4 ms·

Indeed, we find life practically everywhere on Earth and there's no telling what kinds of adaptations alien life might have to all sorts of seemingly inhospitab

Indeed, we find life practically everywhere on Earth and there's no telling what kinds of adaptations alien life might have to all sorts of seemingly inhospitable environments.

VieElm 12y ago
Preexisting life being able to adapt to inhospitable environments does not also mean that they can develop there. We know very little about under what conditions abiogenesis can occur.
- ChrisGranger 12y ago
  >We know very little about under what conditions abiogenesis can occur. I think that's ceejayoz's point though. The less we know about something, the less confident we should be about declaring limits to when that something can occur.
_asummers 12y ago
In response to this, I will offer the suggestion that the life forms that live in the extreme climates lived in less extreme climates first. It is possible that some creatures started in "hard mode", but most likely, they progressively adapted to the extreme environments from more palatable climates.
- millstone 12y ago
  Hard is relative. For example, the filling of the atmosphere with a powerful oxidizer was a major extinction event (the "Oxygen Catastrophe"), yet we do not find it extreme because we are adapted to it. Even environments that are energy-poor, or cold enough as to inhibit chemical reactions, may support rich forms of life that operate on larger time scales.
maaku 12y ago
Everywhere on Earth is still within the habitable zone of the solar system.
- ceejayoz 12y ago
  The "habitable zone" isn't so well defined, though. Europa's believed to have an ocean of liquid water and heat from tidal forces. Mars may well have liquid water at times, and who knows what we'd find miles down underground - we've found all sorts of extremophile life in mines we never expected to.
  - maaku 12y ago
    Well Mars is inside the traditionally defined habitable zone (which extends halfway into the asteroid belt), but Europa is a point. More generally one can imagine e.g. larger rocky planets whose active core keeps them warm, rather than just their sun.

Indeed, we find life practically everywhere on Earth and there's no telling what kinds of adaptations alien life might have to all sorts of seemingly inhospitable environments.

VieElm 12y ago

Preexisting life being able to adapt to inhospitable environments does not also mean that they can develop there. We know very little about under what conditions abiogenesis can occur.

ChrisGranger 12y ago
>We know very little about under what conditions abiogenesis can occur. I think that's ceejayoz's point though. The less we know about something, the less confident we should be about declaring limits to when that something can occur.

_asummers 12y ago

In response to this, I will offer the suggestion that the life forms that live in the extreme climates lived in less extreme climates first. It is possible that some creatures started in "hard mode", but most likely, they progressively adapted to the extreme environments from more palatable climates.

millstone 12y ago
Hard is relative. For example, the filling of the atmosphere with a powerful oxidizer was a major extinction event (the "Oxygen Catastrophe"), yet we do not find it extreme because we are adapted to it. Even environments that are energy-poor, or cold enough as to inhibit chemical reactions, may support rich forms of life that operate on larger time scales.

maaku 12y ago

Everywhere on Earth is still within the habitable zone of the solar system.

ceejayoz 12y ago
The "habitable zone" isn't so well defined, though. Europa's believed to have an ocean of liquid water and heat from tidal forces. Mars may well have liquid water at times, and who knows what we'd find miles down underground - we've found all sorts of extremophile life in mines we never expected to.
- maaku 12y ago
  Well Mars is inside the traditionally defined habitable zone (which extends halfway into the asteroid belt), but Europa is a point. More generally one can imagine e.g. larger rocky planets whose active core keeps them warm, rather than just their sun.