The expectations for life on Venus have gotten a little more possible in the past couple of years or so. In 2018, researchers put out a study that the atmosphere might just be favorable enough for microbial life. Later, in 2020, scientists found that phosphine, a gas associated with living organisms, could exist in the planet’s clouds. Now, a group of scientists is finding other ways that life could possibly exist in those clouds.
Researchers from the Massachusetts Institute of Technology, Cardiff University and Cambridge University have detected a chemical pathway by which life could counteract the planet’s acidic world to create a self-sustaining, habitable pocket in the atmosphere.
The temperature on the surface of the second planet from the Sun generally hovers around 847 degrees Fahrenheit (453 degrees Celsius), enough to melt lead. It has 167 volcanos that are over 60 miles (100 km) across. Sulfur dioxide and carbon dioxide levels are through the roof. The planet’s clouds blanket the planet in droplets of sulfuric acid caustic enough to burn a hole through human skin. Every lander sent to Venus has lasted minutes at most before melting or getting crushed by the harsh environment (and more probes are on their way). So, forgive one if they believe life as we know it might be hard to come by.
However, despite all of this, researchers have long been hopeful. This enthusiasm has especially been buoyed by puzzling anomalies with the planet’s atmosphere, like ammonia and small concentrations of oxygen and nonspherical particles, called Mode 3 particles, unlike sulfuric acid’s round droplets. By all accounts, ammonia, which was first detected in the 1970s, shouldn’t even be there since it isn’t thought to be produced through any chemical process known on Venus. So what gives?
The scientists attempted to find the answer by modeling a set of chemical processes to show that if ammonia is indeed present, the gas would set off a torrent of chemical reactions that would neutralize adjacent droplets of sulfuric acid and could also explain most of the variances observed in the planet’s clouds. As for the cause of ammonia itself, the authors recommend that the most likely justification is of biological origin, rather than a nonbiological source such as lightning or volcanic eruptions.
Essentially, life could be making its own environment.
“No life that we know of could survive in the Venus droplets,” says study co-author Sara Seager, Professor of Planetary Sciences in MIT’s Department of Earth, Atmospheric and Planetary Sciences. Seager was also an author in the 2020 Venusian phosphine study. “But the point is, maybe some life is there, and is modifying its environment so that it is livable.”
The team discovered that if life were generating ammonia in the most effective way possible, the correlated chemical reactions would naturally produce oxygen. Once present in the clouds, ammonia would dissolve in beads of sulfuric acid, essentially neutralizing the acid to make the droplets relatively habitable. Introducing ammonia into the droplets would alter their formerly round, liquid shape into more of a nonspherical, salt-like slurry. Once ammonia is dissolved in sulfuric acid, the response would trigger any neighboring sulfur dioxide to dissolve as well.
The existence of ammonia then could indeed account for most of the major anomalies seen in Venus’ clouds. The authors go further and explain that sources such as lightning, volcanic eruptions, and even a meteorite strike could not chemically generate the amount of ammonia required to explain the anomalies.
A new study modeled the conditions on the early days of Venus and found little that would be suitable to life as we know it.
Venus is as hellish a planet as you can imagine, but it wasn’t always considered that way. In fact, our understanding of Venus (at least concerning its potential for hosting life) has been pretty topsy-turvy. For most of our astronomical history, Venus was thought to be capable of hosting life. Ancient cultures ascribed the planet mythological value, linking it to the likes of Lucifer or the Greek goddess Aphrodite. In the 17th century, Galileo Galilei observed the planet and found that it had phases like the Moon, and in the 18th century, the atmosphere of Venus was discovered by Russian polymath Mikhail Lomonosov.
From that point on, Venus was considered a sort of ‘twin’ to Earth — which seems to make sense. After all, it’s a rocky planet, comparable in size to Earth, it has an atmosphere, so it should have life-harboring potential too, right? Well, not really.
In the 1960s, more detailed observations showed that Venus is a hellish place, the hottest planet in the solar system. Oh, and its atmosphere? It’s mostly carbon dioxide (which causes an extreme greenhouse effect), with clouds composed of sulfuric acid. So all in all, Venus is still a hellish landscape, with its environment better suited for killing than for hosting life.
But in recent years, model studies have suggested that Venus may have not always been this inhospitable, and in its early days, may have even hosted oceans of liquid water. But was this really the case?
Hot and cold and hot again
When all planets form, they’re initially very hot, but previous models suggested that Venus may have cooled down enough to host liquid water, with the planet’s clouds bouncing the sun’s radiation back into space.
But this study comes with a different conclusion: according to a new model that simulated the Venusian atmosphere in these early days, Venus could have never hosted liquid water.
“We simulated the climate of the Earth and Venus at the very beginning of their evolution, more than four billion years ago, when the surface of the planets was still molten”, explains Martin Turbet, one of the study authors. “The associated high temperatures meant that any water would have been present in the form of steam, as in a gigantic pressure cooker.”
The main difference from previous model findings is that the temperature never got low enough for water vapor to form raindrops and accumulate on the surface. The cause boils back to the clouds: this new model also suggests that clouds formed, but they predominantly formed on the night side of the planet, creating a powerful greenhouse event that prevented Venus from cooling as quickly as previously thought, Turbet explains.
According to the same model, the Earth was very close to suffering the same fate and turning into a permanent hothouse planet. The key that allowed water to accumulate on our planet is the so-called “faint Sun” — in the early days of the solar system, the sun was just 70% as luminous as it is now. Had it been a bit more luminous (just 92% of what it is today), our planet could have turned into a hothouse Venus-type planet.
The study could also help solve the so-called “Faint young sun paradox”. Basically, the argument was that because the sun was fainter than it is today, our planet should have turned to ice. Instead, judging by the findings in this study (and the greenhouse effect caused by the clouds on Earth), the faint sun turned out to be a boon, helping keep the temperature balance in a range that was favorable to liquid water.
“It turns out that for the young, very hot Earth, this weak Sun may have in fact been an unhoped-for opportunity”, says Emeline Bolmont, professor at UNIGE, member of PlaneS and co-author of the study.
Of course, whether or not the model incorporates all the relevant data or some elements still escape it remains to be confirmed. However, this doesn’t bode too well for Venus’ chances of habitability — present or past.
“If the authors are correct, Venus was always a hellhole,” astronomers James Kasting and Chester Harman, of Penn State University and NASA’s Ames Research Center, respectively, wrote in an accompanying “News & Views” piece in the same issue of Nature.
What once seemed like an unlikely but enticing possibility has been all but ruled out. An international group of researchers found that the amount of water in the atmosphere of Venus is so low that even the most drought-tolerant microbes of the Earth wouldn’t be able to survive in those conditions. Essentially, life as we know it just couldn’t exist in these clouds.
The finding dismissed a study published late last year that had theorized microbes could be living in there.
The findings will come as a disappointment to some who have been following the news. Optimistic after the discovery of phosphine, a compound made of atoms of phosphorus and hydrogen that on Earth can be associated with living organisms, in Venus’ atmosphere, researchers had suggested phosphine may be produced by microorganisms living in those clouds. That doesn’t seem to be the case.
In the new study, researchers looked at measurements from probes that flew through the atmosphere of the planet and collected data about temperature, humidity, and pressure in the clouds. From these values, they calculated the so-called water activity – which is the water vapor pressure inside the individual molecules in the clouds.
“We found not only is the effective concentration of water molecules slightly below what’s needed for the most resilient microorganism on Earth, it’s more than 100 times too low. It’s almost at the bottom of the scale, and an unbridgeable distance from what life requires to be active,” John Hallsworth, co-author, told BBC News.
On Earth, microorganisms can survive and proliferate in droplets of water in the atmosphere when temperatures allow. However, the findings of this new study leave virtually a zero chance of anything living in the clouds of Venus. Without being hydrated, living systems including microorganisms can’t be active and proliferate, Hallsworth said.
