≡ Menu

Back into the Clouds of Venus

We’re a long way from knowing what is going on in terms of possible life in the clouds of Venus, but one thing is already clear: The phosphine signature, as well as its implications, is going to be thrashed out in the journals, as witness a new study from Rakesh Mogul (Cal Poly Pomona, Pomona, CA) and colleagues that looks at data from the Pioneer-Venus Large Probe Neutral Mass Spectrometer (LNMS), dating back to the Pioneer Venus Multiprobe mission in 1978. These data seem to support the presence of phosphine, while leaving its origin unknown.

But Clara Sousa-Silva (Harvard-Smithsonian Center for Astrophysics), who was involved in the earlier phosphine work led by Jane Greaves at Cardiff University (see What Phosphine Means on Venus), subsequently examined data collected in 2015 at Mauna Kea and found no sign of phosphine. And now we have another paper, this one submitted to Science by Ignas Snellen and team (Leiden University), that carries its message in the title: “Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine.”

Finally, let me mention a study led by Arijit Manna (Midnapore City College, West Bengal, India) reporting on a possible detection of the amino acid glycine in the Venusian clouds. I’ve given citations for all of these papers below.

There are all kinds of reasons for data discrepancies on phosphine depending on its possible distribution in Venus’ atmosphere, so until we get further information, we’re left to speculate. But let’s welcome Venus back into the spotlight. I’m glad to see the re-emergence of public interest, and the fortunes of Venus in terms of future mission desirability are obviously on the rise, something the Venus science community must welcome as parched desert-crossers welcome an unexpected flowing spring.

Image: Venus from the perspective of the Japanese Akatsuki probe. Credit: JAXA/ISAS/DARTS/Damia Bouic.

Some kind of biology in the Venusian clouds might even implicate Earth and the possibility of biological spread through rocky debris. While speculation continues, I’m interested in the orbital movements of the Mercury-bound BepiColombo probe, which happened to be approaching Venus in October, using the planet to bleed off velocity as it nudges into the innermost system. It will hardly resolve the matter, but Venus and BepiColombo are intimately connected not only gravitationally but thanks to the opportunity Venus offers to check out key onboard systems.

BepiColombo is actually a combination mission, including the Mercury Planetary Orbiter (MPO), constructed by the European Space Agency, and the Mercury Magnetospheric Orbiter (MMO), a product of the Japan Aerospace Exploration Agency (JAXA). The duo are currently joined but will separate into individual orbits once Mercury is attained.

Two Venus flybys are in the works, as we recently saw in these pages, and the first of these, which took place on October 15, brought the craft within 11,000 kilometers of the planet. BepiColombo is swapping some of its kinetic energy to Venus as it in turn reduces speed, with the second Venus flyby planned for August of 2021 and six close Mercury flybys before the craft enters orbit around the planet at the end of 2025. We now get the chance to test BepiColombo’s MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS), which has already been tested in an earlier Earth/Moon flyby that took place in our COVID spring.

Designed to measure the spectra of rock-forming materials on Mercury’s surface, MERTIS can likewise use its infrared sensors to probe the Venusian atmosphere, with a closer approach pending in the second flyby. According to German aerospace center DLR, MERTIS is sensitive to wavelengths of 7 to 14 and 7 to 40 micrometers respectively in its two uncooled radiation sensors. Both sensors were used during the approach to Venus and approximately 100,000 individual images are expected. At the same time, the Japanese Venus orbiter Akatsuki conducted its own observations, along with Earth-based instruments both professional and amateur.

Image: BepiColombo on the long journey to Mercury. Credit: ESA/ATG Medialab.

Phosphine is a short-lived molecule, suggesting that a source on Venus or in its atmosphere is replenishing it, and scientists are still trying to find out if abiotic factors could be in play here, including the possibility of volcanism or reactions following meteorite strikes, even lightning discharges. MERTIS and five other activated instruments on the Mercury Planet Orbiter will not be able to detect phosphine from the flyby distance, but the BepiColombo team has reasons for making these observations that do not involve the gas, says Gisbert Peter, MERTIS project manager at the DLR Institute of Optical Sensor Systems, where the instrument was built:

“During the Earth flyby, we studied the Moon, characterising MERTIS in flight for the first time under real experimental conditions. We achieved good results. Now we are pointing MERTIS towards a planet for the first time. This will allow us to make comparisons with measurements taken prior to the launch of BepiColombo, to optimise operation and data processing, and to gain experience for the design of future experiments.”

Peter Wurz is project leader on STROFIO, which is a mass spectrometer designed at the University of Bern to record the atmosphere of Mercury and examine its composition. Wurz anticipates the results at Venus using not just data from STROFIO but also the spacecraft’s MIPA and PICAM instruments, likewise developed at the university.

