What was early Earth like? Almost like Venus, research shows

Almost like on Venus
An artistic illustration of Earth today and 4.5 billion years ago. Credit: Tobias Stierli / NCCR PlanetS

A team of international scientists led by ETH researcher Paolo Sossi has gained new insights into Earth’s atmosphere of 4.5 billion years ago. Their results have implications for the possible origins of life on Earth.


Four-and-a-half billion years ago, Earth would have been hard to recognize. Instead of the forests, mountains and oceans that we know today, the surface of our planet was covered entirely by magma—the molten rocky material that emerges when volcanoes erupt. This much the scientific community agrees on. What is less clear is what the atmosphere at the time was like. New international research efforts led by Paolo Sossi, senior research fellow at ETH Zurich and the NCCR PlanetS, attempt to lift some of the mysteries of Earth’s primeval atmosphere. The findings were published today in the journal Science Advances.

Making magma in the laboratory

“Four-and-a-half billion years ago, the magma constantly exchanged gasses with the overlying atmosphere,” Sossi begins to explain. “The air and the magma influenced each other. So, you can learn about one from the other.”

To learn about Earth’s primeval atmosphere, which was very different from what it is today, the researchers therefore created their own magma in the laboratory. They did so by mixing a powder that matched the composition of Earth’s molten mantle and heating it. What sounds straightforward required the latest technological advances, as Sossi points out: “The composition of our mantle-like powder made it difficult to melt—we needed very high temperatures of around 2,000° Celsius.”

That required a special furnace, which was heated by a laser and within which the researchers could levitate the magma by letting streams of gas mixtures flow around it. These gas mixtures were plausible candidates for the primeval atmosphere that, as 4.5 billion years ago, influenced the magma. Thus, with each mixture of gasses that flowed around the sample, the magma turned out a little different.

Almost like on Venus
The laser-heated aerodynamic levitation furnace which Sossi’s group used in the experiments. Credit: IPGP

“The key difference we looked for was how oxidized the iron within the magma became,” Sossi explains. In less accurate words: how rusty. When iron meets oxygen, it oxidizes and turns into what we commonly refer to as rust. Thus, when the gas mixture that the scientists blew over their magma contained a lot of oxygen, the iron within the magma became more oxidized.

This level of iron oxidation in the cooled-down magma gave Sossi and his colleagues something that they could compare to naturally occurring rocks that make up Earth’s mantle today—so-called peridotites. The iron oxidation in these rocks still has the influence of the primeval atmosphere imprinted within it. Comparing the natural peridotites and the ones from the lab therefore gave the scientists clues about which of their gas mixtures came closest to Earth’s primeval atmosphere.

A new view of the emergence of life

“What we found was that, after cooling down from

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Not finding life on Venus would be disappointing. But it’s good science at work

Repetition, repetition

The truth is, the story of Venus’s putative phosphine is not a simple case of a sensational finding being shot down upon further scrutiny. In fact, the rush of follow-up research is welcomed; science is doing its thing. This is especially true when it comes to the search for extraterrestrial life—after all, extraordinary claims require extraordinary evidence.

“I think this is a perfect example of how the scientific process works,” says Paul Byrne, a planetary scientist at North Carolina State University, who also wasn’t involved in the studies. “It certainly makes sense that there would be other studies that would try and get at this question.”

The first preprint paper to cast doubt on the original was actually written in part by Greaves herself. After failing to secure more time on telescopes to verify her team’s initial finding—the pandemic has made telescope access difficult and in some cases impossible—she and her colleagues turned to an archive of infrared observations made in 2015 and couldn’t find any sign of phosphine. 

This is frustrating, of course, but as Byrne says, “the absence of proof of a given detection is not proof of absence. It just might mean the problem is more complex than we’d like.” Maybe phosphine doesn’t actually exist on Venus, or maybe it varies over time. Or perhaps the archival observations Greaves analyzed didn’t probe deeply enough into the clouds. 

