Category: Our Solar System (page 1 of 7)

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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Did Ancient Mars Life Kill Itself Off?

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.

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

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

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

Reports From Inside the Sun’s Corona

This movie is built from images taken over 10 days during the full perihelion encounter when the spacecraft was nearing the Sun’s corona. The perihelion is a brief moment during the encounter time, when the spacecraft is at its closest point to the Sun. The movie is from orbit 10 and dates and distances are on the frames, and changing locations of planets are in red.  (AHL/JHU; NASA)

To borrow from singer Paul Simon, these are definitely days of miracles and wonders — at least when it comes to exploring and understanding our Sun.

The Parker Solar Probe has been swinging further and further into the Sun’s corona, having just finished its 12th of 24 descents into a world of super-heated matter (plasma) where no human creation has ever gone.

The probe has dipped as close as 5.3 million miles from the surface of the sun — Mercury is 32 million miles from that solar surface — and is flying through the solar wind, through streamers (rays of magnetized solar material)  and even at times through coronal mass ejections, those huge eruptions of magnetized plasma flying at speeds up to nearly 2,000 miles per second.

This is all a goldmine for solar scientists, an opportunity to study our star — and by extension all stars — up close and to learn much more about how it works.

At a four-day conference at the Johns Hopkins University Applied Physics Lab late last month, scores of scientists described the results of their early observations and analyses of the measurements and images coming from the Parker Probe via its The Wide-Field Imager (WISPR) and instruments that measure energy and magnetic flows.  The results have often surprising and, as some scientists said, “thrilling.”

“Parker Solar Probe was developed to answer some of the biggest puzzles, biggest questions about our Sun,” said Nour Raouafi, project scientist for the Parker Solar Probe.

“We have learned so much that we believe we are getting close to finding some important answers.  And we think the answers will be quite big for our field, and for science.”

The Parker Solar Probe had observed many switchbacks in the corona— traveling disturbances in the solar wind that cause the magnetic field to bend back on itself.  They are an as-yet unexplained phenomenon that might help scientists uncover more information about how the solar wind is accelerated from the Sun. (NASA’s Goddard Space Flight Center/Conceptual Image Lab/Adriana Manrique Gutierrez)

Among the many unexpected solar features and forces detected by the Parker Probe is the widespread presence of switchbacks, rapid flips of the Sun’s magnetic field moving away from the Sun. … Read more

New Research Finds The Very Early Solar System Went Through an Especially Intense Period of Asteroid Collisions

An artist’s view of the very early solar system, where dust was collecting into small rocks, which smashed into each other and some became larger. The height of the crash-ups took place during a surprisingly short period of time. (Tobias Stierli, flaeck / PlanetS)

In the earliest days of our solar system — before any planets had been cobbled together — the recently formed Sun was circled by cosmic gas and dust. Over time, fragments of rock formed from the dust and many of these orbiting rocks smashed together and some became the gradually larger components of planets-to-be.  Others were not part of any planet formation and became asteroids orbiting the Sun, and sometimes falling to Earth as meteorites.

Scientists have found that these asteroids (and their Earth-bound pieces) remained relatively unchanged since their formation billions of years ago.

And so they provide an archive of sorts, in which the conditions of the early solar system are preserved.

Alison Hunt, a planetary scientist at ETH Zurich in Switzerland, led a team that looked at some of that early solar system history and came up with some surprising results.

She and her team at the Swiss National Centre of Competence in Research (NCCR) PlanetS found that almost all of the asteroidal-cores-turned-meteorites they studied had been formed in a short four-million-year period starting almost eight million years the solar system first came into being.  A four million-year time span is short in astronomical terms and also unusual in terms of the precision achieved for the dating.

These results, and some inferences about why this period was so chaotic in the early solar system, were reported in Nature Astronomy late last month.

But before we look at why this might have happened, let’s explore a bit about how the team achieved such precise data about when many asteroids were formed.

One of the iron meteorite samples the team analyzed that was, long ago, the core of an asteroid. (Aurelia Meister)

To access this asteroid/meteorite archive, the researchers had to prepare and examine the extraterrestrial material from iron meteorites that had fallen to Earth.  Once part of the metallic cores of asteroids, samples from 18 different iron meteorites were used in the analysis.

The researchers first had to dissolve the samples to be able to isolate the elements palladium, silver and platinum — the key to their efforts.