“We are expecting data from the ionized particles in Venus’ atmosphere from these two instruments, which are switched on during the Venus flyby. The amount of particle loss and its composition can be determined using the two instruments.”

All of which is an excellent workout for BepiColombo, but MERTIS can also be expected to examine sulphur dioxide concentrations, a reduction of which was recorded about ten years ago. Meanwhile, scientists can study Venus’ atmospheric composition, with the instruments aboard the Japanese Mercury Magnetospheric Orbiter tracking its structure and dynamics. Expect no answers to the astrobiological riddle, but helpful data about Venus otherwise.

And isn’t it interesting seeing how tricky it is to get into the inner system? All those flybys point back to Mariner 10, which used an initial Mercury flyby to enable additional close passes at the planet — these calculations came from Giuseppe ‘Bepi’ Colombo, the Italian physicist for whom the current mission is named. The recent maneuver reduced the craft’s relative speed compared to Mercury to 1.84 kilometers per second, the goal being to orbit the Sun at close to Mercury’s speed and eventually become captured by the gravity of the small world.

The paper referenced in the first paragraph is Mogul et al., “Is Phosphine in the Mass Spectra from Venus’ Clouds?” available as a preprint. The Sousa-Silva paper is “A stringent upper limit of the PH3 abundance at the cloud top of Venus,” in press at Astronomy & Astrophysics (abstract). The paper on glycine is Manna et al., “Detection of simplest amino acid glycine in the atmosphere of the Venus,” submitted to Science (preprint). The “Snellen paper is “Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine,” submitted to Science (abstract).

tzf_img_post
{ 18 comments… add one }
  • Mike Serfas October 22, 2020, 14:34

    What strikes me is that NH2CH2COOH and PH3 both include a sort of “hidden hydrogen” – an element that Venus has lost at least 99% of (relative to deuterium which surely had losses itself). We don’t really know how much hydrogen the planet started with but extracting it from sulfuric acid in the clouds sounds fairly miserable for an organism (they would have to net emit SO3 to have water left, which implies high energy costs). Are there other places proposed, even minerals on the surface, where hidden hydrogen might be discovered in larger amounts than the trace detected here?

    • Alexander Tolley October 23, 2020, 0:50

      I also find the conditions for phosphine production unlikely on Venus. On Earth, it is a product of anaerobic metabolism under certain conditions. There needs to be a good hydrogen source, e.g. carbohydrates, and it usually is found in aqueous conditions.

      This doesn’t preclude an exotic biology on Venus, but there needs to be some viable metabolic route that produces phosphine in the clouds, where oxidized phosphorus is readily available, as are hydrogen sources, most probably from carbon. If life does exist in the Venusian clouds, the biology might be very interesting to produce PH3 in the cloud environment.

      • Mike Serfas October 23, 2020, 10:39

        For some time I’d wondered if PH3 was coming somehow from a geological source, but there’s a preprint https://arxiv.org/ftp/arxiv/papers/2009/2009.12758.pdf which describes a strong PH2D peak. So if the phosphine is real – and this letter thinks so – it really is being made with D-enriched atmospheric hydrogen.

        I still feel suspicious that somehow, with the acidity and immense heat of Venus, that hydrogen ions could have been exchanged for monovalent cations in some familiar mineral, forming a reservoir of hydrogen not counted in the D/H ratio. The old daydream is to have some microorganism capable of surviving the atmosphere, designed to take up energy to convert the C and S into some polymer (perhaps first used as a cell wall) similar to low-grade coal, which precipitates, leaving a less acidic, cooler atmosphere that might recover the mythic geologic hydrogen to create an ocean. But the result above doesn’t do anything to support that.

        • Andrei October 29, 2020, 14:51

          While I do accept the claim of the phospine detection, like you both I have a hard time imagine life. Where Serfas made another good point, while I simply looked at the fact of an organism that on one side needed to protect itself from acid, and at the same time needed to stay afloat and then applying the good old razor by William of Ockham leading to the conclusion that the source must be somewhere else. And indeed, I am inclined to think it’s on the surface that have the right temperature for phosphine production.
          Another daydream are floating cities in the clouds of Venus. While I cannot imagine that to happen – such colonists would be caught in a dead end, other places are more taunting anyway. But the idea could be utilized to protect organisms we do bring to the planet. And let them thrive away from acid and slowly change the planet into a more suitable place – bioforming the planet for later habitation. We need to rethink how we manage our own world and civilization first though. Even though we might disagree on details, I think we all agree that the mismanagement of COVID provide an example that humanity is not even able to deal rationally with a single simple virus.