Replicability is actually a common problem when it comes to these kinds of investigations. Our current characterization of methane on Mars, for example, is under intense debate: NASA’s Curiosity rover has a has a history of detecting enormous spikes of methane on the planet, while ESA’s Trace Gas Orbiter, designed to study the gas on Mars with far more sensitive instruments than Curiosity, has found bupkis. The same goes for the detection of water plumes on Europa by the Hubble Space Telescope: subsequent investigations have struggled to find them.

Still processing

Another problem that plagues the phosphine findings is data processing. The two other preprints were written by teams that tried to reprocess the original data used by Greaves and her team, suspecting that the original analysis was flawed. It’s often a challenge to pull signals out of the massive amounts of noise found in telescopic data. Researchers in the original study used a technique called polynomial fitting, which is supposed to remove background noise around the spectral region where phosphine signals should pop up. But as National Geographic reports, the way they went about it might actually have introduced false phosphine signals. 

Both of these new preprints reprocessed the data from scratch, without using Greaves’s method. One focused solely on the ALMA data and failed to find phosphine. The other paper looked at both the ALMA and JCMT data. Researchers found no phosphine signal in the ALMA data and detected a signal in the JCMT set that might be explained by sulfur dioxide gas. 

Moreover, the ALMA observatory recently found an error in its calibration system used

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Gaseous signs of life on Venus aren’t seen in follow-up observations

Venus
Venus

Computer illustration of a view across the rocky surface of the planet Venus, showing clouds of sulphuric acid obscuring the Sun. Getty Images

This article originally appeared here on Salon.com

Last month, the science world was stunned and excited when Nature Astronomy published a paper indicating that the atmosphere of Venus appeared to contain trace amounts of phosphine, a gas associated with anaerobic bacteria on Earth that would be near-impossible to produce in any other fashion on Venus. If other scientific studies continued to confirm the report’s findings, that could mean that there is life in Venus’ clouds.

Now, two subsequent scientific investigations question the evidence on whether phosphine — and perhaps life — resides in the Venusian atmosphere. 

Scientists study the Venusian atmosphere by analyzing spectra, or plots of light emanating from the planet, and analyzing the wavelengths. Because different molecules produce different wavelengths when light shines through them, scientists can ascertain chemical compositions of various substances using this method. Whenever looking at spectral data, there is the risk that “noise” — meaning, any variable that could alter the wavelengths for reasons unrelated to the composition of the chemical compounds studied — can cause inaccurate results. Notably, the phosphine spectrum from Venus was faint to begin with. 

According to one paper in the scientific journal Astronomy & Astrophysics, written by Thérèse Encrenaz of the Paris Observatory and her colleagues, archived data from an infrared spectrograph in Hawaii called TEXES did not find any indication of phosphine in their data collected between 2012 and 2015. However, the TEXES spectrographic data looked at the cloud tops of Venus, while the original paper claiming phosphine appears in the upper atmosphere analyzed a lower part of the atmosphere, below the cloud tops. 

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While this does not automatically disprove that phosphine exists in the atmosphere, it opens up logistical questions about how it would move around Venus’ atmosphere.

Another paper submitted to Astronomy & Astrophysics that calls into question the evidence for Venusian phosphine was posted online just last week. Authored by astrophysicist Ignas Snellen from Leiden University in the Netherlands and his colleagues, the paper analyzed the same data from the ALMA telescope array in Chile that scientists initially used to find evidence of phosphine on Venus. After reducing the noise, they too concluded that “the presented analysis does not provide a solid basis to infer the presence of PH3 in the Venus atmosphere.”

Though the phosphine discovery is not disproven, these findings certainly put a damper on the exciting prospect of life on the second planet from the sun. Likewise, such scientific call-and-responses epitomize how good research is done. 

“It’s exactly how science should work,” Paul Byrne, a planetary scientist at North Carolina State University in Raleigh, told Science News. “It’s too early to say one way or the other what this detection means for Venus.”

