Tag Archives: #venus

Earth and Venus Grew up as Rambunctious Planets (Planetary Science)

What doesn’t stick comes around: Using machine learning and simulations of giant impacts, researchers at the Lunar and Planetary Laboratory found that the planets residing in the inner solar system were likely born from repeated hit-and-run collisions, challenging conventional models of planet formation. 

Planet formation – the process by which neat, round, distinct planets form from a roiling, swirling cloud of rugged asteroids and mini planets – was likely even messier and more complicated than most scientists would care to admit, according to new research led by researchers at the University of Arizona Lunar and Planetary Laboratory.

The findings challenge the conventional view, in which collisions between smaller building blocks cause them to stick together and, over time, repeated collisions accrete new material to the growing baby planet.

Instead, the authors propose and demonstrate evidence for a novel “hit-and-run-return” scenario, in which pre-planetary bodies spent a good part of their journey through the inner solar system crashing into and ricocheting off of each other, before running into each other again at a later time. Having been slowed down by their first collision, they would be more likely to stick together the next time. Picture a game of billiards, with the balls coming to rest, as opposed to pelting a snowman with snowballs, and you get the idea.

The research is published in two reports appearing in the Sept. 23 issue of The Planetary Science Journal, with one focusing on Venus and Earth, and the other on Earth’s moon. Central to both publications, according to the author team, which was led by planetary sciences and LPL professor Erik Asphaug, is the largely unrecognized point that giant impacts are not the efficient mergers scientists believed them to be.

“We find that most giant impacts, even relatively ‘slow’ ones, are hit-and-runs. This means that for two planets to merge, you usually first have to slow them down in a hit-and-run collision,” Asphaug said. “To think of giant impacts, for instance the formation of the moon, as a singular event is probably wrong. More likely it took two collisions in a row.”

The inner planets: Mercury, Venus, Earth and Mars
The terrestrial planets of the inner solar system, shown to scale. According to ‘late stage accretion’ theory, Mars and Mercury (front left and right) are what’s left of an original population of colliding embryos, and Venus and Earth grew in a series of giant impacts. New research focuses on the preponderance of hit-and-run collisions in giant impacts, and shows that proto-Earth would have served as a ‘vanguard’, slowing down planet-sized bodies in hit-and-runs. But it is proto-Venus, more often than not, that ultimately accretes them, meaning it was easier for Venus to acquire bodies from the outer solar system. Lsmpascal – Wikimedia commons

One implication is that Venus and Earth would have had very different experiences in their growth as planets, despite being immediate neighbors in the inner solar system. In this paper, led by Alexandre Emsenhuber, who did this work during a postdoctoral fellowship in Asphaug’s lab and is now at Ludwig Maximilian University in Munich, the young Earth would have served to slow down interloping planetary bodies, making them ultimately more likely to collide with and stick to Venus.

“We think that during solar system formation, the early Earth acted like a vanguard for Venus,” Emsenhuber said.

The solar system is what scientists call a gravity well, the concept behind a popular attraction at science exhibits. Visitors toss a coin into a funnel-shaped gravity well, and then watch their cash complete several orbits before it drops into the center hole. The closer a planet is to the sun, the stronger the gravitation experienced by planets. That’s why the inner planets of the solar system on which these studies were focused – Mercury, Venus, Earth and Mars – orbit the sun faster than, say, Jupiter, Saturn and Neptune. As a result, the closer an object ventures to the sun, the more likely it is to stay there.

So when an interloping planet hit the Earth, it was less likely to stick to Earth, and instead more likely to end up at Venus, Asphaug explained.

“The Earth acts as a shield, providing a first stop against these impacting planets,” he said. “More likely than not, a planet that bounces off of Earth is going to hit Venus and merge with it.”

Emsenhuber uses the analogy of a ball bouncing down a staircase to illustrate the idea of what drives the vanguard effect: A body coming in from the outer solar system is like a ball bouncing down a set of stairs, with each bounce representing a collision with another body.

“Along the way, the ball loses energy, and you’ll find it will always bounce downstairs, never upstairs,” he said. “Because of that, the body cannot leave the inner solar system anymore. You generally only go downstairs, toward Venus, and an impactor that collides with Venus is pretty happy staying in the inner solar system, so at some point it is going to hit Venus again.”

Earth has no such vanguard to slow down its interloping planets. This leads to a difference between the two similar-sized planets that conventional theories cannot explain, the authors argue.