  • Michael Fidler October 23, 2020, 3:49

    Vega balloon spectra in 1985 finding phosphorus is one of the main elemental constituents of the lower clouds .
    Moroz, V. I. (2001). Spectra and spacecraft. Planetary and Space Science, 49(2), 173–190. doi:10.1016/s0032-0633(00)00130-6

    sci-hub.se/10.1016/S0032-0633(00)00130-6
    This is on page 186 upper right of the text.

    “I think that the most intriguing result was obtained by
    Boris Andreychikov (1987) and his team: they found that
    phosphorus is one of the main elemental constituents of the
    lower clouds. Back in 1967, Boris had designed the first
    instrument for measuring the chemical composition of the
    Venusian atmosphere on Venera 4. Initially, he had worked
    at the Vernadsky Institute, but later moved to IKI where
    he worked in my Department with Lev Mulkhin and then
    replaced him as Chief of Lab when Mukhin left Russia.
    Boris died in harness in 1999.”

    The spectra;

    https://pbs.twimg.com/media/Eh5YtbrUYAE9rxB?format=jpg&name=small

    • Alex Tolley October 23, 2020, 11:38

      “For Venus’ clouds, however, any potential biomass would clearly be dependent on available water, carbon, and other biogenic nutrients (e.g., sulfur, nitrogen, phosphorous, boron, and transition metals). The phototropic reduction of atmospheric CO2 would likely be a major source for carbon acquisition, with an attenuated UV flux within the cloud layer providing the driving energy source. Furthermore, both phosphorus and sulfur (along with iron) have been detected by the X-ray fluorescent radiometer on VeGa 1 and VeGa 2 landers (Andreychikov et al., 1987), with the most abundant phosphorus compound in the lower cloud layer possibly being partially hydrated phosphoric anhydride P2O5+H3PO4 (Krasnopolsky, 2006).”

      Venus’ Spectral Signatures and the Potential for Life in the Clouds

      So the Vega experiments only identified phosphorus. The above source suggests it is mostly in the oxidized state. Above, Mike Serfas suggests that the required hydrogen to reduce phosphorus to PH3 is likely to be an organic source. This is certainly the case with terrestrial anerobes.

      This paper Analysis of the characteristics of phosphine production by anaerobic digestion based on microbial community dynamics, metabolic pathways, and isolation of the phosphate-reducing strain has some work on characterizing the biology of phosphine production. Sadly, both the HTML and PDF docs have a very low resolution image of the key interesting (to me) table of biological pathway labels that make it impossible to read and therefore follow up in KEGG and MetaCyc databases.

      This is becoming one of those tantalizing pieces of evidence that just cries out for more observations, and preferably another atmosphere mission to determine the ground truth, preferably with a way to return a sample. This is where a good space-based lab would be of advantage to ensure that any potential pathogens cannot escape into the terrestrial biosphere. At least we have very good facilities on Earth that will suffice to ensure containment [to adhere to the precautionary principle]. With searches for life on Mars, Venus, and the icy moons, we have an expanded range of possibilities for sample return missions in the future. While I expect we will have good biosignature data for exoplanets well before we get any samples of life on other planets in our system, only our system can possibly provide samples of organisms to study.

    • ljk October 26, 2020, 9:30

      What does that mean that “Boris died in harness in 1999”?

      • Alex Tolley October 26, 2020, 15:17

        While still working is teh usual interpretation. OTOH, perhaps he was also doing manual labor and collapsed on the treadwheel supplying power for the institute! ;)

      • Michael Fidler October 26, 2020, 20:51

        Harness in the spacecraft maybe???

  • ljk October 23, 2020, 13:35

    Presentation on a Venus Flagship Mission (VFM):

    https://www.youtube.com/watch?v=qbFycq-1tgE

    Animation of a VFM lander:

    https://www.youtube.com/watch?v=07j2mja8X0w

    Animation of VFM balloon probe:

    https://www.youtube.com/watch?v=ormW9fq4KB4

  • Michael October 23, 2020, 15:23

    OT due to the very low tilt of Venus and the dense atmosphere the poles show be in daylight or twilight, light is bent and scattered by the very thick atmosphere so would reach quite away from the terminator.

  • ljk October 28, 2020, 9:51

    But what about the phosphine detection from Pioneer Venus in 1978? I found no mention of this in the paper below. Why did they ignore that data, from a probe at the planet no less?