Previous studies on microorganisms living in extreme conditions on Earth found that life can exist at temperatures as cold as minus 40ºC (minus 40 degrees Fahrenheit). For water activity, measured from 0 to 1, the lowest survivable value is 0.585. The water activity level found in the molecules in the Venusian clouds was a very low 0.004.
NASA astrobiologist Chris McKay, one of the co-authors of the paper, said in a news conference that the findings of the study were conclusive. “It’s not a model, it’s not an assumption,” she said. For McKay, the fleet of space missions currently being prepared for Venus won’t change anything about the hope for life on Earth’s closest neighbor.
In the study, the researchers also analyzed data from other planets too and found that the clouds of Jupiter provide sufficient water activity to theoretically support life. Water activity value sits at 0.585, which is above the threshold, while temperatures are also just about survivable, at around 40 degrees Fahrenheit, according to data from the Galileo probe.
McKay said there’s “at least” a layer in the clouds of Jupiter where the water requirements aren’t met. Still, high levels of ultraviolet radiation or lack of nutrients, could prevent potential life from thriving, she added. Completely new measurements will be necessary in the future to find out whether life could thrive there or not.
NASA’s new administrator, Bill Nelson, has announced that the agency is going back to Venus. Their goal — to understand how Venus turned from a mild Earth-like planet to a boiling, scorching, acid hellscape.
Two new robotic missions will be visiting Venus, according to Bill Nelson’s first major address to employees, on Wednesday. Machines will carry them out for us, as Venus is the hottest planet in the solar system. The goal of both will be to better understand the history of the planet, and how Venus came to be what it is today.
Knowing our neighbors
“These two sister missions both aim to understand how Venus became an inferno-like world capable of melting lead at the surface,” Nelson said.
The two missions will be named DaVinci+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) and Veritas (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy). The first will see a ‘small craft’ plunging through Venus’ atmosphere, taking measurements of its physical and chemical properties, while also analyzing the make-up of its clouds. The second will attempt to map out Venus’ surface in a bid to understand its geologic history.
These will be the first missions to Venus that NASA has attempted in over three decades. The last — mission Magellan — reached the planet in 1990.
Both upcoming missions will help us get a better understanding of Venus, from its atmosphere down to the core, NASA scientist Tom Wagner explained.
“It is astounding how little we know about Venus,” he said. “It will be as if we have rediscovered the planet.”
We don’t yet have an exact launch date for these missions, but they’ll both likely take off sometime between 2028 and 2030. Each will receive around $500 million in funding for development (under NASA’s Discovery program). Sadly, although we are going back to Venus, two other proposed missions — to Jupiter’s moon Io and Neptune’s icy moon Triton — didn’t make the cut.
When not looking at the Sun, the Parker probe is focusing on comets. On 2019 September 2, it observed the comet 322P/SOHO in its closest approach to the sun. The spacecraft detected the dust particles being ejected through 322P’s tail. In 2020, a more interesting image showed the NEOWISE comet with its double tail — the brightest comet in the northern hemisphere since. The astonishing photo of NEOWISE depicted above was made with Wide-Field Imager the instrument aboard the Solar Probe (WISPR), designed to provide images of the corona and inner heliosphere in visible light.
This time, WISPR brought us an incredible view of Venus. Parker Solar Probe is tightly intertwined with Venus, as the planet sustains the spacecraft’s orbit, and sometimes there is a good opportunity for a flyby. Scientists didn’t lose the opportunity of photographing the planet and the result was a stunning image of the Venusian surface.
The shot was taken when the spacecraft was 12,380.68 km (7,693 miles). What grabs attention first is the aura-like around the planet which makes the dark sky a little brighter. Scientists believe it is like Earth’s airglow, an emission of light caused by particles in the atmosphere. This is notoriously difficult to overcome in astronomy photography.
If you take a closer look, you will notice a darker region on the surface of the planet. This is the Aphrodite Terra, a highland area roughly as big as the African continent. It seems darker because it is cooler than the surroundings. Aphrodite Terra also features some large mountains and lava flows, which you can’t really see in this photo.
It is however possible to see streaks all around the surface, although scientists are not sure yet what they mean. There are many possibilities, they could be cosmic rays, dust reflected by sunlight or even ejected by the spacecraft itself.
The team had already taken a similar shot with the latest flyby on 2021 February 20, This time they decided to observe in the near-infrared as well. This wavelength is the one used in remote controls of your TV. It is not absorbed by dust, so will be able to see a clear image of the surface of the planet. The results will be received by the end of April, so fingers crossed for more surprising announcements from Venus.
Enthusiasm over a Venusian compound associated with life has been quenched by a new study. It’s probably just sulfur dioxide, researchers now believe.
Phosphine is a colorless, flammable, toxic gas compound — not something you’d be thrilled to see in most cases. But back in September, researchers got really excited about phosphine because it detected in the atmosphere of Venus.
For all its toxicity, phosphine can be produced by life. Finding phosphine on the hellish Venus suggests that life could perhaps exist on Venus, which understandably made a lot of astronomers very curious.
But right from the get-go, some were skeptical about the study. Just one month later, another group of researchers tried to find the phosphine themselves (using telescopes), but couldn’t. Two other groups reprocessed the same data used in the first study and also couldn’t find evidence for phosphine.
“The authors have informed the editors of Nature Astronomy about an error in the original processing of the ALMA Observatory data underlying the work in this Article, and that recalibration of the data has had an impact on the conclusions that can be drawn. Nature Astronomy is working with the authors to resolve the matter.”
“Instead of phosphine in the clouds of Venus, the data are consistent with an alternative hypothesis: They were detecting sulfur dioxide,” said co-author Victoria Meadows, a UW professor of astronomy. “Sulfur dioxide is the third-most-common chemical compound in Venus’ atmosphere, and it is not considered a sign of life.”
Instead of looking for the phosphine in the telescope data, Meadows and colleagues tried a different approach: they created models of what could be observed on Venus. They found that sulfur dioxide can not only explain the observations, but is also consistent with what we already know of Venus.
The initial phosphine study used the Atacama Large Millimeter/submillimeter Array (ALMA) and the James Clerk Maxwell Telescope (JCMT) to make the observations, focusing on the 266.94 gigahertz frequency. Both phosphine and sulfur dioxide absorb radio waves close to this frequency. So what researchers observed could have been sulfur dioxide. The new study modelled how the signals would be picked up by the JCMT and ALMA telescopes.
“This is what’s known as a radiative transfer model, and it incorporates data from several decades’ worth of observations of Venus from multiple sources, including observatories here on Earth and spacecraft missions like Venus Express,” said lead author Andrew Lincowski, a researcher with the UW Department of Astronomy.
There’s another reason why the previous observations are very unlikely to be phosphine, researchers say: the initial signal was found not in the planet’s cloud layer, but far above it, where phosphine would likely be destroyed within seconds, but sulfur dioxide would be more stable.
“Phosphine in the mesosphere is even more fragile than phosphine in Venus’ clouds,” said Meadows. “If the JCMT signal were from phosphine in the mesosphere, then to account for the strength of the signal and the compound’s sub-second lifetime at that altitude, phosphine would have to be delivered to the mesosphere at about 100 times the rate that oxygen is pumped into Earth’s atmosphere by photosynthesis.”
The team also found that the ALMA antenna configuration had an unfortunate side effect: signals from gases like sulfur dioxide give off weaker signals than gases distributed over a smaller scale.
“They inferred a low detection of sulfur dioxide because of that artificially weak signal from ALMA,” said Lincowski. “But our modeling suggests that the line-diluted ALMA data would have still been consistent with typical or even large amounts of Venus sulfur dioxide, which could fully explain the observed JCMT signal.”
“When this new discovery was announced, the reported low sulfur dioxide abundance was at odds with what we already know about Venus and its clouds,” said Meadows. “Our new work provides a complete framework that shows how typical amounts of sulfur dioxide in the Venus mesosphere can explain both the signal detections, and non-detections, in the JCMT and ALMA data, without the need for phosphine.”
