Use this to differentiate in a general sense between the habitability of different environments (as compared to human life on Earth)
Type I Environment (e.g. close to Earth)
Type II Environment (e.g. Life is supported but not Earthlike)
Type III Environment (e.g. Venus, Mars)
Type IV Environment (e.g. outer space, the moon)
Type I Environment (e.g. close to Earth)
- Atmosphere: Somewhat breathable by aliens from a planet with a nitrogen-oxygen mixture
- Gravity: +/- 10% more or less than Earth’s.
- Ecology: Organic life is abundant, water is freely available in the environment.
- Protective Equipment: Required for only extended stay outside of protected areas in that atmosphere. Inhabitants (even those from nitrogen-oxygen planets) can go without it for awhile but may suffer damage long term since it varies based on planet.
Type II Environment (e.g. Life is supported but not Earthlike)
- Atmosphere: May be a nitrogen-oxygen mixture but in reduced or excessive quantities, or a different type but supports an abundance of life there.
- Gravity: +/- 30% more or less than Earth’s.
- Ecology: Organic life akin to earth's would be scarce, water may be limited or poorly accessible (e.g. ice water only). However, it may have unique ways to support life different from earth's and have an abundance of those types of aliens.
- Protective Equipment: Obligatory for Type I planet aliens, may not be for others. Some aliens may even be able to adapt after a few generations depending on the similarity to their home planet.
Type III Environment (e.g. Venus, Mars)
- Atmosphere: Non-nitrogen-oxygen mixture such as carbon dioxide, etc.
- Gravity: >+/- 50% more or less than Earth’s.
- Ecology: Any organic life that is supported is not earth-like at all, or scarce, with water either not present or extremely difficult to access (e.g. locked in the ground).
- Protective Equipment: Obligatory for most organic creatures.
Type IV Environment (e.g. outer space, the moon)
- Atmosphere: Trace or non-existent.
- Gravity: >+/- 100% more or less than Earth’s.
- Ecology: No earth-like organic life present. Water is inaccessible.
- Protective Equipment: Obligatory for all except androids and some extremophiles.
