Why Venus Is Soon to Be the Most Exciting Place in the Solar System Leave a comment
It’s hot. It’s toxic. It spins backwards and is covered in volcanoes. And we’re headed there soon. Three Venus missions, recently announced by NASA and the European Space Agency, are going to reveal more than we’ve ever known about the scorcher of a planet, a place that many scientists describe as Earth’s evil twin.
In recent weeks, NASA green-lit two Venus missions, VERITAS and DAVINCI+, while the ESA announced a Venus orbiter called EnVision. Already, planetary scientists are exhilarated by the possibilities. We spoke with several experts about why Venus is so exciting.
“It’s only beginning to hit me what this means,” said Paul Byrne, a planetary scientist at North Carolina State University, in a video call. “I’m gonna lose my shit every time a new paper comes out of it.” Fundamentally, he said, the reason for our return to Venus comes down to understanding why the planet “is our sibling and not our twin.”
“How is it that you have a planet that is almost the same size as Earth, made of presumably about the same stuff, in about the same compositions, orbiting the same star, and that has the same age—how do you have two worlds that are on paper the same, that are yet so vastly different?” Byrne explained. “EnVision, VERITAS, and DAVINCI+ are going to provide an unbelievable and unexpectedly solid foundation for how we tackle this question.”
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NASA’s VERITAS is an orbiter that will peer through Venus’ dense clouds to understand the planet’s topography, surface chemistry, and even look deeper into the planet to understand its geologic processes. The agency’s second mission, DAVINCI+, will consist of a probe that will descend through Venus’ atmosphere, sampling its chemistry, winds, and pressure and even taking high-resolution images of one region of the planet—a huge upgrade on the only surface images of Venus so far taken, the most recent being by USSR missions nearly 40 years ago. The ESA’s EnVision, also an orbiter, will inspect the planet’s insides and atmosphere, supplementing the goals of both NASA missions. All are set to launch between 2038 and 2031.
“I was a bit giddy all day after I heard the announcement,” said Katie Cooper, a planetary scientist at Washington State University who specializes in tectonic evolution, in an email. “I’m particularly excited to learn more about the plateaus on Venus, which are interesting but challenging analogs to Earth’s own large plateaus. On Earth, plateaus like the Tibetan Plateau or the Altiplano Plateau have their origins in plate tectonics, but on Venus that may not be the case.”
Cooper added that what we learn “will not only give us insight into Venus, but also pre-plate tectonic periods within Earth’s own history.”
Venus is covered in scrunchy land features called tesserae. These tesserae make up large swathes of Venusian regions like Alpha Regio, a sprawling plateau twice the size of Texas that DAVINCI+ is going to image. To date, tesserae have been something of an enigma for scientists, who haven’t had the sort of data that would indicate how those tesserae formed on Venus or how old they are.
“We are for Venus today where we were from Mars in the 80s,” Byrne said. “And in the intervening years, we have come to understand Mars as a far more complex and interesting world. And there is absolutely no doubt in my mind that that is what’s going to happen for Venus.”
And then there’s the volcanoes. These huge warts on the planet’s surface could all be dormant, or they could still be burbling away. It’s another little-understood facet of the planet, shrouded in clouds and not visited up-close by a NASA instrument since the Magellan mission, which concluded in 1994. The lava on the planet and its role in shaping Venus’ surface is also not well understand and thoroughly debated, including when the lava surfaced and cooled and whether it all resurfaced at once or in piecemeal bits.
“As a volcanologist, I am very intrigued by the volcanic processes that took (and perhaps are still taking!) place on Venus,” said Einat Lev, a seismologist and volcanologist at the Lamont-Doherty Earth Observatory at Columbia University, in an email. “Pancake lava domes! Super long lava flows! Complete resurfacing by lava! What’s not to be excited about?!”
Lev added: “I am certain that the new observations of Venus’ surface that VERITAS will be collecting will teach us a lot about all of these unique processes, and, potentially, about volcanism at extreme conditions (i.e., high pressure, high temperature, very fluid lavas) on Earth now and in the remote past.”
Another enigma is the dense Venusian atmosphere, a cloak of carbon dioxide and clouds of sulfuric acid that have so far obscured the more tantalizing questions about the planet’s nature. DAVINCI+ will aim to explore that thick mystery soup, specifically by measuring the atmosphere’s composition and structure—“what it is and where it is,” as put by Hannah Wakeford, an astrophysicist specializing in exoplanet atmospheres at the University of Bristol, in an email.
“You would be amazed at the things we can understand from those two simple things,” Wakeford said. “These will tell us how the whole atmosphere is tied together. Does the lower part near the ground affect what we measure high in the clouds? If it does, this will have huge implications for measurements we can make of exoplanet atmospheres, where we only see the very top of the atmospheres. Venus can tell us if what we measure can give us any more information about the ground conditions and if it is like or unlike our own planet.”
You may recall that last year there was a bit of a frenzy around the apparent discovery of phosphine, a potential biosignature, in some relatively balmy clouds in Venus’ atmosphere. That eagerness was quickly dimmed when results couldn’t be reproduced. Venus isn’t a strong candidate to host alien life, unlike other places in the solar system, like certain ocean moons around Saturn and Jupiter. But there are some scientists who still argue that microbial life could exist in Venus’ clouds. A recent NASA climate model suggested Venus could have been habitable in its early history and even had oceans of liquid water, though there’s no sign of those oceans today. “The loss of oceans may be recent geologically—perhaps only in the last billion years,” said David Grinspoon, an astrobiologist at the Planetary Science Institute, in an email. “This means that our solar system *might* have had two planets with surface oceans and life, sitting right next door to each other, for most of solar system history.”
The three upcoming missions are likely to refine our understanding of whether life could ever have been possible on Venus, but none of the missions are explicitly looking for evidence of life. Alas.
There are plenty of confounding features on Venus that scientists are eager to observe and interpret, and they’re just as intrigued about what those features could reveal about Earth’s evolution to the oasis it is today. The nice thing about your sibling getting a DNA test, of course, is that you learn about your own history in the process.
