NASA's Perseverance Mars rover finds possible signs of ancient Red Planet life

By Sharmila Kuthunur

"On Earth, these types of features in rocks are often associated with the fossilized record of microbes living in the subsurface."

NASA's Perseverance rover has discovered a rock on Mars that may have once hosted microbial life. The rock, nicknamed Cheyava Falls, has chemical compositions and structures that could have been formed by ancient life, although non-biological processes cannot yet be ruled out. 

(Image credit: NASA/JPL-Caltech/MSSS)

NASA's Perseverance rover may have found signs of ancient life in a rock on Mars; the mission team's scientists are ecstatic, but remain cautious as further analysis is needed to confirm the discovery. 

The rover has come across an intriguing, arrowhead-shaped rock that hosts chemical signatures and structures that could have been formed by microbial life billions of years ago, when Mars was significantly wetter than it is today. Inside the rock, which scientists have nicknamed "Cheyava Falls," Perseverance's instruments detected organic compounds, which are precursors to the chemistry of life as we know it. Wisping through the length of the rock are veins of calcium sulfate, which are mineral deposits that suggest water — also essential for life — once ran through the rock.

The rover also found dozens of millimeter-sized splotches, each surrounded by a black ring and mimicking the appearance of leopard spots. These rings contain iron and phosphate, which are also seen on Earth as a result of microbe-led chemical reactions.

"These spots are a big surprise," David Flannery, an astrobiologist and member of the Perseverance science team from the Queensland University of Technology in Australia, said in a statement. "On Earth, these types of features in rocks are often associated with the fossilized record of microbes living in the subsurface."

Related: 

• 'An oasis in the desert': NASA's Curiosity rover finds pure sulfur in Martian rocks

"We've never seen these three things together on Mars before," Morgan Cable, a scientist on the Perseverance team, said in a video NASA posted to YouTube today (July 25).

Cheyava Falls sits at the edge of an ancient, 400-meter-wide (437-yard-wide) river valley named Neretva Vallis. Scientists suspect this ancient channel was carved out long ago due to water gushing into Jezero Crater; Neretva Vallis runs along the inner wall of this region. In one possible scenario, mud that already possessed organic compounds got dumped into the valley and later cemented into the Cheyava Falls rock, which Perseverance sampled on July 21. A second episode of water oozing into the formed rock would have created the object's calcium sulfate veins and black-ringed spots the team sees today.

To be clear, the rock's visible features aren’t irrefutable evidence of ancient microbial life on Mars — not yet, at least. It is possible, for instance, that the observed calcium sulfate entered the rock at uninhabitably high temperatures, perhaps during a nearby volcanic event. However, whether such non-biological chemical reactions could have resulted in the observed black-ringed spots is an open question, the scientists say.

"This trip through the Neretva Vallis riverbed paid off as we found something we've never seen before, which will give our scientists so much to study," Nicola Fox, the associate administrator of NASA's Science Mission Directorate, said in the statement.

"We have zapped that rock with lasers and X-rays and imaged it literally day and night from just about every angle imaginable," Ken Farley, Perseverance project scientist of Caltech in California, said in the statement. "Scientifically, Perseverance has nothing more to give."

RELATED STORIES:

• Little Mars 'snowman' spotted by NASA's Perseverance rover (photo)
• Perseverance rover's Mars rock sample may contain best evidence of possible ancient life
• Perseverance Mars rover digs into intriguing 'Bright Angel' rock formation (photo)

To fully grasp what really unfolded in the ancient river valley billions of years ago, scientists are keen to get the Cheyava Falls sample to Earth, where it can be scrutinized with powerful instruments that Perseverance’s limited suite doesn't have. 

The complex Mars Sample Return effort, however, has run into many snags in recent months after its costs spiked to $11 billion. In its current form, the program requires multiple launches to Mars to place a vehicle on the Red Planet, after which either Perseverance will travel to the vehicle and drop off its collected samples, or pop those samples over to a retrieval helicopter that can complete the handoff. Then, an ascender would launch the samples into orbit, where a spacecraft would collect them and return them to Earth.

