06-12-2019, 09:25 PM
(This post was last modified: 06-12-2019, 09:43 PM by Avalancheon.)
There have been many studys attempting to estimate the habitable zone for an Earthlike planet. The validity of the broader estimates (such as those proposed in the 1993 Kasting study) is dependent on the silicate cycle stabilising a planets climate. However, the silicate cycle can only operate when there is a significant amount of continental crust exposed to aerial weathering.
The 2008 Flament study suggests that ancient Earth was an ocean planet that was 99% covered in water. Thus, we know that the silicate cycle could not have played a factor in regulating its climate. If we assume that all Earth-like worlds start off as ocean planets, we must by necessity conclude that the broader habitable zones (as proposed by Kasting and others) are implausible.
This recent study by Schwieterman is just another nail in the coffin for such estimates.
The 2008 Flament study suggests that ancient Earth was an ocean planet that was 99% covered in water. Thus, we know that the silicate cycle could not have played a factor in regulating its climate. If we assume that all Earth-like worlds start off as ocean planets, we must by necessity conclude that the broader habitable zones (as proposed by Kasting and others) are implausible.
This recent study by Schwieterman is just another nail in the coffin for such estimates.