Big Questions for Hipparcos

Hipparcos was a European Space Agency mission dedicated to the precise measurement of the positions, parallaxes and proper motions of the stars.

How do planets, stars, galaxies and cosmic structure come into being?

In order to understand how the Universe has changed from its initial simple state following the Big Bang (only cooling elementary particles like protons and electrons) into the magnificent Universe we see as we look at the night sky, we must understand how stars, galaxies and planets are formed.

Is there life elsewhere?

Are we alone? This question is as old as humankind itself. For millennia, people have turned their eyes to the stars and wondered if there are others like themselves out there. Does life, be it similar to our own or not, exist elsewhere in our Solar System? Our Galaxy? Until some 15 years ago it was uncertain whether there were even any planets outside those in our own Solar System. Today we know of literally hundreds of planets orbiting other stars. Do any of these planets have conditions that would support life? What conditions favor the formation of terrestrial-class planets in developing planetary systems? NASA can help address these questions by developing missions designed to find and characterize extrasolar planetary systems.