Using a mass spectrometer they measured abundances of different and identifiable isotopes of these elements, and with their results they could put tighter constraints on the timing of events in the early solar system.

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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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“Nature Has Become More Beautiful.” Physicist Eugene Parker and his Life Unlocking Secrets Of The Sun

 

Parker with an image of the solar corona, the outermost portion of Sun’s atmosphere.  Parker brought new understanding to the nature and workings of the corona and the solar wind, which originates in the corona. (University of Chicago)

When  Eugene Parker was 16 years old,  he decided he didn’t want to spend the summer hanging out in suburban Detroit.  So Parker went up to the state capital looking to buy some tax delinquent land held by the state.

He selected a 40-acre piece of woods in far-off Cheboygan County, not far from Mackinac Island.  There was nothing on the land but trees.  He bought it with $120 from his own earlier summertime earnings.

Over the next three summers, Parker, his younger brother and sometimes a cousin and a friend constructed a log cabin on the land.  Because this was during World War II and gas was strictly rationed,  they couldn’t ask their parents for a ride up, and so they often bicycled the more than 300 miles to their homestead.

The cabin still doesn’t have electricity or indoor running water, but it has been used regularly by Parker and his family for almost 80 years.  And in many ways, that cabin reflects the basic character, the drive and the profound originality of the boy who built it and went on to become one of the great theoretical physicists of the 20th century.

The young Parker atop a birch  tree in 1943, on the site where his northern Michigan cabin would be built. (Courtesy of the Parker family.)

Eugene Parker, who passed away earlier this month at 94, has been hailed as the father of solar physics and is perhaps best known as the man who — basically single-handedly and despite many eminent critics –came up with the theory of the “solar wind,” a torrent of charged particles and magnetic fields that always and in all directions is blasting out from the Sun.

Parker’s innumerable achievements in his field, as well as his old-school civility and demeanor, earned him the first and only honor of its kind given by NASA — having a major space mission named after him while alive.

Ailing and aged 91, he nonetheless went with his family down to Florida in 2018 to watch the launch of the Parker Solar Probe — an extraordinary mission that flies through the blast furnace of the Sun’s corona in its effort to learn more about the origins of the solar wind and the forces at play that produce that still mysterious solar corona.… Read more

Venus, as Never Seen Before

The darkside of Venus, as imaged by an optical and near infrared camera on NASA’s Parker Solar Probe. (NASA)

For the first time, the surface of Venus has been imaged in visible wavelengths from space. The camera on the Parker Solar Probe pierced through the thick Venusian cloud cover and captured blurred but extremely valuable images of the highlands and lowlands of the planet.

The breakthrough images came thanks to a spacecraft with an entirely different mission — the Parker Probe, which has been exploring and progressively nearing the Sun in unprecedented ways.  And to get ever closer, it uses trips around Venus to slow down and thereby fly closer to the Sun.

It was during two of those trips around Venus in 2000 and 2001 that the Parker camera, which sees in visible and near infrared wavelengths, was able to  image the night side of Venus.  This was a first and totally unexpected, since Venus is known to have a dense cover of clouds.

The planet is also, of course, stunningly hot, with a mean temperature of 867 degrees Fahrenheit on the surface.  But the temperatures are lower on the elevated Aphrodite Terra, the largest highland region on the Venusian surface, and that is the area that shows as being dark in the images.

“Venus is the third brightest thing in the sky, but until recently we have not had much information on what the surface looked like because our view of it is blocked by a thick atmosphere,” said Brian Wood, lead author on the new study in Geophysical Research Letters and a physicist at the Naval Research Laboratory in Washington.  “Now, we finally are seeing the surface in visible wavelengths for the first time from space.”

The presentation below, put together by NASA, the John’s Hopkins University Applied Physics Lab and Naval Research Lab, is a stitched together video of the Parker Probe’s  Feb. 20, 2021 pass by the dark side of the planet.

Clouds of sulfur dioxide and sulfuric acid obstruct most of the visible light coming from Venus’ surface and so observing from both the ground and from space has relied on radar and observing wavelengths in the infrared that can pierce through the clouds.

But on two passes, the the Parker Probe’s Wide-field Imager for Solar Probe (WISPR) picked up a range of wavelengths from 470 nanometers to 800 nanometers. Some of that light is the near-infrared – wavelengths that we cannot see, but sense as heat – and some is in the visible range, between 380 nanometers and about 750 nanometers.… Read more

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