Enigmas of the universe

400 years ago Galileo took the dark stains on the surface of the moon to be seas. He was wrong. Today, we are sending missions to the moon in search of water. These technological advances have been extraordinary: in the past 20 years 350 planets have been discovered outside of our solar system and several months ago the first images of them reached us via satellite. Yet, the universe remains largely unknown.

From Ibn Haitham Alhazen’s theory about the dark spots on the moon (11th century) to the recent discovery of exoplanets in April 2009, this issue, published on the occasion of the International Year of Astronomy, traces these steps in our long history of observing the stars. More