Category: The Search for Life Beyond Earth (page 1 of 9)

Tantalizing Organic Compounds Found on Mars

The NASA/ESA Perseverance rover on xxx. New findings tell of the presence of organic material — the building blocks of life — in several locations at Jezero Crater — for the first time found in igneous rock.  The long-ago environment when the organics were deposited were deemed to have been “habitable.” (NASA/JPL-Caltech/MSSS)

When searching for signs of ancient life on Mars, NASA scientists increasingly focus on organic material — the carbon-based compounds that are the building blocks of life.  Organics were found by the Curiosity rover in Gale Crater, and now new papers report they have also been identified by the instruments of the Perseverance rover in very different kinds of rock in Jezero Crater.

Unlike the Gale Crater organics that were found in sedimentary rocks, these newly found specimens are in igneous rocks — formed when molten rock cools and crystallizes — and are mixed with other compounds known to preserve organics well.

These rock samples are part of the NASA and European Space Agency Mars Sample Return mission, and so they could be brought to Earth in the future for more intensive study. Scientists are excited about what might some day be found.

The new findings about organics and the geology of Jezero Crater are part of a trio of articles in the journal Science published Wednesday.

The lead author of one of the papers, Michael Tice of Texas A&M University, gave this overview of what the Perseverance team is reporting:

“These three papers show that samples collected in the floor of Jezero should be able to tell us a lot about whether living organisms ever inhabited rocks under the surface of the crater over the past several billion years,”  he wrote to me.

The paper he led, Tice said, shows that small amounts of water passed through those rocks at three different times, and that conditions at each of those times could have supported life. “Even more importantly, minerals were formed from the water that are known to be able to preserve organic matter and even fossils on Earth.”

Different kinds of carbon-based organic compounds were viewed within a rock called “Garde” by SHERLOC, one of the instruments on the end of the robotic arm aboard the Perseverance rover. The rover used its drill grind away a patch of rock so that SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) could analyze its interior.

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Where Might Plumes of Water Vapor Come From on Icy Moons?

This illustration depicts a plume of water vapor that could potentially be emitted from the icy surface of Jupiter’s moon Europa. New research sheds light on what plumes, if they do exist, could reveal about lakes that may be inside the moon’s crust. (NASA/ESA/K. Retherford/SWRI)

It’s been some years since Europa scientists agreed that the Jovian moon has a large global ocean beneath miles of ice.  More recently, scientists have identified what they view as pockets of water surrounded by ice but much nearer the surface than the ocean below.  And there has been research as well into what may be salty, slushy pocket of water further down in the ice covering.

With NASA’s mission to Europa scheduled to launch in about two years, modeling of these all potential collections of liquid water has picked up to prepare for the Europa Clipper arrival to come.

The latest research into what the subsurface lakes on Europa may look like and how they may behave comes in a recently published paper in Planetary Science Journal.

A key finding supports the idea that water could potentially erupt above the surface of Europa either as plumes of vapor or as cryovolcanic activity —  flowing, slushy ice rather than molten lava.

Computer modeling in the paper goes further, showing that if there are eruptions on Europa, they likely come from shallow, wide lakes embedded in the ice and not from the global ocean far below.

“We demonstrated that plumes or cryolava flows could mean there are shallow liquid reservoirs below, which Europa Clipper would be able to detect,” said Elodie Lesage, Europa scientist at NASA’s Jet Propulsion Laboratory and lead author of the research.

“Our results give new insights into how deep the water might be that’s driving surface activity, including plumes. And the water should be shallow enough that it can be detected by multiple Europa Clipper instruments.”

A minimally processed version of this image was captured by JunoCam, the public engagement camera aboard NASA’s Juno spacecraft. It was taken during the mission’s close flyby earlier this fall, almost 950 miles above the moon’s surface. The raw image was processed by “citizen scientist” Navaneeth Krishnan to add enhanced color contrast that allow larger surface features to stand out more.

