Zitat [Submitted on 15 Oct 2020] A stringent upper limit of the PH3 abundance at the cloud top of Venus T. Encrenaz (1), T. K. Greathouse (2), E. Marcq (3), T. Widemann (1), B. Bézard (1), T. Fouchet (1), R. Giles (2), H. Sagawa (4), J. Greaves (5), C. Sousa-Silva (6) ((1) LESIA, Observatoire de Paris, PSL Université, CNRS, Sorbonne Université, Université de Paris, (2) SwRI, (3) LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, (4) Kyoto Sanyo University, (5) School of Physics and Astronomy, Cardiff University, (6) Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology)
Following the announcement of the detection of phosphine (PH3) in the cloud deck of Venus at millimeter wavelengths, we have searched for other possible signatures of this molecule in the infrared range. Since 2012, we have been observing Venus in the thermal infrared at various wavelengths to monitor the behavior of SO2 and H2O at the cloud top. We have identified a spectral interval recorded in March 2015 around 950 cm−1 where a PH3 transition is present. From the absence of any feature at this frequency, we derive, on the disk-integrated spectrum, a 3-σ upper limit of 5 ppbv for the PH3 mixing ratio, assumed to be constant throughout the atmosphere. This limit is 4 times lower than the disk-integrated mixing ratio derived at millimeter wavelengths. Our result brings a strong constraint on the maximum PH3 abundance at the cloud top and in the lower mesosphere of Venus.
Comments: Astronomy & Astrophysics, in press Subjects: Earth and Planetary Astrophysics (astro-ph.EP) Cite as: arXiv:2010.07817 [astro-ph.EP] (or arXiv:2010.07817v1 [astro-ph.EP] for this version)
Zitat [Submitted on 19 Oct 2020] Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine I.A.G. Snellen, L. Guzman-Ramirez, M.R. Hogerheijde, A.P.S. Hygate, F.F.S. van der Tak
Context: ALMA observations of Venus at 267 GHz have been presented in the literature that show the apparent presence of phosphine (PH3) in its atmosphere. Phosphine has currently no evident production routes on the planet's surface or in its atmosphere. Aims: The aim of this work is to assess the statistical reliability of the line detection by independent re-analysis of the ALMA data. Methods: The ALMA data were reduced as in the published study, following the provided scripts. First the spectral analysis presented in the study was reproduced and assessed. Subsequently, the spectrum was statistically evaluated, including its dependence on selected ALMA baselines. Results: We find that the 12th-order polynomial fit to the spectral passband utilised in the published study leads to spurious results. Following their recipe, five other >10 sigma lines can be produced in absorption or emission within 60 km/s from the PH3 1-0 transition frequency by suppressing the surrounding noise. Our independent analysis shows a feature near the PH3 frequency at a ~2 sigma level, below the common threshold for statistical significance. Since the spectral data have a non-Gaussian distribution, we consider a feature at such level as statistically unreliable that cannot be linked to a false positive probability. Conclusions: We find that the published 267-GHz ALMA data provide no statistical evidence for phosphine in the atmosphere of Venus.
Comments: Submitted to A&A. No media enquiries Subjects: Earth and Planetary Astrophysics (astro-ph.EP) Cite as: arXiv:2010.09761 [astro-ph.EP] (or arXiv:2010.09761v1 [astro-ph.EP] for this version)
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat von Earth Sky.org, 13 April 2021In late 2020, scientists studying the atmosphere of Venus announced the surprising – and controversial – discovery of phosphine, a chemical that, on Earth, is produced primarily by living organisms. Jane Greaves at Cardiff University in Wales and her colleagues asked at the time: could the phosphine be a sign of microorganisms inhabiting Venus’ atmosphere? Maybe, other scientists said, but phosphine itself wouldn’t be proof of life, and subsequent studies questioned whether the phosphine was ever there at all. Then – in March 2021 – a study from Rakesh Mogul of Cal Poly Pomona supported the original finding of phosphine and went further. It suggested that other “biologically relevant chemicals” in Venus’ atmosphere appear to be in a state of disequilibrium: another hallmark of life.
The new study focused on the re-analysis of data from the old Pioneer Venus mission, which sent four probes into Venus’ atmosphere in 1978, collecting data as they plunged toward the surface. This was the Pioneer Venus Multiprobe part of the mission, with three small probes and one larger one. The scientists analyzed data from the largest probe. The tantalizing peer-reviewed results were published in Geophysical Research Letters on March 10, 2021.
