Astronomers Made Map of Life in Our Galaxy

According to modern concepts, the main condition for the origin of life is the presence of liquid water on the surface. Most likely, the temperature should be the same as on Earth. Water can remain in the liquid form at very narrow temperature range, so that life can exist in a very narrow range at distances from the star.On the origin of life may affect galactic factors, for example supernova explosions in the neighborhood can completely destroy all life. Moreover, the impact of neighboring stars can destabilize the orbits of the planets, leading them from the “zone of life”. 

According to current concepts, the region of the galaxy, where conditions are relatively favorable for life, is a “donut”, a torus around the galactic  center  with a  diameter of  about  20-30 thousand light years. Canadian and American astronomers led by Michael Gowanlock University of Hawaii found that the galactic “life zone” can be arranged much more complicated. They developed a model of the “habitable zones” in our galaxy, given the recent data about the planets outside our solar system. These data suggest that planets are more likely to form in stars with high metallicity, a larger share of the heavy elements. In turn, the heavy elements are more in the “areas” of the galaxy, where a lot of explosions. However, the same supernova explosion literally “sterilize” the surrounding space.It is estimated that about 1.2% of all stars at any time history of the galaxy may have planets able to maintain the existence of complex life forms. Approximately 4 billion planetary systems in our Galaxy existor have existed a planet with conditions suitable for life.However, 75% of the planets in these systems may be in a tidal resonance with its luminaries, when one of their side is always facing the star. As a result, on the bright side of the planet will reign the extremely high temperatures, and on the other side would be a terrible cold.
source:www.forcetoknow.com