So where does this leave us? We know that Earth’s atmosphere contains small amounts of phosphine, and life may produce phosphine. At this point, it seems more likely that previous observations aren’t of phosphine. But venus also remains as mysterious and ever — with a toxic atmosphere, acidic clouds, and scorching hot temperatures, it’s not the place where you’d expect any life form to exist. Then again, we can’t say that for sure, either.
Scientists have known for some time that the surface of Venus is dotted with volcanic features. However, due to the planet’s hazy atmosphere, it has always been uncertain whether Venus is still volcanically active — until now.
New compelling evidence suggests that Venus is volcanically active. This would make it only the second such planet that we know of, besides Earth.
In the early 1990s, NASA’s Magellan spacecraft beamed back radar images showing extensive lave flows. Subsequent studies and missions, such as ESA’s Venus Express orbiter, measured infrared light released by the planet’s surface at night to determine the age of the lava flows. Although the data was good enough for scientists to carry relative measurements between older and newer lava flows, their age couldn’t be accurately assessed.
Some have speculated from the data that Venus may have been volcanically active as recent as 2.5 million years ago — which is the blink of an eye in geologic time. But new evidence presented in a study led by Dr. Justin Filiberto, a researcher at the Lunar Planetary Institute in Houston, Texas, may mean that Venus may be volcanically active even now.
Researchers simulated Venus’ very dense atmosphere in the lab to assess its influence on lava flows over time. To their surprise, they found that olivine, a mineral that is abundant in some basaltic rocks (covering 90% of Venus), reacts rapidly with chemicals in Venus’ atmosphere, becoming coated with magnetite and hematite, both iron oxide minerals, within days.
The researchers also found that near-infrared light emitted by these minerals would disappear within days, something consistent with data recorded by the Venus Express mission.
“Our results indicate that lava flows lacking VNIR features due to hematite are no more than several years old. Therefore, Venus is volcanically active now,” the authors of the new study wrote in the journal Science Advances.
Now, all that remains is for a new mission to confirm this hypothesis. Besides Earth, the only other confirmed volcanically active worlds that we know of are Io, a moon of Jupiter; Triton, a moon of Neptune; and Enceladus, a moon of Saturn.
However, Mars, Pluto, Jupiter’s moon Europa could also be volcanically active.
“If Venus is indeed active today, it would make a great place to visit to better understand the interiors of planets. For example, we could study how planets cool and why the Earth and Venus have active volcanism, but Mars does not,” Filiberto said.
The next missions bound for Venus are India’s Shukrayaan-1 orbiter and Russia’s Venera-D spacecraft, scheduled to launch by 2023 and 2026, respectively.
With its clouds of sulfuric acid and surface temperatures exceeding 400 degrees Celsius, Venus is often referred to as a sort of incarnation of hell. It could be worse, though. In a new study, astronomers have zoomed in on K2-141b, a planet that is so hot it is covered in oceans of molten lava and rocks rain down from its atmosphere.
This is truly one of the most extreme worlds scientists have found out of the more than 4,000 exoplanets identified to date. In a new study, researchers from McGill University, York University, and the Indian Institute of Science Education examined the scorching planet’s atmosphere and weather system, revealing new insights about the formation and dynamics of so-called “lava planets”.
“The study is the first to make predictions about weather conditions on K2-141b that can be detected from hundreds of light-years away with next-generation telescopes such as the James Webb Space Telescope,” says lead author Giang Nguyen, a PhD student at York University
K2-141b, which is located hundreds of light-years away from Earth, owes its bizarre weather to its close proximity to its parent star. Being so close to the star also causes the planet to be gravitationally locked in its place — meaning the same side always faces the star just like the moon does Earth. As a result, two-thirds of the distant exoplanet experiences perpetual daylight, where surface temperatures 3,000 degrees Celsius (5,400 degrees Fahrenheit).
That’s so hot that rocks melt, covering the planet in a 96-km (60-mile) ocean of magma. It’s actually so hot that some of the molten rock is vaporized into the atmosphere.
On Earth, liquid water evaporates, rising up into the atmosphere where it condenses, ultimately returning to the surface in the form of rain. A similar cycle also occurs on K2-141b, only instead of water there’s sodium, silicon monoxide, silicon dioxide, and other vaporized rocky substances, which are carried by supersonic winds blowing in excess of 3,000 mph to the planet’s dark side.
In the part of the planet shrouded in eternal darkness, temperatures are frigid, hovering at -200 degrees Celsius (-424 degrees Fahrenheit). The cold atmosphere condenses the rocky substances, which rain back into the magma ocean, restarting the cycle.
However, unlike the water cycle on Earth, this rocky cycle is not in equilibrium since the flow of material from the dark side to the dayside is slower. Eventually, the researchers predict that the planet’s surface and atmospheric composition will be altered dramatically.
“All rocky planets, including Earth, started off as molten worlds but then rapidly cooled and solidified. Lava planets give us a rare glimpse at this stage of planetary evolution,” said Nicolas Cowan, a professor in the Department of Earth & Planetary Sciences at McGill University.
While Venus is boiling-hot today, this wasn’t always the case. And the culprit, new research suggests, could be our largest neighbor.
Jupiter, the colossus of our solar system, likely altered the orbit of Venus in the past, condemning it to a state of lifelessness. The findings come from a new study that aimed to understand why Venus’ orbit around the sun is so circular.
“One of the interesting things about the Venus of today is that its orbit is almost perfectly circular,” said UCR astrobiologist Stephen Kane, who led the study.
“With this project, I wanted to explore whether the orbit has always been circular and if not, what are the implications of that?”
Jupiter is by far the largest planet in our vicinity, with a mass over two-and-a-half times greater than that of all other planets in the solar system combined. As such, it can wield quite a lot of (gravitational) influence upon them.
During its early days, Jupiter moved towards the sun and then away from it again. This isn’t really a very peculiar case — observations from other systems show that giant planets follow such orbits pretty often during their formation.
In our corner of space, Jupiter’s motion affected the orbit of Venus. This put it on the path to becoming the planet it is today. Kane says that while it’s very likely that Venus lost some of its water due to other reasons, the passing of Jupiter irrevocably changed its climate and drained its reserves of liquid water. Researchers mostly consider any planet lacking liquid water to be incapable of spawning life, or at least, life as we know it.
“As Jupiter migrated, Venus would have gone through dramatic changes in climate, heating up then cooling off and increasingly losing its water into the atmosphere,” Kane said.
Kane created a model of the solar system during the early days of planetary formation, calculating where each of them was and how their gravitational pull influenced one another. This model showed that Venus used to have a much less circular (more ‘eccentric’) orbit than today. A planet’s eccentricity is denoted by a number between 0 and 1, with the first meaning perfectly circular and 1 meaning completely linear. Kane explains that a planet with an eccentricity of 1 would “simply launch into space”.
Currently, the orbit of Venus has an eccentricity of 0.006, making it the most circular in the whole Solar System. However, the model holds that this value used to be 0.3 before Jupiter came around. Kane says Venus had a much higher probability of being habitable at that time. The recent discovery of phosphine in the atmosphere of Venus — a gas that is typically produced by microbes — could be the signature of “the last surviving species on a planet that went through a dramatic change in its environment.”
Still, any surviving microbes would have needed to live in the clouds of sulfuric acid that drape the planet for over a billion years without liquid water.
“There are probably a lot of other processes that could produce the gas that haven’t yet been explored,” Kane said.
“I focus on the differences between Venus and Earth, and what went wrong for Venus, so we can gain insight into how the Earth is habitable, and what we can do to shepherd this planet as best we can.”
The findings “Could the Migration of Jupiter Have Accelerated the Atmospheric Evolution of Venus?” have been published in The Planetary Science Journal.
The year 2020 started off on a good foot for Venusian lovers. Data from the European Space Agency’s Venus Express probe suggests that not all on the Solar System’s hottest planet is dead. A previous study published in Science Advances had found that active volcanoes most likely still existed on the surface of the planet. Now a new report published in the journalNature Geoscience has identified 37 recently active volcanic structures.