NASA assessed various simpler alternatives from industry and academic groups and awarded $1.5 million contracts to seven companies looking into the endeavor; three of the agency's own research centers are carrying out studies as well.

NASA/JPL-Caltech/ASU/MSSS

NASA/JPL-Caltech/ASU/MSSS

NASA/JPL-Caltech/MSSS

{ https://www.space.com/ }

28-07-2024 om 01:41 geschreven door peter  

Telescopes Shooting Lasers, Assembling Telescopes in Space, Growing Plants on Mars | Overtime Q&A 2

What are those lasers shooting out from telescopes? Can we build a space elevator? Could we grow plants in Mars regolith? Why not assemble telescopes in space? Answering all these questions and more in this week's Overtime Q&A.

• https://youtu.be/CB5JBkDqmu0

{ https://www.youtube.com/@frasercain }

28-07-2024 om 01:12 geschreven door peter  

Earth is wobbling and days are getting longer — and humans are to blame

However, human-caused climate change is another factor that can alter the length of our days, and scientists are just starting to realize how much this will affect our planet's spin in the coming years.

Over the past few decades, the rate of ice loss from Earth's polar regions, particularly Greenland and Antarctica, has been increasing rapidly due to global warming, leading to rising sea levels. Most of this extra water accumulates near the equator, causing our planet to bulge slightly around the middle. This, in turn, slows the planet's spin because more weight is distributed farther away from the planet's center — similar to how spinning figure skaters slow down by moving their arms away from their bodies.

In the new study, published July 15 in the journal PNAS, researchers used an advanced artificial intelligence program that combines real-world data with the laws of physics to predict how the planet's spin will change over time.

Related: 

• Everything you need to know about planet Earth

The results back up a similar study published in March, which suggested that Earth's days will get longer in the future. However, the new program offered much more precise estimates of how days will lengthen over time.

The same research team behind the new paper also released another study, published July 12 in the journal Nature Geoscience, which showed that the increased water near the equator is moving Earth's axis of rotation. This is making the magnetic poles wobble farther away from the axis every year.

Scientists previously found that this effect has likely been happening for at least the past three decades. However, the new study suggests the axis will move even farther from its current position than previous studies predicted.

"We humans have a greater impact on our planet than we realise," Benedikt Soja, a geodesist at ETH Zurich in Switzerland who was a co-author on both the new studies, said in a statement. "And this naturally places great responsibility on us for the future of our planet."

Spinning slower

Earth's days have always varied in length. Around 1 billion years ago, our planet likely took only 19 hours to complete a single rotation, before slowing to the 24 hours we experience today.

It also changes on shorter timescales. For example, in 2020, Earth was spinning more quickly than at any point since records began in 1960. In 2021, the planet's rotation began to slow down again even though we experienced the shortest-ever recorded day in June 2022.

But in general, Earth's rotation has been slowing for millennia, mainly due to a process known as lunar tidal friction, in which the moon's gravitational effect on our oceans pulls water away from the poles. At the moment, this effect is lengthening our days by around 2.3 milliseconds every century.

The new studies show that climate change is currently lengthening our days by around 1.3 milliseconds every century. However, based on current global temperature models, the researchers predict that this could increase to 2.6 milliseconds per century by the end of the 21st century, which would make climate change the biggest influence on our planet's spin.

Potential impacts

One of the most likely effects of longer days would be the need to introduce negative leap seconds — where we'd occasionally lose a second from some future days to accommodate the lengthening days, similar to how leap years work.

The March study suggests that this may need to start happening as soon as 2029, mainly to accommodate for how much the days have already lengthened over the past few millennia.

In the past, scientists have suggested this introduction could mess with the timekeeping of computers and smartphones. However, not everyone is convinced this will be a major issue.

The researchers of the new studies also noted that future changes could impact space travel.