The question of whether or not Europa has plumes is not settled.  While the plumes coming from Saturn’s moon Enceladus have been well studied and even had a spacecraft fly through one, Europa has only some fuzzy Hubble Space Telescope, Galileo mission and ground-based telescope images that suggest a plume.… Read more

The Virtual Planetary Lab and Its Search for What Makes an Exoplanet Habitable, or Even Inhabited

As presented by the Virtual Planetary Laboratory, exoplanet habitability is a function of the interplay of processes between the planet, the planetary system, and host star.  These interactions govern the planet’s evolutionary trajectory, and have a larger and more diverse impact on a planet’s habitability than its position in a habitable zone. (Meadows and Barnes)

For more than two decades now, the Virtual Planetary Laboratory (VPL) at the University of Washington in Seattle has been at the forefront of the crucial and ever-challenging effort to model how scientists can determine whether a particular exoplanet is capable of supporting life or perhaps even had life on it already.

To do this, VPL scientists have developed or combined models from many disciplines that characterize and predict a wide range of planetary, solar system and stellar attributes that could identify habitability, or could pretty conclusively say that a planet is not habitable.

These include the well known questions of whether water might be present and if so whether temperatures would allow it to be sometimes in a liquid state, but on to questions involving whether an atmosphere is present, what elements and compounds might be in the atmospheres, the possible orbital evolution of the planet, the composition of the host star and how it interacts with a particular orbiting planet and much, much more, as shown in the graphic above.

This is work that has played a significant role in advancing astrobiology — the search for life beyond Earth.

More specifically, the VPL approach played a considerable part in building a body of science that ultimately led the Astro2020 Decadal Study of the National Academy of Sciences to recommend last year that the NASA develop its  first Flagship astrobiology project — a mission that will feature a huge space telescope able to study exoplanets for signs of biology in entirely new detail.  That mission, approved but not really defined yet, is not expected to launch until the 2040s.

With that plan actually beginning to move forward, the 132 VPL affiliated researchers at 28 institutions find themselves at another more current-day inflection point:  The long-awaited James Webb Space Telescope has begun to collect and send back what will be a massive and unprecedented set of spectra  of chemicals from the atmospheres of distant planets.

The Virtual Planetary Laboratory has modeled the workings of exoplanets since 2001, looking for ways to predict planetary conditions based on a broad range of measurable factors.

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A Detailed New Mapping of Where Mars Once Had Plentiful Water

Measurements from the OMEGA instrument of European Space Agency’s Mars Express and NASA’s Mars Reconnaissance Orbiter’s CRISM spectrometer were used to map where formed-in-water minerals can found across Mars. This is an especially concentrated spot at Jezero Crater, where the Perseverance rover is located. (ESA)

NASA’s long-time motto for exploring Mars has been “Follow the water.”  That has changed some in recent years, as the presence of long-ago H2O has been confirmed in many locales around the planet.   Moving on, the motto today is more “Follow the organics” — the carbon-based building blocks of life — in the search for habitable environments and maybe signs of ancient life.

But water remains crucial to any discussion of habitability on Mars, and so a new set of global water maps from the European Space Agency, ten years in the making, is both useful and intriguing.

Specifically, the map shows the locations and abundances of these aqueous minerals — rocks that have been chemically altered by the action of water in the past, and have typically been transformed into clays and salts.

And the message that the maps deliver, said planetary scientist John Carter, is that these hydrated minerals are common across many parts of the planet.

Ten years ago, planetary scientists knew of around 1, 000 water-altered outcrops on Mars, he said.  This made them interesting as geological oddities.

But the new map has reversed the situation, revealing hundreds of thousands of such areas in the oldest parts of the planet.

“This work has now established that when you are studying the ancient terrains in detail, not seeing these minerals is actually the oddity,” says Carter, an assistant professor at the Institut d’Astrophysique Spatiale (IAS) in  France.

Global map of hydrated minerals on Mars. (ESA)

Now, Carter said in a release, the big question is whether the water was persistent or confined to shorter, more intense episodes. While not yet providing a definitive answer, the new results certainly give researchers a better tool for pursuing the answer.

“I think we have collectively oversimplified Mars,” says Carter, who was lead author in a paper published in the journal Icarus.

He explained that planetary scientists have tended to think that only a few types of clay minerals on Mars were created during its wet period — roughly 3.5 billion to 4 billion years ago — then as the water gradually dried up salts were produced across the planet.

