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Enceladus: New Organic Compounds via Cassini Data

While I’m working on the project I discussed the other day, I’m trying to keep my hand in with the occasional article here, looking forward to when I can get back to a more regular schedule. Things are going to remain sporadic for a bit longer this month, and then again in mid-November, but I’ll do my best to follow events and report in when I can. I did want to take the opportunity to use an all too brief break to get to the Enceladus news, which has been receiving attention from the space media and, to an extent, the more general outlets.

We always track Enceladus news with interest given those remarkable geysers associated with its south pole, and now we return to the Cassini data pool, which should be producing robust research papers for many years. In this case, Nozair Khawaja (University of Berlin) and colleagues have tapped data from the spacecraft’s Cosmic Dust Analyzer (CDA) to study the ice grains Enceladus emits into Saturn’s E ring, finding nitrogen- and oxygen-bearing compounds. These are similar to compounds found on Earth that can produce amino acids. Says Khawaja:

“If the conditions are right, these molecules coming from the deep ocean of Enceladus could be on the same reaction pathway as we see here on Earth. We don’t yet know if amino acids are needed for life beyond Earth, but finding the molecules that form amino acids is an important piece of the puzzle.”

Image: This illustration shows how newly discovered organic compounds — the ingredients of amino acids — were detected by NASA’s Cassini spacecraft in the ice grains emitted from Saturn’s moon Enceladus. Powerful hydrothermal vents eject material from Enceladus’ core into the moon’s massive subsurface ocean. After mixing with the water, the material is released into space as water vapor and ice grains. Condensed onto the ice grains are nitrogen- and oxygen-bearing organic compounds. Credit: NASA/JPL-Caltech.

So let’s clarify the process. What the Cosmic Dust Analyzer is looking at appears to be organics that would have been dissolved in the ocean beneath Enceladus’ surface. These would have evaporated from the ocean and then condensed, freezing on ice grains inside fractures in the crust. Rising plumes would have accounted for these materials being blown into space.

We begin to get a window into what might be produced within the ocean, though the view is preliminary. In the excerpt below, note that the scientists classify various types of ice grains on Enceladus according to a taxonomy: Type 1 represents grains of almost pure water ice, Type 2 shows features consistent with grains containing significant amounts of organic material, and Type 3 is indicative of salt-rich water ice grains. The study homes in on Type 2:

It is highly likely that there are many more dissolved organic compounds in the Enceladean ocean than reported here… In this investigation of Type 2 grains, the initial constraints, in particular the choice of salt-poor spectra, favoured the identification of compounds with high vapour pressures. Despite the expected solubility of potential synthesized intermediate- or high-mass compounds, their low vapour pressures mean that they will not efficiently evaporate at the water surface and thus remain undetectable not only in the vapour, but also those Type 2 grains forming from it. Potential soluble biosignatures with higher masses might therefore be found in spectra from Type 3 grains, which are thought to form from oceanic spray (Postberg et al. 2009a, 2011). Finding and identifying such biosignatures will be the main goal of future work.

Image: With Enceladus nearly in front of the Sun from Cassini’s viewpoint, its icy jets become clearly visible against the background. The view here is roughly perpendicular to the direction of the linear “tiger stripe” fractures, or sulci, from which the jets emanate. The jets here provide the extra glow at the bottom of the moon. The general brightness of the sky around the moon is the diffuse glow of Saturn’s E ring, which is an end product of the jets’ material being spread into a torus, or doughnut shape, around Saturn. North on Enceladus (505 kilometers, or 314 miles across) is up and rotated 20 degrees to the left. Credit: NASA/JPL/Space Science Institute.

The researchers believe that similarities between the hydrothermal environment found on Enceladus and what we see on Earth prioritizes the exploration of the Saturnian moon for life. After all, we know of many places on our planet where life develops without sunlight, with the vents supplying the energy that fuels reactions leading to the production of amino acids. Despite the remarkable strides made by Cassini, its Cosmic Dust Analyzer was not, the authors say, designed for deep probing of this question. That makes high-resolution mass spectrometers a key component of any dedicated mission designed to explore the organic chemistry beneath the ice.

The paper is Khawaja et al., “Low-mass nitrogen-, oxygen-bearing, and aromatic compounds in Enceladean ice grains,” Monthly Notices of the Royal Astronomical Society Vol. 489, Issue 4 (November 2019), pp. 5231–5243 (full text).


Comments on this entry are closed.

  • Brett October 8, 2019, 12:33

    It’s so promising a target for biosignature analysis. Congress should authorize funding specifically for an Enceladus Life Finder mission.

  • Gary Wilson October 8, 2019, 13:41

    This paper presents more evidence that Enceladus is a very interesting place indeed. The major challenge would be sample collection and possible return to Earth or in situ analysis. Could we be looking at the most likely place other than Earth in the solar system for life to have arisen? I’m still betting on subsurface Mars as a site for microbial life but this moon seems a very likely alternative or additional candidate.

  • Rob Flores October 8, 2019, 14:08

    Yes, this could be a organic soup, just waiting for a few billion more years for something to develop,

    However consider an unlikely alternative. Mars has been in a cold state for few billion years, if life exists there it’s probably subsurface. and adapted Mars’ current geophysical state. It might even be beneath the ice sheets that are assumed to be there, (under pressure the bottom ice could be liquid) These would be chemical reducing organism. What about a transport via asteroid strike of these microorganisms from Mars to Enceladus, there could be similar enough conditions for
    life to take root there.