"Even if the Earth's rotation is changing only slowly, this effect has to be taken into account when navigating in space — for example, when sending a space probe to land on another planet," Soja said. It is therefore important to monitor these changes closely, he added.

The team also warned that the changes to Earth's rotational axis could alter the rotation of Earth's inner core, which could further increase how fast days lengthen. However, this potential interaction is still largely unknown.

{ https://www.space.com/ }

28-07-2024 om 01:06 geschreven door peter  

Beneath the skin of Mercury, the smallest planet in our solar system, expect the unexpected. Reaching out across the cosmos with this fascinating revelation is a new study that points to a 9-mile-thick layer of diamonds concealed beneath the planet's surface.

While instance of such valuable encrustation might sound tantalizing, turning these precious stones into fashionable jewelry remains an impossibility due to their inaccessible location deep within the planet.

Mercury, seen in this false-color image, may have a deep layer of inner diamonds, new research finds. 

(Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

However, these gems could hold the key to unraveling some of the big unanswered questions circling around Mercury' composition and its rather curious magnetic field.

The scientist leading the charge is Yanhao Lin, a staff scientist based out of the Center for High Pressure Science and Technology Advanced Research in Beijing.

Mercury's hidden diamond

Oddly enough, for a planet its size, Mercury has a magnetic field. It is weaker than its Earth counterpart, but is still intriguing considering the planet's overall inactivity in geological terms.

What truly sparked Lin's interest, however, were the unusually dark patches on the surface of Mercury that were identified as graphite by NASA's Messenger mission.

This revelation triggered exploration into the possibility of something unique brewing within the planet's interior.

Birth of Mercury's diamond layer

Utilizing a team comprised of Chinese and Belgian researchers, Lin sought to explore the possibility of diamond formation deep in Mercury's core.

The team began by creating chemical mixtures that replicated Mercury's magma ocean. The concoction included iron, silica, and carbon, elements similar to certain kinds of meteorites, and was subjected to crushing pressures and extreme temperatures.

The team's rigorous experiments and computer simulations confirmed that Mercury's mantle would indeed be conducive to forming diamonds, especially under the revised conditions that the team established.

If these diamonds do exist, they could form a 9-mile average thick layer at the core-mantle boundary of Mercury, which is approximately 300 miles below the surface.

A diagram showing the proposed layer of diamond at Mercury's core-mantle boundary. 

(Image credit: Dr. Yanhao Lin and Dr. Bernard Charlier)

Mercury's magnetism

The hypothesized existence of this layer of diamonds is more than just an intriguing fact. It could potentially explain the origin of Mercury's magnetic field.

These diamonds may facilitate heat transfer between the core and mantle, thereby creating temperature differences and causing liquid iron to circulate – a process that would kickstart the creation of a magnetic field.

Implications for future research

The discovery of a potential diamond layer within Mercury opens new avenues for planetary research and composition studies not only of Mercury but also of other celestial bodies.

Understanding the unique geological characteristics of Mercury could provide deeper insight into the formation and evolution of the solar system.

Future missions to Mercury may focus on directly exploring its interior structure through advanced geophysical measurements and remote sensing techniques to verify the existence of this diamond layer and its impact on the planet's magnetic field.

Planetary formation and Mercury's diamonds

This revelation also prompts a reconsideration of the processes involved in planetary formation.

Diamonds are typically associated with high-pressure environments, suggesting that similar conditions may exist in other distant rocky exoplanets and moons within our solar system.

Lin and his team's findings underline the importance of studying extreme planetary conditions, which can reveal not only the composition of these bodies but also the historical processes that formed them, leading to a more comprehensive understanding of geology across the cosmos.

Evolution of exoplanets

The potential discovery casts a new light on the evolution of carbon-rich exoplanets. According to Lin, the process that led to the formation of a diamond layer on Mercury could also be at play on other planets, possibly leaving similar traces.