Zitat As well as phosphine, the new analysis suggested the existence of additional chemicals including hydrogen sulfide, nitrous acid, nitric acid, hydrogen cyanide, carbon monoxide, ethane, and potentially ammonia and chlorous acid.
The data for this study come from the Large Probe Neutral Mass Spectrometer (LNMS), which was on the largest of the four probes that descended to Venus’ surface in 1978. The composition of the atmosphere was measured several times during descent. LNMS targeted gas molecules in the atmosphere that have a neutral charge. Phosphine would be one of those gases.
The Pioneer Venus data are important, especially since they were obtained in situ, in the atmosphere itself, instead of remotely by Earth-based telescopes, as the other data last year had been.
The disequilibrium in Earth’s atmosphere is due to life, but whether the same is true for Venus is still unknown. This latest study supports that it could be, but more data are still needed, most likely from a return mission, to know for sure. Astronomers also say that this kind of disequilibrium could be used to search for evidence of life on exoplanets.
"Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds," Rakesh Mogul, Sanjay S. Limaye, M. J. Way, Jaime A. Cordova. Geophysical Research Letters. First published: 10 March 2021
Zitat Venus' clouds harbor several proposed trace chemical species that suggest the potential for chemistries yet to be discovered. Exemplar trace species include ammonia, oxygen, hydrogen, methane, and ethene, which were detected remotely or in situ (Kumar et al., 1981; Moroz, 1981; Oyama et al., 1980; Pollack et al., 1993; Smirnova & Kuz'min, 1974; Surkov, 1977). Recently, phosphine was reported by Greaves, Richards, Bains, Rimmer, Sagawa, et al. (2020), with both the detection and interpretation as a biosignature spurring significant debate within the community (Bains et al., 2020; Encrenaz et al., 2020; Greaves, Bains, et al., 2020; Greaves, Richards, Bains, Rimmer, Clements, et al., 2020; Snellen et al., 2020; Villanueva et al., 2020). In this context, we sought to examine available in situ data for signatures of trace species at Venus. Given the recent interest in the potential habitability of the lower/middle cloud deck (Greaves, Richards, Bains, Rimmer, Sagawa, et al., 2020; Limaye et al., 2018; Seager et al., 2020), we concentrated on data obtained from within the clouds by the Pioneer Venus (PV) Large Probe Neutral Mass Spectrometer (LNMS), which sampled the atmosphere during descent on December 9, 1978 (Hoffman, Hodges, & Duerksen, 1979).
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat von NASA - PressemitteilungJun 2, 2021 RELEASE 21-073 - NASA Selects 2 Missions to Study ‘Lost Habitable’ World of Venus
NASA has selected two new missions to Venus, Earth’s nearest planetary neighbor. Part of NASA’s Discovery Program, the missions aim to understand how Venus became an inferno-like world when it has so many other characteristics similar to ours – and may have been the first habitable world in the solar system, complete with an ocean and Earth-like climate.
These investigations are the final selections from four mission concepts NASA picked in February 2020 as part of the agency’s Discovery 2019 competition. Following a competitive, peer-review process, the two missions were chosen based on their potential scientific value and the feasibility of their development plans. The project teams will now work to finalize their requirements, designs, and development plans.
NASA is awarding approximately $500 million per mission for development. Each is expected to launch in the 2028-2030 timeframe.
The selected missions are:
DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging)
DAVINCI+ will measure the composition of Venus’ atmosphere to understand how it formed and evolved, as well as determine whether the planet ever had an ocean. The mission consists of a descent sphere that will plunge through the planet’s thick atmosphere, making precise measurements of noble gases and other elements to understand why Venus’ atmosphere is a runaway hothouse compared the Earth’s.
In addition, DAVINCI+ will return the first high resolution pictures of the unique geological features on Venus known as “tesserae,” which may be comparable to Earth’s continents, suggesting that Venus has plate tectonics. This would be the first U.S.-led mission to Venus’ atmosphere since 1978, and the results from DAVINCI+ could reshape our understanding of terrestrial planet formation in our solar system and beyond. James Garvin of Goddard Space Flight Center in Greenbelt, Maryland, is the principal investigator. Goddard provides project management.
VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy)
VERITAS will map Venus’ surface to determine the planet’s geologic history and understand why it developed so differently than Earth. Orbiting Venus with a synthetic aperture radar, VERITAS will chart surface elevations over nearly the entire planet to create 3D reconstructions of topography and confirm whether processes such as plate tectonics and volcanism are still active on Venus.
VERITAS also will map infrared emissions from Venus’ surface to map its rock type, which is largely unknown, and determine whether active volcanoes are releasing water vapor into the atmosphere. Suzanne Smrekar of NASA’s Jet Propulsion Laboratory in Southern California, is the principal investigator. JPL provides project management. The German Aerospace Center will provide the infrared mapper with the Italian Space Agency and France’s Centre National d'Etudes Spatiales contributing to the radar and other parts of the mission.
Zitat Venus: Hinweise auf „Eisschollen“-Tektonik auf dem Planeten
Raleigh – Bislang ist die Erde der einzig bekannte Planet mit einer aktiven Plattentektonik. Nur hier lassen sich driftende Kontinentalplatten vorfinden. Sie werden angetrieben durch Konvektionsströmungen im Erdmantel, die die Kruste in Bewegung halten und Gebirge, Vulkanketten oder Tiefseegräben entstehen lassen.
Doch eine aktuelle Studie im Fachmagazin PNAS zeigt: Auch die Venus ist wohl geologisch aktiv. Es häufen sich Hinweise, dass unser Nachbarplanet nicht völlig starr und unveränderlich ist. Die Forschung könnte uns Aufschlüsse über die junge Erde und weit entfernte Welten liefern.
Der Mars gilt als zu kalt, um eine ausreichend starke Mantelkonvektion auszubilden. Die Venus hingegen galt als zu heiß, da die Kruste zu weich und flexibel wäre, um feste Platten zu bilden. „Im Gegensatz zum Mosaik mobiler tektonischer Platten, das die Erde charakterisiert, besitzt die Venus gängiger Annahme nach eine global durchgängige Lithosphäre“, erklären Paul Byrne von der North Carolina State University in Raleigh und sein Team. „Die Venus zeigt mindestens seit 0,5 bis einer Milliarde Jahren alle Anzeichen eines Ein-Platten-Planeten.“
Das internationale Forschungsteam hat sich alte Radar-Aufnahmen der Magellan-Mission der Nasa, die 2004 zu Ende ging, genauer angeschaut. Auf ihnen erkannte man auffallend große Krustenblöcke, vor allem in den Tiefebenen der Venus. Diese geben Anzeichen dafür, dass sie sich im Laufe der Zeit gedreht und/oder seitlich zueinander verschoben haben – ähnlich wie „sich anrempelnde Eisschollen im Packeis“, heißt es. Die Krustenteile sind von Dehnungsfugen und Verwerfungen umgeben. Im Schnitt seien diese Ebenen „100 bis 1.000 Kilometer“ groß.
Zitat "A globally fragmented and mobile lithosphere on Venus" Paul K. Byrne, Richard C. Ghail, A. M. Celâl Şengör, Peter B. James, Christian Klimczak, and Sean C. Solomon PNAS June 29, 2021 118 (26) e2025919118; https://doi.org/10.1073/pnas.2025919118 Contributed by Sean C. Solomon, May 16, 2021 (sent for review December 16, 2020; reviewed by Eric B. Grosfils and Lyal B. Harris)
Zitat Abstract
Venus has been thought to possess a globally continuous lithosphere, in contrast to the mosaic of mobile tectonic plates that characterizes Earth. However, the Venus surface has been extensively deformed, and convection of the underlying mantle, possibly acting in concert with a low-strength lower crust, has been suggested as a source of some surface horizontal strains. The extent of surface mobility on Venus driven by mantle convection, however, and the style and scale of its tectonic expression have been unclear. We report a globally distributed set of crustal blocks in the Venus lowlands that show evidence for having rotated and/or moved laterally relative to one another, akin to jostling pack ice. At least some of this deformation on Venus postdates the emplacement of the locally youngest plains materials. Lithospheric stresses calculated from interior viscous flow models consistent with long-wavelength gravity and topography are sufficient to drive brittle failure in the upper Venus crust in all areas where these blocks are present, confirming that interior convective motion can provide a mechanism for driving deformation at the surface. The limited but widespread lithospheric mobility of Venus, in marked contrast to the tectonic styles indicative of a static lithosphere on Mercury, the Moon, and Mars, may offer parallels to interior–surface coupling on the early Earth, when global heat flux was substantially higher, and the lithosphere generally thinner, than today.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Quintessenz: Auf dem Saturnmond Enceladus entsteht Methan. Es gibt keinen bekannten abiotischen Prozess, der Methan in den hier beobachteten Mengen entstehen lassen würde. Entweder gibt es also noch völlig unbekannte andere abiotische Prozesse - oder auf dem Enceladus gibt es Leben. Spannend, oder?