    If there were such organisms:

    1 ) could they be ejected into space somewhat intact.
    2) would its remains be clearly evident in the Cassini plume data

    • Gaylon B Arnold October 9, 2019, 2:44

      There are theories that conditions on early Mars were better than on Earth for the rise of life. An asteroid strike may not have the energy to send material all the way out to Enceladus, but we have recovered rocks on Earth that originated on Mars, and may have brought life to Earth from Mars.

      • Rob Flores October 10, 2019, 12:09

        Actually if you have an organism that adapted on Mars to salty
        glacier melt under the sheets on Mars, An asteroid event could also transfer them to Europa, Too. If we assume Mars has been in cold state for 3 billion years or so, that is a long deep time to have these types of transfer events take place. It is possible that any and all microbial life we find on icy moons of the solar system might be related, and have a single origin.
        Europa like Enceladus has a relatively thin crust so a very large asteroid event is not necessary, the more numerous smaller ones would do just fine.

  • Robin Datta October 8, 2019, 14:17

    Questions that come up:
    • Are any of the molecules chiral?
    • If chiral, is the distribution as would be expected from non-biological processes?

    An unexpected predominance of one chiral form over another could suggest processes of a biological nature.

    • Brad in Dallas October 8, 2019, 17:18

      Cool idea. What equipment would the mission require to test that? Would we need to purify and then crystallize the organic matter first in order to determine its chirality, or is my chemistry knowledge hopeless outdated?

      • Alex Tolley October 9, 2019, 12:36

        Here is a proposal for chirality testing for a Mars rover. If it or others are viable, then I see no reason why such an instrument could not be used on an icy moon mission. Instrument mass is going to be the constraint.

  • Alex Tolley October 8, 2019, 16:09

    This study primarily looks at the volatile, low molecular weight, organic compounds in the ice grains of the Enceladan plumes and Saturn’s E-ring. This is in contrast to the review paper on high molecular weight organics interpreted as a prebiotic state (c.f. CD post Is Enceladus Prebiotic?

    While authors do not identify specific compounds, just general classes, it is clear that these are the types of compounds that have been widely found in space, such as comets and meteorites.

    The authors make much of the potential of these compounds to be able to act as feedstocks in reaction pathways to form important biological base elements, such as amino acids. Yet interestingly, these compounds are not found, as their molecular weights exceed the spectral indicators of atomic mass. What are we yo make of this? One interpretation is that Enceladus is dead, and these materials are released from the asteroidal and cometary material composing Enceladus. That we do do not apparently detect biosignature molecules seems to suggest that life is not present, nor that the hypothesized reactions are occurring. If life was present, then we might expect these low weight organics to be largely absent as they would be food for any life form that was present. If there was life, we might also expect different isotope ratios of these compounds compared to material elsewhere in the solar system. Unfortunately, this was not available. In addition, as Robin notes, we might expect these organic carbon molecules to have a strongly biased chirality. This may require different instruments to determine.

    My sense is that these results indicate that Enceladus is lifeless. Despite the presence of liquid water and probably hydrothermal vents, unlike Earth’s deep ocean volcanic vents, there is no life populating these hot spots, nor anywhere else in the water column. We won’t know until we look much more carefully, but I think we may be disappointed with the results from the upcoming Europa Clipper mission.

    Whether this has bearing on the Fermi question I don’t know. rather than suggesting Earth is unique, it may just indicate that icy moons may not be likely abodes for subsurface life. The lack of energy may be a serious constraint too. Exoplanets in the HZ may be far more likely to support life, although we will be constrained to analyzing spectral data remotely for a long time to come before we can hope for a sampling mission.

    • ljk October 9, 2019, 9:15

      Then why is that giant black monolith telling us to back off from Europa, huh?

    • tesh October 9, 2019, 10:49

      My quibble is the following:
      – Yes there is life in and around hydro-thermal vents on Earth
      – Are we at all certain that that life originated/emerged in and around the vents or did it in fact emerge (first) in a far different environment and then slowly over time evolve to live there?

      My (lay) feeling is that the spark of life on Earth is due to the proximity of the Earth to the Sun and not due to Earth having hot hydro-thermal vents.

  • Thomas Hair October 8, 2019, 22:11

    Alex Tolley has an excellent (if deflating for some) point in all of this. Abiogenesis is a tough nut that we have not come close to cracking. As a freshman at University of Florida I vividly remember my biology professor discussing the topic of amino acids being found in space (something not yet found on Enceladus) and the possibility that this recent (at the time) discovery could have on the possibility for extraterrestrial life. His response was close to “an amino acid is to a cell, what a rivet is to an aircraft carrier.” Cold Enceladus, with our very limited information does not appear promising for life.

    • ljk October 9, 2019, 9:14

      Enceladus is only cold on its icy surface. Underneath in the water is another matter.

      Remember, before 1977 most experts would have told you that creatures living and thriving around boiling hot hydrothermal vents deep in Earth’s oceans would have been virtually impossible. In fact they used to think most of the ocean floors were essentially deserts so far as biology was concerned. A little direct exploration changed that thinking real fast.

