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NASA’s Hubble, MAVEN Help Solve the Mystery of Mars’ Escaping Water
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NASA’s Hubble, MAVEN Help Solve the Mystery of Mars’ Escaping Water NASA, ESA, STScI, John T. Clarke (Boston University); Processing: Joseph DePasquale (STScI)Mars was once a very wet planet as is evident in its surface geological features. Scientists know that over the last 3 billion years, at least some water went deep underground, but what happened to the rest? Now, NASA’s Hubble Space Telescope and MAVEN (Mars Atmosphere and Volatile Evolution) missions are helping unlock that mystery.
“There are only two places water can go. It can freeze into the ground, or the water molecule can break into atoms, and the atoms can escape from the top of the atmosphere into space,” explained study leader John Clarke of the Center for Space Physics at Boston University in Massachusetts. “To understand how much water there was and what happened to it, we need to understand how the atoms escape into space.”
Clarke and his team combined data from Hubble and MAVEN to measure the number and current escape rate of the hydrogen atoms escaping into space. This information allowed them to extrapolate the escape rate backwards through time to understand the history of water on the Red Planet.
Escaping Hydrogen and “Heavy Hydrogen”Water molecules in the Martian atmosphere are broken apart by sunlight into hydrogen and oxygen atoms. Specifically, the team measured hydrogen and deuterium, which is a hydrogen atom with a neutron in its nucleus. This neutron gives deuterium twice the mass of hydrogen. Because its mass is higher, deuterium escapes into space much more slowly than regular hydrogen.
Over time, as more hydrogen was lost than deuterium, the ratio of deuterium to hydrogen built up in the atmosphere. Measuring the ratio today gives scientists a clue to how much water was present during the warm, wet period on Mars. By studying how these atoms currently escape, they can understand the processes that determined the escape rates over the last four billion years and thereby extrapolate back in time.
Although most of the study’s data comes from the MAVEN spacecraft, MAVEN is not sensitive enough to see the deuterium emission at all times of the Martian year. Unlike the Earth, Mars swings far from the Sun in its elliptical orbit during the long Martian winter, and the deuterium emissions become faint. Clarke and his team needed the Hubble data to “fill in the blanks” and complete an annual cycle for three Martian years (each of which is 687 Earth days). Hubble also provided additional data going back to 1991 – prior to MAVEN’s arrival at Mars in 2014.
The combination of data between these missions provided the first holistic view of hydrogen atoms escaping Mars into space.
These are far-ultraviolet Hubble images of Mars near its farthest point from the Sun, called aphelion, on December 31, 2017 (top), and near its closest approach to the Sun, called perihelion, on December 19, 2016 (bottom). The atmosphere is clearly brighter and more extended when Mars is close to the Sun.Reflected sunlight from Mars at these wavelengths shows scattering by atmospheric molecules and haze, while the polar ice caps and some surface features are also visible. Hubble and MAVEN showed that Martian atmospheric conditions change very quickly. When Mars is close to the Sun, water molecules rise very rapidly through the atmosphere, breaking apart and releasing atoms at high altitudes. NASA, ESA, STScI, John T. Clarke (Boston University); Processing: Joseph DePasquale (STScI)
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A Dynamic and Turbulent Martian Atmosphere
“In recent years scientists have found that Mars has an annual cycle that is much more dynamic than people expected 10 or 15 years ago,” explained Clarke. “The whole atmosphere is very turbulent, heating up and cooling down on short timescales, even down to hours. The atmosphere expands and contracts as the brightness of the Sun at Mars varies by 40 percent over the course of a Martian year.”
The team discovered that the escape rates of hydrogen and deuterium change rapidly when Mars is close to the Sun. In the classical picture that scientists previously had, these atoms were thought to slowly diffuse upward through the atmosphere to a height where they could escape.
But that picture no longer accurately reflects the whole story, because now scientists know that atmospheric conditions change very quickly. When Mars is close to the Sun, the water molecules, which are the source of the hydrogen and deuterium, rise through the atmosphere very rapidly releasing atoms at high altitudes.
The second finding is that the changes in hydrogen and deuterium are so rapid that the atomic escape needs added energy to explain them. At the temperature of the upper atmosphere only a small fraction of the atoms have enough speed to escape the gravity of Mars. Faster (super-thermal) atoms are produced when something gives the atom a kick of extra energy. These events include collisions from solar wind protons entering the atmosphere or sunlight that drives chemical reactions in the upper atmosphere.