Clara Sousa-Silva, an astrochemist at the Harvard-Smithsonian Center for Astrophysics, expressed a similar view to Science News, telling the publication that

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Venus Is Dead! New Analysis Shows Phosphine, A Possible Biosignature, Is Absent

In one of the biggest surprises in the history of planetary science, a September 2020 study announced the presence of phosphine gas in Venus’s cloud decks: a tantalizing hint that could be due to biological processes. Phosphine (PH3), which is chemically similar to ammonia (NH3) except with phosphorus standing in for nitrogen, is only produced naturally on Earth by biochemical processes, but was claimed to exist on Venus at the 20 parts-per-billion level. With two separate observatories claiming this detection — both the JCMT and ALMA — the signal appeared to be quite robust.

The discovery raised the exciting possibility that Venus’s clouds are home to life, and that those biological life forms are producing this phosphine. Indeed, photochemical processes from the Sun’s radiation, chemical processes from thermodynamic atmospheric effects, and geochemical processes from surface chemistry reactions were all deemed insufficient for producing these levels of phosphine.

So, is it life? Maybe. But that’s assuming phosphine is actually present, and a new study has just been submitted that calls the entire detection into doubt. Here’s what it means, and why the evidence that Venus might be anything other than a completely dead, hellish planet might have just evaporated entirely.

Back in September, a team of scientists led by Professor Jane Greaves announced the discovery of phosphine by applying a well-known and very straightforward technique in astronomy.

  • They measured light in the radio part of the spectrum,
  • modeled the known components and conditions of the atmosphere from prior observations,
  • made a prediction for what signals should appear when the light was broken up into individual wavelengths,
  • made a prediction for what features should be present (or absent) if phosphine were actually there (or not),
  • and then break that light up, spectroscopically, to analyze that light to determine the presence and abundance of phosphine.

What they saw, in two independent data sets from both JCMT and ALMA, was an absorption feature at the same wavelength and of the same signal strength, indicating that something was there causing that radio light to be absorbed at a particular frequency. That frequency corresponds to a natural transition in phosphine molecules. If this analysis was performed correctly, it means that phosphine is really there.

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BepiColombo Snaps Incredible Venus Images

  • On October 15, the ESA/JAXA spacecraft BepiColombo swung by Venus, gathering critical data and snapping some incredible photos.
  • This week’s close approach was the first of two Venus flybys the spacecraft will make before reaching Mercury in 2025.
  • The ESA and JAXA launched BepiColombo—Europe’s first mission to Mercury—in October 2018.

    In October 2018, the European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) launched BepiColombo, Europe’s inaugural mission to Mercury. But before the spacecraft can get to the first planet, it’s taking a scenic Venusian detour.

    🌌 You like badass space stuff. So do we. Let’s explore the universe together.

    This week, BepiColombo swung past Venus and snapped a handful of incredible images of the gas-shrouded world. It’s the first of two scheduled flybys of Venus. Taking the long way ’round, so to speak, capitalizes on the planet’s gravitation pull in an effort to save fuel on the journey to Mercury.

    although it looks like an image of saturn thanks to one of bepicolombo's booms, this is an image from the spacecraft's first venus flyby
    Although it looks like an image of Saturn (thanks to one of BepiColombo’s booms), this is an image from the spacecraft’s first Venus flyby.

    ESA/JAXA

    The flyby follows last month’s news of researchers discovering traces of the chemical compound phosphine, which is considered a biomarker on Earth, in the clouds that shroud Venus. (The chemical is produced geochemically on other planets, such as inside the cores of Saturn and Jupiter, but there isn’t enough heat and pressure in the clouds of Venus for it to be generated this way.)

    Researchers noted shortly after the news broke that BepiColombo—already scheduled to do a close approach of Venus—could potentially point some of its instruments toward the cloud-shrouded planet. Right before the flyby, the BepiColombo team booted up two of the spacecraft’s three cameras and switched on a number of sensors.

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    “We’ll have to be patient while our Venus specialists look carefully into the data,” Johannes Benkhoff, ESA’s BepiColombo Project Scientist, said in a statement. “We hope to be able to provide some atmosphere temperature and density profiles, information about the chemical composition and cloud cover, and on the magnetic environment interaction between the Sun and Venus.”