      • Alex Tolley October 9, 2019, 11:17

        All true, but we can detect life around hydrothermal vents chemically. No way to test whether such biosigns would be detectable at Earth’s surface due to the biomass above the vent. But on Enceladus or Europa? If life can exist near the vents on icy moons, then I would expect it to evolve to maximize opportunities in the whole subsurface ocean. I would not expect high molecular weight species floating just below the crust as these would be food for any life form. I would any such life to be present in the plumes. So far, with the detection instruments we have, there is no sign of that life. Therefore the best I think we can hope for is a prebiotic state. However, I am skeptical of even that.

        Which isn’t to say we shouldn’t look, just that we should expect disappointment. Rather like the SETI results to date.

        • ljk October 9, 2019, 16:10

          As wonderful as the Cassini probe was, it was not really designed to look for evidence of life – which I think was a bit foolish simply because of Titan if nothing else, but their experiences with the Voyagers should have taught them to be prepared for such a situation.

          Obvious statement of the week: We need to get a dedicated mission to Enceladus to find out if there is native life or not.

  • Gary Wilson October 9, 2019, 11:53

    With respect might isn’t it a little early to be so negative about the possibilities of life on Enceladus Alex? You’re basing your conclusion on the results from one mission. Surely we would need to explore the subsurface ocean of Enceladus much more thoroughly to come to any conclusions? Also do we know with certainty how long Enceladus has orbited Saturn? Could have been captured fairly recently (only millions or tens of millions of years ago)? If so might it be in a prebiotic state?

    • Alex Tolley October 10, 2019, 13:48

      As you say, we don’t know where abiogenesis started. Hot vents, Darwin’s “warm little pond”, or someplace else. However, we do have some clues:

      1. The early Earth was CO2 rich, and we know methanogens can use CO2 to extract energy and release CH4
      2. The Archaea prokaryotes are the type that contains the predominant number of methanogens.
      3. While we cannot know which prokaryotes are the most ancient, the relationship of Archaea, methanogens, and early Earth conditions hints at this group being the most ancient (but it is only a hint).
      4. Methanogens are found in anoxic environments, including hot vents. So these could be where they started, or they could be a retreat. I don’t think we can know which).
      5. Another source of energy is sulfur reduction, and again, the prokaryotes that engage in this metabolism are found in hot springs.
      6. Extremophiles, especially those found in hot liquids, tend to be Archaea.

      So whilst the evidence is circumstantial, it seems more likely that abiogenesis occurred in extreme conditions, perhaps in

    • Alex Tolley October 10, 2019, 14:20

      With respect might isn’t it a little early to be so negative about the possibilities of life on Enceladus Alex

      Could have been captured fairly recently (only millions or tens of millions of years ago)? If so might it be in a prebiotic state?

      A prebiotic state and a living state are very different. I am not ruling either out, just offering my opinion as to why I am skeptical. I have said we should investigate further, much as we should investigate the subsurface of Mars.

      The pendulum seems to swing in either direction over time. Optimistic, pessimistic for life to exist elsewhere in the solar system. Ever since Viking’s ambiguous results, Nasa, in particular, has been very wary of looking for life directly, preferring to look for water, organic molecules, but not life. ESA’s failed Beagle mission was much more direct. The idea of life in the subsurface oceans of icy moons seems to have escalated based on no more that there are liquid water and volcanic vents with conditions that might mimic those of Earth’s. In addition, it is possible that such vents may be where abiogenesis on Earth occurred. Together, they offer an optimistic view of the possibility of life in these moons, particularly Europa and Enceladus.

      But since we really don’t know the place where abiogenesis occurred, or even if life is rare or not, this is just speculation. Certainly worth exploring. After all, we keep putting landers and rovers on Mars, and we get back a lot of interesting information irrespective of whether Mars ever had life or not.

      If I had to bet, I suspect that we will find biosignatures around other stars long before we have any proof (or can rule out) life elsewhere in our solar system. But as I have also said, exoplanet biosignatures would be frustrating. They may tell us about the frequency of life elsewhere which is important, but we will not be able to do any detailed work on that life as we cannot reach those planets. Even the very best telescopes we can imagine will give us just hazy images of exoplanets and be unable to show an individual animal or plant, let alone give us any idea of the biology of that life. It is that unreachable nature that makes finding life elsewhere in the solar system so attractive. Even if there are only simple unicellular life forms resulting from a different abiogenesis, we can collect samples and gain a lot of very useful information from them. That is what impels spending resources on looking for such evidence.

      If we found such evidence tomorrow, then that might immediately indicate that life is ubiquitous in the universe and that we might expect to find many exoplanets with biosignatures. It would also likely stimulate more SETI effort. Conversely, if we find no life in the solar system, and exoplanet biosignatures prove very rare, I would expect that to support the solution to the Fermi Question being that we are quite possibly alone in the galaxy. That might make us lonely, but I think it would also mean that there would be a stronger interest in ensuring Earth’s biosphere remains as viable as possible, and possibly to promote a mission to “green the galaxy” as part of our future. That might become almost a religious quest, much like Christianity was once pushed by the Catholic church to be the religion for all the people of Earth. I could quite imagine a century from now, tiny seed ships being sent out to the stars like dandelion seeds to try to bring life to sterile worlds and which might just make some worlds be suitable for human colonization in the far future.