Mars was once a very wet planet. Scientists know that over the last 3 billion years, some of the water went underground, but what happened to the rest? Credit: NASA’s Goddard Space Flight Center; Lead Producer: Paul Morris; Mars Animations Producer: Dan Gallagher Serving as a ProxyStudying the history of water on Mars is fundamental not only to understanding planets in our own solar system but also the evolution of Earth-size planets around other stars. Astronomers are finding more and more of these planets, but they’re difficult to study in detail. Mars, Earth and Venus all sit in or near our solar system’s habitable zone, the region around a star where liquid water could pool on a rocky planet; yet all three planets have dramatically different present-day conditions. Along with its sister planets, Mars can help scientists grasp the nature of far-flung worlds across our galaxy.
These results appear in the July 26 edition of Science Advances, published by the American Association for the Advancement of Science.
About the MissionsThe Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
MAVEN’s principal investigator is based at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder. LASP is also responsible for managing science operations and public outreach and communications. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN mission. Lockheed Martin Space built the spacecraft and is responsible for MAVEN mission operations at Goddard. NASA’s Jet Propulsion Laboratory in Southern California provides navigation and Deep Space Network support. The MAVEN team is preparing to celebrate the spacecraft’s 10th year at Mars in September 2024.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubbleMedia Contacts:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Ann Jenkins and Ray Villard
Space Telescope Science Institute, Baltimore, MD
Science Contact:
John T. Clarke
Boston University, Boston, MA
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble Science Highlights
MAVEN
The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission is the first mission devoted to understanding the Martian upper atmosphere.
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BepiColombo's best images yet highlight fourth Mercury flyby
The ESA/JAXA BepiColombo mission has successfully completed its fourth of six gravity assist flybys at Mercury, capturing images of two special impact craters as it uses the little planet’s gravity to steer itself on course to enter orbit around Mercury in November 2026.
The closest approach took place at 23:48 CEST (21:48 UTC) on 4 September 2024, with BepiColombo coming down to around 165 km above the planet’s surface. For the first time, the spacecraft had a clear view of Mercury’s south pole.
Eclipses Create Atmospheric Gravity Waves, NASA Student Teams Confirm
Student teams from three U.S. universities became the first to measure what scientists have long predicted: eclipses can generate ripples in Earth’s atmosphere called atmospheric gravity waves. The waves’ telltale signature emerged in data captured during the North American annular solar eclipse on Oct. 14, 2023, as part of the Nationwide Eclipse Ballooning Project (NEBP) sponsored by NASA.
Through NEBP, high school and university student teams were stationed along the eclipse path through multiple U.S. states, where they released weather balloons carrying instrument packages designed to conduct engineering studies or atmospheric science experiments. A cluster of science teams located in New Mexico collected the data definitively linking the eclipse to the formation of atmospheric gravity waves, a finding that could lead to improved weather forecasting.
“Climate models are complicated, and they make some assumptions about what atmospheric factors to take into account.”Angela Des Jardins
Director of the Montana Space Grant Consortium, which led NEBP.
“Understanding how the atmosphere reacts in the special case of eclipses helps us better understand the atmosphere, which in turn helps us make more accurate weather predictions and, ultimately, better understand climate change.”
Catching Waves in New MexicoPrevious ballooning teams also had hunted atmospheric gravity waves during earlier eclipses, research that was supported by NASA and the National Science Foundation. In 2019, an NEBP team stationed in Chile collected promising data, but hourly balloon releases didn’t provide quite enough detail. Attempts to repeat the experiment in 2020 were foiled by COVID-19 travel restrictions in Argentina and a heavy rainstorm that impeded data collection in Chile.
Project leaders factored in these lessons learned when planning for 2023, scheduling balloon releases every 15 minutes and carefully weighing locations with the best potential for success.
“New Mexico looked especially promising,” said Jie Gong, a researcher in the NASA Climate and Radiation Lab at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, and co-investigator of the research on atmospheric gravity waves. “The majority of atmospheric gravity sources are convection, weather systems, and mountains. We wanted to eliminate all those possible sources.”
The project created a New Mexico “supersite” in the town of Moriarty where four atmospheric science teams were clustered: two from Plymouth State University in Plymouth, New Hampshire, and one each from the State University of New York (SUNY) Albany and SUNY Oswego.