“The prevailing idea has been that it doesn’t really matter if planets collide and don’t merge right away, because they are going to run into each other again at some point and merge then,” Emsenhuber said. “But that is not what we find. We find they end up more frequently becoming part of Venus, instead of returning back to Earth. It’s easier to go from Earth to Venus than the other way around.”

Simulated aftermath of a hit-and-run collisions between the young Earth and  another planetary body
The moon is thought to be the aftermath of a giant impact. According to a new theory, there were two giant impacts in a row, separated by about 1 million years, involving a Mars-sized ‘Theia’ and proto-Earth. In this image, the proposed hit-and-run collision is simulated in 3D, shown about an hour after impact. A cut-away view shows the iron cores. Theia (or most of it) barely escapes, so a follow-on collision is likely.A. Emsenhuber/University of Bern/University of Munich

To track all these planetary orbits and collisions, and ultimately their mergers, the team used machine learning to obtain predictive models from 3D simulations of giant impacts. The team then used these data to rapidly compute the orbital evolution, including hit-and-run and merging collisions, to simulate terrestrial planet formation over the course of 100 million years. In the second paper, the authors propose and demonstrate their hit-and-run-return scenario for the moon’s formation, recognizing the primary problems with the standard giant impact model.

“The standard model for the moon requires a very slow collision, relatively speaking,” Asphaug said, “and it creates a moon that is composed mostly of the impacting planet, not the proto-Earth, which is a major problem since the moon has an isotopic chemistry almost identical to Earth.”

In the team’s new scenario, a roughly Mars-sized protoplanet hits the Earth, as in the standard model, but is a bit faster so it keeps going. It returns in about 1 million years for a giant impact that looks a lot like the standard model.

“The double impact mixes things up much more than a single event,” Asphaug said, “which could explain the isotopic similarity of Earth and moon, and also how the second, slow, merging collision would have happened in the first place.”

The researchers think the resulting asymmetry in how the planets were put together points the way to future studies addressing the diversity of terrestrial planets. For example, we don’t understand how Earth ended up with a magnetic field that is much stronger than that of Venus, or why Venus has no moon.

Their research indicates systematic differences in dynamics and composition, according to Asphaug.

“In our view, Earth would have accreted most of its material from collisions that were head-on hits, or else slower than those experienced by Venus,” he said. “Collisions into the Earth that were more oblique and higher velocity would have preferentially ended up on Venus.”

This would create a bias in which, for example, protoplanets from the outer solar system, at higher velocity, would have preferentially accreted to Venus instead of Earth. In short, Venus could be composed of material that was harder for the Earth to get ahold of.

“You would think that Earth is made up more of material from the outer system because it is closer to the outer solar system than Venus. But actually, with Earth in this vanguard role, it makes it actually more likely for Venus to accrete outer solar system material,” Asphaug said.

The co-authors on the two papers are Saverio Cambioni and Stephen R. Schwartz at the Lunar and Planetary Laboratory and Travis S. J. Gabriel at Arizona State University in Tempe, Arizona.

Featured image: Artist’s illustration of two massive objects colliding.NASA/JPL-Caltech


Provided by University of Arizona

New Evidence of Recent (Geologically Speaking) Venusian Volcanism (Planetary Science)

New data analysis techniques allow evidence of recent volcanism to be found in old Magellan spacecraft data. It is unclear if this activity is occurring today, or if it occurred within tens of million years, but geologically speaking, either case is recent. This adds to the growing body of evidence that volcanoes on Venus didn’t go extinct as long ago as many had thought. This work was conducted by Planetary Science Institute (PSI) researchers Megan Russell and Catherine Johnson. 

In the 31 years since NASA’s Magellan spacecraft entered orbit around Venus, researchers have been using the mission’s radar images, topography and gravity mapping to understand the surface history of this cloud-covered world. Early results made it clear that Venus has significantly fewer impact craters on its surface than its cousins Mars and Mercury, and the craters that it does have are randomly scattered across the planet. Craters build up over time, and Venus’s low number of craters means it has a surface that was somehow wiped clean roughly 300 million to 1 billion years ago. It is unclear if this was a catastrophic event that resurfaced the entire planet at once, or randomly distributed ongoing events that systematically resurfaced Venus over time, or some combination of both options. To understand what happened, it is necessary to understand when volcanoes have been active. 

“The question of whether Venus has had geologically recent or ongoing volcanism has been an enduring enigma from the Magellan mission:  we still have no smoking gun regarding this but more and more lines of evidence suggest a recently, and potentially currently, active planet,” said PSI Senior Scientist Catherine Johnson. 