      • ljk October 11, 2019, 9:53

        As the comic strip Pogo said in 1959, either there are more advanced brains in the Universe, or we have the most advanced minds. Either way, it’s a mighty sobering thought.

        I honestly have a lot of trouble with the idea that we are the only intelligent beings in the galaxy for many reasons. We have a LONG way to go before we can make such a statement. And if it is true, it will only reinforce the view that existence is a random crap shoot.

        • Alex Tolley October 11, 2019, 11:23

          We should be careful when using the word “intelligent”. SETI assumes that intelligence will be like us, resulting in a technological civilization, perhaps with convergent interests. But “intelligence” encompasses a range of capabilities, and I ascribe more to Hofstadter’s idea that there is a continuous gradation from the simplest life forms through to us. As usual, Douglas Adams suggested that the dolphins were more intelligent than us, and escaped before the Vogons destroyed Earth. We are starting to build AIs that may eventually become AGIs. But the space their intelligence will operate in may be very different from ours, although I would hope they become like the machines in the novel “The Medusa Chronicles” by Baxter and Reynolds, a sequel to Clarke’s “A Meeting with Medusa”.

          Bottom line is that life may be ubiquitous in the galaxy, with many species exhibiting some recognizable intelligence, but none that have progressed [yet?] to a high tech civilization as ours is. We don’t even know if our kind of civilization is sustainable, although I see no intrinsic reason why it should not be, albeit with a change in our economic and social systems to ensure it becomes so (e.g. exponential economic and resource-based growth is not sustainable. It must be logistic.)

        • Gary Wilson October 11, 2019, 12:14

          That makes a lot of sense Alex. The obvious first place to look for life is Mars. It’s the closest target. We know it had large amounts of surface water for a relatively long period of time. We know there is still frozen water ice on the surface. And we know microbes can thrive below the surface of Earth. If we find a new class of microorganism on Mars we will know that life is fairly common. There may be no other examples in our solar system if investigation of the ice moons proves fruitless but we should continue to look. So then robotic exploration of exoplanets will be the next step. If we can make the machines small enough we can get them to their targets in tens of years using systems like Breakthrough Starshot. We will probably attempt these things whether or not we discover life on Mars but having a second home for life (Mars) would certainly be exciting!

  • Robin Datta October 9, 2019, 19:46

    Come to think of it, are the quantities of organic molecules in meteorites adequate to check for chirality and for isotope studies? Probably not, because otherwise very intelligent folk would have thought of it and done it.

    • Alex Tolley October 10, 2019, 16:08

      IIRC, some bias in the chirality of has been detected with the Murchison meteorite organics. AFAICT, this has not been done for any comets, such as 67P/Churyumov-Gerasimenko (Philae lander could not deploy the instrument as no samples were able to be collected after it failed to land correctly). Nor on Mars, but these tests will be on the 2020 EXOMARS mission. The missions to the Ryugu and Bennu asteroids will return samples which will be tested for chiral organics, so we can expect some results from Ryugu (2020) and Bennu (2023). The samples from asteroid Itokawa (2010) were found not to contain organics at a detectable level, therefore no chirality testing was possible.

      The game is wide open for the first solid evidence of strong chirality bias in samples of organic molecules from an extraterrestrial source.

  • Robin Datta October 9, 2019, 21:22

    All we need is one worm-like specimen of microfauna in one plume from one vent…

  • NS October 10, 2019, 4:14

    Centauri Dreams discussion about sample return missions from Enceladus and other places:


  • Michael Fidler October 10, 2019, 9:08

    “Well I hate to be an optimist”: You do not hear that phrase too often, but that may be our error when looking for extraterrestrial life. We look at our planet as the paradise for life, which it most definitely is not, our love of rocky planets assumes that is the the only place life will spring forth. The actual situation is just the opposite, most of the organic compounds are beyond the snow line and we have just started to explore it. The rocky planets are mostly dry lifeless deserts with an occasional oasis, but further out water, carbon, and the many elements that make life are common. You say it is frozen, well Jupiter, and the three other gas giants all are active planets with the “right stuff” for life. Now we are seeing that active oceans exist on many of the gas giant’s moons! So I would rather be living under 6 feet of snow instead of 6 feet of hot sand! ;-{)

    These alien geysers spew life’s building blocks.


    • Thomas Hair October 11, 2019, 8:06

      Come on Michael, pull the other one. I’ve got all the ingredients to make a cake right in my kitchen, but without the oven and my serendipitous mixing skills nothing is going to happen. As stated in the article, Enceladus does not even have detectable levels of amino acids. Alex has a very valid point that flies in the face of those who would, via wish fulfillment, subscribe to Carl Sagan’s flawed numbers approach to the possibility of alien life in general and SETI in particular. Lastly, Earth is a paradise for life that I prove to myself as I type while watching the sun rise over the Caloosahatchee in the deep, sweaty, fecund smelling sub-tropics of south Florida. There’s no place like home.

      • Michael Fidler October 11, 2019, 10:57

        As I have said before on these very pages Earth is nothing but a large asteroid with slime growing on it!