Students began launching balloons at 10 a.m. the day before the eclipse.
“They worked in shifts through the day and night, and then everyone was on site for the eclipse,” said Eric Kelsey, research associate professor at Plymouth State and the NEBP northeast regional lead.
“Our hard work really paid off. The students had a real sense of accomplishment.”Eric Kelsey
Research Associate Professor at Plymouth State and the NEBP Northeast Regional Lead.
Each balloon released by the science teams carried a radiosonde, an instrument package that measured temperature, location, humidity, wind direction, and wind speed during every second of its climb through the atmosphere. Radiosondes transmitted this stream of raw data to the team on the ground. Students uploaded the data to a shared server, where Gong and two graduate students spent months processing and analyzing it.
Confirmation that the eclipse had generated atmospheric gravity waves in the skies above New Mexico came in spring 2024.
“We put all the data together according to time, and when we plotted that time series, I could already see the stripes in the signal,” Gong said. “I bombarded everybody’s email. We were quite excited.”
Plymouth State University students Sarah Brigandi, left, and Sammantha Boulay release a weather balloon from Moriarty, New Mexico, to collect atmospheric data on Oct. 14, 2023.NASA For Students, Learning Curves Bring OpportunityThe program offered many students their first experience in collecting data. But the benefits go beyond technical and scientific skill.
“The students learned a ton through practicing launching weather balloons,” Kelsey said. “It was a huge learning curve. They had to work together to figure out all the logistics and troubleshoot. It’s good practice of teamwork skills.”
“All of this is technically complicated,” Des Jardins said. “While the focus now is on the science result, the most important part is that it was students who made this happen.”
NASA’s Science Mission Directorate Science Activation program funds NEBP, along with contributions from the National Space Grant College and Fellowship Project and support from NASA’s Balloon Program Office.
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Explaining Different Kinds of Meteor Showers. It’s the Way the Comet Crumbles
The Universe often puts on a good show for us down here on Earth but one of the best spectacles must be a meteor shower. We see them when particles, usually the remains of comets, fall through our atmosphere and cause the atmosphere to glow. We see them as a fast moving streak of light but a new paper has suggested that the meteor showers we see can explain the sizes of the particles that originally formed the comet from where they came.
Comets are mostly composed of ice but with a little rock mixed in for good measure. They’ve often been called dirty snowballs to describe this mix of ice and rock. They travel around the Sun in elongated, elliptical orbits which bring them close to the Sun. The intense heat from the Sun causes the ice to instantly turn into a gas in a process known as sublimation which releases the trapped dust. The pressure from the Sun known as the solar wind presses against the gas and dust released from a comet to produce the tail which always points away from the Sun.
A recent animation of Comet 12P. Image credit: Michael Jaeger.As the comet travels around the Solar System, it deposits debris along its orbit almost like a trail of celestial breadcrumbs. The debris at this stage is known as meteoroids but, if the Earth travels through it then they create the stunning meteors that we see streak across the sky. The Earth passes through the debris field from a number of comets on a regular, annual basis and this gives rise to the regular meteor showers we see such as he Perseids or Leonids.
A Geminid meteor outburst from 2020. Image credit and copyright: Jeff SullivanA team of 45 researchers have been studying meteor showers and have discovered something rather curious. They have found that not all comets crumble in the same way as they approach the Sun. The team studied 47 young meteor showers by using special low light video cameras all over the world. The cameras measured the path of the meteors enabling the team to work out how high up they were when they first light up and how they then slowed down in the atmosphere. They were also able to measure the composition enabling them to deduce the size of the particles.
In a paper published in the journal Icarus, the team theorised that a comet will simply crumble into the size of the ‘pebbles’ they are made of. This does seem to make complete sense given that the comets form as chunks of dust, rock and ice. More ice will slowly form as the comet orbits out in the dark cold reaches of the Solar System but as it heats on its journey inwards, it will just fall apart again as the ice sublimates.
The results of the paper showed that longer period comets, such as those originating in the Oort Cloud generally crumble into sizes of particulates indicative of slow and gentle accretion conditions. The resultant meteoroids have a lower density and tend to only brighten deeper into the Earth’s atmosphere. Comets from the Jupiter-family on the other hand crumble up into smaller, denser meteoroids with 8% more solid material on average.
