It is said that the Gauls were afraid that the sky would fall on their heads. In any case, many words come from up there. A star, we sometimes forget, is first and foremost a star, and from hurricane to disaster, from cosmetics in our toiletry kits to mischief-makers, we remain amazed by the influence of the sky on our vocabulary. This sky in our heads means so many often-forgotten descendants, so many often-funny stories to tell.

Our earthly refuge is certainly one of these, and it seems luminous to us. And yet the Universe as a whole is incredibly dark, not to say black. But what is black? And why is night black? This is a great mystery, the solution to which only emerged in the last century! What can we say about all this darkness: dark matter, dark energy and the fascinating black holes?

The universe is vast, takes its time and is expanding. So we can read the sky like a history book and go back in time by observing the stars. To achieve this, ever more powerful instruments are being invented, either by increasing the size of telescopes, or by exploring the entire electromagnetic spectrum. The conference will describe the projects that will see the light of day around 2010 - 2020, notably the 45 m diameter giants such as the E-ELT telescope at ESO (Chile) and the large infrared or radio mirrors, such as the 7 m JWST that will be deployed in space or SKA. They will be the 'eyes of the Earth', scanning the sky to decipher the most remote mysteries of our origins.

It's an ever-present, burning social issue that scientists don't like to talk about, but which nevertheless catches up with them. This lecture takes a scientist's critical look at the parasciences and astrology in particular, and is based on a “Que sais-je” entitled “L'astrologie”.

In psychoanalysis, this contradictory phrase raises the question of whether destruction can go hand in hand with creativity. What are the conditions for a (symbolic) murder to be foundational, and what is the intended object? The cosmos is a way of addressing the notions of death, murder and birth within the Universe. In our approach, science evolves in the same way, breaking down old ideologies (or, on the contrary, refusing to break them down) to finally create a new scientific conception, which obviously comes with a potential new error.

Deciphering the world. It's about knowing our origins, our future and mastering the world around us. Royal powers were already interested, seeing it as a means of controlling and extending their influence. Architects designed places to serve astronomers and political or religious power. They sought to inscribe their works in time and place mankind back in the cosmos. The symbols they used are self-explanatory: orientations, spheres, squares, pillars... Astronomers, for their part, observed the universe “Hannah and her sisters”. I start with the Hubble Space Telescope's image of the deep sky and the one recently obtained by the Planck satellite, which shows the universe 300,000 years after the Big Bang... then I explain the development of complexity right up to the origin of life.