“This is the first time we are able to point to specific structures and say ‘Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead,'” said Laurent Montesi, a professor of geology at the University of Maryland (UMD) and co-author of the research paper. “This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes.”
Venus has been found to harbor more volcanoes than any other planet in the solar system with over 1,600 major known volcanoes or volcanic features. Some say that there could be anywhere from 100,000 to one million smaller ones.
Scientists have known for quite some time that Venus has a younger surface than planets like Mercury and Mars, which have cold interiors. Evidence of a warm interior and geologic activity dots the surface of the planet in the form of ring-like structures known as coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust. This is similar to the way mantle plumes formed the volcanic Hawaiian Islands.
However, it was originally believed that the coronae on the planet most likely pointed to signs of ancient activity, and that Venus had cooled enough to slow geological activity in the planet’s heart and harden the crust so much that any warm material from deep inside Venus would not be able to puncture through. The specific processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for discussion.
Named after the Roman goddess of love and beauty, Venus is similar in structure and size to Earth, but the former planet’s thick, toxic atmosphere traps heat in a runaway ‘greenhouse effect.’ The scorched world is the hottest in our Solar System (the average temperature is 864 degrees Fahrenheit / 422 Celsius) and has temperatures high enough to melt lead. So hot, that the longest a probe was ever able to survive on the surface was the Russians’ Venera 13 which lastest just a shade over two hours.
The active coronae on Venus are clustered in a handful of locations, which suggests areas where the planet is most volcanically active, which can provide clues as to the workings of the planet’s interior. The study’s results can also help identify target areas where geologic instruments should be placed on future missions to Venus, such as Europe’s EnVision which is scheduled to launch in 2032.
In this latest study, the researchers used numerical models of thermo-mechanic activity beneath the surface of Venus to create high-resolution, 3D simulations of coronae formation. This helped identify features that are present only in recently active coronae. The UMD researchers were then able to match the observed features to those found on the surface of Venus, revealing that some of the variation in coronae across the globe represents different stages of geological development.
“The improved degree of realism in these models over previous studies makes it possible to identify several stages in corona evolution and define diagnostic geological features present only at currently active coronae,” said Montesi. “We are able to tell that at least 37 coronae have been very recently active.”
The report provides some of the first evidence that coronae on the planet are still evolving, indicating that the interior of the planet is still churning away.
When it comes to the surface temperature of planets, distance to the Sun is the main factor, but it’s not the only one. Turns out, the atmosphere (and in some cases geological processes) can have a major impact.
This is why the hottest planet in the solar system isn’t Mercury (the closest to the Sun), but Venus — and the reason has to do with something we’re very familiar with: carbon dioxide.
A familiar culprit: greenhouse gas
Venus, named after the Roman goddess of Love (Aphrodite for the Greeks), is not exactly an inviting place. Its scorching surface can reach 880°F (471°C), and if that doesn’t scare you, Venus is riddled with active volcanoes and hot, toxic sulfur fumes.
It’s no surprise that Venus is hot since it’s much closer to the Sun than the Earth. Venus lies 108.93 million km away from the Sun, 30% closer than the Earth. But why is Venus hotter than Mercury, which lies only 59.187 million km from the Sun?
The answer lies in the Venusian atmosphere.
The atmospheric pressure on Venus is 92 times stronger than that of Earth — it would feel like being 900 m (3,000 ft) underwater. This thick atmosphere wraps the planet like a blanket, and to make matters even hotter, the atmosphere is 96% carbon dioxide — which, as you’re probably aware, is an important greenhouse gas and a driver of rising temperatures. In other words, Venus has a runaway greenhouse gas problem that traps heat in the atmosphere.
Meanwhile, Mercury has a very thin atmosphere. Much of the heat that Mercury receives from the sun is quickly lost back into space, whereas heat on Venus doesn’t escape.
It’s a never-ending cycle of heat being trapped inside by carbon dioxide and releasing more carbon dioxide. This is what happens when an atmosphere absorbs too much carbon dioxide: the heat has nowhere to go and it triggers a self-enforcing feedback loop.
This becomes even more obvious when we look at the difference between the maximum temperature and the average temperature.
The day is longer than the year
Both Mercury and Venus rotate very slowly; on Venus, a day lasts 243 Earth days, while a year lasts 225 Earth days — the Venusian day is longer than the year.
Because they rotate so slowly, you’d expect the planets to have massive temperature differences between the sunny side and the dark side — and that’s exactly what we see on Mercury. There’s a huge, over 1000 °F difference between day and night. But for Venus, that’s not really the case.
Because Venus has such a thick and greenhouse-potent atmosphere, the temperature is relatively constant on the entire planet. While the hottest temperature on Mercury is close to that of Venus, if we we were to take an average, it wouldn’t even be close.
Planet / Satellite
Minimum surface Temperature
Maximum Surface Temperature
-275 °F (- 170°C)
840 °F (449°C)
870 °F (465°C)
870 °F (465°C)
– 129 °F (- 89°C)
136 °F (58°C)
– 280 °F (- 173°C)
260 °F (127°C)
– 195 °F (- 125°C)
70 °F (20°C)
If Venus didn’t have the atmosphere it does, its night temperature would also be much lower, like Mercury’s — and the average temperature would also be lower than Mercury’s.
Another consequence of this atmosphere is that there’s no ice on Venus, which is hardly surprising given the average temperature. While on Mercury, ice can find shelter in the polar, always-shaded impact craters where temperatures are below freezing. NASA’s MESSENGER mission detected evidence of water ice at both of Mercury’s poles, probably delivered by comet impacts.
Meanwhile, the surface of Venus is extremely dry.
It’s not always clear if the planet was always like this. During its early evolution, Venus likely had liquid water on its surface, but it was ultimately evaporated by ultraviolet rays from the Sun. If, through some magical experiment, you were to create some water on Venus, it would boil away almost immediately. Yet despite all these differences, Venus was once considered Earth’s twin.
The reason for this is mostly regarding the planet’s size and mass. Venus and Earth, two neighboring planets, are very similar in some regards: Earth has a mean radius of 6,371 km, while Venus has a radius of about 6,052 km. Meanwhile, the mass of the Earth is 5,972,370,000 quadrillion kg, compared to 4,867,500,000 quadrillion kg for Venus. So essentially, Venus is 0.9499 the size of Earth and 0.815 the mass. It also has an atmosphere… and that’s pretty much where the similarities end.
Around 60% of Venus is covered by flat, smooth plains, marred by thousands of active volcanoes, ranging from 0.5 to 150 miles (0.8 to 240 km) wide. Venus features long, winding canals that run for more than 3,000 miles (5,000 km) — longer than any other planet.
The temperature is ungodly, as we’ve already mentioned, the atmosphere is thick and heavy, permanently covered in clouds. Most man-made materials would melt rapidly on Venus, and a human mission to Venus is nothing more than a pipe dream at this point.
Venus also rotates in the opposite direction than the Earth, and as we mentioned previously, it rotates very slowly.
If Venus is Earth’s twin, it can only qualify as its evil twin.
How we study Venus
Up until the 1960s, there was rich speculation that Venus may harbor life forms — but all that dwindled quickly when spacecraft actually started studying Venus.
Studying Venus is no easy feat. In fact, Venus is so inhospitable that many scientists were skeptical that a mission would even be possible. The Soviets sent a few missions to Venus, but the first ones all failed.
Mariner 2 was the first spacecraft to visit Venus in 1962. Eventually, in 1981, the Venera 13 mission finally managed to make it through the hot layers of the atmosphere and land on the surface. It managed to survive for 127 minutes, during which it sent color photos and measurements to Earth.
Then, transmission stopped and Venera 13 melted.
In 1990, the US spacecraft Magellan used radars to map the Venusian surface — an extremely important step, since Venus is always shrouded by sulfur layers that make it impossible for visible light to pass. Magellan mapped 98% of the surface with a resolution of approximately 100 meters and are still the most detailed maps we have of Venus. In more recent times, interest in Venus has decreased and recent missions have only been flybys, taking snapshots of Venus en route to other destinations. The Japanese mission Akatsuki, plagued by problems, is currently studying Venus’ atmosphere.