As computers have improved, it has become possible to do more and more with Magellan’s finite data set. Russell and Johnson used a high resolution stereo topography data set generated by other researchers to look at a volcano at the edge of the 350-kilometer across Aramaiti Corona. 

Corona are roughly circular features, surrounded by a ring of cracks that appear roughly like a crown, and are thought to be large faults. At some coronae, like Aramaiti, volcanoes and/or lava flows are observed close to or on these fractures. The volcano studied by the PSI researchers was part of the lucky 20% of Venus’ surface to be imaged in stereo with synthetic aperture radar (SAR), which revealed the elevations across the 3-D structure, providing a better view than a simple image. 

“Instead of looking at the surface of the volcano or flows, we look at how the volcano deforms the ground around it.  In response to the weight of the volcano, the ground around it bends, like flexing a plastic ruler,” said Megan Russell, a Research Associate at PSI and lead author of Evidence for a Locally Thinned Lithosphere Associated With Recent Volcanism at Aramaiti Corona, Venus that appears in Journal of Geophysical Research Planets. “The same kind of deformation is seen in the bending of the seafloor around the Hawaiian islands. From this deformation, we can infer properties like heat flow local to the volcano.” 

To go beyond simply indicating younger versus older, it is necessary to use complex computer models to model the surface deformation. It is from this modeled deformation that properties like heat flow can be inferred. 

Over time, these kinds of structures can evolve, and the degree of deformation that is observed hints at how old or young a feature might be and how much heat might be flowing under the surface. 

Russell goes on to explain, “Modeling studies suggest that the shape and topography of this corona indicate that it is also geologically young, and would have similarly geologically young volcanism associated with it.” 

This particular structure seems to be unique in Magellan’s limited data set. Only seven other coronae in the 20% of Venus that Magellan studied with SAR have steep-sided volcanoes on or near their fractured ring like that studied by Russell and Johnson. In addition, the stereo topography data on the feature in this study was of particularly high quality. With three future missions planned for Venus, this team looks forward to exploring this question in greater detail in the future. “Happily for those of us who were lucky enough to start our careers working on the Magellan mission, there are now three new missions slated to fly to Venus in the next decade or so.” 

For Johnson, Venus has already played a multi decade role; she worked on her Ph.D. in 1984-1989 with a Guest Investigator on Magellan. For Russell, this work is a great start to her career. This research was performed while Russell was a graduate student at the Department of Earth, Ocean and Atmospheric Sciences, at the University of British Columbia.

Featured image: Magellan  SAR image of Aramaiti Corona. Narina Tholus (center left)appears as two adjacent domes that are superposed on the west outer fracture ring. © PSI


Provided by Planetary Science Institute

Space-based Infrared Imaging Reveals the Nighttime Weather On Venus (Planetary Science)

Little is known about the weather at night on Venus as the absence of sunlight makes imaging difficult. Now, researchers have devised a way to use infrared sensors on board the Venus orbiter Akatsuki to reveal the first details of the nighttime weather of our nearest neighbor. Their analytical methods could be used to study other planets including Mars and gas giants as well. Furthermore, the study of Venusian weather granted by their methods could allow researchers to learn more about the mechanisms underpinning Earth’s weather systems.

Earth and Venus share a lot in common. They are similar in size and mass, they’re both within the same orbital region known as the habitable zone (thought to support liquid water, and possibly life), they both have a solid surface, and both have a narrow atmosphere that experiences weather. Therefore, the study of the weather on Venus can actually aid researchers in their quest to better understand the weather on Earth too. To do this, researchers need to observe cloud motion on Venus day and night at certain wavelengths of infrared light. However, until now only the weather on the daylight-facing side was easily accessible. Previously some limited infrared observations were possible of the nighttime weather, but these were too limited to paint a clear picture of the overall weather on Venus.

Enter the Venus Climate Orbiter Akatsuki. Launched in 2010, it is the first Japanese probe to orbit another planet. Its mission is to observe Venus and its weather system using a variety of onboard instruments. Akatsuki carried an infrared imager which does not rely on illumination from the sun to see. However, even this cannot directly resolve details on the nightside of Venus, but it did give researchers the data they needed to see things indirectly.

“Small-scale cloud patterns in the direct images are faint and frequently indistinguishable from background noise,” said Professor Takeshi Imamura from the Graduate School of Frontier Sciences at the University of Tokyo. “To see details, we needed to supress the noise. In astronomy and planetary science, it is common to combine images to do this, as real features within a stack of similar images quickly hide the noise. However, Venus is a special case as the entire weather system rotates very quickly, so we had to compensate for this movement, known as super-rotation, in order to highlight interesting formations for study. Graduate student Kiichi Fukuya, developed a technique to overcome this difficulty.”