Hintergrund: Enceladus bekommt sehr wenig Sonnenlicht ab und ist zudem sehr weiß (=stark reflektierend). Deshalb müsste er eigentlich sehr kalt sein. Allerdings ist er so nahe am Saturn, dass er durch die dadurch entstehenden Gezeitenkräfte ordentlich durchgeknetet wird - und das erzeugt innere Wärme. Unterhalb eines kilometerdicken Wassereis-Panzers gibt es deshalb einen großen Ozean aus flüssigem Wasser. In diesem Ozean gibt es vulkanische Aktivität. Auf der Erde sind vulkanische heiße Punkte am Ozeanboden Orte, wo (z.T. sehr interessantes) Leben existiert. Ähnliches wäre auch auf Enceladus vorstellbar.
Ich würde den Tag nicht vor den Abend loben. Für mich gehören die Sensationsmeldungen über den Saturnmond Enceladus momentan in die selbe Kategorie wie der UFO-Report der US-Regierung. Unter strengste Beobachtung, hochbrisantes Thema, aber bisher noch nichts konkretes. Die Spekulation über den Jupitermond Ganymed ist sogar noch windiger, soweit ich das beurteilen kann.
Das mit der Venus scheint mir um einiges härter zu sein.
Potenzielle Kandidaten für Leben in Kosmos gibt es immer mehr. Wir können uns glücklich schätzen, in dieser Epoche geboren worden zu sein.
Stand 05.06.2021: Das SARS-CoV-2-Virus könnte jetzt doch aus einem Labor kommen. 23.06.: Dem BMWi fällt auf, dass der Strombedarf nicht bis 2030 konstant bleibt. to be continued
Zitat von Florian im Beitrag #6 Auf der Erde sind vulkanische heiße Punkte am Ozeanboden Orte, wo (z.T. sehr interessantes) Leben existiert. Ähnliches wäre auch auf Enceladus vorstellbar.
Das berührt einen der Kernpunkte in der Frage zur Entstehung des Lebens, in dem noch eine ganze Reihe von entscheidenden Punkten ungeklärt sind. Die den Lebensformen an den Tiefseespalten, die Schwefel als metaolische Energiequelle nützen, geht die bisherige Theorie ja davon aus, daß es sich um "Ableger" das allgemeinen Stammbaums des Lebens hier auf der Erde handelt. Der genetische Code ist für dieselben Peptide zuständig wie beim Rest; bei unabhängier Entstehung sollte es unterschiedliche Codierungen geben. Genau weiß es niemand, wo (d.h. unter welchen Umständen sich das entwickelt hat). Allgemein werden Flachwasserbedingungen angenommen (bis zu 10m Wassertiefe als Schutz vor der harten UV-Strahlung und ausreichend Sonnenlicht als Energiequelle. Auch wenn die Mehrzahl der Biologen, die sich mit der Frage befaßt haben, heute eher zu der These neigen, daß die RNS vor der DNS funktionstragend war: wissen tut es keiner. Es ist ungeklärt, ob es sich beim Methan auf Enceladus - oder auch auf dem Mars, in dessen Atmosphäre das seit 2003 nachgewiesen ist - um Hinweise auf biotische Prozesse handelt.
Auf Sol III, vulgo Erde, erfolgt ein großer Teil des Methaneintrags in die Atmosphäre durch Schlammvulkane. Und genau solch eine geologische Formation befindet sich gut 3 km westlich des chinesischen Marsrovers Zhurong. Es gibt jetzt genügend Fachleute, die hoffen, daß der Rover länger als die avisierte Missionsdauer von 90 Erdtagen durchhält und sich auf den Weg dorthin machen könnte - wie im Fall von Curiosity, der für ein Marsjahr (669 Sols) ausgelegt war und mittlerweile seit 3143 Sonnentagen (= 3329 Erdtage) unterwegs ist.