Understanding the atmosphere and atmospheric processes on Venus could help us better understand some of the atmospheric phenomena we see here on Earth.
Venus’ runaway greenhouse effect could show us how the Earth might look in the future if we don’t take climate change seriously. It’s an important lesson on what can happen when a planet has a high carbon dioxide level in the atmosphere. According to recent studies, Venus may have had a liquid ocean and a habitable surface for up to 2 billion years of its early history — an important cautionary tale.
Lastly, although Venus is hellish and inhospitable, some researchers still believe that extremophiles (organisms adapted to extreme conditions) could still survive on Venus. In 2019, researchers proposed that an unexplained absorption phenomenon could be explained by colonies of microbes in the atmosphere on Venus. While far from being a promising place to look for life, it’s still intriguing enough to study.
Venus studies have been great lessons, enabling researchers to better understand other rocky planets, as well as the Earth.
It’s a hot, hellish place — the hottest planet in the solar system. But we can still learn from it.
Venus might still harbor active volcanoes, a new paper reports.
Earth and Venus are similar enough in size and mass that they are sometimes referred to as being ‘sister planets’. But, apart from that, the two are very different. Venus is covered in a super-thick and opaque atmosphere, so we have had very few opportunities to actually see its surface. However, new research at the USRA’s Lunar and Planetary Institute (LPI) suggests that the second planet from the Sun may still be volcanically active.
So far, Earth has been the only planet in the solar system with confirmed volcanic activity. The other three bodies known to have active volcanoes are Io, a moon of Jupiter, Triton, a moon of Neptune, and Enceladus, a moon of Saturn.
Volcanoes near you
“If Venus is indeed active today, it would make a great place to visit to better understand the interiors of planets,” explains Dr. Justin Filiberto, a staff scientist with the LPI. “For example, we could study how planets cool and why the Earth and Venus have active volcanism, but Mars does not.”
“Future missions should be able to see these flows and changes in the surface and provide concrete evidence of its activity.”
Most planets and moons in the solar system show signs of ancient volcanism. Venus is no exception: readings in the 1990s showed that Venus had been volcanically active as recently as 2.5 million years ago and that its surface is littered with volcanic features to this day. However, because Venus is so hard to observe and visit, we’re not sure if its volcanoes are active or dormant.
The new study, led by Dr. Filiberto, drew on data recorded during the 2000s by ESA’s Venus Express orbiter, which measured infrared light coming from the planet’s surface at night. Through this data, the team was able to map the lava flows on Venus’ surface and, by comparing this against previous data, track how they evolved between the 1990s and 2000s. ESA’s data also allowed them to tease apart fresh lava flows from dormant ones.
One thing that prevented us from accurately determining when Venus’ volcanoes erupted was that we didn’t know how fast its (fresh) magma alters once on the surface. In order to determine this, Dr. Filiberto and his team simulated Venus’ atmosphere in their laboratory and then investigated how it impacts the evolution of lava.
They showed that olivine (a heavy, green mineral that’s very abundant in basalt rock) would rapidly react with gases in Venus’ atmosphere, becoming coated with magnetite and hematite (iron oxide minerals) within days. The near-infrared light emitted by these minerals are consistent with data obtained by the Venus Express mission, the team explains, and would disappear within days. This observation means that the lava flows seen on Venus must have only been a few days old at most, which would strongly indicate that the planet is still volcanically active
We won’t be able to fact-check the findings until we send a new craft to Venus. Several such missions are in the works for the future, including India’s Shukrayaan-1 orbiter and Russia’s Venera-D spacecraft, scheduled to launch by 2023 and 2026, respectively.
The paper “Present-day volcanism on Venus as evidenced from weathering rates of olivine” has been published in the journal Science Advances.
If you’d ask most people what; the closest planet to Earth, you’d probably come across one answer: Venus. That answer, while apparently logical, is not really true. Mercury is the planet closest to us.
Even more surprising is the fact that Mercury is the closest neighbor, on average, to each of the other seven planets in the solar system. How can this be?
Image credits: Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington (Wikimedia Commons).
Mercury’s in retrograde
What’s the planet closest to the Earth? Even without any prior knowledge, a decent guess would be Venus or Mars — these are our planetary neighbors, after all. A simple Google search reveals that Venus’ orbit is closer to that of Earth’s so, naturally, Venus must be the answer, right?
Wrong. Mercury is the planet closest to Earth — at least on average.
As it turns out, Venus being the closest planet to Earth is simply a misconception — one that has propagated greatly through the years.
“By some phenomenon of carelessness, ambiguity, or groupthink, science popularisers have disseminated information based on a flawed assumption about the average distance between planets,” write engineers Tom Stockman, Gabriel Monroe, and Samuel Cordner in a commentary published in Physics Today.
Instead, they recommend a different method of measuring which planet is closest, which they demonstrated using the motions of the planets within the last 10,000 years.
“By using a more accurate method for estimating the average distance between two orbiting bodies, we find that this distance is proportional to the relative radius of the inner orbit.”
Using this method, Mercury is closer to Earth on average. A GIF created by Reddit user u/CharcoalCharts does a great job at depicting this (the Earth is in Blue). The Earth is usually closest to Mercury, although, at some points of the year, it’s closest to Venus or Mars.
It feels intuitive that the average distance between every point on two concentric ellipses is closer than ellipses which are farther apart, but this is not necessarily the case. While Venus can get very close to the Earth (at only 0.28 Astronomical Units, with 1 AU being the distance from the Earth to the Sun), the two planets can also be quite far apart, at 1.72 AU. In total, Venus is 1.14 AU from Earth, but Mercury is a much closer 1.04 AU.
There are also two other shocking conclusions from this: first of all, on average, the Sun is closest to the Earth than any other planet (because it’s at 1 AU by definition). Secondly, it’s not just the Earth — Mercury is the closest neighbor of all planets in the solar system. In other words, Uranus is, on average, closer to Mercury than its presumed neighbor, Neptune. The same stands for even the dwarf planet Pluto (we still love you, Pluto!).
A simulation of an Earth year’s worth of orbits by the terrestrial planets begins to reveal that Mercury (gray in orbital animation) has the smallest average distance from Earth (blue) and is most frequently Earth’s nearest neighbor. Image credits: Tom Stockman/Gabriel Monroe/Samuel Cordner.
The whirly-dirly corollary
Researchers also found that the distance between two orbiting bodies is at a minimum when the inner orbit is at a minimum — something which they call the “whirly-dirly corollary” — after an episode of the cartoon Rick and Morty.
The method might also be useful in estimating distances between other orbiting bodies such as satellites or extrasolar planets or stars. In the Physics Today commentary, the researchers explain:
“As best we can tell, no one has come up with a concept like PCM to compare orbits. With the right assumptions, PCM could possibly be used to get a quick estimate of the average distance between any set of orbiting bodies. Perhaps it can be useful for quickly estimating satellite communication relays, for which signal strength falls off with the square of distance. In any case, at least we know now that Venus is not our closest neighbor—and that Mercury is everybody’s.”
ESA’s spacecraft probed Venus’ nightside for the first time. After astronomers reviewed the data, they were surprised to find unusual cloud formations that shouldn’t be there according to computer models.
This mosaic illustrates the atmospheric super-rotation at the upper clouds of Venus. Credit: ESA, JAXA, J. Peralta and R. Hueso.
Earth’s hellish twin
If there’s a hell in our solar system, it’s on Venus. The brightest object in the night sky after the moon has, for a very long time, conjured the imagination of scientists, artists, and free-thinking folk around the world. Shrouded in a thick haze, people imagined that under this blanket lies a hot jungle world, maybe teeming with life. In 1962, the U.S.-launched Mariner 2 space probe found something totally different, though.
