Cassini confirms global ocean at Enceladus

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Discussion Overview

The discussion centers on the recent findings regarding Enceladus, specifically the confirmation of a global ocean beneath its icy surface as interpreted by NASA. Participants explore the implications of these findings, including the potential for liquid water and its significance for habitability, as well as comparisons to other celestial bodies with similar features.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that NASA's interpretation is based on measurements of the gravitational field and surface rotation, suggesting that the observed libration indicates a lack of solid connection between the ice and the core.
  • There is a consensus among some that the findings support the existence of a liquid layer within Enceladus, likely composed of water, but opinions diverge on its implications for habitability.
  • One participant expresses skepticism about the viability of Enceladus as a habitat for life or future human habitation, citing the challenges of accessing liquid water beneath several kilometers of ice.
  • Another participant mentions the concept of a lander that could melt through the ice to investigate the ocean, referencing methods used in Antarctic drilling, while also raising concerns about contamination from Earth organisms.
  • References to other celestial bodies, such as Ganymede, are made to contextualize the discussion and highlight similar findings regarding subsurface oceans.

Areas of Agreement / Disagreement

Participants generally agree on the existence of a subsurface ocean at Enceladus, but there are multiple competing views regarding its implications for life and the feasibility of exploration. The discussion remains unresolved on the significance of these findings for potential habitability.

Contextual Notes

Some limitations include the reliance on NASA's interpretation and the lack of detailed information from the press release. There are also unresolved questions about the methods of exploration and the implications of contamination.

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At least according to NASA's interpretation.

Both measurements of the gravitational field and of the rotation rate of the surface agree on that. If the surface is not connected to the core, its libration is stronger, and apparently the observed magnitude is not compatible with a solid connection between ice and core.

NASA press release

The research is presented in a paper published online this week in the journal Icarus.
I don't find it there yet, the press release doesn't give much detail.
 
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This corroborates upon previous evidence that this Moon probably has a liquid layer of it's interior and almost certainly it's water.
I don't think this makes it potentially viable as a habitat though, either for indigenous life or for possible future human habitation.
We can't investigate or make use of liquid water existing several kilometers beneath a solid ice surface, so while the discovery is interesting it's probably not of much consequence.
 
mfb said:
At least according to NASA's interpretation.

Both measurements of the gravitational field and of the rotation rate of the surface agree on that. If the surface is not connected to the core, its libration is stronger, and apparently the observed magnitude is not compatible with a solid connection between ice and core.

NASA press release

I don't find it there yet, the press release doesn't give much detail.

Nice result! Here are names of a couple of co-authors:
Matthew S. Tiscareno, Peter C. Thomas
We can search for the paper on arXiv later.
I did not see it when I looked just now.
 
Earlier Emily Lakdawalla posted a graphic showing which bodies might have subsurface oceans.
I see she included Enceladus.
oceans.png

Source:
http://www.planetary.org/blogs/emily-lakdawalla/2015/03121716-ganymede-ocean.html

She reports here on evidence that the jovian moon Ganymede has a subsurface ocean. Among the sources she cites is this NASA release:
http://hubblesite.org/newscenter/archive/releases/2015/09/full/
 
Last edited:
rootone said:
This corroborates upon previous evidence that this Moon probably has a liquid layer of it's interior and almost certainly it's water.
I don't think this makes it potentially viable as a habitat though, either for indigenous life or for possible future human habitation.
We can't investigate or make use of liquid water existing several kilometers beneath a solid ice surface, so while the discovery is interesting it's probably not of much consequence.
There are ideas of a lander that would melt itself through the ice to investigate the ocean below. That concept is the usual way drilling happens in Antarctica today, Lake Vostok has been reached that way for example.
Complete sterilization of the probe would be a serious issue. We certainly don't want to introduce life from Earth, especially if there happens to be life (which is more likely for the larger moons I think, but we don't know).
 

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