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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).


Comments on this entry are closed.

  • 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

    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;


    • 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):


    Animation of a VFM lander:


    Animation of VFM balloon probe:


  • 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?


    [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)


  • ljk November 3, 2020, 12:34


    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:


  • 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:


  • 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:


  • ljk November 12, 2020, 11:18

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


    I found it online here:


    From this abstract/cite page:


    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



  • ljk November 12, 2020, 11:20


    [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)


  • Laintal November 17, 2020, 3:24

    Re-analysis of Phosphine in Venus’ Clouds

  • ljk January 18, 2021, 15:17

    JANUARY 15, 2021

    Six-wavelength spectroscopy can offer new details of surface of Venus

    A trio of papers provide new insight into the composition and evolution of the surface of Venus, hidden beneath its caustic, high temperature atmosphere. Utilizing imaging from orbit using multiple wavelengths—six-band spectroscopy proposed as part of the VERITAS and EnVision missions—scientists can map the iron content of the Venusian surface and construct the first-ever geologic map.

    “Previous missions have only imaged one wavelength, and used 30-year-old topographic data to correct the spectra. Moreover, they were based on theoretical ideas about what Venus spectra look like, at very high temperatures. So the prior data have all been fairly qualitative,” said M. Darby Dyar, a Senior Scientist at the Planetary Science Institute and author on three recent papers on the topic.

    Full article here:


  • ljk January 22, 2021, 12:19


    Three Different Ways to Explain the Sulfur Depletion in the Clouds of Venus

    Source: astro-ph.EP

    Posted January 21, 2021 11:07 PM

    The depletion of SO2 and H2O in and above the clouds of Venus (45 — 65 km) cannot be explained by known gas-phase chemistry and the observed composition of the atmosphere.

    We apply a full-atmosphere model of Venus to investigate three potential explanations for the SO2 and H2O depletion: (1) varying the below-cloud water vapor (H2O), (2) varying the below-cloud sulfur dioxide (SO2), and (3) the incorporation of chemical reactions inside the sulfuric acid cloud droplets. We find that increasing the below-cloud H2O to explain the SO2 depletion results in a cloud top that is 20 km too high, above-cloud O2 three orders of magnitude greater than observational upper limits and no SO above 80 km. The SO2 depletion can be explained by decreasing the below-cloud SO2 to 20 ppm.

    The depletion of SO2 in the clouds can also be explained by the SO2 dissolving into the clouds, if the droplets contain hydroxide salts. These salts buffer the cloud pH. The amount of salts sufficient to explain the SO2 depletion entail a droplet pH of ∼1 at 50 km. Since sulfuric acid is constantly condensing out into the cloud droplets, there must be a continuous and pervasive flux of salts of ~1e-13 mol cm−2 s−1 driving the cloud droplet chemistry. An atmospheric probe can test both of these explanations by measuring the pH of the cloud droplets and the concentrations of gas-phase SO2 below the clouds.

    Paul B. Rimmer, Sean Jordan, Tereza Constantinou, Peter Woitke, Oliver Shorttle, Richard Hobbs, Alessia Paschodimas

    Comments: Submitted to The Planetary Science Journal. We kindly ask the planetary science community for feedback and comments. (64 pages, 7 Figures, 5 Tables, Full Model Output Data: this https URL)

    Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

    Cite as: arXiv:2101.08582 [astro-ph.EP] (or arXiv:2101.08582v1 [astro-ph.EP] for this version)

    Submission history

    From: Paul B. Rimmer

    [v1] Thu, 21 Jan 2021 12:51:46 UTC (9,428 KB)



  • ljk January 28, 2021, 14:08

    JANUARY 27, 2021

    Purported phosphine on Venus more likely to be ordinary sulfur dioxide, new study shows

    by James Urton, University of Washington


    The paper online:


    Time to stop speculating and get a probe to Venus and properly analyze its atmosphere so there is no further ambiguity.

    Two different groups detected phosphine. So did Pioneer Venus. Anyone know what the Venera probes found, especially the Vega balloons?

  • ljk January 29, 2021, 16:01

    JANUARY 28, 2021

    Thick lithosphere casts doubt on plate tectonics in Venus’s geologically recent past

    by Brown University


  • ljk February 12, 2021, 16:38

    What life on Venus would really look like

    Space jellyfish make good science fiction, but reality might be even stranger.

    Maddie Stone

    February 6, 2021


    To quote:

    For more than a century, scientists and science fiction writers alike have dreamt about life on Venus. Once envisioned as a tropical swamp world, the first missions to Venus in the 1960s revealed that our planetary neighbor is actually a scorching hellscape. But early spacecraft missions also showed that 30 miles above the surface, conditions are more hospitable. After that, the dream of life on Venus moved to the clouds.