Zitat von Forbes.com, 20 May 2021Of great interest to scientists is a pitted, cone-shaped feature seen in images, about 3,000 meters northwest of Zhurong’s position: this could be a volcano formed from lava or mud. On Earth, mud volcanoes are associated with the degassing of sediments, squeezing water and mud out of the ground. Still active mud volcanoes on Mars might help to explain puzzlingly large quantities of methane that had been previously detected in the Martian atmosphere, with methane concentrations fluctuating during a Martian year. Terrestrial mud volcanoes are also habitats for bacteria, so there is even (a remote) possibility to discover signs of life in volcanic deposits.
(Wobei: sooo "puzzingly large" ist der Methangehalt nicht: der liegt um ein Sechsmillionstel. Er sollte nur bei Null liegen.)
Das ist aber erst die halbe Miete. Die Aufgabe, hier Materialproben zu gewinnen, um sie in irdischen Labors entsprechend analysieren zu können, ist, wie wir aktuell sehen, um noch einiges aufwendiger. Die Steine, die Perseverance demnächst zusammentragen wird, damit sie zwischen 2028 und 2030 vom nächsten Lander eingesackt und zurückgebreacht werden, werden nicht vor 2032-33 untersucht werden können. Für Missionen zu den Monden der äußeren Gasplaneten kommt da entsprechend noch einiges drauf. Das Projekt, Eiskrusten zu durchbohren, die Dutzende von Kilometern stark sind, dürfte etwas für kommende Jahrhunderte sein. Am einfachsten dürfte des noch im Fall des Jupitermonds Europa sein, wo die dunklen Striche auf der Eisoberfläche auf Risse im Eispanzer zurückzuführen sein dürften, entlang denen mineralhaltiges Wasser aus dem Ozean darunter verdunstet ist. Wenn man in diesem Material genügend organische Spuren nachweisen könnte, wäre man der Frage, OB es dort Leben gibt, einen entscheidenden Schritt näher.
PS. Zu den Zeitspannen. Die Entdeckung des Cryovulkanismus am Südpol von Enceladus ist durch die Cassini-Sonde im Mai 2005 erfolgt; die erste Analyse und der Nachweis einfacher organischer Verbindungen im dort austretenden Dampf beim Durchflug durch die Wolke 7 Wochen später. Der Vorschlag für die LIFE-Mission für Probengewinnung ist formell im August 2012 zur Begutachtung an die NASA gegangen und im September 2015 abgelehnt worden.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat von Florian im Beitrag #6 Auf der Erde sind vulkanische heiße Punkte am Ozeanboden Orte, wo (z.T. sehr interessantes) Leben existiert. Ähnliches wäre auch auf Enceladus vorstellbar.
Stichwort Vulkanismus.
Zitat Paul Byrne @ThePlanetaryGuy BREAKING: For the first time ever, scientists have identified *active volcanism* on Venus. The paper, by Herrick and Hensley, has just been published in @ScienceMagazine
Over eight months in the early 1990s, NASA's Magellan radar mission took images that showed a *major* change to a large volcano on Venus. At some point over those eight months, a volcanic caldera about 2 km across underwent a huge collapse, ending up 4 km in size. This change in shape and size of this volcanic crater is *at least* as big as the growth of the Kilauea summit caldera in 2018. The volcanic crater looks small of Magellan radar images only because those data are fairly coarse. But the newly collapsed structure is enormous.
It's not clear as to whether this collapse was accompanied by a big eruption, as was the case for Kilauea in 2018. But it's also possible that the movement of *magma* underground could have led to the collapse of overlying material, enlarging the volcanic crater.
On the one hand, it's not all that surprising that Venus has these kinds of features—it has lots of volcanic features that we recognise on Earth. But we have *never*, not in the six decades we've been sending spacecraft to Venus, never found evidence of ACTIVE volcanism.
Eight months elapsed between Magellan taking the left and right pics in the first tweet. We don't know when the collapse happened, nor how long it took, just that it was within that eight-month window. And that has HUGE implications for ongoing geological activity on Venus.
It's *possible* that this collapse (and possible eruption) was the one such event that took place in the last million years. But that's probably bullshit. It's MUCH more likely that this kinda thing happens on Venus *all the time* Just like it does on Earth.
