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　　To sum up,/in order for a planet to support life,/it has to satisfy certain conditions.// First,/it must have water in liquid form.// Second,/the temperature must be just right/—not too hot or not too cold—/so that water may remain liquid.// Third,/the mass,/which determines the gravity of the planet,/must be just right/—not too big or not too small.// In short,/a habitable planet must be/in a so-called “Goldilocks Zone”:/“just right” between two extremes.// Even though the conditions which sustain life/are very special,/it is likely/that life exists elsewhere/because there are so many planets.//
　　Although we have not discovered life on other planets,/I hope to have shown/how much science can tell us.// Our search for life is not random;/our scientific knowledge equips us/to seek out meaningful information/and to identify habitable planets.// We need much more information/than we have now,/but we can at least ask sensible questions/and get sensible answers.// We don’t have to invent implausible stories;/we have the joy/of real scientific investigation and discovery.// In the end,/that is more exciting than science fiction.//