Planetary Habitable Zone (CHZ)
| Within any plantery system there is an area that could support life. Astronomers call this zone the circumstellar habitable zone (CHZ) and it is the area that would contain liquid water. Of course the planet will have to maintain this temperature for several billion years so that life could evolve. |
| What are the factors that determine the size of this zone? |
| The ellipticity of the Planets Orbit | Presence of a Moon |
| The presense of Large Planets | Type of Star |
| Size of the Planet | Metallicity of the star |
| Mixture of land and ocean |
Galactic Habitable Zone (GHZ)
| Within our galaxy, the miklyway there is an area that could support life. Astronomers call this zone the Galactic habitable zone (GHZ). This is an area that is based on its distance from the centre of the galaxy. Too close and |
| What are the factors that determine the size of this zone? |
|
The availabiltiy of material to build habitable planets. Seclusion from cosmic threats such as asteriod & comet impacts and blasts of radiation. Percentage of metaticity of the parent star Abundance of different Elements |
See Scientific American article: October 2001
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