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NASA study finds life-sparking energy source and molecule at Enceladus

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Re: NASA study finds life-sparking energy source and molecule at Enceladus

#111

Post by malfist »

hesk wrote: post #79
yieldcrv wrote: post #55

Earlier quoted context omitted.

absence of evidence is not evidence of absence sorry your life has created this crusade of rhetorically reminding people about the absence is evidence

Provided you're actively and systematically looking for evidence, then absence of evidence is evidence of absence.

But we've not even started doing that yet. None of the mars rovers have landed anywhere close to where we think is must likely to currently harbor life due to fear of contamination.

We've just now learned how to analyze atmospheres of exoplants.

5 years ago, we couldn't see exoplanets smaller than jupiter.

A decade ago, we couldn't see exoplanets at all.

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#113

Post by richardw »

superposeur wrote: post #6

This is intriguing and I’m very happy this exploration is being done. But, for decades, I’ve been reading reports of the discovery of evidence for the trappings of life elsewhere: water and organics and “habitable” exoplanets. These are valuable discoveries, but the tone of the reports suggest they imply life is about to turn up. It’s worth remembering that there is not one single shred of evidence that life has ever…

We’re looking for the shreds of evidence. What would you prefer people do?

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#114

Post by bvirb »

superposeur wrote: post #6

This is intriguing and I’m very happy this exploration is being done. But, for decades, I’ve been reading reports of the discovery of evidence for the trappings of life elsewhere: water and organics and “habitable” exoplanets. These are valuable discoveries, but the tone of the reports suggest they imply life is about to turn up. It’s worth remembering that there is not one single shred of evidence that life has ever…

What a fun thread. I've always heard this as one of The Great Filters related to the Fermi paradox. FWIW the wikipedia for the Fermi paradox even mentions that:

> The most commonly agreed-upon low probability event is abiogenesis

...which I read as saying that the most commonly agreed-upon reason we haven't found life anywhere else yet is because we _are_ special and abiogenesis is the rare event (the great filter).

All the various great filter theories are pretty fun reading.

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#115

Post by [deleted] »

superposeur wrote: post #6

This is intriguing and I’m very happy this exploration is being done. But, for decades, I’ve been reading reports of the discovery of evidence for the trappings of life elsewhere: water and organics and “habitable” exoplanets. These are valuable discoveries, but the tone of the reports suggest they imply life is about to turn up. It’s worth remembering that there is not one single shred of evidence that life has ever…

[deleted]

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#116

Post by fastball »

vlovich123 wrote: post #54
superposeur wrote: post #23

Earlier quoted context omitted.

These factors are what I call the “trappings of life”. It is a completely open question (and I mean completely ) how likely life is to arise spontaneously when these factors are present. One single instance of life elsewhere or successful abiogenesis in the lab would change that, but we have neither.

I agree it’s an open question, but I think it’s highly likely with lots of circumstantial evidence that life is an evolutionary emergent phenomenon where inorganic material reactions create life. We already know that’s the case in highly controlled environments. We don’t yet have confidence about the exact mechanism on Earth but based on those experiments it’s likely (& generally currently accepted as the most likely…

I don't think inorganic material reactions can be described as an evolutionary phenomenon.

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#117

Post by qqtt »

superposeur wrote: post #6

This is intriguing and I’m very happy this exploration is being done. But, for decades, I’ve been reading reports of the discovery of evidence for the trappings of life elsewhere: water and organics and “habitable” exoplanets. These are valuable discoveries, but the tone of the reports suggest they imply life is about to turn up. It’s worth remembering that there is not one single shred of evidence that life has ever…

> Moreover, no one has succeeded in hatching living matter from non living matter and we must honestly say we do not know how this process came about or the faintest estimate of how likely it is to occur (despite much speculation

Just want to comment on this point. The research in this field is pretty esoteric. It doesn't really benefit us to understand how this process came about (ie, there is little practical gain here, no medical advancements or otherwise), and moreover it requires a simulation which can estimate behavior over hundreds of millions of years. The usefulness of cracking the early earth/life creation part of our history is really not immediately clear, and thus research is limited.

