Many Worlds

Author: Marc Kaufman (page 1 of 25)

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 Late Heavy Bombardment Brought Oceans of Water to Ancient Mars, New Research Says

November 17, 2022 / / 0 Comments

Mars was bombarded by water and carbon-rich asteroids in its infancy, delivering oceans of water and organic compounds needed for life.  (Detlev Vans Ravenswaay/Science Source)

Mars looks largely desiccated today,but long ago it had oceans full of water delivered by asteroids during the Late Heavy Bombardment period, new research reports

During that tumultuous time solar system history some 4.1 to 3.8 billion years ago, an intense barrage of primordial asteroids called chondrites crashed into Mars.

Using a measure called a global equivalent layer (GEL), the findings conclude that if all the water from the chondrites was in liquid form and was resting on the planet’s surface and not tied up within the crust or polar ice, it would fill a global ocean roughly 300 meters (almost 1,000 feet) deep.

What’s more, said Martin Bizzarro of the University of Copenhagen’s Centre for Star and Planet Formation and a co-author of the new paper, “our study is the first to firmly establish that organic molecules relevant for life must have been present in the early evolution of the planet together with water.” 

This is because carbon-containing chondrites carried prebiotic elements essential to life.

That asteroids brought water (and organics) to Mars and other planets during the Bombardment is not new.  But to quantify the amount and find such a huge delivery of water could change some of the long-running debate about early Mars and water.

A specimen of the Murchison meteorite specimen at the National Museum of Natural History in Washington.  Among the most studied meteorites in the world, it is a carbonaceous chondrite from Mars that landed as a meteorite in Australia in 1969.   It contains about 12 percent water and is the kind of broken-apart asteroid originally from the outer solar system could have delivered massive amounts of water to Mars, and Earth as well.  (Wikipedia Commons)

As described in the new paper in Science Advances, the consensus view on Mars water has been that much of it came from outgassing from the planet’s mantle as it cooled and while the crust was forming.

But lead author Ke Zhu of the Université de Paris, Institut de Physique du Globe de Paris and colleagues report that a substantial amount of water came instead from the carbonaceous chondrites from the outer Solar System.  Chondrites are primordial asteroids and generally contain water.  Asteroids from the inner solar system are generally water-poor because their proximity to the Sun leads to a significant drying out.… 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

Spacecraft Smashes Into A Near-Earth Asteroid in the First Major Test of NASA’s Planetary Defense Program

September 26, 2022 / / 0 Comments

The asteroid moon Didymous just before the Dart spacecraft crashed into it. (NASA)

As a test of our ability to damage a potentially hazardous asteroid heading our way, or perhaps to give it enough of a push that the asteroid’s path is changed enough to render it harmless, a NASA spacecraft tonight successfully collided with an asteroid some 6.8 mllion miles away.

The Dart spacecraft – short for Double Asteroid Redirection Test – crashed at high speed into the asteroid Dimorphos and self-destructed yesterday evening.

It was unclear yesterday exactly how much damage was sustained by the asteroid, which is the size of a football stadium. But images taken aboard the 1,200-pound spacecraft showed that it got closer and closer to the asteroid and then the camera froze — presumably on impact.

The spacecraft was going at 14,000 miles-an-hour and hit the moon of a gravitationally-bound pair of near-Earth asteroids.

Asteroid 65803 Didymos is a binary near-Earth asteroid. The primary body has a diameter of around a half mile and a rotation period of 2.26 hours, whereas the Didymoon secondary body has a diameter of around 525 feet and rotates around the primary at a distance of around 9 miles from the primary surface in around 12 hours. (ESA)

With that impact, the orbit of Dimorphos around the larger asteroid is expected to be slightly altered, resulting in a change in the direction of the two asteroids.

While cameras and telescopes watched the crash, it will take days or even weeks to find out if it actually altered the asteroid’s orbit.

To calculate how much the moon’s orbit is altered over time it’s ‘light curve’ will be measured by observing the sunlight reflected from it with telescopes on the ground, and using this to calculate the change in the orbital period of the double-asteroid system. Satellites in orbit, including the Hubble and James Webb space telescopes will also join the effort.

This was the first  full-scale planetary defense test by the NASA, with others on the way.  Dart was launched in November, 2021.

Planetary defense experts have not found any decent-sized asteroids likely to head our way for at least a  century and likely much longer. But they also report that as many as 15,000 smaller, undetected asteroids are in the near-Earth region and their potential paths are not known.

This is part of the logic behind the planetary defense program:  The risks of an asteroid of any size hitting the Earth are extremely small, but they are not well defined and, of course, a large asteroid crash on Earth could be cataclysmic. 

… 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
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