Venus has an average surface temperature of 460°C, hotter than the surface of Mercury despite being considerably farther away than the sun. The leading explanation right now is that Venus’ enormous heat is trapped in the atmosphere due to a runaway greenhouse effect (some speculate something similar might happen to Earth).
Scientists at the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) are more interested in Venus’ winds than its clouds. Venus is the slowest-turning body in the solar system completing a single revolution around its own axis in 234 Earth days. Winds on the planet, however, are 60 times faster than its rotation which has always intrigued scientists. This phenomenon, known as ‘super-rotation’, is more pronounced in the upper atmosphere where the winds push and drag clouds.
To learn more, scientists turned to ESA’s Venus Express which revealed that the nightside of the planet behaves radically different from the dayside of the planet, which is facing the sun. Writing in Nature Astronomy, researchers report finding unexpected and previously-unseen cloud types, morphologies, and dynamics.
“This is the first time we’ve been able to characterise how the atmosphere circulates on the night side of Venus on a global scale,” says Javier Peralta of the Japan Aerospace Exploration Agency (JAXA), Japan, and lead author of the new study.
High velocity filaments seen on the night side upper clouds of Venus, as seen through the eye of the VIRTIS instrument on Venus Express. Credit: ESA, S. Naito, R. Hueso and J. Peralta.
“While the atmospheric circulation on the planet’s dayside has been extensively explored, there was still much to discover about the night side. We found that the cloud patterns there are different to those on the dayside, and influenced by Venus’ topography.”
Super-rotation has always been perplexing because scientists back on Earth were never able to reproduce it in their computer models. With the help of the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on ESA’s Venus Express spacecraft, they could observe the clouds on the dark side of the planet in the infrared. This revealed phenomena on Venus’ nightside that have never before been seen on the dayside.
The main finding is that the super-rotation seems to be more irregular and chaotic on the night side. That’s contrary to the weather models of Venus compiled so far that predicted super-rotation occurs in much the same way on Venus’ night side as on its dayside.
“It was an exciting moment when we realised that some of the cloud features in the VIRTIS images didn’t move along with the atmosphere,” said Peralta in a statement.
What’s more, the nightside seems to produce large, wavy, and irregular clouds in filament-like patterns that were never seen before on the sunny side. Scientists think these cloud formations are made by unmoving phenomena known as stationary waves.
“Stationary waves are probably what we’d call gravity waves–in other words, rising waves generated lower in Venus’ atmosphere that appear not to move with the planet’s rotation,” says co-author Agustin Sánchez-Lavega of University del País Vasco in Bilbao, Spain.
“These waves are concentrated over steep, mountainous areas of Venus; this suggests that the planet’s topography is affecting what happens way up above in the clouds.”
New types of cloud morphology on Venus. Credit: ESA, NASA, J. Peralta and R. Hueso
Strangely, these sort of clouds weren’t found in the lower atmospheric levels. Topography might be involved, which can only mean our climate and weather models of Venus need a revamp.
“This study challenges our current understanding of climate modelling and, specifically, the super-rotation, which is a key phenomenon seen at Venus,” said Håkan Svedhem, ESA Project Scientist for Venus Express.
Long ago, Venus might have harbored an entire ocean.
Artist’s concept of a Super Venus (left) and a Super Earth (right). Image credits NASA / JPL-Caltech
A team of researchers led by Université de Versailles Saint-Quentin-en-Yvelines (Guyancourt, France) planetary scientist Emmanuel Marcq believe it’s very likely early Venus had an ocean.
Their theory is based on a number of computer simulations the team ran to understand how the molten crust of young rocky planets interacts with their burgeoning atmospheres and incoming energy from parent stars. These simulations showed that if an early-Venus-like planet had carbon dioxide levels similar to those seen today, it would only need about 10% of Earth’s water volume to form a stable planetary ocean. If you tweak some of the planet’s characteristics — like cloud reflectiveness, for example — to get the least ocean-conductive environment possible, you’d still need just 30% of Earth’s water to form a stable ocean.
Whether or not a planet can maintain liquid water on its surface mainly comes down to it keeping within a specific range of temperatures and pressures. Both of these are the result of how much energy a planet gets from its parent star versus how much it can dump back into space — which in turn can be boiled down to the complex interplay between the atmosphere’s chemistry, the reflectivity of its clouds, and other factors such as distance from the star.
Marcq’s team’s findings build on the results of a paper published last year, which found that Venus’ slow rotation speed could have allowed for a continuous, sufficiently-thick cloud cover to form and keep average temperatures around 15° Celsius as recently as 715 million years ago. That’s a very far cry from present Venus’ crisp average of 460° C, but more importantly, it’s cold enough to allow for a shallow ocean to form.
So the fact that Venus could harbor an ocean isn’t that surprising, Marcq says. But it’s still “very much a hotly debated, open question” if Venus did harbor an ocean. The team’s work comes to prop up the theory that it did, as their results suggest it was much more likely for water vapor to condense into an ocean during Venus’ early days than previously believed.
However, their simulations don’t offer any insight into how later changes on Venus would’ve impacted this ocean — if there was an ocean at all. It also doesn’t offer any answers as to how long this grace period lasted on Venus, or where the ocean went afterward to create the decidedly-dry neighbor we have today. So far from settling the debate, the results are likely to fan the flames even further.
But on the plus side, the simulations can help planetary scientists refine their search for habitable planets outside of the solar system by offering a better idea of what conditions in a planet’s atmosphere and on the ground level are likely to make it suitable for life.
The paper “The relative influence of H2O and CO2 on the primitive surface conditions and evolution of rocky planets” has been published in The Journal of Geophysical Research: Planets.
Venus might be tectonically active, a new paper reveals — but it’s not the plate tectonics we know and love from back home.
Computer-generated synthetic aperture radar mosaics of Venus from the first cycle of Magellan mapping. Image credits NASA / JPL.
It’s so similar to Earth that it’s often called its twin, and yet, Venus seems to lack one of the defining features of Earth: tectonic plates. This has been bugging planetary scientists for a long time now because our pearly neighbor should be an ideal host for such processes — but they insist on popping up on Mercury or Europa — a moon out of all places — and pointedly absenteeing from Venus.
So why is Venus such a good candidate for plate tectonics? Well, it’s really similar to the Earth as far as size and chemical composition are concerned. Its surface is also littered with volcanoes. We don’t know for sure which are active or not — the surface is hidden behind thick clouds that make repeated observations nigh impossible — but at least they’re proof that there once was a lively geology in the mantle. The proverbial coffin nail is that Venus is pockmarked by craters and material accumulated over hundreds of millions of years or successive eruptions. So tectonic recycling clearly doesn’t take place here.
Men come from Mars, evidence of tectonics comes from Venus
But it may be the case that Venus just has its own flavor of tectonics. For instance, there are some features on Venus, such as trenches and rifts, that point to some kind of tectonic activity. Under normal circumstances, researchers would try to digitally model internal processes and progressively tweak them until the model matched what we see on the surface — but, according to the team of French and US researchers behind the paper, the models currently at our disposal simply aren’t powerful enough to handle a 3D model of Venus’ mantle and crustal activity in enough detail.
Instead, they used an old-fashioned physical model to figure out what was happening. The team used a solution of silica nanoparticles (i.e. finely ground sand) in suspension in water to match the physical properties of semi-solid rock. Put over a heating plate, this medium re-created the convection cells generated in Venus’ mantle as hot (and thus less dense) material pushes up from the planet core towards the crust.
The team used cameras to monitor the evolution of their model. Over time, as water evaporated, a thin crust started to form on top of the container. On this crust, something similar to distinctive features of Venus’ crust (formations called coronae) began forming on the simulated crust. These “volcano-tectonic features unique to Venus” are circular structures which can grow to a few thousand kilometers across, with a mound-like rise in the center. The rise is predominantly made up of igneous rocks, while the edge is bumpy and ends with a deep trench. This trench is very similar to what happens in the areas where tectonic plates get subducted back on Earth, although the rest of the corona isn’t.
