Searching for extra-terrestrial intelligence and the discovering of extrasolar planets

In this paper, the significance, instrumentality, and the status in the search for extra-terrestrial intelligence, and, in addition, the SETI program and its development, are introduced. Especial emphasis is on the discovery of extrasolar planets, its purpose, ways and means, achievement, and future.Finding extrasolar planets is one of the most popular issues at present. It will be one of the most fruitful research fields in astronomy in the 21st century. Since the first affirmation of an extrasolar planetary system in the pulsar PSR1257+12, and the first discovery in 1995 of a planet in a main-sequence star, 51 Peg, some fifty extrasolar planets have been discovered. The discovery cannot be detached from the search for extra-terrestrial intelligence, and it also opens up new problems. During the past 10 years the research has been developing rapidly. Not only in astronomy, but also in other sciences, like spaceflight, astrochemistry, astrobiology, even in philosophy, it plays an advancing function. [Copyright &y& Elsevier]