Search for Planets

Formation of the Solar System

Page 3 of 5

To advance our knowledge of how planetary systems really form, we need to observe a statistically significant number of stars and planets and classify the observations taking into account the orbital parameters of the planet (eccentricity, period, inclination), its mass, and the type of parent star it is orbiting.

Are There Other Planets Apart From Earth Capable of Supporting Life?

If life elsewhere follows what we know about life on Earth, it requires liquid water and a solid-liquid interface to develop. The only objects in space where these conditions can be fulfilled are terrestrial planets in the habitable zone, i.e. solid planets at the appropriate distance from the star to allow for liquid water.

Complex life may only have developed on planets orbiting solar-type stars. These stars are old enough that complex organisms would have had time to evolve and they possess a relatively stable energy output which permits stable conditions in the orbiting planet.

The simultaneous existence of at least one massive planet orbiting far from the star and a terrestrial planet orbiting in the habitable zone may be a favourable configuration for the presence of complex life on the inner planet, as it would be protected from collisions by comets, events that could destroy life.

  

ESA Science Home page