Side views of the model. Plume shown in red, effect on surface in yellow, subduction zones in white. Blue arrows show the movement of rocks. Image credits A. Davaille et al., (2017), Nature.
The team believes that a phenomenon underlying plate tectonics on Earth also creates Venus’ coronae: mantle plumes. Think of them like really big convection cells, with the upwelling material burning through the crust like a blowtorch. On Earth, mantle plumes are responsible for hotspots of volcanic activity especially for volcanoes that are smack-dab in the middle of plates, like Yellowstone or Iceland, and those stringy volcanic island arcs like Hawaii. Sometimes, they can be powerful enough to burn through whole tectonic plates and break them apart.
But that happens because Earth’s crust is pretty thick and solid. Venus is a much hotter place, with average surface temperatures revolving around 450 degrees C (840 F), making its crust thinner and more flexible — so mantle plumes have a different effect. As the team’s model showed, when a plume hits the crust, molten rock is pushed up fractures and faults to the surface. This added weight causes the crust to sag, widening the fractures, making more material pile on, and so forth. Eventually, the whole section of the crust will rupture, sink, and melt into the mantle.
The Artemis corona is actually made up of 5 different coronae. a) Combined radar (greyscale) and topography (color scale) image; corona-like features labeled ‘c’. Rift segments radiating out from the trench labeled ‘r’. b) Terrain shape along the B-B′ line. c) Radar image showing a 200-km-wide area with graben-like lineation, on average 300 km in length and 1 km in width, spaced at 6-12 km. Image credits A. Davaille et al., (2017), Nature.
This unique take on tectonics is what we see as a corona. The central igneous bit is deposited by material pushed up by the plume, surrounded by a circular equivalent of a subduction trench. The authors compare their model’s result to two important coronae, Artemis and Quetzalpetlatl, and find that the features observed in the lab line up pretty well to those seen on Venus.
Venus’ coronae might hold an unexpected glimpse into the Earth’s past, too. The team notes that temperature conditions on Venus today are very similar to what Earth had for much of its early history. So it’s possible that there was a more Venus-like tectonic system in place down here before the Earth cooled down enough for plate tectonics to take a hold.
The full paper “Experimental and observational evidence for plume-induced subduction on Venus” has been published in the journal Nature Geosciences.
NASA’s Glenn Research Center has developed a new class of computers that can withstand the hellscape of Venus. The devices are built from a different semiconductor than regular hardware, which can carry more voltage at much higher temperatures.
SiC transistor gate electroluminesces blue while cooked at more than 400°C. Image credits NASA / Glenn RC.
Mars has been getting a lot of attention as humanity’s first planned colony. So it’s easy to forget that it’s neither the closest nor the most Earth-like terrestrial planet in the Solar System. Both those distinctions belong to Venus — so why aren’t we looking towards it for our otherworldly adventures?
The goddess of love and beauty
Well, the thing is that Venus is awful. It’s an objectively dreadful place, a scorching hot ball of rock covered in thick clouds of boiling acid. Ironic, right?
These conditions not only make it nigh-impossible for real-estate agents to put a positive spin on the planet, it also makes it frustratingly hard to explore. Any mission to Venus has to work around one simple fact: your run of the mill computer wouldn’t like it there. Normal silicone chips can still function up to 240-250°C (482°F). After that, the chip turns from a semiconductor into a fully fledged conductor, electrons start jumping all over the place, and the system crashes.
The longest any human-made object has made it on Venus is 127 minutes, a record set in 1981 by the Soviet spacecraft Venera 13. It was designed to survive for only 32 minutes and used all kinds of tricks to make that happen — such as cooling of internal systems to -10°C (14°F) before entering the atmosphere, hermetically sealed internal chambers for instruments, and so on. Venera braved sulphuric rain, surface temperatures of 470°C (878°F), and an atmosphere 90 times that of Earth long enough to capture the first color pictures of the planet’s surface.
The face of love. Image credits Morbx / Reddit.
After the mission, the Soviets flew three more crafts to Venus — Venera 14, Vega 1, and Vega 2 — making the last attempted landing on the planet in 1985.
Since that time, the transistor industry has developed alternative materials it can use for integrated systems. One of the most promising class of materials are silicon carbides (SiC). Their ability to support high voltages at huge temperatures has already drawn interest from the military and heavy industries, and make them ideal for a mission to Venus.
NASA’s Glenn Research Center has developed two prototype SiC chips which can be used in future Venus missions. The researchers have also worked to overcome another vulnerability of traditional integrated circuits: they’ve developed interconnects — the wires that tie transistors to other hardware components — which can withstand the extreme conditions on the planet.
Five hundred hours of fire
SiC chip designed by NASA, before and after GEER tests. Image credits NASA / Glenn RC.
To see if the technology lives up to expectations, the team put these SiC transistors and interconnects together and housed them in ceramic-packed chips. The chips were then placed in the GEER (Glenn Extreme Environments Rig) which can simulate the temperatures and pressures on Venus for hundreds of hours at a time.
One of the chips, housing a simple 3-stage oscillator, kept stable at 1.26MHz over 521 hours (over 21 days) before the GEER had to be shut down. The second chip fizzled out after 109 hours (4,5 days), but NASA determined that it was caused by faulty setup, not the chip itself.
The results for the two chips. Image credits NASA / Glenn RC.
This performance is a far cry from that seen in the 80’s, especially considering that the chips didn’t benefit from any pressure vessels, cooling systems, or other types of protection. It’s the first system shown able to withstand the condition on Venus for weeks at a time.
“With further technology maturation, such SiC IC electronics could drastically improve Venus lander designs and mission concepts, fundamentally enabling long-duration enhanced missions to the surface of Venus,” the researchers conclude.
But it’s not only transistors we’ll need for a successful Venus rover. Drills, cameras, wheels — everything has to be adapted to work in a high pressure, high temperature, highly acidic environment. Materials science has evolved a long way since the last missions, so creating a mechanically-sound lander should be feasible. A full-fledged rover with multiple moving parts that can survive on Venus would be a lot harder to develop — NASA Glenn is working on such a machine, a land-sailing rover, which they estimate will be ready by 2033.
The full paper “Prolonged silicon carbide integrated circuit operation in Venus surface atmospheric conditions” has been published in the journal AIP Advances.
Anthropologists have shown that Mayan tablets of math and astronomy have been greatly underestimated and the civilization’s astronomical knowledge may have been significantly greater than we thought.
The Preface of the Venus Table of the Dresden Codex, first panel on left, and the first three pages of the Table. Image courtesy of University of California – Santa Barbara
Ever since the Venus Table of the Dresden Codex was discovered 120 years ago, scientists have appreciated its significance. The accuracy of astronomical observations, especially those regarding ‘leap years’ was impressive, and archaeologists wondered how the Mayan civilization developed such a keen sense for astronomy. But in a new article, UC Santa Barbara’s Gerardo Aldana, a professor of anthropology, found that the importance and finesse of the Venus Table may have been underestimated.
He says he “discovered a discovery”:
“That’s why I’m calling it ‘discovering discovery,’ ” he explained, “because it’s not just their discovery, it’s all the blinders that we have, that we’ve constructed and put in place that prevent us from seeing that this was their own actual scientific discovery made by Mayan people at a Mayan city.”
Using a multidisciplinary approach which blends in archaeology, astronomy, linguistics and anthropology, Aldana was able to present a new interpretation of the Venus Table, which tracks the movement of the second planet from the Sun. He uncovered a surprising mathematical precision to the astronomical observations and predictions, likely developed at the city of Chich’en Itza during the Terminal Classic period (AD 800-1000). The calculations were likely done under the patronage of K’ak’ U Pakal K’awiil, one of the city’s most prominent historical figures.
K’ak’ U Pakal K’awiil is the most widely mentioned personal name in the surviving Maya inscriptions at Chichen Itza, and also appears on monumental inscriptions at other Yucatán Peninsula sites such as Uxmal. He was likely a scientist or a scholar of the time.
