Date Reading TR 15-18 The solar system* is known to have eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Mars seems to be an especially interesting planet to the scientists who study planets. Robert Zubrin* is one of those scientists. There are two main reasons why he is so interested in Mars. の 5。 One reason is that Zubrin wants to determine if human beings will be able to live on Mars in the future. Though Mars is now a cold and dry planet, 。it is more similar to Earth の- than any other planet in the solar system. So there is a possibility that Mars is a place where human beings can live. In what ways are Mars and Earth alike? First, the soil and atmosphere of Mars is similar to those of Earth. Scientists found that the soil and 10 atmosphere of Mars contains many of the main elements* essential for human life. A Mars exploration rover* named Curiosity has been working on the surface of Mars to gather various scientific information about its environment. Second, the rotation* period of Mars is 24 hours and 39 minutes, which is very close to that of Earth. Third, there are seasons on Mars as there are on Earth. 15 等 The other reason is that, studying Mars, Zubrin thinks we can better predict the future of Earth. It is believed that there used to be a liquid like water on Mars a long time ago. If we can find out how and why Mars has changed into a (A) and (B) place, we may be able to better understand the Earth's future. Zubrin says, “We humans have changed the Earth's environment through our actions and activities. From our research on Mars, 20 we may be able to solve such problems as global warming. Mars may be the key to our survival on Earth." Not only Zubrin but also many other scientists are doing research on Mars. Studying Mars might not seem to be connected with our daily life, but actually it is. New discoveries can influence our future. We should remember that in that regard* Mars is a 25 very important planet for our future. (357 words) Robert Zubrin:ロバート·ズブリン main element:主要元素(人間の生命維持に必要な元素。窒素, 水素など) rotation:自転 (注) solar system: 太陽系 exploration rover : 探査車 in that regard:その点で