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    During the flyby, BepiColombo came within more than 6,000 miles of Venus, according to ESA. The next flyby will take place in 2021 and will bring the spacecraft as close as 341 miles to the planet’s surface.

    BepiColombo is scheduled to arrive at Mercury in 2025 and will set

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    Astonishing New Images Show Venus Like You’ve Never Seen It Before

    From Popular Mechanics

    • On October 15, the ESA/JAXA spacecraft BepiColombo swung by Venus, gathering critical data and snapping some incredible photos.

    • This week’s close approach was the first of two Venus flybys the spacecraft will make before reaching Mercury in 2025.

    • The ESA and JAXA launched BepiColombo—Europe’s first mission to Mercury—in October 2018.

    In October 2018, the European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) launched BepiColombo, Europe’s inaugural mission to Mercury. But before the spacecraft can get to the first planet, it’s taking a scenic Venusian detour.

    🌌 You like badass space stuff. So do we. Let’s explore the universe together.

    This week, BepiColombo swung past Venus and snapped a handful of incredible images of the gas-shrouded world. It’s the first of two scheduled flybys of Venus. Taking the long way ’round, so to speak, capitalizes on the planet’s gravitation pull in an effort to save fuel on the journey to Mercury.

    Photo credit: ESA/JAXA
    Photo credit: ESA/JAXA

    The flyby follows last month’s news of researchers discovering traces of the chemical compound phosphine, which is considered a biomarker on Earth, in the clouds that shroud Venus. (The chemical is produced geochemically on other planets, such as inside the cores of Saturn and Jupiter, but there isn’t enough heat and pressure in the clouds of Venus for it to be generated this way.)

    Researchers noted shortly after the news broke that BepiColombo—already scheduled to do a close approach of Venus—could potentially point some of its instruments toward the cloud-shrouded planet. Right before the flyby, the BepiColombo team booted up two of the spacecraft’s three cameras and switched on a number of sensors.

    “We’ll have to be patient while our Venus specialists look carefully into the data,” Johannes Benkhoff, ESA’s BepiColombo Project Scientist, said in a statement. “We hope to be able to provide some atmosphere temperature and density profiles, information about the chemical composition and cloud cover, and on the magnetic environment interaction between the Sun and Venus.”

    🚀 Our Favorite LEGO Space Kits

    During the flyby, BepiColombo came within more than 6,000 miles of Venus, according to ESA. The next flyby will take place in 2021 and will bring the spacecraft as close as 341 miles to the planet’s surface.

    BepiColombo is scheduled to arrive at Mercury in 2025 and will set out to demystify one of the strangest and most mysterious planets in our solar system. The mission is a two-for-one deal: One orbiter, the Mercury Planetary Orbiter (MPO), will map our solar system’s innermost planet, while another, the Mercury Magnetospheric Orbiter (Mio), will measure the planet’s magnetosphere in detail.

    Mercury won’t be an easy place to explore. According to ESA, the spacecraft could be exposed to temperatures of up to 662 degrees Fahrenheit during its year-long orbit of the planet.

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    A spacecraft en route to Mercury just caught this fresh new look at Venus

    BepiColombo, a Mercury-bound mission jointly run by the European Space Agency and the Japan Aerospace Exploration Agency (JAXA), is snapping up a wealth of new images and collecting some new data that may tease out new clues about the Venusian atmosphere—and whether it could be home to extraterrestrial life.

    What happened: On Thursday morning, as part of a long journey to Mercury, BepiColombo made a close pass of Venus at a distance of about 6,660 miles. The flyby is meant to use Venus’s gravity as a speed-reducing force to adjust the trajectory of the spacecraft on to its eventual destination. 

    Hype of life: Although the flyby was planned for maneuvering purposes, it afforded scientists an opportunity for a closer look at Venus. The interest around the flyby is bigger since last month’s revelations that Venus’s clouds contain phosphine, a possible sign that there is biological activity on the planet. If the phosphine is there, then there’s a good chance it’s a result of biology, and that means life might be residing within the thick, carbon-rich atmosphere. However, it’s also possible those traces of phosphine might be the result of exotic natural chemistry not found on Earth. Still cool, but not aliens.

