General Science, Space, Space Science, Technology and Society

Phosphine

43 Comments

This may be a sign of life in the Venerian clouds, but not necessarily.

I do think that Venus gets far too little attention. Maybe this will spur more action in that regard.

[Wednesday-afternoon update]

This is a six-year-old article, but it’s relevant. Seeing what it looks like at the one-bar level of the atmosphere should be a high priority.

[Bumped]

[Sunday-afternoon update]

Bob Zubrin: Let’s explore the Venerian atmosphere with solar balloons.

[Bumped]

43 thoughts on “Phosphine”

  1. Venus makes close approaches to Earth twice a year. Transit time is much shorter than to Mars. In a robust space development environment we’d have done several crewed fly-bys by now. Maybe even an orbital stay. But the 21st Century is not the 20th Century so there is hope again. Just about 20 years behind where we could have been if Space were important or perhaps if Apollo had never happened?

  5. Not buying phosphine in a sulfuric acid atmosphere at hundreds of degrees Fahrenheit as a sign of life. It’s not enough that, at on Earth, certain microbes can produce phosphine.

    I wish people would at least glance at James Lovelock’s idea that life will generate an atmosphere far out of chemical equilibrium. I seem to remember that as exotic as it may be, the Venusian atmosphere is in fact at equilibrium.

    Show me a shell in Martian sediment. Show me an atmosphere with both methane and oxygen. Show me freon, a gas not known to arise naturally.

    Otherwise, stop pestering me with weird chemistries in extreme environments.

    1. Whatever works for getting a research grant, or gets a NASA program over the funding top. “There may be life on ….” is now a hackneyed statement when it comes from the government-science complex.

      1. I’m always amazed that the government-science complex is so adept at coming up with planetary missions guaranteed to tell us that the next mission after this one will definitely answer the question.

          1. Not to my knowledge, although Dr. Levin’s proposed a cluster analysis of his LR Viking experiment as an (apparently unconvincing) “pro” signal for life. The problem is that Mars soil chemistry is just too novel and the problem with most of our experiments sent up so far are burdened with the “….according to mechanisms on Earth” analogies… Bottom line: researchers say it bucks the consensus science on Mars:

            https://www.npr.org/templates/story/story.php?storyId=5573659

            Another take:
            https://en.wikipedia.org/wiki/Viking_lander_biological_experiments

            Levin bio: + cluster analysis
            https://en.wikipedia.org/wiki/Gilbert_Levin

          2. I have this fantasy of playing Powerball for an enormous jackpot, winning, and placing a call to Gilbert Levin that we are a go to launch a private space probe to Mars with his enhanced chiral LR detector.

            Life will be detected on Mars, Levin will receive a Nobel Prize or something, and I will go down in history as the chump who parted with his Powerball winnings.

            All of this presupposes I buy a Powerball ticket . . .

      2. More than a few planetary science missions have ended up getting funded by scientists braying the “search for life” mantra.

    2. The speculation is that the phosphine is being produced in the milder layer of atmosphere 50 to 60 kilometers above the planet surface where the temperatures and pressures (but not the chemistries) are very Earth-like. As far as the scientist understand at this point, the phosphine is out of equilibrium from what would otherwise be expected from natural sources by a factor of 10,000 or so.

      I’m still on the skeptical side that the phosphine will ultimately prove to come from simple cells in the Venusian atmosphere, but even a 2% to 5% chance it is, is pretty exciting. It’s within our technology to fully resolve this question within the next 15 to 20 years which is the most exciting part for me. If it is indeed life and it is in a completely separate branch from life on Earth, the implications are pretty staggering and this would be one of the greatest scientific discoveries of all time. However, if it were demonstrated that Earth and Venus originated from a common origin via panspermia it would be a very, very interesting discovery.

  6. @Raoul Ortega: Speaking of SF, my first thought was the poisonous and corrosive fungal Threads in Anne McCaffrey’s Dragonriders of Pern stories.

  7. This would be a great time for SpaceX to step forward and volunteer a Falcon Heavy (used?) launch and a Dragon 2 capsule to NASA. The capsule could be retrofitted for a descent to a 60 km altitude in Venus where a NASA built balloon/probe could be released into the Venusian atmosphere to confirm the phosphine concentrations and perhaps find its origins. The Super Draco thrusters could be used to hover the capsule for a few moments while the balloon/probe is gently released at just the right altitude. Is there anything technically that would prevent such a scenario?

    It would be an ideal demonstration of having an inexpensive launch capability and commercial space infrastructure in place that such a mission could be done within a few years rather than a decade for pennies on the dollar that it might otherwise cost.

