a star similar to Kepler-444, it would be 5 billion years more advanced than we are. Let’s try to project our future and see what happens. In particular, suppose our civilization gets motivated enough to colonize another planet. Kepler indicates that most stars have potentially habitable (and colonizable) planets, so roughly how far away is the typical “nearest" planet? d) The New Horizons probe on its way to Pluto took 9 years to travel 30 AU. If we could send colony ships with the same average speed, roughly how long would it take to reach the typical nearest planet? уears old.arrow_forwardThe principle cause of our intense interest in Mars in the decades before the dawn of the space age was that Answers: A. a few astronomers believed that they saw evidence of an intelligent civilization on Mars. B. Mars has seasons just like the Earth and therefore should be inhabitable by humans. C. Mars has an unusual surface color and global dust storms, creating strange weather patterns. D. Mars has unusual orbital properties making our understanding of its motion around the Sun very difficult.arrow_forwardWhich of the following is least reasonable regarding the concept of a habitable zone? Group of answer choices M-type stars have wider habitable zones than G-type stars. It is a region around a star where liquid water could be found on a planet's surface. The habitable zone of a less massive star would be closer to the star. In the course of millions of years, our habitable zone will slowly shift from Earth to Mars. The Galactic habitable zone cannot be too close to the Galactic center because the radiation from the bright stars and supernovae in the crowded inner part of the Galaxy would probably be detrimental to life.arrow_forward
- What is the best way to determine if a exoplanet has life inside it? Group of answer choices Detect the star the exoplanet is orbiting and compare it to the Sun. Detect the exoplanet and determine if it is in the habitable zone of the star. Detect the exoplanet and study the atmosphere of the exoplanet. Detect the exoplanet and determine its age to see if it is similar to the age of the Earth.arrow_forwardImpact Energy. Consider a comet about 2 kilometers across with a mass of 4 × 1012 kg. Assume that it crashes into Earth at a speed of 30,000 meters per second (about 67,000 miles per hour). a. What is the total energy of the impact, in joules? (Hint: The kinetic energy formula tells us that the impact energy in joules will be 1 × m × v2, where 2 m is the comet’s mass in kilograms and v is its speed in meters per second.) b. A 1-megaton nuclear explosion releases about 4 × 1015 joules of energy. How many such nuclear bombs would it take to release as much energy as the comet impact? c. Based on your answers, comment on the degree of devastation the comet might cause.arrow_forwardConsidering what you learned from the solar nebula theory, how likely do you think it is to find habitable planets in other solar systems? Visit NASA’s Kepler mission to learn more about this search, and write a ½ page summary on the mission.arrow_forward
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