SDO habitability index - Revision history

Maxisnt at 16:34, 16 January 2026

2026-01-16T16:34:42Z

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	HI3 planets are fully inhabitable and require little to no terraforming. These planets are exceedingly rare, and may already present complete biospheres, at which point colonisation may be discouraged.		HI3 planets are fully inhabitable and require little to no terraforming. These planets are exceedingly rare, and may already present complete biospheres, at which point colonisation may be discouraged.

			=== Additional classes ===

			==== HIX ====
			HIX planets have been struck by an extinction event that has rendered the planet either completely uninhabitable or simply destroyed in its entirety. This class was created after much debate as to whether [[Earth]] should've been designated HI0 or a subclass of HI3 that included dead planets.
	[[Category:SDO]] [[Category:Astronomy]]		[[Category:SDO]] [[Category:Astronomy]]

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Maxisnt at 18:18, 15 July 2025

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The '''SDO habitability index''' or '''HI score''' is a system for classifying planets based on their habitability, with an [[elmian]] bias. It was created by the [[SDO]] during their early ventures into the universe after the discovery of the [[Dess]], and has been consistently expanded upon ever since.

== Classes ==

=== HI0 ===
HI0 planets are not only completely uninhabitable to [[elmians]], they are also dangerous to colonise. These planets may present extreme temperatures, may be too close to their star and receive excessive UV radiation from it, experience frequent collisions, or any other factor that may render the planet deadly. A classic example of a HI0 planet is [[ShE022-I]], which sits at an orbit so low it will end up tearing the planet apart within the next million years.

=== HI1 ===
HI1 planets are uninhabitable, but colonisable. Colonies in HI1 planets may be domed or underground, made to be comfortable for life on the planet. An example of this is [[Torch]], whose toxic atmosphere renders it unbearable to live on the surface, but has been inhabited by [[elmians]] and [[juleans]] in subterranean and domed colonies for hundreds of years.

=== HI2 ===
HI2 planets are on their way to being inhabitable, but require terraforming for life on their surface to be survivable. This is most commonly due to their atmosphere, either being composed of toxic gases, not containing enough oxygen, and/or being low-pressure.

=== HI3 ===
HI3 planets are fully inhabitable and require little to no terraforming. These planets are exceedingly rare, and may already present complete biospheres, at which point colonisation may be discouraged.

[[Category:SDO]] [[Category:Astronomy]]