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The James Webb Space Telescope Begins Looking at Exoplanets

 

Artist rendering of Gliese (GJ) 436 b  is a Neptune-sized planet that orbits a red dwarf  star.  Red dwarfs are cooler, smaller, and less luminous than the Sun. The planet completes one full orbit around its parent star in just a little over 2 days. It is made, scientists say, of extremely hot ice.  (NASA/JPL-Caltech/UCF)

The James Webb Space Telescope has begun the part of its mission to study the atmospheres of 70 exoplanets in ways, and at a depth, well beyond anything done so far.

The telescope is not likely to answer questions like whether there is life on distant planet — its infrared wavelengths will tell us about the presence of many chemicals in exoplanet atmospheres but little about the presence of the element most important to life on Earth, oxygen.

But it is nonetheless undertaking a broad study of many well-known exoplanets and is likely to produce many tantalizing results and suggest answers to central questions about exoplanets and their solar systems.

Many Worlds has earlier looked at the JWST “early release” program, under which groups are allocated user time on the telescope under the condition that they make their data public quickly.  That way other teams can understand better how JWST works and what might be possible.

Another program gives time to scientists who worked on the JWST mission and on its many instruments.  They are given guaranteed time as part of their work making JWST as innovative and capable as it is.

One of the scientist in this “guaranteed time observations program” is Thomas Greene, an astrophysicist at NASA Ames Research Center.  The groups he leads have been given 215 hours of observing time for this first year (or more) of Cycle 1 of JWST due to his many contributions to the JWST mission as well as his history of accomplishments.

In a conversation with Greene, I got a good sense of what he hopes to find and his delight at the opportunity.  After all, he said, he has worked on the JWST idea and then mission since 1997.

“We will be observing a diverse sample of exoplanets to understand more about them and their characteristics,” Greene said.  “Our goal is to get a better understanding of how exoplanets are similar to and different from those in our solar system.”

And the JWST spectra will tell them about the chemistry, the composition and the thermal conditions on those exoplanets, leading to insights into how they formed, diversified and evolved into planets often so unlike our own.Read more

Icy Moons, And Exploring The Secrets They Hold

Voyager 2’s flew by the Uranian moon Miranda in 1986 and the spacecraft spent 17 minutes taking  photos to make this high-resolution portrait.  Miranda has three oval and trapezoid coronae, tectonic features whose origins remain debated. (NASA / JPL / Ted Stryk)

When it come to habitable environments in our solar system, there’s Earth, perhaps Mars billions of years ago and then a slew of ice-covered moons that are likely to have global oceans under their crusts.  Many of you are familiar with Europa (a moon of Jupiter) and Enceladus (a moon of Saturn) — which have either been explored by NASA or will be in the years ahead.

But there quite a few others icy moons that scientists find intriguing and just possibly habitable.  There is Ganymede,  the largest moon of Jupiter and larger than Mercury but only 40 percent as dense, strongly suggesting a vast supply of water inside rather than rock.

There’s Saturn’s moon Titan, which is known for its methane lakes and seas on the surface but which has a subterranean ocean as well.  There is Callisto, the second largest moon of Jupiter and an subsurface-ocean candidates and even Pluto and Ceres, now called dwarf planets that show signs of having interior oceans.

And of increasing interest are several of the icy moons of Uranus, particularly Ariel and Miranda.  Each has features consistent with a subsurface ocean and even geological activity.  Although Uranus is a distant planet, well past Jupiter and Saturn and would take more than a decade to just get there, the possibility of a future Uranus mission is becoming increasingly real.

The National Academy of Sciences (NAS) Decadal Survey for planetary science rated a Uranus mission as the highest priority in the field, and just today (Aug. 18) NASA embraced the concept.

At a NASA Planetary Science Division town hall meeting, Director Lori Glaze said the agency was “very excited” about the Uranus mission recommendation from the National Academy and that she hoped and expected some studies could be funded and begun in fiscal 2024.

If a Uranus mission is fully embraced,  it would be the first ever specifically to an ice giant system — exploring the planet and its moons.  This heightened interest reflects the fact that many in the exoplanet field now hold that ice giant systems are the most common in the galaxy and that icy moons may well be common as well.… Read more

Mars Was Once Wetter and Warmer And It Had Life-Essential Organic Carbon. Was There Enough for Life to Emerge?

Yellowknife Bay in Gale Crater, Mars, was extensively studied by the Curiousity rover in 2011-12 and was declared to have been “habitable” long ago.  But the amount of life-essential organic carbon at the site appeared to be low, and now has been measured in detail. (NASA)

In the early days of the Curiosity mission on Mars, scientists were excited by what they found in what was once a mud-flat they called Yellowknife Bay.  After months of drilling and testing, the mission team concluded that the site once had the roughly neutral water, an array of chemicals that could support metabolism and the organic carbon compounds needed for life.  So Yellowknife Bay and the surrounding Gale Crater were deemed to have once been “habitable.”

The finding of organic carbon was a major step forward because it is essential as a building block for the emergence of life as we know it.  The readings were clear that the organic carbon was present, but it has taken a decade to produce the first measurement of how much of the precious organic carbon was present.

The results, published late last month in the Proceedings of the National Academy of Sciences, show higher organic carbon levels than in some “low-life” environments on Earth.  But those levels are still quite reduced and point to an unwelcoming Mars even in an area declared to be habitable billions of years ago when Mars was wetter and warmer.

“Total organic carbon is one of several measurements that help us understand how much material is available as feedstock for prebiotic chemistry and potentially biology,” said Jennifer Stern of NASA’s Goddard Space Flight Center.

“We found at least 200 to 273 parts per million of organic carbon. This is comparable to or even more than the amount found in rocks in very low-life places on Earth, such as parts of the Atacama Desert in South America, and more than has been detected in Mars meteorites.”

The Atacama is one of the driest places on Earth, but it does support some life — bacteria under the surface of the desert and even some desert flowers in areas that experience fog.  Not surprisingly, NASA and other scientists often use the Atacama when they study conditions on ancient Mars.

The Atacama desert in Chile is one of the driest places on Earth and is often studied as a Mars analog. (Shudderstock)

This carbon data has been a long time coming.

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NASA’s Perseverance Rover on Mars; an Update

 

The composite images of “Delta Scarp” in Jezero Crater reveal that billions of years ago, when Mars had an atmosphere thick enough to support water flowing across its surface, Jezero’s fan-shaped river delta apparently experienced a late-stage flooding events that carried rocks and debris into it from the highlands well outside the crater. (RMI: NASA/JPL-Caltech/LANL/CNES/CNRS/ASU/MSSS).

NASA’s Perseverance rover has been on Mars for fifteen months now and is about to begin its trek into the fossil delta of Jezero Crater.  It’s a big deal for the mission, because the delta is where water once flowed long enough and strongly enough to smooth, round and move large rocks.

Since proof of the long-ago presence of water means the area was potentially habitable — especially a delta that spreads out into what were once calm rivulets — this is where the astrobiology goals of the mission come to the fore.

Or so the Perseverance team thought it would play out.

But the big surprise of the mission so far has been that the rover landed on igneous rock, formed in the Martian interior, spewed out and crystalized and solidified on the surface.

That Perseverance would land on igneous rock was always seen as a possibility, but a more likely outcome was landing on sedimentary rock as in  Gale Crater, where the Curiosity rover continues its decade-long explore. Sedimentary rock is laid down in layers in the presence of water.

Perseverance takes a selfie in Jezero. The rover is a twin of the Curiosity rover, but with some upgrades and new instruments (NASA/JPL-Caltech/MSSS)

As explained last week at the Ab-Sci-Con 2022 conference in Atlanta, the deputy program scientist for the mission — Katie Stack Morgan of NASA’s Jet Propulsion Lab — from the mission’s perspective the presence of both igneous and nearby sedimentary rock offers the best of both worlds.

While sedimentary rock is traditionally where scientists look for signs of ancient life, igneous rock can date the site more exactly and it can potentially better preserve any signs of early microbial life.

And in the context of Perseverance, the presence of accessible and compelling igneous formations provides for the diversity of rock samples called for in the Mars Sample Return effort — another central part of the rover’s mission.

“We did a lot of work with our different instruments to come to the conclusion that we landed on  igneous rock,” Stack Morgan later said in an interview. … Read more

A Clue Into The Makeup of Jupiter’s Moon Europa Provided by the Greenland Ice Sheet

Double ridge ice formations seen on Europa are similar to formations detected on the Greenland Ice Sheet. This artist’s rendering shows how double ridges on the surface of Jupiter’s moon Europa may form over shallow, refreezing water pockets within the ice shell. This mechanism is based on the study of an analogous double ridge feature found on Earth’s Greenland Ice Sheet. (Justice Blaine Wainwright)

Europa’s ice crust is crossed by thousands of double ridges, pairs of long parallel raised lines with a small valleys in between, sometimes as much as hundreds of miles long and skyscraper-height tall rims. While these double ridges are ubiquitous on Europa’s surface, how they form remains something of a mystery to scientists.

Dustin Schroeder, an associate professor of geophysics at Stanford University’s School of Earth, Energy & Environmental Sciences, was working on an issue related to climate change when he saw double ridges similar to those seen on Europa here on Earth.  The ridges, in Northwest Greenland, were tiny when compared with those on Europa, but the found the same “M”-shaped crest as found everywhere on that Jovian moon.

“We were working on something totally different related to climate change and its impact on the surface of Greenland when we saw these tiny double ridges – and we were able to see the ridges go from ‘not formed’ to ‘formed,’ ” Schroeder said.

Could the double ridges be forming as a result of processes similar to those that form the double ridges on Europa?

If so, then Greenland would provide a possibly important new window into a central question about Europa:  Is that thick ice shell surrounding the subsurface ocean completely solid, or does it have what are called “water sills” within the shell?

This is important because, as the Nature Communications paper concludes, “If the same process is responsible for Europa’s double ridges, our results suggest that shallow liquid water is spatially and temporally ubiquitous across Europa’s ice shell.”

Or as Schroeder put it, “If the mechanism we see in Greenland is how these things happen on Europa, it suggests there’s water everywhere,” he said in a release.

They can make this inference because the double ridges formed in Greenland are the known, and detectable, result of the dynamics of subsurface water surrounded by the ice sheet.

Surface imagery comparison of a double ridge on Europa (a) and on Earth (b), on the Northwest Greenland Ice Sheet.

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The James Webb Space Telescope And Its Exoplanet Mission (Part 1)

 

This artist’s conception of the James Webb Space Telescope in space shows all its major elements fully deployed. The telescope was folded to fit into its launch vehicle, and then was slowly unfolded over the course of two weeks after launch. (NASA GSFC/CIL/Adriana Manrique Gutierrez)

 

The last time Many Worlds wrote about the James Webb Space Telescope, it was in the process of going through a high-stakes, super-complicated unfurling.  About 50 autonomous deployments needed to occur after launch to set up the huge system,  with 344 potential single point failures to overcome–individual steps that had to work for the mission to be a success.

That process finished a while back and now the pioneering observatory is going through a series of alignment and calibration tests, working with the images coming in from the 18 telescope segments to produce one singular image.

According to the Space Telescope Science Institute,  working images from JWST will start to appear in late June, though there may be some integrated  “first light” images slightly earlier.

Exciting times for sure as the observatory begins its study of the earliest times in the universe, how the first stars and galaxies formed, and providing a whole new level of precision exploration of exoplanets.

Adding to the very good news that the JWST successfully performed all the 344 necessary steps to unfurl and that the mirror calibration is now going well is this:  The launch itself went off almost exactly according to plan.  This means that the observatory now has much more fuel on hand than it would have had if the launch was problematic. That extra fuel means a longer life for the observatory.

 

NASA announced late last month that it completed another major step in its alignment process of the new James Webb Space Telescope, bringing its test images more into focus. The space agency said it completed the second and third of a seven-phase process, and had accomplished “Image Stacking.” Having brought the telescope’s mirror and its 18 segmented parts into proper alignment, it will now begin making smaller adjustments to the mirrors to further improve focus in the images. (NASA/STScI)

Before launch, the telescope was expected to last for five years.  Now NASA has said fuel is available for a ten year mission and perhaps longer.  Quite a start.

(A NASA update on alignment and calibration will be given on Wednesday. … Read more

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