The arrival of the BepiColombo spacecraft, a joint mission of the European Space Agency and the Japan Aerospace Exploration Agency, in 2025 will provide better opportunities to delve deeper into this intriguing discovery.

Mercury, it seems, continues to dazzle us with new surprises, keeping the scientific community and general public on their toes.

Who'd have thought that this small, seemingly quiet planet could hold such vast volumes of precious stones deep within its confines?

• The study is published in the journal Nature Communications.

{ https://www.msn.com/en-us/channel/topic/Science/ }

27-07-2024 om 15:23 geschreven door peter  

Er is mogelijk nog veel meer pure zwavel aanwezig, want in de buurt liggen nog verschillende gelijkaardige stenen. Dat stelt wetenschappers voor vragen, want ze dachten niet dat er zich op die plek op Mars ooit zwavel zou hebben gevormd.

"Een veld vinden met stenen gemaakt uit puur zwavel, is zoals een oase in de woestijn vinden", vertelt Ashwin Vasavada van de NASA. "Het zou daar niet moeten liggen, dat veld, dus nu moeten we proberen om een verklaring te vinden. Het ontdekken van onverwachte en rare dingen maakt het verkennen van de ruimte zo opwindend." 

De ontdekking gebeurde in het kanaal van Gediz Vallis, een bedding aan de voet van de 5 kilometer hoge Mount Sharp. Ooit moet daar water door gestroomd hebben, zeggen specialisten. Maar er is nog veel onderzoek nodig om te begrijpen hoe het landschap er zich precies heeft gevormd. De jongste ontdekking maakt die uitdaging nog wat groter. 

Curiosity maakte een close-up van een witte steen, gelijkaardig aan degene die onlangs openbarstte. Er ligt in de buurt een heel veld.

© Foto: NASA/JPL - Caltech/MSSS

{ https://www.msn.com/nl-be/feed?ocid=msedgntp&pc=acts }

27-07-2024 om 00:22 geschreven door peter  

Venus is known for being really quite inhospitable with high surface temperatures and Mars is known for its rusty red horizons. Even the moons of some of the outer planets have fascinating environments with Europa and Enceladus boasting underground oceans. Recent observations from the James Webb Space Telescope show that Ariel, a moon of Uranus, is also a strong candidate for a sub surface ocean. How has this conclusion been reached? Well JWST has detected carbon dioxide ice on the surface on the trailing edge of features trailing away from the orbital direction. The possible cause, an underground ocean!

Uranus is the seventh planet in the Solar System and has five moons. Ariel is one of them and is notable for its icy surface and fascinatingly diverse geological features. It was discovered back in 1851 by William Lassell who funded his love of astronomy from his brewing business! The surface of Ariel is a real mix of canyons, ridges, faults and valleys mostly driven by tectonic activity. Cryovolcanism is a prominent process on the surface which drives constant resurfacing and has led to Ariel having the brightest surface of all Uranus’ moons. 

Studying Ariel closeup reveals that the surface is coated with significant amounts of carbon dioxide ice. The trailing hemisphere of Ariel seems to be particularly coated in the ice which has surprised the community. At the distance of Uranian system from the Sun, an average of 2.9 billion kilometres, carbon dioxide will usually turns straight into a gas and be lost to space, it’s not expected to freeze!

Until recently, the most popular theory that supplies the carbon dioxide to Ariel’s surface is interactions between its surface and charged particles in the magnetosphere of Uranus. The process known as radiolysis breaks down molecules through ionisation. A new study just published in the Astrophysical Journal Letters suggests an intriguing alternative, the carbon dioxide molecules are expelled from Ariel, possibly from a subsurface liquid ocean!

A team of astronomers using JWST have undertaken a spectral analysis of Ariel and compared the results with lab based findings. The results revealed that Ariel has some of the most carbon dioxide rich deposits in the solar system. The deposits are not just wisps and trace amounts instead adding up to about 10 millimetres across the trailing hemisphere. Furthermore, the results also showed signals from carbon monoxide too which should not be there given the average temperatures. 

