Tuesday, December 16, 2014

The Galactic Habitable Zone

In astrobiology and planetary astrophysics, the galactic habitable zone is the region of a galaxy in which life is most likely to develop. More specifically, the concept of a galactic habitable zone incorporates various factors, such as metallicity and the rate of major catastrophes such as supernovae, in order to calculate which regions of the galaxy are more likely to form terrestrial planets, initially develop simple life, and provide a suitable environment for this life to evolve and advance.

Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf

Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf
For the Milky Way this region is commonly believed to be an annulus with an outer radius of about 10 kiloparsecs and an inner radius close to the Galactic Center, both of which lack hard boundaries.

The galactic habitable zone is often viewed as an annulus 4–10 kpc from the galactic center, though in reality it is quite different.

Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf

Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, these qualities make the Sun one of the few stars in the Galaxy capable of supporting complex life. - See more at: http://www.astrobio.net/news-exclusive/galactic-habitable-zones/#sthash.NrKGJfh8.dpuf

Our Milky Way Galaxy is unusual in that it is one of the most massive galaxies in the nearby universe. Our Solar System also seems to have qualities that make it rather unique. According to Guillermo Gonzalez, Assistant Professor of Astronomy at the University of Washington, thesemqualities make the Sun one of the few stars in the Galaxy capable of supporting complex life.


For one thing, the Sun is composed of the right amount of “metals.” (Astronomers refer to all elements heavier than hydrogen and helium as “metals.”) Moreover, the Sun’s circular orbit about the galactic center is just right; through a combination of factors it manages to keep out of the way of the Galaxy’s dangerous spiral arms. Our Solar System is also far enough away from the galactic center to not have to worry about disruptive gravitational forces or too much radiation.

When all of these factors occur together, they create a region of space that Gonzalez calls a “Galactic Habitable Zone.” Gonzalez believes every form of life on our planet – from the simplest bacteria to the most complex animal – owes its existence to the balance of these unique conditions.

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