So what does this mean for Venus? In this scientist's opinion, it means that there are eruptions, and collapses, and other volcanic events all over Venus all the time. Most such events are probably small, just like they are on Earth, and probably too small for Magellan to see.
But we'll be able to search for geological activity like this to a much greater extent with the upcoming VERITAS and EnVision missions, due to fly to Venus in the next ten years. And when they do, we're going to see Venus in a whole new light.
But this announcement today is bittersweet. Because we've learned that NASA has delayed the VERITAS mission by *at least* three years, and the money that was going to be used for VERITAS has been almost fully taken back by NASA. Right when we need new radar data for Venus!
This is one of the most exciting discoveries we've made for Venus—with data that are decades old! But there are still a huge number of questions we have for Venus that we can't answer, for which we have to get into the clouds and onto the surface. We're just getting started. 7:07 PM · Mar 15, 2023
Zitat von 15 Mar 2023Surface changes observed on a Venusian volcano during the Magellan mission
Abstract Venus has a geologically young surface, but it is unknown whether it has ongoing active volcanism. From 1990 to 1992, the Magellan spacecraft imaged the planet’s surface using synthetic aperture radar. We examine volcanic areas on Venus that were imaged two or three times by Magellan and identify a ~2.2 km2 volcanic vent that changed shape in the eight months between two radar images. Additional volcanic flows downhill from the vent are visible in the second epoch images, though we cannot rule out that they were present but invisible in the first epoch due to differences in imaging geometry. We interpret these results as ongoing volcanic activity on Venus.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Aus den Meldungen geht (anders als aus den Überschriften) eindeutig hervor, daß es sich beim nachweis von Sauerstoff in der Venusatmosphäre um einen photolytischen Effekt handelt, und nicht um einen Biomarker.
Zitat First direct detection by measurements performed with the upGREAT terahertz spectrometer Atomic oxygen on the day and night side of Venus' atmosphere
There are two strong currents in the atmosphere of Venus. Below approximately 70 kilometres, there are hurricane-force winds blowing against the direction of Venus' rotation, but above 120 kilometres, strong winds flow in the direction of rotation. A layer of atomic oxygen exists between these two opposing atmospheric currents. This layer is produced by ultraviolet radiation from the Sun, which breaks down the carbon dioxide and carbon monoxide in Venus' atmosphere into atomic oxygen and other products.
Previous and current detection methods are indirect and are based on measurements of other molecules in combination with photochemical models. In November 2021, researchers from the DLR Institute of Optical Sensor Systems, the Max Planck Institute for Radio Astronomy and the University of Cologne succeeded in directly detecting the extremely reactive oxygen atoms in the atmosphere of Venus for the first time. The measurements were carried out using the upGREAT spectrometer on SOFIA. "The measurements were particularly challenging because Venus could only be observed with SOFIA for approximately 20 minutes on three days and was only slightly above the horizon. Thanks to upGREAT’s outstanding measurement sensitivity and SOFIA's unique capabilities, it was possible to create a map of the oxygen distribution on Venus," says Heinz-Wilhelm Hübers, Director of the DLR Institute of Optical Sensor Systems and first author of the publication announcing the results
Zitat Published: 07 November 2023 "Direct detection of atomic oxygen on the dayside and nightside of Venus," Heinz-Wilhelm Hübers, Heiko Richter, Urs U. Graf, Rolf Güsten, Bernd Klein, Jürgen Stutzki & Helmut Wiesemeyer Nature Communications volume 14, Article number: 6812 (2023)
Abstract Atomic oxygen is a key species in the mesosphere and thermosphere of Venus. It peaks in the transition region between the two dominant atmospheric circulation patterns, the retrograde super-rotating zonal flow below 70 km and the subsolar to antisolar flow above 120 km altitude. However, past and current detection methods are indirect and based on measurements of other molecules in combination with photochemical models. Here, we show direct detection of atomic oxygen on the dayside as well as on the nightside of Venus by measuring its ground-state transition at 4.74 THz (63.2 µm). The atomic oxygen is concentrated at altitudes around 100 km with a maximum column density on the dayside where it is generated by photolysis of carbon dioxide and carbon monoxide. This method enables detailed investigations of the Venusian atmosphere in the region between the two atmospheric circulation patterns in support of future space missions to Venus.
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