Many people have been so interested in the mysterious space, the Universe, and have longed for going into space since science developed and we could think about the bigger world. So to speak, they turn their mind from the earth to other planets. There are some reasons that we have to go to the outer world.
        First of all, mankind is a curious animal, and the universe is an almost unknown world, so many of us wonder uncertainly about UFOs, aliens, solar systems, the planet Mars, and the like. Some people say that they have seen UFOs and aliens, but others don't believe in them. There are many theories about unidentified objects, but nobody know which are really true. So, we have to get more information about outer space phenomena to know what is true.
        Second, we have to be ready for the future in the 21st century, because the place we live at that time may not be the lands of the earth. We could live under the earth or sea, or we could live on another planet. The first two possibilities are parts of the earth and limited, but the last possibility is the most likely choice because it is the largest and has so many potentialities. (For example, we can get a lot of unknown energy, foods, facts, and so on. Energy which is more powerful and effective, foods which can make humans live longer, or power to communicate without words. . . .) For this reason, we have sent a lot of spaceships to explore space.
        Lastly, we have many problems on earth, including the environmental pollution, over-population, energy shortages, lack of clean water, etc. In fact, the problems on earth are not too urgent now, but the time when people will have to leave the earth is coming. These are serious matters on their own. Therefore, we need to search for new planets to live on, and so NASA scientists sent the Sojourner--a probe that landed on Mars and sends many photographs back to earth by radio--to find out if there are traces of life and if we can live on the planet Mars.
        In conclusion, it is time to get ready for the future, and scientists must study harder and try to explore the interesting space beyond our planet. Besides, governments must invest more money in such areas and educators must give students more chances to learn about the Universe. This will be the best way to solve many fatal problems which are coming and get more information about other planets.