    And what puts the words of the people who wrote this report over the original phosphine detection report? Do they have some kind of special knowledge or authority that we plebians are not privy to?

    https://arxiv.org/abs/2010.14305

    [Submitted on 27 Oct 2020]

    No phosphine in the atmosphere of Venus

    Geronimo Villanueva, Martin Cordiner, Patrick Irwin, Imke de Pater, Bryan Butler, Mark Gurwell, Stefanie Milam, Conor Nixon, Statia Luszcz-Cook, Colin Wilson, Vincent Kofman, Giuliano Liuzzi, Sara Faggi, Thomas Fauchez, Manuela Lippi, Richard Cosentino, Alexander Thelen, Arielle Moullet, Paul Hartogh, Mr. Edward Molter, Steve Charnley, Giada Arney, Avi Mandell, Nicolas Biver, Ann Vandaele, Katherine de Kleer, Ravi Kopparapu

    The detection of phosphine (PH3) has been recently reported in the atmosphere of Venus employing mm-wave radio observations (Greaves et at. 2020). We here demonstrate that the observed PH3 feature with JCMT can be fully explained employing plausible mesospheric SO2 abundances (~100 ppbv as per the SO2 profile given in their figure 9), while the identification of PH3 in the ALMA data should be considered invalid due to severe baseline calibration issues.

    We demonstrate this by independently calibrating and analyzing the ALMA data using different interferometric analysis tools, in which we observe no PH3 in all cases. Furthermore, for any PH3 signature to be produced in either ALMA or JCMT spectra, PH3 needs to present at altitudes above 70 km, in stark disagreement with their photochemical network.

    We ultimately conclude that this detection of PH3 in the atmosphere of Venus is incorrect and invite the Greaves et al. team to revise their work and consider a correction or retraction of their original report.

    Comments: Submitted to Nature Astronomy “Matters Arising” on Oct/26/2020 – Submitted to arXiv on Oct/27/2020 as encouraged and recommended by the journal

    Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)

    Cite as: arXiv:2010.14305 [astro-ph.EP]
    (or arXiv:2010.14305v1 [astro-ph.EP] for this version)

    Submission history

    From: Geronimo Villanueva [view email]

    [v1] Tue, 27 Oct 2020 14:08:59 UTC (632 KB)

    https://arxiv.org/ftp/arxiv/papers/2010/2010.14305.pdf

  • ljk November 3, 2020, 12:34

    UPDATE: LIFE ABOVE HELL? SERIOUS DOUBT CAST ON VENUS PHOSPHINE FINDING

    Phil Plait @BadAstronomer

    October 26, 2020, 9:00 AM EDT (Updated)

    In September, a team of astronomers made a startling announcement: They had detected the signature of a gas called phosphine in the atmosphere of Venus, a chemical that, on Earth, is created by life. Venus has no known non-biological way to produce this molecule in the quantities observed. Had they found evidence of life in the clouds of Venus?

    It was a big announcement, prompting other scientists to take a look at the claim as well (in fact, the original team asked for and welcomed it). It’s been a few weeks now and reports are coming… and they cast serious doubts on the reality of the detection.

    Full article here:

    https://www.syfy.com/syfywire/update-life-above-hell-serious-doubt-cast-on-venus-phosphine-finding

  • ljk November 7, 2020, 23:35

    Not finding life on Venus would be disappointing. But it’s good science at work.

    Doubts about the existence of phosphine gas on Venus—a possible sign of biology—are part of the normal course of testing an extraordinary finding.

    by Neel V. Patel

    October 31, 2020

    Last month’s report that there may be phosphine gas in the Venusian clouds came with a stunning implication: extraterrestrial life. On Earth, phosphine is a chemical produced by some kinds of bacteria that live in oxygen-poor conditions.

    Its presence on Venus, announced by a team led by Cardiff University’s Jane Greaves, raised the possibility that there could be life in what has long been thought one of the most inhospitable environments in the solar system: a planet that’s covered in thick clouds of sulfuric acid, with an atmosphere that’s 96% carbon dioxide, and where the pressure at the surface is 100 times greater than Earth’s. Oh, and it experiences temperatures up to 471 °C—well above the melting point of lead.

    Since the initial report, though, doubt about the finding has crept in. Three different preprint papers (none of which have been published in a peer-reviewed journal, although one has been accepted) were unable to find the same evidence of phosphine on Venus.

    On the surface, the new reports might seem to suggest the team behind the initial findings messed up badly, or is suffering a backlash from overhyping the results. But it was a solid study. The original detections were announced after Greaves and her team found phosphine signals in infrared-to-microwave readings of the Venusian atmosphere made with the James Clerk Maxwell Telescope (JCMT) in Hawaii and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. “The authors were super clear.