“This is the part that I find to be most rewarding, that when we get in here, we’re looking at the work of an individual Mayan, and we could call him or her a scientist, an astronomer,” Aldana said. “This person, who’s witnessing events at this one city during this very specific period of time, created, through their own creativity, this mathematical innovation.”
Venus has an irregular cycle of 583.92 days. So if you construct your astronomical calendar based on that period, it’s really easy to make errors – and any error accrues year after year. Scholars figured out the math for the Venus Table’s leap in the 1930s, Aldana said, “but the question is, what does it mean? Did they discover it way back in the 1st century BC? Did they discover it in the 16th? When did they discover it and what did it mean to them? And that’s where I come in.”
Intriguingly, their calendar wasn’t based on numerology, but rather on historical observations – but we don’t know exactly why. This carries a curious resemblance to the work of Nicolaus Copernicus, a Polish astronomer who lived 500 years after the Mayan civilization. When he was trying to predict the future dates of Easter, Copernicus found that the heliocentric model (the Sun at the center of the solar system) fits in much better mathematically. That’s what Aldana noticed in the Venus Table.
“They’re using Venus not just to strictly chart when it was going to appear, but they were using it for their ritual cycles,” he explained. “They had ritual activities when the whole city would come together and they would do certain events based on the observation of Venus. And that has to have a degree of accuracy, but it doesn’t have to have overwhelming accuracy. When you change that perspective of, ‘What are you putting these cycles together for?’ that’s the [final] component.”
We don’t know exactly who made this discovery, and we may never know. It could have been a singular figure or a group of astronomers, but whoever it was – the discovery was way ahead of its time.
Journal Reference: Aldana, Gerardo. Discovering Discovery: Chich’en Itza, the Dresden Codex Venus Table and 10th Century Mayan Astronomical Innovation. Journal of Astronomy in Culture, August 2016
Our closest neighboring planet, Venus, is not a place you’d like to visit. Scorching surface temperatures, an atmosphere so dense it would crush your bones, and acid thunderstorms. It’s about as far from a life-friendly planet as you could get. But, a NASA research team proposes that Venus’ hellish surface used to be very comfortable and pristine — up until some 700 million years ago.
Image credits Mattias Malmer/NASA/JPL.
“Both planets probably enjoyed warm liquid water oceans in contact with rock and with organic molecules undergoing chemical evolution in those oceans,” David Grinspoon at the Planetary Science Institute in Tucson, Arizona told Aviva Rutkin at New Scientist.
“As far as we understand at present, those are the requirements for the origin of life.”
Venus has all the makings of a planet that should sustain life: it’s very similar in size, density, and chemical composition to our own planet. Its proximity to Earth further suggests that the two planets were formed from the same primordial materials.
“Venus also has an unusually high ratio of deuterium to hydrogen atoms, a sign that it once housed a substantial amount of water, mysteriously lost over time,” says Rutkin.
But at surface level, the two planets couldn’t be more different. Venus is the hottest planet in the Solar System, so hot in fact that rainfall on the planet evaporates before reaching the ground. This is probably for the best as it rains sulphuric acid, not water, on Venus. Its lightning-and-greenhouse-gas-choked atmosphere is dense enough that carbon dioxide becomes liquid at ground level, so potential human visitors would have a very pressing need for protection.
Still, researchers believe that Venus wasn’t always the hellish place we see today. A recent NASA study lends weight to this theory, showing that up to 3 billion years ago the planet could have had mild, Earth-like temperatures and bodies of water.
Michael Way and his team from the NASA Goddard Institute for Space Studies simulated four versions of early Venus, each with slightly altered factors — such as length of days, incoming energy from the Sun, etc. Left to cook for a few billions of years, the most promising model evolved to have moderate surface temperatures, dense cloud cover to protect the surface from solar radiation, even snow. This model produces habitable conditions in 2-billion-year stretches and estimates that the planet remained habitable up to 715 million years ago.
One catch is that for the model to work, it requires Venus to have been spinning as slowly as it does today – something that researchers have yet to prove. We know that Earth’s rotation has been steadily slowing down over time, and some researchers argue that the same could be true for Venus.
“If Venus was spinning more rapidly, all bets are off,” said Michael Way.
“But, under the right conditions, “You get temperatures almost like Earth. That’s remarkable.”
If the models are accurate, however, the implications could be huge — a few billion years is more than enough time for life to have evolved on Venus during its milder days. Unfortunately, the Venus of today doesn’t really lend well to searching for clues of long-lost life. And we don’t know why it got this way, we don’t know what or when went wrong.
“It’s one of the big mysteries about Venus. How did it get so different from Earth when it seems likely to have started so similarly? The question becomes richer when you consider astrobiology, the possibility that Venus and Earth were very similar during the time of the origin of life on Earth,” Grinspoon said.
The only way to find out if Venus was ever habitable, if life ever evolved here, to figure out what happened for it to end up as it is, is to go there and poke around — something that NASA is already considering.
The full paper, “Was Venus the First Habitable World of our Solar System?” has been accepted for publication in Geophysical Research Letters.
Venus has an “electric wind” powerful enough to remove all the water from its atmosphere, something which may have led a significant role in stripping the planet of its oceans.
Venus, alongside Earth. Similar and yet so different.
It’s so strong that it took astronomers by surprise.
“It’s amazing and shocking,” said Glyn Collinson, previously at UCL Mullard Space Science Laboratory and now a scientist at NASA’s Goddard Space Flight Center. “We never dreamt an electric wind could be so powerful that it can suck oxygen right out of an atmosphere into space. This is something that definitely has to be on the checklist when we go looking for habitable planets around other stars.”
The Venusian electric field is so strong that it accelerates the heavy electrically charged component of water – oxygen – to speeds fast enough to escape the planet’s gravity. So any water in the atmosphere, and even on the planet, gets broken into hydrogen and oxygen. The oxygen then gets blown away by the electric field. This could explain how Venus (and other bodies like it) have become so barren in terms of water.
Image via Science.
Venus is the planet most like Earth in terms of its size and gravity, and there is reason to believe that it once had oceans full of water. But Venus is also very different from the Earth: it’s the hottest planet in the solar system, and it’s pretty much a hellish environment.
If Venus did have water, then most or all of it likely boiled away at temperatures of around 860 degrees Fahrenheit (460 Celsius). But if all the water boiled, then where’s all the steam? There is no evidence of what must have been a huge quantity of water, and now scientists believe this “electric wind” is to blame. Previously, solar wind was the main culprit.
The same thing may be happening on other bodies as well. Co-author, Professor Andrew Coates of the UCL MSSL, who leads the electron spectrometer team, said:
“We’ve been studying the electrons flowing away from Titan and Mars as well as from Venus, and the ions they drag away to space to be lost forever. We found that over 100 metric tons per year escapes from Venus by this mechanism – significant over billions of years. The new result here is that the electric field powering this escape is surprisingly strong at Venus compared to the other objects. This will help us understand how this universal process works.”
But this discovery poses just as many questions as it answers. How exactly did this electric field become so strong on Venus?
Just like any planet has its own gravitational field, it is believed that every planet with an atmosphere is also surrounded by a weak electric field. The two fields are trapped in a tug of war, with the electric field trying to rip the atmosphere’s top layers and gravity trying to keep them down; on Earth, gravity won, but on Venus, this wasn’t the case – but we don’t really know why.
“We don’t really know why it is so much stronger at Venus than Earth,” said Collinson, “but, we think it might have something to do with Venus being closer to the sun, and the ultraviolet sunlight being twice as bright. It’s a really challenging thing to measure and to date all we have are upper limits on how strong it might be here.”
This could also have significant implications for Mars. The Red Planet may have undergone a similar process. NASA’s current MAVEN mission is orbiting Mars to see what caused it to lose all the water. Titan is also a place of interest, as it’s in a mid-water-losing process.
“With ESA’s Mars Express, we have already caught this process in action at Mars, and MAVEN can now determine its relative importance. With NASA’s Cassini spacecraft we found that Titan loses 7 metric tonnes per day this way.”