There are a few meteor showers that originate from asteroids and these too have been studied. The team found that they tend to produce meteor showers with smaller particles that have evidence of aggressive fragmentation during their formation. The team acknowledge there will be exceptions to their findings but it their study has helped to build a more fuller picture of the early stages of the evolution of the Solar System and to the nature of comets that grant us the beauty of meteor showers.
Source : Meteor showers shed light on where comets formed in the early solar system
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Sentinel-2C launch highlights
The Copernicus Sentinel-2C satellite lifted off on 5 September at 03:50 CEST (4 September 22:50 local time) aboard the last Vega rocket, flight VV24, from Europe’s Spaceport in French Guiana.
Sentinel-2C will continue the legacy of delivering high-resolution data that are essential to Copernicus – the Earth observation component of the EU Space Programme. Developed, built and operated by ESA, the Copernicus Sentinel-2 mission provides high-resolution optical imagery for a wide range of applications including land, water and atmospheric monitoring.
Sentinel-2C was the last liftoff for the Vega rocket – after 12 years of service this was the final flight, the original Vega is being retired to make way for an upgraded Vega-C.
Sol 4294: Return to McDonald Pass
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Sol 4294: Return to McDonald Pass This image was taken by Front Hazard Avoidance Camera (Front Hazcam) aboard NASA’s Mars rover Curiosity on sol 4293 — Martian day 4,293 of the Mars Science Laboratory mission — Sept. 3, 2024 at 04:09:27 UTC. NASA/JPL-CaltechEarth planning date: Tuesday, Sept. 3, 2024
Curiosity has returned to “McDonald Pass,” a block within Gediz Vallis that we first spotted about a month ago (as seen in the above Front Hazcam image). The block shows some interesting zonation — the distribution of textures and colors into different areas, or zones. We’re hoping that by studying the well-exposed relationships between white, gray, and tan material at this location that we’ll be able to better understand similar relationships that we’ve observed elsewhere. The drive over the weekend got us back to McDonald Pass, but perhaps one step too far. We realized that the best spot to study these zones is directly beneath the rover, so today’s plan includes contact science and a short bump to position the rover for even more science tomorrow.
Today was a rare one-sol plan, to account for the U.S. holiday yesterday. I was on shift as the Long Term Planner and it was a fairly straightforward day once we established the best locations for contact science. The plan starts with a DRT and APXS on the central part of the slab, at a target named “Erin Lake.” Then we have a remote sensing block, which begins with some environmental monitoring to search for dust devils, measure atmospheric opacity, and monitor the movement of fines on the rover deck. The Geology Theme group planned ChemCam LIBS on the darker gray rim of this block at “Paris Lake,” along with a ChemCam passive observation on an interesting dark float block nearby. There’s also a long distance RMI mosaic to assess the yardang unit higher on Mount Sharp, and a Mastcam mosaic to evaluate the textures in a row of large clasts. Later in the afternoon, Curiosity will acquire MAHLI images of Erin Lake and another target, “Picture Puzzle,” which captures the white, gray, and tan zones. Then Curiosity will take a short drive back about 1 meter (about 3.3 feet) to position a white and gray clast in our workspace for even more contact science tomorrow.
Will McDonald Pass be the key to understanding the zonation observed in blocks throughout this region? Stay tuned!
Written by Lauren Edgar, Planetary Geologist at USGS Astrogeology Science Center
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Sols 4291-4293: Fairview Dome, the Sequel
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Sols 4291-4293: Fairview Dome, the Sequel This image was taken by Left Navigation Camera aboard NASA’s Mars rover Curiosity on sol 4289 — Martian day 4,289 of the Mars Science Laboratory mission — on Aug. 30, 2024 at 03:48:38 UTC. To the left of the crescent-shaped formation in the low-center part of the image, a wheel track is visible along with an “intriguing” batch of shattered rock where Curiosity had previously driven. NASA/JPL-CaltechEarth planning date: Friday, Aug. 30, 2024
Our backwards drive to “McDonald Pass” got hung up on the steep slopes of “Fairview Dome,” but unlike a lot of movie sequels, our inadvertent return visit to Fairview Dome was at least as good as the original. We took full advantage of the chance to investigate this bedrock rise within Gediz Vallis with multiple contact and remote science targets.