        Ancient fossils reveal fresh clues about early life on land.
        Slime has been present on Earth for a very long time — almost 2 billion years, according to a recent reassessment of fossil evidence.


        All we are is a large slimy worm that will be wiped out by the next asteroid impact!
        Jupiter is where it’s happening and life flourishes their, more carbon then a thousand earths and water overflowing. While you are scrubbing the slime mold off your bathroom walls the next large asteroid impact into Jupiter will of occurred without all the inhabitants even noticing. Like the flat earths believers the earth centered universe believers will slowly slime their way under a rock no longer to be heard or accepted.
        Can you blame them (ET), who would want to talk to some self centered worms…

        • Alex Tolley October 11, 2019, 11:59

          The slime now has migrated deep into the crust. Earth cannot be sterilized. If we successfully create extraterrestrial biospheres on other worlds or in artificial habitats, even our technological slimy species will not be vulnerable to asteroid extinction, nor will the rich ecosystems we populate space with. If we can forgo the human centeredness for a moment, no cosmic event in 5 billion years has sterilized the Earth. Mammals and we primates only came to dominate after an asteroid struck a mere 65 mya. Sadly, we seem to be doing a good job extinguishing a lot of the descendants of those survivors.

          As for life in Jupiter, I just hope I am still alive when a probe discovers those Medusas living in a clement atmospheric layer. However, Thomas Hair’s point about ingredients and baking is very relevant in this regard. If there is life in Jupiter, I would think it far more likely due to panspermia from Earth and not a second genesis, at least by what we know of the baking equipment needed on Earth. That rock may be very important!

          • Michael Fidler October 11, 2019, 18:26

            Panspermia from Earth, just look at Jupiter, the biggest mixing vat in our solar system with the largest oven to boot! Compare the surface area of earth’s surface to Jupiter’s surface or should I say 3D surface and the small asteroid comparison is not too far from reality. Just think how much mixing has been going on for 4 billion years with every element for life readily available. Why what we should be doing is sending a thousand CubeSats to flutter down into Jupiter’s atmosphere, is NASA afraid they will open Pandora’s box and the earth first worms will pull funding???

            • Michael Fidler November 1, 2019, 19:26

              Jupiter’s Great Red Spot –“Could It Be a Way Station on the Road to Life?”

              Many scientists believe that it is, suggests Paul Davies, theoretical physicist at Arizona State University and director of the Beyond Center, in The Demon in the Machine, observing that the Great Red Spot is an example of a “dissipative structure” first recognized in the 1970’s by the chemist Ilya Prigogine, who defined life as operating far from equilibrium with its environment and supporting a continued throughput of matter and energy.


      • Alex Tolley October 11, 2019, 11:46

        I’ve got all the ingredients to make a cake right in my kitchen, but without the oven and my serendipitous mixing skills nothing is going to happen.

        Exactly right. So far we only have hints on the mixing, proving and baking instructions. We certainly have no idea of the bake time either.

        In the far distant future, I envisage a galactic equivalent of “The Great British Bake Off” where species all over the galaxy compete to create life. Technical challenge: Create a metabolism that can evolve on a water world. Showstopper: Create a life form that will not destroy its own planet in less than 5 billion years. It should be spectacular, exhibit technological prowess, be able to converse with the extant species in the galaxy, but exhibit predatory or “berzerker” behaviors, silencing other species.

  • John Freeman October 11, 2019, 17:24

    On the one hand I’d like to point out to Alex Tolley and his cohorts that writing off Enceladus as neither home to any form of life, nor any life-relevant prebiotic processes, based on the evidence we have from Cassini, is very premature. Indeed, even if that were true, understanding why that was so would actually make Enceladus a more interesting target, and even provoke thoughts of experimenting in seeing what terrestrial organisms might take root there.

    On the other hand honesty compels me to point out to their detractors that they haven’t done any of the above – they’re just engaging in some reasonable speculation based on the fairly limited data obtained so far.

    The goal, as I understand it, is a greater understanding of life, its origins, and its place in the Universe. That can be done many ways, and discovering the ‘holy of holies’ – that extraterrestrial microbe – would at most be one piece of that puzzle (yes a very cool one, but that’s NOT relevant).
    Hell we have more solid data pointing to abiogenesis relevant processes going on in meteorite patent bodies billions of years ago than we do of them at Enceladus OR the beloved Mars today. Go to Atacama and start picking up rocks!

    There’s lots of justification to explore the whole solar system. I suggest we all do what we can to keep exploration funded and appreciated, see what gets turned up, and remember that right now this is all speculation based on some limited data.

    • Alex Tolley October 12, 2019, 17:23

      Clarke’s 1st Law: “When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

      Which is a nice way of saying do not make arguments from authority.

      I hope it is clear from my comments on this and other posts that I support getting experimental data, i.e. sending instruments to look for life using various methods including direct visual examination. I may be skeptical based on the sparse data we have to date, but I do want to find life elsewhere because it would be a fantastic opportunity to study such life to determine its similarities and differences from terrestrial life. But we also need to moderate our expectations when spending resources for finding life. The funding inevitably draws resources away from terrestrial science (biology). It is high risk, with a possible high return. Ideally, it would be better if we could make such missions cheaper. In a tangential direction, the JWST is now so expensive that the returns had better be spectacular to justify the investment and the ignoring that costs are sunk. It has become a “too big to fail” big science project.