A scrolling amorphous orange and purple shape
Clouds on Venus. Data from the Venus orbiter Akatsuki showing the thermal signatures of clouds on the nightside of the planet for the first time. © 2021 Imamura et al.

Super-rotation is one significant meteorological phenomenon that, thankfully, we do not get down here on Earth. It is the ferocious east-west circulation of the entire weather system around the equator of the planet, and it dwarfs any extreme winds we might experience at home. Imamura and his team explore mechanisms that sustain this super-rotation and believe that characteristics of Venusian weather at night might help explain it.

“We are finally able to observe the north-south winds, known as meridional circulation, at night. What’s surprising is these run in the opposite direction to their daytime counterparts,” said Imamura. “Such a dramatic change cannot occur without significant consequences. This observation could help us build more accurate models of the Venusian weather system which will hopefully resolve some long-standing, unanswered questions about Venusian weather and probably Earth weather too.”

U.S. space agency NASA recently announced two new missions to explore Venus with probes named DaVinci+ and Veritas, and the European Space Agency also announced a new Venus mission named EnVision. Combined with the observational capacity of Akatsuki, Imamura and his team hope they will soon be able to explore the Venusian climate not just in its present form but also over its geological history.

Featured image: Weather on Venus. The three main weather patterns on Venus. Researchers think the dayside poleward circulation and newly discovered nightside equatorial circulation may fuel the planetwide super-rotation that dominates the surface of Venus. © 2021 JAXA/Imamura et al.


Papers

Kiichi Fukuya, Takeshi Imamura, Makoto Taguchi, Tetsuya Fukuhara, Toru Kouyama, Takeshi Horinouchi, Javier Peralta, Masahiko Futaguchi, Takeru Yamada, Takao M. Sato, Atsushi Yamazaki, Shin‐ya Murakami, Takehiko Satoh, Masahiro Takagi, Masato Nakamura, “Unveiling of nightside cloud-top circulation of Venus atmosphere,” Nature: July 22, 2021, doi:10.1038/s41586-021-03636-7.
Link (Publication)


Provided by University of Tokyo

New Research Suggests Explosive Volcanic Activity On Venus (Planetary Science)

Traces of the gas phosphine point to volcanic activity on Venus, according to new research from Cornell University.

Last autumn, scientists revealed that phosphine was found in trace amounts in the planet’s upper atmosphere. That discovery promised the slim possibility that phosphine serves as a biological signature for the hot, toxic planet.

Now Cornell scientists say the chemical fingerprint support a different and important scientific find: a geological signature, showing evidence of explosive volcanoes on the mysterious planet.

“The phosphine is not telling us about the biology of Venus,” said Jonathan Lunine, professor of physical sciences and chair of the astronomy department at Cornell. “It’s telling us about the geology. Science is pointing to a planet that has active explosive volcanism today or in the very recent past.”

Lunine and Ngoc Truong, a doctoral candidate in geology, authored the study, “Volcanically Extruded Phosphides as an Abiotic Source of Venusian Phosphine,” published July 12 in the Proceedings of the National Academy of Sciences.

Truong and Lunine argue that volcanism is the means for phosphine to get into Venus’ upper atmosphere, after examining observations from the ground-based, submillimeter-wavelength James Clerk Maxwell Telescope atop Mauna Kea in Hawaii, and the Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile.

If Venus has phosphide – a form of phosphorous present in the planet’s deep mantle – and, if it is brought to the surface in an explosive, volcanic way and then injected into the atmosphere, those phosphides react with the Venusian atmosphere’s sulfuric acid to form phosphine, Truong said.

Lunine said their phosphine model “suggests explosive volcanism occurring,” while “radar images from the Magellan spacecraft in the 1990s show some geologic features could support this.”

In 1978, on NASA’s Pioneer Venus orbiter mission, scientists uncovered variations of sulfur dioxide in Venus’ upper atmosphere, hinting at the prospect of explosive volcanism, Truong said, similar to the scale of Earth’s Krakatoa volcanic eruption in Indonesia in 1883.

But, Truong said, “confirming explosive volcanism on Venus through the gas phosphine was totally unexpected.”

Funding for the research was provided by the NASA Goddard Space Flight Center in Greenbelt, Maryland.