MAHLI and APXS paired up on two different DRT targets of more- and less-nodular spots of bedrock at “Lower Boy Scout Lake” and “Upper Boy Scout Lake.” You can see in the Navcam image above that just beyond the bedrock slab we stopped on, there is a wheel track and a shattered batch of rock. We crushed that bit of rock as we drove backward and were left with a great view of it, including some intriguing bright rock interiors. ChemCam targeted one of those bright rock faces at “North Palisade” and Mastcam acquired a mosaic across the whole field of broken rocks at “Ritter-Banner Saddle.” The churned-up sand of Ritter-Banner Saddle also made for a convenient change detection target as we keep our eye on the wind effects of a potential dust storm rising on Mars. ChemCam had two other opportunities for LIBS analyses at a nodular bedrock target called “Regulation Peak,” and another intriguing vertical rock face with strong color differences called “Simmons Peak.” ChemCam used RMI mosaics to image a collection of higher albedo rocks in Gediz Vallis at a site called “Buckeye Ridge.” Mastcam planned a mosaic of a different part of Gediz Vallis that is in the direction we are driving next, which will help plot those drives and also give us some insight into the boulders strewn about that part of the valley. Closer to the rover, the “Outguard Spire” target was of interest for Mastcam imaging because of its color zonation — the way colors are distributed across different areas, or zones, of the rock. It’s the kind of zonation we intend to study at McDonald Pass. The trough of sand at the “Whitney-Russell Pass” target was of interest for its potential insights into how bedrock blocks break up on Mars.
Monitoring the potential rise of a dust storm meant that the plan was busy with environmental observations. ChemCam acquired a passive sky observation, Navcam collected two rounds of dust-devil imaging, cloud movies, and atmospheric dust measurements, Mastcam acquired multiple atmospheric dust measurements, and REMS ran in longer blocks throughout each sol than it does in normal weather conditions. Dust or not, RAD and DAN passive were planned regularly through the three sols of the plan.
Written by Michelle Minitti, Planetary Geologist at Framework
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Sentinel-2C joins the Copernicus family in orbit
The third Copernicus Sentinel-2 satellite launched today aboard the final Vega rocket from Europe’s Spaceport in French Guiana. Sentinel-2C will continue providing high-resolution data that is essential to Copernicus – Europe’s world leading Earth observation programme.
Sentinel-2C launched into orbit on 5 September at 03:50 CEST (4 September 22:50 local time) and separated from the Vega rocket at approximately 04:48 CEST.
Dark Oxygen Could Change Our Understanding of Habitability
The discovery of dark oxygen at an abyssal plain on the ocean floor generated a lot of interest. Could this oxygen source support life in the ocean depths? And if it can, what does that mean for places like Enceladus and Europa?
What does it mean for our notion of habitability?
Oxygen is key to complex life on Earth, where photosynthesis generates most of it. The Great Oxygenation Event (GOE), which occurred about 2.5 billion years ago, led to the development of complex life and changed Earth forever. In the GOE, the oxygen was generated by living things.
Our notions of habitability rest on a planet’s proximity to its star, and part of that is because we know that the Sun drives life on Earth by allowing water to remain liquid and providing energy for organisms. But dark oxygen on the ocean floor is strictly abiotic, meaning no life was involved in its production and sunlight isn’t involved.
In recent years, we’ve learned that other Solar System bodies, far beyond the circumstellar habitable zone, could be habitable. The icy ocean moons of Europa, Ganymede, and Enceladus may harbour vast, warm oceans under frigid caps of ice. If Earth produces dark oxygen on its ocean floors, maybe these worlds do, too.
New research examines Earth’s dark oxygen and what it might mean for biology here and on other worlds. It’s titled “Dwellers in the Deep: Biological Consequences of Dark Oxygen.” The lead author is Manasvi Lingam from the Department of Aerospace, Physics, and Space Sciences at the Florida Institute of Technology. The research is awaiting peer review.
Dark oxygen comes from metal deposits called polymetallic nodules. These nodules generate enough electricity to drive electrolysis, which splits water molecules apart and releases oxygen. The amount of oxygen is not large, but it’s there, and it’s measurable.
By Hannes Grobe/AWI – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=104756773“The striking recent putative detection of “dark oxygen” (dark O2) sources on the abyssal ocean floor in the Pacific at ~4 km depth raises the intriguing scenario that complex (i.e., animal-like) life could exist in underwater environments sans oxygenic photosynthesis,” the authors write.
The amount of dark oxygen in the ocean is small, which limits the size of organisms. Organisms use oxygen through diffusion and circulation, and oxygen levels place restraints on the sizes of both types.