      • John Freeman October 15, 2019, 10:25

        I agree, I simply remember many encounters with exploration enthusiasts who – unwittingly it seems to me – believe that space exploration starts and ends with the search for alien life, and alien life at their favoured destination (usually but not always Mars) at that – some of them heading their own advocacy organisations. And that bothers me, firstly because that is terrible science and a tunnel vision strategy, secondly because the evidence we currently have points towards many interesting things to explore that are at most only tangentially related to searching for currently extant life, and thirdly because putting all our intellectual and PR eggs in one basket that way is asking for a disappointment, and a backlash that could damage space exploration generally in major ways.

        • Alex Tolley October 16, 2019, 13:01

          In 2017/2018, I recall an article in the BIS’ Spaceflight magazine about whether NASA should refocus on finding life as its primary mission. This seems like a relatively new idea, driven by the exoplanet discoveries and the excitement of potentially finding an Earth II. Prior to this, AFAIK, searching for life was a relatively low priority for NASA, especially after the Viking experience. Few of the spaceflight and astronomy books in my personal library put finding life as anything more than a small chapter, if at all.

          I’m biased, but I would say that finding (and returning) extraterrestrial life, especially from a unique abiogenesis, would be of immense value, both scientifically (my bias) and culturally.

          There would probably also be another flowering of biomedical applications after a decade or two. It would truly have “spin off” value of immense proportions. [But hopefully not of Weyland-Yutani bioweapons applications]. If the solar system proves sterile apart from Earth, but it becomes clear that life is either ubiquitous in the galaxy, very rare in the galaxy, or even absent elsewhere, then there should be cultural implications about those different scenarios. At its most trivial, [scifi] movies will either be alien-rich, or alien-absent. More importantly, the scenarios should shape our positions when we have the capability to explore the galaxy physically.

          • John Freeman October 17, 2019, 17:43

            Weerrrlll… now, my own bias is towards abiogenesis research – and not just the pathways from chemistry to life on Earth, but the scope of alternate pathways, and alternate chemical outlines (for example using some of the many non biological amino acids) that could arise – and that’s just water-carbon chemistry. I think I can say with confidence that, should we manage to map the chemical routes from non-life, to proto-life, to life / alternate life systems we will get much if not all that you hope to gain from discovering extra terrestrial life. And don’t get me wrong – finding extra terrestrial life is part of it. But so is so much else. At this stage in the game I’m looking more at the parent bodies of carbonaceous chondrite meteorites, comets, Titan, and yes locations with water, and carbon, that have headed down a different chemical route than Earth did (so far). I’m wanting a 6u cubesat probe with some basic capabilities at every icy Moon, dwarf planet, and carbon rich asteroid (and comets), not huge rovers to study one location on Mars in incredible depth – not yet. But, hell, I might be dead wrong, And I’ll take whatever we get of our wonderful universe gratefully. Even if it all goes side ways because it cost too much and never achieved its PR mandated goals, and that becomes ground based astronomy and doing meteorite studies one day.

  • Gary Wilson October 12, 2019, 13:16

    Will people like Elon Musk push NASA out of its torpor and get us started on manned exploration of Mars? Because all I see NASA doing is fumbling around, spending huge amounts of money on the equivalent of the Apollo program which is outdated conceptually (SLS, Orion etc.), and continually announcing new delays to actually doing anything. I hope this sounds like someone who is completely disillusioned by NASA because it is. Let’s get going again! Get some value for the billions NASA is spending NOT developing a next generation manned exploration program. Read some of the blogs by engineers at NASA and you will also find out about their frustration with the agency. It seems they are nothing but fancy PR these days.
    As an afterthought we finally have our electric car and our solar panels up and running!!! Yahoo!!!!

    • Alex Tolley October 12, 2019, 17:07

      I share your frustration at Nasa’s glacial progress on manned spaceflight. This is distinct from the scientific space probes primarily from JPL which have made really impressive progress. Nasa seems to excel at paper studies and “visions” that never come close to fruition. Part of the problem is that it operates at the whim of the administration and congressional funding.

      However, I am cautious of putting my eggs in the SpaceX basket. Currently, there seems to be an excessive optimism that the Starship will fly, at the costs and cadence that Musk optimistically puts forward.

      [As an aside, Starship seems to be following the script of “Destination Moon”, based on Heinlein’s “The Man Who Sold the Moon”. Starship is a stainless steel reusable rocket, built in Texas, and out in the open. It has fins and a vaguely V2 shape. Musk often rails at the bureaucracy slowing down his progress (but at least not insinuating “Commies”/Socialists are behind it).]

      SpaceX could easily implode financially, especially given Musk’s track record with Tesla/Solar City. That could create a more than a little “disappointment”, not to mention a backlash. If Starship flies successfully, but the circumlunar trip with teh Japanese patron and his guests goes wrong, the backlash could hinder the democratization of human spaceflight for a quite a while, if not permanently in the West.

      So while I wish him all luck and goodwill, I worry about SpaceX’s almost cowboy attitude to rocketry. In “Destination Moon”, the flight of the Luna moon ship was done without testing of going through simpler missions. The flight was even moved up, with hasty recalculations, and a substitute navigator and communications crewman. Is SpaceX following in those footsteps?

      • Paul Gilster October 12, 2019, 18:24

        Alex, let’s not forget the superb work that APL has delivered as well as its counterpart on the west coast. New Horizons especially, but many others.

        • Alex Tolley October 12, 2019, 19:45

          Yes. Looking forward to their DragonFly mission to Titan.

          • Gary Wilson October 14, 2019, 12:32

            Yes, I’m skeptical about SpaceX’s ability to proceed at the pace outlined by Musk. However, at least they are demonstrating repeated ability to develop innovative ways to get the job done. They have demonstrated the ability to land and re-use first stage components (not perfectly yet but really quite well) which NASA gave up on years ago. Their new Raptor engine looks very capable and interesting as well, with many design improvements over the use of the old liquid O2/ liquid H2 systems. Raptor uses liquid O2 and liquid methane I believe. It is referred to as a re-usable methalox staged-combustion engine and similar concepts are used on some Russian and NASA rockets. Apparently there are several very important advantages. Don’t write off the Starship just because it looks old fashioned. There are convincing arguments that stainless steel is a much better choice than advanced carbon composites. Let’s see what the competition between the private companies and NASA leads to. My bet is NASA gets left in the dust of history. It is just too much “pork” for my taste.

    • Mike Serfas October 14, 2019, 20:51

      Question: will private spaceflight push NASA out of a torpor, or into one? There are many public-minded organizations like Wikipedia and Mozilla that appear to be undermined by gradual infiltration by private interests, and there have been more clear-cut attempts to sabotage government agencies such as the lobbying wars against PubMed and the National Weather Service. One might call it the tragedy of the commons, as in “what a pity we have to lay waste to your commons to make you come pay to use ours”. When do private space companies lobby NASA down to an office that signs their checks?

      • Alex Tolley October 16, 2019, 13:05

        When do private space companies lobby NASA down to an office that signs their checks?

        I look forward to the day when private space-based companies can write checks to NASA to support its basic research and pathfinding, and I am writing checks to these enterprises for a vacation in space.

  • Mike Serfas October 14, 2019, 6:58

    I think there is a misunderstanding in some of the commentary above. The paper did not find amino acids because it was looking at mass spectrometry of positively charged fragments of whatever molecules were present.

    To quote the authors, “Although not a unique interpretation, many relevant precursor molecules (MACs, pyruvate-like O-bearing molecules, and small amino acids) are in agreement with the spectral features of the compositional groups (Types 2A, 2O, 2N, respectively) found in this work. This is also true for low-mass carboxylic acids (2O).”

    The study is extraordinarily limited in how much it can say, especially negative results, because they are looking at only the masses of fragments of molecules after doing a mass spec of … dirt. (And water, lots of water with lots of annoying background peaks) But it is a most inspiring accomplishment to figure out even that much about the chemical composition of a moon without matching velocity with even a speck of dust from it.

  • Gary Wilson October 16, 2019, 12:20

    47 years and counting since the last Apollo manned moon mission. NASA isn’t working as far as human exploration is concerned. They have done a wonderful job with unmanned missions. Absolutely incredible. But no progress whatsoever with the manned side of their mission. Nearly half a century has gone by! Other countries will begin to step forward. Personally I would rather see an international effort to explore Mars with humans from many countries involved. It’s the way forward. Otherwise we’ll get military bases from various countries and attempts to claim resources for nation states. Whatever happens humans will explore the solar system. NASA can either be involved or be left behind permanently. I understand the concern about NASA writing cheques to fund private companies but they have made no significant progress in their manned program. Non reusable rockets are not the way forward. Billion dollar single launches are not the way forward. As with climate change, humans (including NASA) must adapt and become innovative. NASA is a dinosaur now thanks to a lack of imagination. I think we all know what happened to the dinosaurs.

  • Michael Fidler October 21, 2019, 7:05

    Key Found to Origin of Life on Earth? Deliquescent Salts and Hot, Humid Summers.

    Seemingly minor differences, like changing the ambient humidity from 50% to 70%, can lead to profound differences in the tendency of samples to absorb water, and hence, large differences in the yields of reactions they host. And while potassium and sodium are neighbors on the periodic table with almost identical reactivities, many potassium salts are deliquescent where their sodium counterparts are not. The salt K2HPO4 fostered yields of peptides from glycine ten times greater than in Na2HPO4.

    The team believes their system may provide clues relevant to solving the mystery of why all life on Earth spends so much energy enriching potassium inside cells and throwing sodium out. ;-{)


    Any body have a clue???

    The spark of LIFE??? Hmmm.

    Potassium-40 (40K) is a radioactive isotope of potassium which has a long half-life of 1.251×109 years. It makes up 0.012% (120 ppm) of the total amount of potassium found in nature.

    Potassium-40 is a rare example of an isotope that undergoes both types of beta decay. In about 89.28% of events it decays to calcium-40 (40Ca) with emission of a beta particle (β−, an electron) with a maximum energy of 1.31 MeV and an antineutrino. In about 10.72% of events it decays to argon-40 (40Ar) by electron capture (EC), with the emission of a neutrino and then a 1.460 MeV gamma ray.