    The truth about those clouds, however, may be stranger than fiction. If alien life is present up there, it probably isn’t carnivorous plants or electric blue space jellyfish. Instead, the skies of Venus might be home to microbial refugees that escaped the surface eons ago as the oceans boiled away, took up residence inside droplets of sulfuric acid, and have been kept aloft ever since by ripples in the atmosphere.

    That, at least, is what a team of scientists proposes in a paper published recently in the journal Astrobiology. Starting with the now fifty-year-old hypothesis that Venus’ clouds might harbor life, the study attempts to answer a simple question: How would that actually work? Assuming Venus’ high-flying life forms don’t have airships, how would they stay put up there over millions to billions of years?

    “No one really thought about that,” MIT astronomer and lead study author Sara Seager told The Science of Fiction. “How could life stay up there long enough? How could it reproduce fast enough?”

    The paper is online here:


  • ljk February 25, 2021, 13:38

    FEBRUARY 25, 2021

    Parker Solar Probe Offers Stunning View of Venus

    By Michael Buckley

    NASA’s Parker Solar Probe captured stunning views of Venus during its close flyby of the planet in July 2020.

    Although Parker Solar Probe’s focus is the Sun, Venus plays a critical role in the mission: The spacecraft whips by Venus a total of seven times over the course of seven years, using the planet’s gravity to bend the spacecraft’s orbit. These Venus gravity assists allow Parker Solar Probe to fly closer and closer to the Sun on its mission to study the dynamics of the solar wind close to its source.

    But — along with the orbital dynamics — these passes can also yield some unique and even unexpected views of the inner solar system. During the mission’s third Venus gravity assist on July 11, 2020, the onboard Wide-field Imager for Parker Solar Probe, or WISPR, captured a striking image of the planet’s nightside from 7,693 miles (12,381 kilometers) away.

    Full article here:


  • ljk April 5, 2021, 10:24

    Published: 11 February 2021

    BepiColombo Science Investigations During Cruise and Flybys at the Earth, Venus and Mercury

    Valeria Mangano, Melinda Dósa, […]Wolfgang Baumjohann

    Space Science Reviews volume 217, Article number: 23 (2021) Cite this article


    The dual spacecraft mission BepiColombo is the first joint mission between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) to explore the planet Mercury. BepiColombo was launched from Kourou (French Guiana) on October 20th, 2018, in its packed configuration including two spacecraft, a transfer module, and a sunshield.

    BepiColombo cruise trajectory is a long journey into the inner heliosphere, and it includes one flyby of the Earth (in April 2020), two of Venus (in October 2020 and August 2021), and six of Mercury (starting from 2021), before orbit insertion in December 2025.

    A big part of the mission instruments will be fully operational during the mission cruise phase, allowing unprecedented investigation of the different environments that will encounter during the 7-years long cruise.

    The present paper reviews all the planetary flybys and some interesting cruise configurations. Additional scientific research that will emerge in the coming years is also discussed, including the instruments that can contribute.

    Full paper here:


  • ljk April 5, 2021, 10:27

    dimanche 4 avril 2021

    On the night side of Venus: ozone bursts and sulfur dioxide volatility

    In the nighttime atmosphere of Venus at altitudes of 85–100 km, there is extremely little ozone, and the sulfur dioxide content changes significantly over several days. These conclusions were made based on the results of processing the data from the SPICAV instrument on board the Venus Express spacecraft, created with the active participation of the Space Research Institute of the Russian Academy of Sciences. An article with the results of the work was published in the Journal of Geophysical Research: Planets.

    The Venus Express orbital spacecraft of the European Space Agency operated near Venus in 2006–2014. On board was installed, among other scientific instruments, a complex of spectrometers SPICAV / SOIR (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Venus), created with the active participation of the Space Research Institute of the Russian Academy of Sciences. The ultraviolet channel of the SPICAV spectrometer was the only instrument on board the Venus Express capable of simultaneously studying the distribution of elevated concentrations of such trace gases as ozone (O₃) and sulfur dioxide (SO₂) in the upper mesosphere of Venus.

    Full article here:


  • ljk April 6, 2021, 13:18


    The Phosphene Controversy: Is it Phosphene? Is there life on Venus?

    On 14th September 2020, the Royal Astronomical Society made an official statement coupled with a webinar on the discovery of phosphine on Venus.

    Single-line millimetre-waveband spectral detections of phosphine (with a signal-to-noise ratio of ≈ 15σ) from the JCMT and ALMA telescopes indicated a phosphine abundance of 20 ppb (parts per billion), 1000 times more than that on the Earth. Phosphine is an important biomarker and immediate speculation in the media about indicators of life being found on Venus followed.