Diffusion is a simple process in which nutrients, waste, and water diffuse through a few layers of tissue. Circulation is more complex and involves a heart pumping fluid to an organism’s cells, delivering nutrients and removing waste. The amount of environmental oxygen places limits on the sizes of both types of organisms.
“The maximal sizes attainable by idealized unicellular or multicellular organisms (i.e., constrained by internal or external diffusion processes) for the estimated concentrations of dark O2 may be ~ 0.1–1 mm.,” the authors write.
For animals with circulation systems, the upper size boundary is higher but still limited.
“In contrast, the upper-size bounds of organisms with internal circulation systems for the distribution of oxygen could range between ~ 0.1 cm to ~ 10 cm, with the latter threshold falling under the umbrella of “megafauna,” the researchers explain.
Aside from the size of individual organisms, there’s the overall biomass density. In an optimistic scenario, the researchers report that biomass density could exceed the reported density. “Under optimistic circumstances, the biomass densities might reach as high as ~ 3–30 g m?2, in principle exceeding the reported macrofaunal densities at depths of ~ 4 km in global deep-sea surveys,” the authors write.
This work inspires a multitude of questions. We know that microorganisms in groundwater use dark oxygen. What types of microorganisms have adapted to these ocean dark oxygen environments? What about their metabolism allows them to live there? Have larger organisms adapted to these environments? Did organisms in these environments play a role in the evolution of life on Earth?
The discovery also compels us to consider its implications for astrobiology. On Earth, abyssal deep sea plains represent about 70% of the ocean floor, making them the largest ecosystem on Earth. Even with a low biomass density, the region is significant.
This cross-section of an oceanic basin shows the relationship of the abyssal plain to a continental rise and an oceanic trench. On Earth, 70% of the sea floor is abyssal plain, making it the largest ecosystem on Earth. Image Credit: By Chris_huh – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1812130When considering the habitability of the ocean moons, we’re at a disadvantage. We don’t know what the sea floors look like on these bodies. In fact, despite all of the enthusiasm, we don’t even know for certain if these moons have oceans. We also don’t know if the oceans, if any of them exist, can produce polymetallic nodules that generate dark oxygen.
However, there are other ways dark oxygen can be generated without nodules. One of them is radiolysis.
Radiolysis is the breaking apart of molecules by ionizing radiation, and there’s plenty of that in the vicinity of Jupiter. Spacecraft have spotted O2 trapped in bubbles on Europa, Ganymede, and Callisto. Does that mean it’s available for life that might exist in their hypothetical oceans?
Radiation from Jupiter can break apart molecules on Europa’s surface. This can free oxygen, which could percolate in brines through the surface into the ocean under the ice. Credit: NASA/JPL-Caltech“The production of oxidants on the surface and their delivery to the ocean can effectively input O2 to the latter even sans photosynthesis,” the authors explain. Europa’s icy shell isn’t all solid ice. Scientists think that briny liquid can percolate through the ice, and that could potentially deliver surface dark oxygen to the ocean.
There’s a third pathway for dark oxygen called microbial dismutation. Though it’s biotic, it doesn’t rely on photosynthesis. It could be an overlooked source of oxygen.
The evidence we have so far says that worlds like Earth are extremely rare, while environments like Europa could be widespread. “To round off our preliminary venture into this eclectic subject, we reiterate our
prefatory statement that marine habitable settings implausible for photosynthesis, especially on icy worlds with subsurface oceans, are likely widespread in the Universe,” the authors write in their conclusion.
“Therefore, if dark oxygen production is feasible and commonplace on this class of worlds – whether via seawater electrolysis or the prior two routes – then our analysis may broadly encapsulate the profound consequences of dark oxygen for the prevalence of abiogenesis, complex multicellularity, and perhaps even technological intelligence in the Cosmos,” the authors explain.
The fact that we’ve only now discovered dark oxygen on the ocean floor should make us all pause. We’re discovering things about nature that could be critical in the search for life and habitable worlds. If we can confirm that the so-called ocean moons really do have oceans and that dark oxygen is either produced in or transported to those oceans, then we have to adapt our thinking about habitability. Proximity to a star may not be critical, which would simultaneously broaden our understanding while deepening the mystery of life in the cosmos.
That’s the intriguing part of science. It’s equal part mysteries and answers.
The post Dark Oxygen Could Change Our Understanding of Habitability appeared first on Universe Today.