    Yes, GAMMA RAYS!!!

    Solving the mystery of why all life on Earth spends so much energy enriching potassium inside cells and throwing sodium out!

    Melanin’s Mysterious Properties.

    Melanin is, indeed, one of the most interesting biomolecules yet identified. The first known organic semiconductor, it is capable of absorbing a wide range of the electromagnetic spectrum (which is why it appears black), most notably, converting and dissipating potentially harmful ultraviolet radiation into heat. It serves a wide range of physiological roles, including free radical scavenging, toxicant chelation, DNA protection, to name but a few. It is also believed to have been one of the original ingredients essential for life on this planet. I’ve reported previously on its potential in converting sunlight into metabolic energy, but converting ionizing gamma radiation into useful energy? Beyond the realm of comic book heroes, who would have ever thought such a thing possible?

    The first time (I am aware of) that this possibility surfaced in the literature was a 2001 Russian report on the discovery of a melanin-rich species of fungi colonizing and apparently thriving within the walls of the still hot Chernobyl meltdown reactor site.1 In 2004, the same observation was made for the surrounding soils of the Chernobyl site.2 We also know that, based on a 2008 report, pyomelanin-producing bacteria have been found in thriving colonies within uranium-contaminated soils.3 There is also a 1961 study that found, amazingly, melanin-rich fungi from soils of a Nevada nuclear test site survived radiation exposure doses of up to 6400 Grays (about 2,000 times a human lethal dose!).4 Clearly, something about melanin in these species not only enables them to survive radiation exposures that are normally lethal to most forms of life, but actually attracts them to it. Could the fungi actually be using melanin to ‘feast’ on the free lunch of anthropogenic radioactivity ?

    Remarkably, back in 2007, a study published in PLoS titled, ‘Ionizing Radiation Changes the Electronic Properties of Melanin and Enhances the Growth of Melanized Fungi,” revealed that fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation. The irradiated melanin from these fungi also changed its electronic properties, which the authors noted, raised “intriguing questions about a potential role for melanin in energy capture and utilization.”

    Potassium-40 and the
    Evolution of Higher Life
    by John Walker
    15th July 1996
    In 1955, in his last scholarly publication[1], Isaac Asimov calculated the radiation dose to the human body (or for that matter, any living cell) from endogenous sources (Potassium-40, Carbon-14, and Tritium) and found the total dose was roughly equal to the sea-level dose due to cosmic rays. 86% of the total endogenous dose is from K-40 and essentially all the rest from C-14, but the C-14 is believed to be much more significant biologically since carbon is integral to the DNA chain and bases while potassium is used only in metabolism. Still, the bulk of whole-body beta absorption is from K-40.

    Since the half-life of C-14 is only 5700 years, the amount in the biosphere is in equilibrium between creation by cosmic rays and sequestration in biomass and carbonate rocks, and is presumably roughly constant over very long intervals (enough to average out magnetic field reversals, mass extinctions, volcanic outgassing, ice ages, etc.)

    But K-40 has a half-life of 1260 million years, right in the mid-range of geological time, with the K-clock being wound by the supernova that expelled what became the solar nebula and continuing to run down ever since. Consider the following table, which takes the current K-40 dose as one and extrapolates over the age of the Earth and into the future. “Fraction remaining” arbitrarily starts at 1 at the time the Earth was formed—the actual isotopic abundance will vary from star to star depending on the properties of the medium from which it formed.

    When life appeared in the geological record, it incorporated potassium which gave it a radiation dose almost 7 times higher than typical contemporary lifeforms endure. This would both argue for a higher mutation rate, but also constrain the complexity by rendering a long genome with low redundancy too unreliable in such a high radiation environment.

    Could it be that the long delay between the emergence of protists and metazoans—about 2.5 billion years, was due to the need for endogenous K-40 radiation to abate to a level compatible with the vastly greater complexity of eukaryotic metazoans?

    If there is something to this, it would have all kinds of interesting anthropic consequences that constrain the time in which life must emerge based on the condensation of a star from a supernova remnant, and how long that star had to remain on the main sequence. Projecting into the future, one sees a dramatically falling K-40-induced mutation rate. Perhaps there is a relatively short window in which we are living during which the mutation rate is high enough to produce intelligent life and low enough to allow multicellular life at all.

    [1] Asimov, I. “The Radioactivity of the Human Body”. Journal of Chemical Education, February 1955.



    • Alex Tolley October 22, 2019, 13:07

      The idea that higher K-40 could impact evolution is testable in some ways. However, the large differences in radiation resistance between different species of both prokaryotes and eukaryotes would seem to falsify the theory. Organisms with high resistance have evolved to handle DNA repair in a number of ways to reduce replication errors. The idea that metazoa didn’t evolve until the K-40 levels were sufficiently reduced is perhaps not as compelling as the idea that increasing O2 levels after the GOE allowed for the needed energy levels of organisms where the cells were no longer fully exposed to the environment and that specialization, rather than just clusters of the same cells, was now possible. But the reason[s] for the evolution of multicellularity is still not known AFAIK, but I would think that a number of conditions had to be met so that it was not only possible but also advantageous.