    This article presents an analysis of the study and the results on the observation of the spectral absorption feature of phosphine in the clouds of Venus, thus implying as a potential biosignature.

    If phosphine is produced through biotic, as opposed to abiotic pathways, the discovery could imply a significant biomass in the Venusian atmosphere. The discovery led to a major controversy with criticism of the analysis and results and responses to it. The issue remains unresolved, leading to a fresh interest in the study of Venus including ground-based observations as well as space-probes that can answer these questions conclusively.

    Priya Hasan

    Comments: Published in Astrobiology Newsletter, 14(1), 4, 2021, DOI: 10.13140/RG.2.2.13819.23847

    Subjects: Popular Physics (physics.pop-ph); Earth and Planetary Astrophysics (astro-ph.EP)

    Cite as: arXiv:2104.01932 [physics.pop-ph] (or arXiv:2104.01932v1 [physics.pop-ph] for this version)

    Submission history

    From: Priya Hasan

    [v1] Fri, 2 Apr 2021 17:11:40 UTC (4,753 KB)



  • ljk April 12, 2021, 15:15


    Contributed by Jeff Spry

    Apr 11, 2021, 6:26 PM EDT

    Born out of the winds of imagination, an innovative new project to deliver a swarm of tiny spacecraft for investigating the dense atmosphere of Venus just received an encouraging financial boost of funding dollars from NASA in the amount of $500,000.

    According to a NASA press release, Ohio Aerospace Institute (OAI) scientists engineered these diminutive soaring sensors that they’ve appropriately named Lofted Environmental and Atmospheric Venus Sensors (LEAVES), which will be scattered towards Venus like cosmic kites, then transmit data back to Earth.

    Full article here:


  • ljk April 15, 2021, 10:24

    Breakthrough Discuss 2021: Yuri’s Night Panel Discussion

    Gagarin, Venus, and Beyond


  • ljk April 16, 2021, 10:29

    Nancy Atkinson • Mar 25, 2021

    NASA Mission to Venus in 1978 May Have Detected Phosphine, a Gas Related to Life

    A group of scientists say a 43-year-old NASA mission may have detected phosphine and other gases linked to life in Venus’ atmosphere.

    The data come from NASA’s Pioneer Venus Multiprobe mission, which deployed a series of probes into the planet’s clouds in 1978. The findings are the latest salvo in a spirited debate over whether another team of scientists detected phosphine during ground-based telescopic observations in 2017 and 2019.

    That discovery, after being announced in 2020, has been questioned by other scientists, with a flurry of papers and studies probing the small amount of available data. The new analysis of the Pioneer Venus Multiprobe data, which was published in the journal Geophysical Research Letters, is one of the few to provide supportive evidence.

    While phosphine itself is not an indicator of life, nothing we know of on Venus could produce it in large quantities. For decades, some scientists have theorized that life could exist in Venus’ atmosphere, where temperatures and pressures are remarkably Earth-like.

    The Pioneer Venus Multiprobe findings come from a team led by Rakesh Mogul, a professor of biological chemistry at Cal Poly University in Pomona, California. Mogul’s team examined archival data from the Large Probe Neutral Mass Spectrometer, or LNMS, an instrument on the mission’s largest probe that measured Venus’ atmospheric composition while descending to the surface under parachute.

    Mogul’s team says the instrument also found other biologically relevant chemicals, and that part of Venus’ atmosphere is not in equilibrium—meaning a process related to life could be happening there.

    Full article here:


  • ljk April 16, 2021, 14:09

    Parker Solar Probe Captures First Complete View of Venus Orbital Dust Ring

    By Jeremy Rehm

    NASA’s Parker Solar Probe captured the first complete view of Venus’s dust ring, a band of particles that stretches for the entirety of the planet’s path around the Sun.

    The new images, published April 6 in The Astrophysical Journal, cover nearly the entire 360-degree view of the ring, completing a picture that scientists had seen only hints of before, with images from the Helios probes in the 1970s and multiple observations from NASA’s twin Solar Terrestrial Relations Observatory (STEREO) probes from 2007 to 2014.


  • ljk April 20, 2021, 14:40


    [Submitted on 19 Apr 2021]

    Recovery of Spectra of Phosphine in Venus’ Clouds

    Jane S. Greaves, Anita M. S. Richards, William Bains, Paul B. Rimmer, David L. Clements, Sara Seager, Janusz J. Petkowski, Clara Sousa-Silva, Sukrit Ranjan, Helen J. Fraser

    We recover PH3 in the atmosphere of Venus in data taken with ALMA, using three different calibration methods. The whole-planet signal is recovered with 5.4{\sigma} confidence using Venus bandpass self-calibration, and two simpler approaches are shown to yield example 4.5-4.8{\sigma} detections of the equatorial belt. Non-recovery by Villanueva et al. is attributable to (a) including areas of the planet with high spectral-artefacts and (b) retaining all antenna baselines which raises the noise by a factor ~2.5.