Reference: N. Truong and J. I. Lunine, “Volcanically extruded phosphides as an abiotic source of Venusian phosphine”, PNAS July 20, 2021 118 (29) e2021689118; https://doi.org/10.1073/pnas.2021689118


Provided by Cornell University

Life Could Exist in the Clouds of Jupiter But Not Venus (Planetary Science)

Jupiter’s clouds have water conditions that would allow Earth-like life to exist, but this isn’t possible in Venus’ clouds, according to the groundbreaking finding of new research led by a Queen’s University Belfast scientist with participation of the University of Bonn. The study has been published in the journal Nature Astronomy.

For some decades, space exploration missions have looked for evidence of life beyond Earth where we know that large bodies of water, such as lakes or oceans, exist or have previously existed. However, the new research shows that it isn’t the quantity of water that matters for making life viable, but the effective concentration of water molecules – known as ‘water activity’.

The new study also found that research published by an independent team of scientists last year, claiming that the phosphine gas in Venus’ atmosphere indicates possible life in the sulphuric acid clouds of Venus, is not plausible.

Through this innovative research project, Dr John E. Hallsworth from the School of Biological Sciences at Queen’s and his team of international collaborators devised a method to determine the water activity of atmospheres of a planet. Using their approach to study the sulphuric acid clouds of Venus, the researchers found that the water activity was more than a hundred times below the lower limit at which life can exist on Earth.

Dr Hallsworth comments: “Our research shows that the sulphuric acid clouds in Venus have too little water for active life to exist, based on what we know of life on Earth. We have also found that the conditions of water and temperature within Jupiter’s clouds could allow microbial-type life to subsist, assuming that other requirements such as nutrients are present.”

Co-author of the report, an expert on physics and chemical biology of water, Dr Philip Ball, says: “The search for extraterrestrial life has sometimes been a bit simplistic in its attitude to water. As our work shows, it’s not enough to say that liquid water equates with habitability. We’ve got to think too about how Earth-like organisms actually use it – which shows us that we then have to ask how much of the water is actually available for those biological uses.” 

A plant scientist in extraterrestrial spheres

Dr Jürgen Burkhardt of the Institute of Crop Science and Resource Conservation (INRES), a member of the Phenorob Cluster of Excellence and the Transdisciplinary Research Area “Innovation and Technology for Sustainable Futures” at the University of Bonn, contributed to this study primarily by making calculations of water activity and sulphuric acid concentration in the cloud droplets of the Venusian atmosphere. The fact that a scientist researching plant nutrition is contributing to Life in the Venus Atmosphere is due to Dr Burkhardt’s earlier work. He had previously used the aerosol model used in the study to characterize the state of deposited hygroscopic aerosols on leaf surfaces.

Dr. Jürgen Burkhardt – from the Institute of Crop Science and Resource Conservation (INRES) at the University of Bonn.© Photo: Maximilian Meyer

“These aerosols allow microorganisms to survive under certain conditions,” Burkhardt says. A shared interest in this habitat and its very specific physicochemical conditions, such as high acid concentrations and minimal amounts of water, led to contact years ago with the study’s first author, John Hallsworth. Experimental electron microscopy studies by Hallsworth and Burkhardt on this topic had already resulted in two earlier joint publications that also addressed the question of extraterrestrial life.

Participating institutions and funding:

Co-authors of this paper include planetary scientist Christopher P. McKay (NASA Ames Research Center, CA, USA); atmosphere chemistry expert Thomas Koop (Bielefeld University, Germany); expert on physics and chemical biology of water Philip Ball (London, UK); biomolecular scientist Tiffany D. Dallas (Queen’s University Belfast); biophysics-of-lipid-membrane expert Marcus K. Dymond (University of Brighton, UK); theoretical physicist María-Paz Zorzano (Centro de Astrobiologia [CSIC-INTA], Spain); micrometeorology and aerosol expert Juergen Burkhardt (University of Bonn, Germany); expert on acid-tolerant microorganisms Olga V. Golyshina (Bangor University, UK); and atmospheric physicist and planetary scientist Javier Martín-Torres (University of Aberdeen, UK).

The research was funded by Research Councils UK (RCUK) | Biotechnology and Biological Sciences Research Council (BBSRC) and Ministry of Science and Innovation.

Featured image: Thunderclouds on Jupiter – based on images from the Juno mission’s Stellar Reference Unit camera (NASA).© NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Heidi N. Becker/Koji Kuramura


Publication: John E. Hallsworth et al.: Water activity in Venus’s uninhabitable clouds and other planetary atmospheres, Nature Astronomy, DOI: 10.1038/s41550-021-01391-3


Provided by University of Bonn

Venus and Mars, Two Neighboring Planets (Planetary Science)

A rather tight conjunction between the planets Venus and Mars is expected in the July evening sky. The tips for observing it, along with the constellations, planets and conjunctions visible this month

A July in the sign of Venus and Mars. The two planets, visible from the beginning of the month after sunset, towards the west, will gradually approach, day after day, until the evening of the 13th , when they will reach the minimum distance between them and will therefore be in conjunction. The two planets will be quite close in the sky, as much as the apparent diameter of the moon. However, the approach will be simply due to a perspective effect: on that day Venus will be 213 million kilometers from Earth, while Mars at 372, so the two planets will be almost 160 million kilometers from each other! Apart from astronomical distances, observing the conjunction of Venus and Mars will be truly spectacular, even if only with the naked eye or with binoculars, provided you have an obstacle-free horizon. The two planets, when they appear in the twilight, will be quite low on the horizon, with Venus being much brighter than Mars. And if you really can’t observe the conjunction of 13, don’t lose heart: the two planets will still be pretty close for practically the whole month!

But the July evening sky has much more to offer us. To discover the constellations, the planets and the main astronomical events visible this month you can follow the usual video below that we have prepared for you:

Featured image: Venus and Mars as they will appear on the evening of July 13, on the occasion of their conjunction. Credits: M. Galliani / Stellarium


Provided by INAF

Crustal Block Tectonics Offer Clues to Venus’ Geology, Study Finds (Planetary Science)

New study that includes contributions by Baylor planetary geophysicist Peter James, identifies previously unrecognized pattern of tectonic deformation on Venus

A new analysis of Venus’ surface shows evidence of tectonic motion in the form of crustal blocks that have jostled against each other like broken chunks of pack ice. Published in the PNAS (Proceedings of the National Academy of Sciences), the study — which includes contributions by Baylor University planetary physicist Peter James, Ph.D. — found that the movement of these blocks could indicate that Venus is still geologically active and give scientists insight into both exoplanet tectonics and the earliest tectonic activity on Earth.

“We have identified a previously unrecognized pattern of tectonic deformation on Venus, one that is driven by interior motion just like on Earth,” said Paul Byrne, Ph.D., associate professor of planetary science at North Carolina State University and lead and co-corresponding author of the work. “Although different from the tectonics we currently see on Earth, it is still evidence of interior motion being expressed at the planet’s surface.”

Venus had long been assumed to have an immobile solid outer shell, or lithosphere, just like Mars or Earth’s moon. In contrast, Earth’s lithosphere is broken into tectonic plates, which slide against, apart from, and underneath each other on top of a hot, weaker mantle layer.

James, an assistant professor of planetary geophysics and founder of Baylor University’s Planetary Research Group, was part of the international group of researchers involved with the study. He has taken part in three NASA missions and specializes in using spacecraft data to study the crusts and mantles of planets and moons.

“Earth is the only planet in the solar system with plate tectonics, so our planet is quite exceptional in that regard,” James said. “That is particularly interesting when it comes to Venus: Why does a planet like Venus — roughly the same size as Earth and made of the same types of rocks — not behave the same way as Earth geologically?”

Baylor University planetary physicist Peter James, Ph.D., provided calculations of the various mechanisms that could be responsible for the force driving the geologic activity on Venus. (Robert Rogers/Baylor University)

To answer that question, the team used radar images from NASA’s Magellan mission to map the surface of Venus. In examining the extensive Venusian lowlands that make up most of the planet surface, they saw areas where large blocks of the lithosphere seem to have moved: pulling apart, pushing together, rotating and sliding past each other like broken pack ice over a frozen lake.

James provided calculations of the various mechanisms that could be responsible for the force driving the geologic activity on Venus. NASA’s Magellan spacecraft measured the gravity field of Venus — the subtle changes in the strength of gravity in different places on the planet. James was able to use this gravity field to demonstrate that viscous mantle flow, or slow churning, is strongly coupled to the crust.

“The mantle inside Venus pushes and pulls on the surface of the planet more strongly than Earth’s mantle does. These calculations of the driving forces corroborated the discovery of block motion and helped us have a better understanding of how it works,” James said.

The interior mantle flow found by the study’s calculations is significant because it hasn’t been demonstrated on a global scale previously. The movement of these crustal blocks could also indicate that Venus is still geologically active.

“We know that much of Venus has been volcanically resurfaced over time, so some parts of the planet might be really young, geologically speaking,” Byrne said. “But several of the jostling blocks have formed in and deformed these young lava plains, which means that the lithosphere fragmented after those plains were laid down. This gives us reason to think that some of these blocks may have moved geologically very recently – perhaps even up to today.”

The researchers are optimistic that Venus’ newly recognized “pack ice” pattern could offer clues to understanding tectonic deformation on planets outside of our solar system, as well as on a much younger Earth.

“One of the neat things about planet research like this is that it helps us understand why our own planet works the way it does,” James said. “The theme of our Planetary Research Group at Baylor is a quote from C.S. Lewis’s Mere Christianity: ‘Aim at heaven and you will get Earth thrown in.’ That quote is intended in a spiritual context — we should seek the kingdom of God before all else, and then this kingdom-mindset can even bear fruit in a secular sense. We like the double meaning of using space research to understand our own planet better.”

Science related to Venus is especially timely — NASA recently announced that it would be sending two new spacecrafts to Venus, VERITAS and DAVINCI+. These will be the first NASA missions launched to Venus since the 1980s. Additionally, the European Space Agency announced last week that it would be sending its own spacecraft called Envision to Venus.

“Strategically, this research is positioning Baylor to be involved with upcoming spacecraft missions. Venus is becoming a bigger priority for space agencies around the world, and we’re plugged in to the exciting science opportunities that are on the horizon,” James said.

Baylor will continue to be part of Venus research through James’ lab. Rudger Dame, a Ph.D. candidate in James’ lab, is focusing on Venus for his dissertation research. He has an internship this summer with the NASA Jet Propulsion Laboratory, under the advisement of Sue Smrekar, the principal investigator for the recently announced VERITAS spacecraft.

In addition, James is collaborating with NASA’s Goddard Space Flight Center to study the planet Mercury’s crust. He also led a recent study published in the journal Geophysical Research Letters about the discovery of a mysterious huge mass of material on the far side of the Moon — beneath the largest crater in our solar system. The mass — at least five times larger than the Big Island of Hawaii — may contain metal from an asteroid that may have crashed into the Moon and formed the crater.

The South Pole-Aitken basin — thought to have been created about 4 billion years ago — is “one of the best natural laboratories for studying catastrophic impact events, an ancient process that shaped all of the rocky planets and moons we see today.”

*Sean Solomon of Columbia University is co-corresponding author. Richard Ghail of the University of London, Surrey; A. M. Celâl Şengör of Istanbul Technical University; and Christian Klimczak of the University of Georgia also contributed to the work.

Featured image: Study identifies previously unrecognized pattern of tectonic deformation on Venus. © Baylor University


Reference: Paul K. Byrne, Richard C. Ghail, A. M. Celâl Şengör, Peter B. James, Christian Klimczak, Sean C. Solomon, “A globally fragmented and mobile lithosphere on Venus”, Proceedings of the National Academy of Sciences Jun 2021, 118 (26) e2025919118; https://doi.org/10.1073/pnas.2025919118


Provided by Baylor University

Green light for European Space Agency mission to Venus (Astronomy)

With the EnVision mission, Europe flies to discover the Earth’s twin planet. On board the probe, an Italian instrument that sees the involvement of the Italian Space Agency and the responsibility of the University of Trento

Oxford University scientists will play a leading role in a new mission to study the geology and atmosphere of Venus, our neighbouring planet, helping determine whether it was once habitable – and why Earth became the only known planet that can sustain life.

Researchers from the University of Oxford, Royal Holloway, University of London and Imperial College London will make key contributions to the mission, called EnVision, which has been selected as the fifth Medium Class mission in the European Space Agency’s (ESA) Cosmic Vision programme. With ESA mission costs of €610 million, EnVision aims to investigate Venus by researching past and present volcanic activity and tracking the key volcanic gases that sustain its clouds and hostile environment.

Understanding the evolution of Venus

Working with European and American scientists, the UK team will compare geologic and atmospheric processes to those on Earth and other planets and aim to discover more about how interactions between its interior, surface and atmosphere have shaped its evolution.

Venus is the most Earth-like planet in size, composition and distance to our Sun.  When they initially formed, Earth and Venus were probably once quite similar, with oceans of molten rock and thick atmospheres of carbon dioxide and steam. But Earth evolved to become the habitable planet we enjoy today; Venus may or may not have had a habitable phase with liquid water oceans before developing a runaway greenhouse effect which today cooks its surface to an inhospitable 450 degrees Centigrade. The EnVision mission has been designed to study how geological activity throughout time has driven the evolution of Venus’ climate and habitability.

Exciting scientific insights

I have been working towards getting ESA to choose a Venus mission for over 15 years now, including balloons, probes and landers and we have been developing this orbiter proposal since 2009

Dr Colin Wilson, Senior Research Fellow at Oxford’s Department of Physics and a Deputy Lead Scientist of the mission comments: ‘It is great news that we will be getting back to Venus. The selection of this mission, along with the two Venus missions seelcted by NASA last week, shows the widespread recognition of how important Venus is in understanding how Earthlike planets evolve to be the way they are.

‘I have been working towards getting ESA to choose a Venus mission for over 15 years now, including balloons, probes and landers and we have been developing this orbiter proposal since 2009. Today’s announcement comes as a great reward for the huge efforts put in over this time by the whole team of scientists and engineers who have brought us this far. The real work lies ahead of us, of course, in getting the mission realised and to the launchpad; I’m then really looking forward the exciting scientific insights it will yield!

The real work lies ahead of us, of course, in getting the mission realised and to the launchpad; I’m then really looking forward the exciting scientific insights it will yield!

‘Oxford has a long history in Venus exploration: Professor Fred Taylor led an instrument which went to Venus in 1978, and was one of the proposers of ESA’s Venus Express mission which orbited Venus from 2006-2014. It is fantastic to be able to carry on this legacy. This Venus mission is relevant to a wide range of planetary research being carried out across the University from terrestrial exoplanet research in the Department of Physics to planetary formation and interior research at the Department of Earth Sciences.’

The EnVision orbiter is expected to launch in 2031-2032. It will take 15 months to reach Venus, where it will take a further 16 months of aerobraking to get into its low circular orbit. Once this stage is achieved, the satellite will start its 4-year scientific study.

For more information, visit www.envisionvenus.eu

Featured image: EnVision: Understanding why Earth’s closest neighbor is so different – Copyright: NASA / JAXA / ISAS / DARTS / Damia Bouic / VR2Planets


To know more:


Provided by University of Oxford

With Veritas, Italy Returns to Venus (Astronomy)

NASA announces the launch of two missions to Venus: Davinci + and Veritas. The Italian Space Agency also participates in the latter, which will have the objective of revealing the internal functioning of the planet, and among the members of the scientific team is Gaetano Di Achille, researcher at the National Institute of Astrophysics in Teramo

Italy also flies to Venus. By 2030, NASA’s Veritas (Venus Emissivity, Radio Science, InSar, Topography, and Spectroscopy) mission will set out for Venus to uncover the inner workings of Earth’s mysterious twin planet.

The announcement was released by NASA President Bill Nelson , who also announced the launch of a second mission, called Davinci + , which will start as Veritas with Venus target. Both are part of NASA’s Discovery Program and are managed by the Jet Propulsion Laboratory, in California.

Italy participates in the Veritas mission through a partnership collaboration between the Italian Space Agency and Jet Propulsion Laboratory, which has assigned to our country the responsibility for the development and construction of three on-board instruments: the Idst transponder  (Integrated Deep Space Transponder) , necessary to ensure communications and to perform radio science experiments useful for understanding the gravity of the planet, the radiofrequency part of the Visar  (Venus Interferometric Synthetic Aperture Radar), useful for studying the morphology of the planet and the phenomena of volcanism, and ‘ antenna Hga (High-Gain Antenna).

“Since Veritas”, says Barbara Negri , head of the Italian Space Agency of the Human Flight and Scientific Experimentation Unit, “will investigate the geological history of the planet closest to Earth, mapping its surface to study processes such as tectonics o volcanism, and given the Italian contribution described above, we can say with certainty that Italy will contribute in a determined way to the main scientific themes of the mission, without neglecting the technological contribution of the parts of our responsibility that have been identified thanks to the experience gained on other collaborations with Jpl such as Cassini and Juno ».

“This will be a unique opportunity to study the geological activity of the planet and verify if Venus is currently active”, comments Gaetano Di Achille , researcher at the National Institute of Astrophysics in Teramo, co-investigator of the mission and expert in planetary geology. . “The instrumentation on board will allow us to have an unprecedented vision of the planet and its variations that have occurred since the visit of the latest missions, Magellan of NASA and Venus Express of ESA”.

The mission could also provide new data on the evolution of our planet, helping us better understand the rocky planets orbiting other stars.

Featured image: Artist’s impression of active volcanoes on Venus, depicting a subduction zone in which the crust in the foreground plunges into the interior of the planet. Credits: Nasa / Jpl-Caltech / Peter Rubin


For more:

https://www.nasa.gov/press-release/nasa-selects-2-missions-to-study-lost-habitable-world-of-venus


Provided by INAF