That said, the Miller-Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment) showed animo acids organizing over conditions similar to early earth, and a follow up experiment dubbed Planet Simulator (https://en.wikipedia.org/wiki/Planet_Simulator) was extended to show the organization of protocells as part of this early earth environment.

It seems only a matter of time before science can connect the dots along the rest of the hundreds of millions of years regarding this process to show the line between chemical young earth evolving to be biological.

As an aside, why do you think it is "important to remember" that we haven't found life or that we don't fully understand the process by which biology evolved from chemistry? Why exactly is it "important to remember" such things?

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#118

Post by brokeAstronomer »

superposeur wrote: post #90
vlovich123 wrote: post #54

Earlier quoted context omitted.

I agree it’s an open question, but I think it’s highly likely with lots of circumstantial evidence that life is an evolutionary emergent phenomenon where inorganic material reactions create life. We already know that’s the case in highly controlled environments. We don’t yet have confidence about the exact mechanism on Earth but based on those experiments it’s likely (& generally currently accepted as the most likely…

This is what I referred to as "speculation" in the literature for life's origins on Earth. This speculation is a good first theoretical stab... or it might not be. Until life is created from inorganic matter in a laboratory (enabling us subsequently to estimate how rare or not it might be elsewhere in the observable universe), we should substantially dial back our confidence from "life is likely extremely plentiful t…

I agree that we are limited to "speculating" due to n=1. However, personally my sense is that simple life is more likely to be ubiquitous than not. This is informed by the fact that currently there is no evidence that conditions on early Earth were particularly unique in comparison to first principles modelling of rocky planet atmospheres**. This coupled with the relative speed with which simple life emerged points to it being a relatively probably event, though we can't be certain. I expect that with missions such as PLATO and the upcoming HWOs we'll have a better sense of the conditions on mature Earth like planets in the habitable zone. Though studying a large sample of early Earth's shortly after formation may be out of our reach for a while yet, depending on which particularly mission gets chosen.

**Not my sub-field. Extremely complex models. Much is still unknown.

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#119

Post by fastball »

idlewords wrote: post #22
superposeur wrote: post #6

This is intriguing and I’m very happy this exploration is being done. But, for decades, I’ve been reading reports of the discovery of evidence for the trappings of life elsewhere: water and organics and “habitable” exoplanets. These are valuable discoveries, but the tone of the reports suggest they imply life is about to turn up. It’s worth remembering that there is not one single shred of evidence that life has ever…

I would turn your logic around and say, everywhere we are able to look, we find evidence that life is more likely than expected. Until the 1990's it was an open question whether any other star had planets; as soon as we got the tools to test that, we found they were ubiquitous. As soon as we got the right instruments to Mars, we found signs of moving water, methane sources, and complex organic molecules in what is ba…

You call these factors "circumstantial evidence", but they are only circumstantial evidence if our ideas about what allows/causes/etc life are correct, which we have not validated at all.

If we can't promote abiogenesis in a lab our understanding is clearly limited, which is itself surprising. How many other processes in nature have we observed and not been able to replicate ourselves (or at least make progress towards replicating)?

Re: NASA study finds life-sparking energy source and molecule at Enceladus

#120

Post by vlovich123 »

antihipocrat wrote: post #88
ghaff wrote: post #60

Earlier quoted context omitted.

>Our type of society is probably much much rarer because you need access to mineral and energy deposits to go through each technological phase. For example, because of all the mining we’ve done, if humanity were to disappear it’s highly likely the Earth would not sustain another technological society because all the “easy to get to” deposits of crucial metals & things like oil are gone and there’s no way to bootstrap…

Readily obtainable hydrocarbons are lost for the forseeable future. However, haven't we made it easier for future civilizations to obtain minerals and metals? We have extracted, refined and placed them all in concentrated surface areas all over the planet (i.e. city limits)

Except a huge amount of it is alloys. You’d have to reprocess it to extract out the raw materials which is much harder than mining ore and requires a lot more tech. Like things may be bronze plated but you’re not going to find a whole lot of bronze in 1 spot.
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