Publisher's Synopsis
Outer space has always been a fascinating topic in my mind. How big is the universe? How many stars and galaxies are out there? Are we alone? The new discoveries of exoplanets suggests that we are not alone! Chances are that life of some sort is out there, only the distances to other star systems is so immense that we, or they, will never cross interstellar space to meet.
SETI, the organization involved in the Search for Extraterrestrial Intelligence, has actively been looking for signals from space. We have also used Voyager 1, launched in 1977, to send evidence of ourselves into outer space: a golden record containing greetings in 59 languages and one whale language and 116 pictures of Earth's cultures and science, our music including songs by Beethoven, Bach and Mozart. Will extraterrestrials in exoplanets be able to decipher what we've sent out there into space? There are 400 billion stars in the Milky Way alone. It may be that there are 100 billion Galaxies in the observable universe. Maybe civilizations arise and fall all the time, but the urge of intelligent beings is to leave some evidence of their existence behind. In 1964, Nikolai Kardashev suggested that civilizations might exist at three levels: Type 1 where beings use fossil fuels, like we do on Earth, Type 2 where beings tap energy from their star, and Type 3 where beings tap energy from their galaxy. Since that time, other scientists have speculated that civilizations might go all the way up to a Type 7 civilization where beings have become pure energy.