    We release a data-processing script that enables our whole-planet result to be reproduced. The JCMT detection of PH3 remains robust, with the alternative SO2 attribution proposed by Villanueva et al. appearing inconsistent both in line-velocity and with millimetre-wavelength SO2 monitoring. SO2 contamination of the ALMA PH3-line is minimal. Net abundances for PH3, in the gas column above ~55 km, are up to ~20 ppb planet-wide with JCMT, and ~7 ppb with ALMA (but with signal-loss possible on scales approaching planetary size). Derived abundances will differ if PH3 occupies restricted altitudes – molecules in the clouds will contribute significantly less absorption at line-centre than equivalent numbers of mesospheric molecules – but in the latter zone, PH3 lifetime is expected to be short.

    Given we recover phosphine, we suggest possible solutions (requiring substantial further testing): a small collisional broadening coefficient could give narrow lines from lower altitude, or a high eddy diffusion coefficient could allow molecules to survive longer at higher altitudes. Alternatively, PH3 could be actively produced by an unknown mechanism in the mesosphere, but this would need to be in addition to cloud-level PH3 detected retrospectively by Pioneer-Venus.

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

    Cite as: arXiv:2104.09285 [astro-ph.EP]
    (or arXiv:2104.09285v1 [astro-ph.EP] for this version)

    Submission history

    From: Janusz Petkowski [view email]

    [v1] Mon, 19 Apr 2021 13:22:50 UTC (618 KB)


  • ljk May 3, 2021, 13:15

    May 3, 2021

    NASA’s Parker Solar Probe Discovers Natural Radio Emission in Venus’ Atmosphere

    During a brief swing by Venus, NASA’s Parker Solar Probe detected a natural radio signal that revealed the spacecraft had flown through the planet’s upper atmosphere. This was the first direct measurement of the Venusian atmosphere in nearly 30 years — and it looks quite different from Venus past. A study published today confirms that Venus’ upper atmosphere undergoes puzzling changes over a solar cycle, the Sun’s 11-year activity cycle. This marks the latest clue to untangling how and why Venus and Earth are so different.

    Born of similar processes, Earth and Venus are twins: both rocky, and of similar size and structure. But their paths diverged from birth. Venus lacks a magnetic field, and its surface broils at temperatures hot enough to melt lead. At most, spacecraft have only ever survived a couple hours there. Studying Venus, inhospitable as it is, helps scientists understand how these twins have evolved, and what makes Earth-like planets habitable or not.

    On July 11, 2020, Parker Solar Probe swung by Venus in its third flyby. Each flyby is designed to leverage the planet’s gravity to fly the spacecraft closer and closer to the Sun. The mission — managed by Johns Hopkins Applied Physics Laboratory in Laurel, Maryland — made its closest flyby of Venus yet, passing just 517 miles (833 km) above the surface.

    Full article here:


  • ljk May 4, 2021, 11:25

    28 Apr 2021 | 15:00 GMT

    The Radio We Could Send to Hell

    Silicon carbide radio circuits can take the volcanic heat of Venus

    By Alan Mantooth, Carl-Mikael Zetterling and Ana Rusu


  • ljk May 7, 2021, 14:52

    How long is a day on Venus? It’s always changing, new study reveals

    By Meghan Bartels about 8 hours ago

    There’s a reason scientists haven’t been able to get their measurements to line up.


  • ljk May 10, 2021, 10:33

    What we’ve Learned About Venus From the Parker Solar Probe


    The Parker Solar Probe has been getting in a lot of extracurricular activity lately. Originally designed to observe the Sun, the probe has been taking full advantage of its path through the solar system. In addition to snapping pictures of comets, the probe has repeatedly focused on Venus, including capturing an image peering underneath the cloud cover of the notoriously hot world. Now a team led by Glyn Collinson of Goddard Space Flight Center found another serendipitous discovery in the data Parker collected during its latest flyby in the summer of 2020 – the probe actually flew through Venus’ upper atmosphere, and that atmosphere appeared different than it was almost 30 years ago.

    Parker has been using Venus in a gravity assist maneuver, but not in the traditional way of sending a object hurling faster out into the outer reaches of the solar system. It is trying to slow down so that it can spend a longer time close to the Sun, the primary target of its observations. While it was on its latest close approach to Venus, the mission team, located at the Applied Physics Laboratory at John Hopkins, decided it would collect some data. Some of that data resulted in the picture beneath the clouds, but some used a different instrument.

    Full article here: