Many Worlds

Category: Astrobiology (page 1 of 18)

Tantalizing Organic Compounds Found on Mars

November 29, 2022 / / 0 Comments

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.

… Read more

The Cosmos, As Viewed By The James Webb Space Telescope

November 7, 2022 / / 0 Comments

The iconic “Pillars of Creation” image, on left, was taken in visible light by the Hubble Space Telescope in 2014. A new, near-infrared-light view from NASA’s James Webb Space Telescope, at right, helps us peer through more of the dust in this star-forming region. The thick, dusty brown pillars are no longer as opaque and many more red stars that are still forming come into view.  The pillars of gas and dust seem darker and less penetrable in Hubble’s view, and they appear more permeable in Webb’s. (NASA)

The James Webb Space Telescope was developed to allow us to see the cosmos in a new way — with much greater precision, using infrared wavelengths to piece through dust around galaxies, stars and planets, and to look further back into time and space.

In the less than four months since the first Webb images were released,  the pioneering telescope has certainly shown us a remarkable range of abilities.  And as a result, we’ve been treated to some dazzling new views of the solar system, the galaxy and beyond.  This is just the beginning and we thankfully have years to come of new images and the scientific insights that come with them.

Just as the Hubble Space Telescope, with its 32 years of service and counting, ushered in a new era of space imagining and understanding, so too is the Webb telescope revolutionizing how we see and understand our world writ large.  Very large.

Neptune as seen by Voyager 2 during a flyby more than three decades ago, the Hubble Space Telescope last year, and the JWST this summer. ( NASA/ESA/CSA))

The differences between the Webb’s image and previous images of Neptune are certainly dramatic, in terms of color, precision and what they tell us about the planet.

Surely most striking in Webb’s new image is the crisp view of the planet’s rings, some of which have not been seen since NASA’s Voyager 2 became the first spacecraft to observe Neptune during its flyby in 1989. In addition to several bright, narrow rings, the Webb image clearly shows Neptune’s fainter, never-seen dust bands as well.

Neptune is an ice giant planet. Unlike Jupiter and Saturn, which consist primarily of hydrogen and helium, Neptune has an interior that is much richer in heavier elements (“heavier is the sense of not hydrogen or helium.) One of the most abundant heavy molecules is methane, which appears blue in Hubble’s visible wavelengths but largely white in the Webb’s near-infrared camera.… Read more

Clues About Conditions on Early Earth As Life Was Emerging

October 27, 2022 / / 0 Comments

What set the stage for the emergence of life on early Earth?

There will never be a single answer to that question, but there are many partial answers related to the global forces at play during that period.  Two of those globe-shaping dynamics are the rise of the magnetic fields that protected Earth from hazardous radiation and winds from the Sun and other suns,  and plate tectonics that moved continents and in the process cycled and recycled the compounds needed for life.

A new paper published in the Proceedings of the National Academies of Science (PNAS)  reports from some of the world’s oldest rocks in Western Australia evidence that the Earth’s crust was pushing and pulling in a manner similar to modern plate tectonics at least 3.25 billion years ago.

Additionally, the study provides the earliest proof so far of the planet’s magnetic north and sound poles swapping places — as they have innumerable times since.  What the switching of the poles tells researchers is that there was an active, evolved magnetic field around the Earth from quite early days,.

Together, the authors say, the two findings offer clues into how geological  and electromagnetic changes may have produced an environment more conducive to the emergence of life on Earth.

 

The early Earth was a hellish place with meteor impact galore and a choking atmosphere.  Yet fairly early in its existence, the Earth developed some of the key geodynamics needed to allow life to emerge.  The earliest evidence that microbial life was presented is dated at 3.7 billion years ago, not that long after the formation of the planet 4.5 billion years ago. (Simone Marchi/SwRI)

According to author Alec Brenner, a doctoral student at Harvard’s Paleomagnetics Lab,  the new research “paints this picture of an early Earth that was already really geodynamically mature. It had a lot of the same sorts of dynamic processes that result in an Earth that has essentially more stable environmental and surface conditions, making it more feasible for life to evolve and develop.”

And speaking specifically of the novel readings of continental movement 3.25 billion years ago, fellow author and Harvard professor Roger Fu said that “finally being able to reliably read these very ancient rocks opens up so many possibilities for observing a time period that often is known more through theory than solid data.”… Read more

Did Ancient Mars Life Kill Itself Off?

October 21, 2022 / / 0 Comments

The study revealed that while ancient Martian life may have initially prospered, it would have rendered the planet’s surface covered in ice and uninhabitable, under the influence of hydrogen consumed by microbes and methane released by them into the atmosphere. (Boris Sauterey and Regis Ferrière)

The presence of life brings many unexpected consequences.

On Earth, for instance, when cyanobacteria spread widely in ancient oceans more than two billion years ago, their production of increasingly large amounts of oxygen killed off much of the other anaerobic life present at the day because oxygen is a toxin, unless an organism  finds ways to adapt.   One of the first global ices followed because of the changed chemistry of the atmosphere.

Now a group of researchers at the University of Arizona has modeled a similar dynamic that could have potentially taken place on early Mars.

As the group reports in the journal Nature Astronomy, their work has found that if microbial life was present on a wetter and warmer ancient Mars — as some now think  that it potentially was — then it would almost certainly have lived below the surface.  The rock record shows that the atmosphere would then have consisted largely of carbon dioxide and hydrogen, which would have warmed the planet with a greenhouse effect.

By using a model that takes into account how processes occurring above and below ground influence each other, they were able to predict the climatic feedback of the change in atmospheric composition caused by the biological activity of these microbes.

In a surprising twist, the study revealed that while ancient Martian life may have initially prospered, its chemical feedback to the atmosphere would have kicked off a global cooling of the planet by the methanogen’s use of the atmospheric hydrogen for energy and the production of methane as a byproduct.

That replacement of hydrogen with methane ultimately would render its surface uninhabitable and drive life deeper and deeper underground, and possibly to extinction.

“According to our results, Mars’ atmosphere would have been completely changed by biological activity very rapidly, within a few tens or hundreds of thousands of years,” said Boris Sauterey, a former postdoctoral student at the University of Arizona who is now a fellow at Sorbonne Université in Paris. .

“By removing hydrogen from the atmosphere, microbes would have dramatically cooled down the planet’s climate.”

Jezero Crater is where the Perseverance rover has been exploring since landing in early 2021.

… Read more

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

October 12, 2022 / / 0 Comments

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 Juno Spacecraft Images Jupiter’s Moon Europa as it Speeds Past

September 30, 2022 / / 0 Comments

The first image from NASA’s Juno spacecraft as it passed close by Europa as part of its extended mission.  (NASA)

For NASA to extend its space science missions well past their original lifetime in space has become such a commonplace that it is barely noticed.

The Curiosity rover was scheduled to last on Mars for two years but now it has been going for a decade — following the pace set by earlier, smaller Mars rovers.  The Cassini mission to Saturn was extended seven years beyond it’s original end date and nobody expected that Voyager 1, launched in 1977,  would still flying out into deep space and sending back data 45 years later.

The newest addition to this virtuous collection of over-achievers is the Juno spacecraft, which arrived at Jupiter in 2016.  Its prime mission in and around Jupiter ended last year and then was extended until 2025, or beyond.

And now we have some new and intriguing images of Jupiter’s moon Europa thanks to Juno and its extension.

Traveling at a brisk 14.7 miles per second, Juno passed within 219 miles of the surface of the icy moon on Thursday and images from the flyby were released today (Friday.)  That gave the spacecraft only a two-hour window to collect data and images, but scientists are excited.

“It’s very early in the process, but by all indications Juno’s flyby of Europa was a great success,” said Scott Bolton, Juno principal investigator from Southwest Research Institute in San Antonio, in a NASA release.

“This first picture is just a glimpse of the remarkable new science to come from Juno’s entire suite of instruments and sensors that acquired data as we skimmed over the moon’s icy crust.”

Candy Hansen, a Juno co-investigator who leads planning for the Juno camera at the Planetary Science Institute in Tucson, called the released images “stunning.”

“The science team will be comparing the full set of images obtained by Juno with images from previous missions, looking to see if Europa’s surface features have changed over the past two decades,” she said.

An image of Europa taken by the Galileo spacecraft as it passed the moon in 1998. (NASA/JPL-Caltech)

During the flyby, the mission collected what will be some of the highest-resolution images of the moon (0.6 miles per pixel) taken so far and obtained valuable data on Europa’s ice shell structure, interior, surface composition, and ionosphere, in addition to the moon’s interaction with Jupiter’s magnetosphere.… Read more

How Planetary Orbits, in Our Solar System and Beyond, Can Affect Habitability

September 22, 2022 / / 0 Comments

Varying degrees of orbital eccentricity around a central star. (NASA/JPL-Caltech)

As scientists work to understand what might make a distant planet habitable, one factor that is getting attention is the shape of the planet’s orbit, how “eccentric” it might be.

It might seem that a perfect circular orbit would be ideal for habitability because it would provide stability, but a new model suggests that it is not necessarily the case.  The planet in question is our own and what the model shows is that if Jupiter’s orbit were to change in certain ways, our planet might become more fertile than it is.

The logic play out as follows:

When a planet has a perfectly circular orbit around its star, the distance between the star and the planet never changes and neither does the in-coming heat. But most planets — including our own — have eccentric orbits around their stars, making the orbits oval-shaped. When the planet gets closer to its star it receives more heat, affecting the climate.

Using multi-factored models based on data from the solar system as it is known today, University of California, Riverside (UCR) researchers created an alternative solar system. In this theoretical system, they found that if Jupiter’s orbit were to become more eccentric, it would in turn produce big changes in the shape of Earth’s orbit.  Potentially for the better.

“If Jupiter’s position remained the same but the shape of its orbit changed, it could actually increase this planet’s habitability,” said Pam Vervoort, UCR Earth and planetary scientist and study lead author.

The paper upends two long-held scientific assumptions about our solar system, she said.

“Many are convinced that Earth is the epitome of a habitable planet and that any change in Jupiter’s orbit, being the massive planet it is, could only be bad for Earth,” Vervoort said in a release. “We show that both assumptions are wrong.”

Size comparison of Jupiter and Earth shows why any changes relating to the giant planet would have ripple effects. (NASA)

 

As she and colleagues report in the Astronomical Journal, if Jupiter pushed Earth’s orbit to become more eccentric based on its new gravitational pull, parts of the Earth would sometimes get closer to the sun.  As a results, parts of the Earth’s surface that are now sub-freezing would get warmer, increasing temperatures in the habitable range.

While the Earth-Jupiter connection is a focus of the paper and forms a relationship that’s not hard to understand, the thrust of the paper is modeling how similar kinds of exoplanet orbits and solar system relationships can affect habitability and the potential for life to emerge and prosper.… Read more

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

September 14, 2022 / / 0 Comments

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.

… Read more

A Detailed New Mapping of Where Mars Once Had Plentiful Water

September 8, 2022 / / 0 Comments

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.

… Read more

The James Webb Space Telescope Begins Looking at Exoplanets

August 24, 2022 / / 0 Comments

 

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

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