    What did the mission actually observe? Most of BepiColombo’s instruments are still stored away until the rendezvous with Mercury—including its primary camera. Those that are functional at the moment (10 in total) are still designed primarily for studying the atmosphere-less Mercury. But there are still some bits of data the spacecraft collected that may be useful. 

    bepicolombo venus flyby
    A sequence of images taken during BepiColombo’s flyby of Venus on October 15.

    ESA/BEPICOLOMBO/MTM

    Two smaller cameras facing the spacecraft itself are turned on, and they managed to take several photos of Venus (obscured a bit by the probe’s magnetometer and antenna). An onboard spectrometer (which measures emissions of electromagnetic wavelengths to unravel the chemistry of other objects) took over 100,000 spectral images of the Venusian atmosphere. Other instruments studied the planet’s temperature and density as well as its magnetic environment and how it interacts with solar winds. 

    Don’t hold your breath: It’s unlikely that the spectrometer and other activated instruments were able to study phosphine molecules on Venus during this flyby. But they might be able to hint at the presence of other biosignatures that could bolster evidence for possible life on Venus. 

    Moreover, this first flyby of Venus could be thought of as a practice run for a second one BepiColombo will make in August 2021. Now that the mission team has a better sense of how to better calibrate these instruments to study Venus more closely, they’ll have a better opportunity to do some better data collection next year, when the distance will shrink down to just 340 miles. The chances of detecting phosphine on that flyby are still slim, but not zero. And traces of other biosignatures could be spotted too.

    And what about Mercury? The mission will make its first flyby of Mercury the following October. The three

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    Is There Life On Venus? ESA Rocket To Skim Planet For Signs Of Life

    KEY POINTS

    • Phosphine has been found in the clouds of Venus
    • The discovery has led scientists to look more into Venus and its atmosphere
    • BepiColombo will make its first close approach with Venus on Oct. 14

    It was only a month ago when scientists discovered phosphine was present in the clouds on Venus — an indicator that there may be life on the planet. Luckily, BepiColombo will be flying by the Earth’s sister planet this Wednesday, Oct. 14 — giving scientists a chance to confirm if these observations are due to possible lifeforms on the planet.

    When the subject of Venus comes up in a conversation, it is almost inevitable to bring up its extreme temperatures, toxic gases and dangerously crushing air pressure. A recent discovery of the presence of phosphine on the planet’s clouds has led scientists and researchers to think about the possibility of life on Venus, according to an article by Astronomy.com on Oct. 14.

    Phosphine is a toxic gas that can only be produced by microbial life. To date, there are no known non-biological processes that could create this gas on Venus. However, the presence of phosphine could also be due to some unknown chemical processes occurring on the planet, so this alternative reason is always in scientists’ peripheral.

    The scientists looking into this are determined to do more research to answer this mind-boggling question and are happy to know that BepiColombo will be making its close encounter with the sister planet tonight, Oct. 14, at 11:58 EDT, when it will be 30 times closer to Venus than the Akatsuki spacecraft, an orbiter designed to study Venus’ atmosphere. BepiColombo is expected to fly by at a distance of 10,720 kilometers from Venus’ surface.

    Although BepiColombo isn’t necessarily designed for Venus, its close approach gives scientists an opportunity to look into Venus’ atmosphere up close. A number of the spacecraft’s instruments are also capable of studying the chemical composition and cloud cover of the planet’s atmosphere, which will allow scientists to gather more information on the planet.

    BepiColombo’s first flyby won’t be able to procure all the data needed by researchers to find out if life does exist on Venus, but its second flyby looks more promising. During this time, the spacecraft will be zipping past Venus at a close distance of just 550 kilometers away from its surface.

    BepiColombo is a joint spacecraft made by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). It was launched in 2018 with the sole purpose of heading to the innermost planet, Mercury, and exploring it.
     

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