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Posts Tagged ‘Galactic Habitable Zone

Living in the Galactic Danger Zone

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Not every place within a galaxy experiences the same conditions for habitability - some parts are lethal thanks to supernovae, whilst others do not possess enough heavy elements to allow rocky planets and life to develop.

Summary: Although stars closer to the galactic center are exposed to more radiation, new research finds that there are more chances to find habitable planets there than in the outer regions of our galaxy

We know for certain that life exists in the Milky Way galaxy: that life is us. Scientists are continually looking to understand more about how life on our planet came to be and the conditions that must be met for its survival, and whether those conditions can be replicated elsewhere in the Universe. It turns out that looking at our entire Galaxy, rather than focusing just on life-giving properties of our planet or indeed the habitability of regions of our own Solar System, is a good place to start.

How far our planet orbits from the Sun, along with other factors such as atmospheric composition, a carbon cycle and the existence of water, has told astronomers much about the conditions that are required for life to not only originate, but to survive on rocky worlds. This distance from a star is referred to, quite simply, as the ‘Habitable Zone’ or sometimes the ‘Goldilocks Zone’ because conditions here are neither too hot or too cold for water to be liquid on the planet’s surface — conditions just right for life as we know it to thrive.

Copernican theory tells us that our world is a typical rocky planet in a typical planetary system. This concept has spurred some astronomers to start thinking bigger, way beyond the simplicity of any one planetary system and instead towards much grander scales. Astronomers are exploring whether there is a Galactic Habitable Zone (GHZ) in our Galaxy – a region of the Milky Way that is conducive to forming planetary systems with habitable worlds. The Galactic Habitable Zone implies that if there are conditions just right for a planet around a star, then the same must go for a galaxy.

A supernova sterilizes an alien world in this artist's impression.

This concept was first introduced by geologist and paleontologist Peter Ward and Donald Brownlee, an astronomer and astrobiologist, in their book, ‘Rare Earth’. The idea of a GHZ served as an antagonistic view point to the Copernican principle….. Read the rest of this entry »

Written by physicsgg

September 23, 2011 at 2:27 pm