    They did a fantastic job of saying that they did not find life—that they found something associated with life on Earth that they cannot explain on Venus,” says Stephanie Olson, a planetary scientist at Purdue University who was not involved with any of these studies. The team went so far as to publish a paper in the journal Astrobiology investigating—and ruling out—known natural causes for phosphine in Venus.

    Full article here:

    https://www.technologyreview.com/2020/10/31/1011487/not-finding-life-on-venus-disappointing-good-science-phosphine-biosignature/

  • ljk November 10, 2020, 11:03

    Controversy erupts among astronomers over whether phosphine really was discovered on Venus

    06 Nov 2020

    Doubt has been cast on the supposed discovery of phosphine in the atmosphere of Venus after several papers were published on the arXiv preprint server challenging the result. The discovery had been announced in September when a team of researchers led by Jane Greaves of Cardiff University, UK, claimed it had observed the spectral fingerprint of phosphine (PH3) in the clouds of Venus. If true, the paper would have been our strongest evidence yet of life beyond Earth, but the tone of some of the resulting criticism – as well as a surprising statement from an international body over the press coverage of the work – has outraged astronomers.

    Phosphine – a potential biosignature – is created in the high temperatures and pressures within the interiors of Jupiter and Saturn, but on Earth it is only produced by anaerobic microbial life. To detect phosphine on Venus, the researchers used the James Clerk Maxwell Telescope (JCMT) in Hawaii and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

    As John von Neumann once said: with four parameters I can fit an elephant and with five I can make him wiggle his trunk

    Mark Thompson

    Shortly after the announcement, however, the organizing committee of the International Astronomical Union (IAU) Commission F3 on Astrobiology released a statement lambasting Greaves’ team for the resulting press coverage of the claimed discovery.

    “It is an ethical duty for any scientist to communicate with the media and the public with great scientific rigour and to be careful not to overstate any interpretation which will be irretrievably picked up by the press,” they wrote, adding that the commission “would like to remind the relevant researchers that we need to understand how the press and the media behave before communicating with them”.

    The IAU statement was met with scorn from many quarters, including the commission’s own members, many of whom said the organizing committee did not speak for them. The statement was then swiftly retracted by the IAU executive, who insisted that it did not reflect the view of the organization. In its own statement, the executive added that the organizing committee of Commission F3 had “been contacted to retract their statement and to contact the scientific team with an apology”. The IAU said it will now produce a procedure for future public communication that all members will be advised to follow.

    Full article here:

    https://physicsworld.com/a/controversy-erupts-among-astronomers-over-whether-phosphine-really-was-discovered-on-venus/

  • ljk November 12, 2020, 11:18

    So Moa Perssons has written her doctoral thesis on this subject:

    http://astrobiology.com/2020/11/surprisingly-little-water-has-escaped-from-venus.html

    I found it online here:

    http://umu.diva-portal.org/smash/get/diva2:1477000/FULLTEXT01.pdf

    From this abstract/cite page:

    http://umu.diva-portal.org/smash/record.jsf?pid=diva2%3A1477000&dswid=1375

    And this earlier paper:

    The Venusian Atmospheric Oxygen Ion Escape: Extrapolation to the Early Solar System

    M. Persson Y. Futaana R. Ramstad K. Masunaga H. Nilsson M. Hamrin A. Fedorov S. Barabash

    First published: 18 March 2020

    https://doi.org/10.1029/2019JE006336

    https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JE006336

  • ljk November 12, 2020, 11:20

    https://arxiv.org/abs/2011.03402

    [Submitted on 6 Nov 2020]

    The journey of the German expedition to observe the transit of Venus on December 9, 1874 at the Kerguelen Islands and its sojourn there

    Emmanuel Davoust

    Astronomers are the surveyors of the sky. They have always dedicated much time and resources to determining the scale of distances in the universe. Today, the Hubble constant; yesterday, the solar parallax. The following account, attributed to Ladislas Weinek, a modest actor of this scientific epic, describes one of its numerous chapters.

    Comments: Translation of a paper in French published in Pulsar, n°733, p.8-12,1999

    Subjects: History and Philosophy of Physics (physics.hist-ph)

    Cite as: arXiv:2011.03402 [physics.hist-ph]
    (or arXiv:2011.03402v1 [physics.hist-ph] for this version)

    Submission history

    From: Emmanuel Davoust [view email]

    [v1] Fri, 6 Nov 2020 15:02:46 UTC (877 KB)

    https://arxiv.org/ftp/arxiv/papers/2011/2011.03402.pdf

  • Laintal November 17, 2020, 3:24

    Re-analysis of Phosphine in Venus’ Clouds
    https://arxiv.org/abs/2011.08176

Leave a Comment