What is the special role of the hydrogen atmosphere? Isn't water in contact with hot rocks at the bottom of an ocean enough even if the "atmosphere" is ice as in Titan or Enceldes?
The hydrogen is not really important for life itself. What they are showing with these hydrogen worlds instead is that oxygen is not vital for life, as we often assume, and that in fact other kinds of world, which appear very alien to us, are actually candidates for living creatures. Since many worlds have hydrogen atmospheres, the fact that they could host life means there are a lot more potentially habitable worlds out there.
Great article. Unless we point a radio telescope at it and hear radio transmissions, a chemical signature is not sufficient to claim the discovery of extraterrestrial life.
Something to think about: Even if we find extraterrestrial life on other stars….we probably couldn’t communicate with it given the sheer distance and limits of physics. This is a bit awkward and makes one wonder if other life forms know we are here already, but, like shouting into a void, we cannot hear each other.
Dimethyl sulphide is not an unequivocal sign of life:
"DMS, OCS, CS2, and simple thiols, species previously considered potentially robust biosignatures in exoplanetary atmospheres, have possible abiotic production pathways via planetary organic haze chemistry."
But given that the geometry of the universe appears to be flat, and so extends far beyond the "Hubble Bubble" that we can observe, it does seem almost certain that life exists elsewhere.
The Enceladus Explorer will probably find life signatures in the plumes (IMO).
Thanks
What is the special role of the hydrogen atmosphere? Isn't water in contact with hot rocks at the bottom of an ocean enough even if the "atmosphere" is ice as in Titan or Enceldes?
The hydrogen is not really important for life itself. What they are showing with these hydrogen worlds instead is that oxygen is not vital for life, as we often assume, and that in fact other kinds of world, which appear very alien to us, are actually candidates for living creatures. Since many worlds have hydrogen atmospheres, the fact that they could host life means there are a lot more potentially habitable worlds out there.
Thanks for this detailed break down!
"I want to believe"... and hopefully someday the sober analysis will justify doing just that.
Great article. Unless we point a radio telescope at it and hear radio transmissions, a chemical signature is not sufficient to claim the discovery of extraterrestrial life.
Something to think about: Even if we find extraterrestrial life on other stars….we probably couldn’t communicate with it given the sheer distance and limits of physics. This is a bit awkward and makes one wonder if other life forms know we are here already, but, like shouting into a void, we cannot hear each other.
Dimethyl sulphide is not an unequivocal sign of life:
"DMS, OCS, CS2, and simple thiols, species previously considered potentially robust biosignatures in exoplanetary atmospheres, have possible abiotic production pathways via planetary organic haze chemistry."
https://iopscience.iop.org/article/10.3847/2041-8213/ad74da
But given that the geometry of the universe appears to be flat, and so extends far beyond the "Hubble Bubble" that we can observe, it does seem almost certain that life exists elsewhere.
The Enceladus Explorer will probably find life signatures in the plumes (IMO).