  8. Phosphine and methylphosphine production by simulated
    lightning—a study for the volatile phosphorus cycle and
    cloud formation in the earth atmosphere (PDF)

    ABSTRACT: Phosphine (PH3), was recently found worldwide even in the remote atmosphere [ref]. It is of interest to find natural mechanisms which could produce phosphine gas and drive a volatile link of the atmospheric phosphorus cycle and the formation of phosphoric acid as possible condensation nuclei for clouds.

    Here, we report on simulated lightning exposing sodium phosphate in a reducing medium (methane model atmosphere or organic matter) for 5 sec to a spark induced by microwave. The gas product analyzed by gas chromatography contained phosphine (yield up to 0.6 g/kg phosphate) and methylphosphine (CH3)PH2 (yield up to 0.02 g/kg phosphate).

    We suggest a plasma-chemical formation mechanism where organic compounds or methane or secondary hydrogen thereof reduce phosphate to phosphine of which a small fraction can subsequently react with methyl radicals to form methylphosphine. A small yield of 6 mg phosphine per kg phosphate P was even obtained in methane free medium, by simple plasmatic recombination of inorganic phosphorus. We believe that methane and hydrogen are useful model substances of pyrolytic gases with high reducing power which may form if lightning strikes biomass, soil and aerosol.

    These results suggest evidence that phosphine and methylphosphine (detectable in the field by intense garlic odor) are produced when atmospheric lightning strikes the ground or aerosol which is containing oxidized forms of phosphorus and chemical reductants.

    Additional reviewed data show that laboratory lightning was able to reduce a much more significant portion of phosphate to phosphite (up to 25% yield), methylphosphonic acid (up to 8.5% yield) and traces of hypophosphite in a matter of seconds.

    From this, I’m guessing they found evidence of lightning on Venus.

    1. If there is lightening couldn’t we use super sensitive telescopes like the Hubble to see it? This doesn’t seem out if the realm of possibility unless that lightening is so deep in the atmosphere the light cannot escape. If fact at closest approach most of the Venusian disk is unlit by the Sun. Has no one bothered to look?

    3. Well, they’ve tried to factor that in the new paper, and their estimate for phosphine production on Venus by lightning (while the biggest natural source IIRC) was several orders of magnitude too small to account for the observed signal.

      Error is still the most likely situation, but it’s certainly interesting.

      1. I don’t think anybody has even bothered to ask whether the Sprites and Elves that occur over a thunderstorm could produce reactions like that.

        Basically, from all the papers I looked over, we can’t even explain why the Earth has atmospheric phosphine.

  9. I’m very intrigued by the claimed phosphine find. It’s a very hard molecule to put together. It does, however, occur in the extreme environments of Jupiter and Saturn. Venus too has extreme conditions in pressure, chemistry, and temperature. So, I consider this far from conclusive, though hopeful.

    I’m far more bothered by how this has been handled. They embargoed publishing or revealing this until today, as if it was a major find. Instead, we learn that they aren’t even sure there’s really phosphine there – it’s a case of processed signals, rather than the usually-required multiple frequency fingerprints.

    To me, this has earmarks of being more hype than substance. I hope I’m wrong.

  10. I wonder how much phosphine could be outgassing from the several pressurized and non-sterilized Venera probes that have been cooking on the surface for decades. At least one of them landed somewhere up in the Maxwell Montes, where it recorded a more benign environment. Be funny if we detect life on Venus and it’s coliform bacteria…

  11. Well my first question where did the hydrogen come from? At least the atmospheric composition I’ve seen is ~40 parts per million in the atmosphere.

    1. The atmosphere of Venus includes H2O, HCl, and HF, and it rains H2SO4. Most of the atmospheric phosphorus is phosphorous anhydride, P4O6, at 2 ppm below 25 km, which reacts with sulfuric acid to form phosphoric acid (H3PO4) and sulfur dioxide (SO2) in the lower cloud decks. As it sinks lower, it should form P4O10.

      One reaction with phosphine is:
      sulfuric acid + phosphine –> water + phosphoric acid + sulfur dioxide
      4H2SO4 + PH3 –> 4H2O + H3PO4 + 4SO2

      And as the above paper shows, lightning can produce phosphine in an atmosphere.

  12. I ran across another tidbit in the phosphine Wiki, which is that they don’t actually know that the decay of organic matter produces phosphine.

    Phosphine is a constituent of the Earth’s atmosphere at very low and highly variable concentrations. It may contribute significantly to the global phosphorus biochemical cycle. The most likely source is reduction of phosphate in decaying organic matter, possibly via partial reductions and disproportionations, since environmental systems do not have known reducing agents of sufficient strength to directly convert phosphate to phosphine.

    So we know from a paper I posted above that lightning can generate phosphine from compounds commonly found in the atmosphere of Venus, and we know that Venus has tremendous lightning storms. We don’t actually know that phosphine can be produced by the decay of organic matter, and yet modern science concludes that phosphine in the atmosphere of Venus is evidence of, um, dead cows on Venus?

    1. With an average temperature of -214 Celsius, it is difficult to account for the 585 kilometer per hour wind speeds on Uranus.

      Every time I see NASA or planetary scientists say something like that, I’m tempted to note that the change in volume of a body of gas, per delta T, is vastly larger at low temperatures than at high temperatures. At 727 C, a 10 C change in temperature causes a 1% change in volume (pressure being determined almost entirely by mass and gravity). At -214 C, a 10 C change causes a 17% change in volume.

      I should probably scratch out some code and explore how that works out. But basically, wind is a heat engine, and heat engine formulas often have terms like efficiency = 1 – Tcold/Thot. In this case, a heat engine running off a +10 C difference is 14.5% efficient at Uranus temperatures, but only 1.4% efficient on the surface of Venus.

      Or maybe I’m barking up the wrong tree.

      1. It’s not the T, it’s the delta T that drives the winds. Weather is a heat engine. You can still have significant delta T at lower T. After all, this is still well about zero Kelvin.

  15. …atmosphere should be a high priority.

    And it is. We’ll be there in about 5 years.

    DAVINCI is one of five Discovery-class missions selected by NASA in October 2015 for Phase A studies. Launching in November 2021 and arriving at Venus in June of 2023, DAVINCI would be the first U.S. entry probe to target Venus atmosphere in 45 years. DAVINCI is designed to study the chemical and isotopic composition of a complete cross-section of Venus atmosphere at a level of detail that has not been possible on earlier missions and to image the surface at optical wavelengths and process-relevant scales

      1. Looking at the revised proposal for Discovery 15/16, it appears to be doing two Venus flybys, and only later, an orbital insertion:

        Launch: May 25, 2026
        1st Venus Flyby: Dec 2026
        2nd Venus Flyby: Sept 2027
        Atmospheric Probe release & entry: April 2028
        Orbiter orbital insertion: Nov. 2028

        Link: https://www.hou.usra.edu/meetings/lpsc2020/pdf/2599.pdf

        I’m assuming that this profile must be premised on a low end Atlas V, as usual for Discovery proposals.

  16. It’s worth noting that microbial life has been found at the 100,000 ft level in earth’s atmosphere. It may well be that any life in Venus’s atmosphere would have worthwhile samples at a similar Bar. So, assuming further research shows that a Venus atmosphere sample return is worthwhile, getting that sample may be far easier than many are assuming. (That’s about the same altitude and density that the Grand Teton Bolide of 1972 came down to, before exiting Earth’s atmosphere and resuming solar orbit). A simple, dense probe could do the same.

    I’m still skeptical though – if I had to bet, I’d bet that if the phosphine find is real, the cause is either lightning, or the extreme surface temperature/chemistry/pressure. Or both.

    1. You can’t skim an atmosphere and return to a planetary or sun orbit with a useful sample of anything except maybe a noble gas and even then the atmospheric mass fraction is distorted. At those speeds there’s too much chemistry to learn anything useful about the atmosphere. This has been proposed before and analysis and experiments always shows it won’t work.

    1. I have to think that DAVINCI+ got a bit more leg up in Discovery 15/16 selection than VERITAS did with this week’s news, for obvious reasons.

      If I were a betting man, I’d say that TRIDENT and DAVINCI+ are likely in pole position, without knowing anything about the engineering reliability or project management of each proposal. But I am not a betting man.

      Still, I think you have to like Venus’s chances this time around.

  18. The numbers for the HAVOC (or is it HELTERSKELTER?) program are ridiculous. The energy storage requirement of 1,959 kW-hr would by itself require 11,660 kg of the most advanced batteries we have – yet the total mass of the power and propulsion is listed as 4,511 kg. The figure for a 60,000 kg (132,300 lb in real units) ascent vehicle to carry two people into orbit is just laughable, given that it’s almost as difficult a shot as getting from the surface of the Earth into LEO. Gemini-Titan was a two-stage, two person vehicle of much higher performance than any solid propellant rocket (and really fantastic propellant mass fractions), and it weighed 340,000 lb at liftoff – 154,195 kg for those from Rio Linda. The entire scenario they’ve painted is just plain stupidly wrong, and can’t happen as portrayed. That’s not to say that it is impossible, just that the description given doesn’t match what would be required.

    But the real reason such a crewed sortie into the Venusian atmosphere will never, ever, ever happen is that it will never, ever, ever get past the “risk reduction phase” – that magical, endless phase of all new NASA programs where phenomenal amounts of money are showered on Boeing, Northrop-Grumman, and Lockheed-Martin to show that the two suckers in that blimp will under no circumstances come to any harm whatsoever. As in any “risk reduction phase” I’ve seen in recent years, the risk will be reduced to zero by never attempting the task being studied. It won’t be an actual decision point…just a perpetual “attempt” to reach a decision point, keeping a whole lot of aerospace employees “employed.”

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