It is still possible that radiolysis is responsible for at least some of the deposits but the replenishment from the subsurface ocean is thought to be the main contributor. This hypothesis has been supported by the discovery of signals from carbonate minerals, salts that can only be present due to the interaction between rock and water. 

The only way to be absolutely sure is for a future space mission to Uranus. Such a mission will undoubtedly explore the moons of Uranus. Ariel is covered in canyons, fissures and grooves and it is suspected these are openings to its interior. A robotic explorer in the Uranian system will be able to uncover the origin of the carbon oxides on Ariel. Without such a mission we are still somewhat in the dark given that Voyager 2 only imaged around 35% of the moon’s surface. 

Source : 

• Carbon Oxides on Uranus’ Moon Ariel Hint at Hidden Ocean, Webb Telescope Reveals

{ https://www.universetoday.com/ }

26-07-2024 om 18:47 geschreven door peter  

“As policymakers and as scientists, we’re trying to account for where carbon comes from and how that impacts the planet,” said climate scientist Lesley Ott at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “You see here how everything is interconnected by these different weather patterns.”

The video starkly shows that it doesn’t matter where CO₂ emissions come from; we all deal with the outcomes. Yet there are some interesting global differences.

Above the USA, South Asia, and China, most of the carbon comes from industry, power plants, and transportation. But over Africa and South America, most of the emissions come from burning, including forest fires, agricultural burning, and land clearing. Emissions also come from fossil fuels like oil and coal.

via GIPHY

The image pulses for a couple of reasons. Forest fires tend to flare during the day and then slow down at night. Also, trees and plants photosynthesize during the day, releasing oxygen and absorbing CO2. The land masses and the oceans act as carbon sinks.

There’s more pulsing in South America and the tropics because the data was collected during their growing season.

In this version, the video zooms in on the USA, showing individual CO₂ sources.

via GIPHY

These visualizations are based on GEOS, the Goddard Earth Observing System. GEOS is an integrated system for modelling Earth’s coupled atmosphere, ocean, and land systems. NASA calls it a “high-resolution weather analysis model,” and it uses supercomputers to show what’s happening in the atmosphere. GEOS is based on billions of data points, including data from the Terra satellite’s MODIS and the Suomi-NPP satellite’s VIIRS instruments. GEOS has a resolution that’s more than 100 times greater than typical weather models.

• Interested users can download the visualizations at the Scientific Visualization Studio.
• Image Credit for all videos, images, and clips: NASA’s Goddard Space Flight Center

{ https://www.universetoday.com/ }

26-07-2024 om 18:37 geschreven door peter  

Hier zijn de Pilaren der Creatie zoals niemand ze ooit heeft gezien: NASA publiceert 3D-videotour

Door Janine

NASA, ESA, CSA, STScI; J. DePasquale, A. Koekemoer, A. Pagan (STScI)

Er is niemand die de Pilaren der Creatie niet minstens één keer in zijn leven heeft gezien. Sinds ze beroemd zijn geworden door de Hubble ruimtetelescoop, heeft het buitengewone schouwspel van deze nevelachtige formaties astronomen en liefhebbers gefascineerd. Na de onthullingen van de James Webb Space Telescope heeft NASA een nieuwe voorstelling gepubliceerd waarmee het mogelijk is om de Pilaren der Creatie in 3D te verkennen. Laten we eens kijken hoe.

De Pilaren der Creatie, van Hubble tot JWST

De zogenaamde Pilaren der Creatie, die zich op ongeveer 7000 lichtjaar van de aarde bevinden, zijn nevelachtige formaties. Ze worden zo genoemd vanwege de visuele impact van eerst de weergave van Hubble en later JWST. Het zijn eigenlijk kolommen van gas en stof die na verloop van tijd bijdragen aan de vorming van nieuwe sterren.

De Pilaren der Creatie worden verlicht door het licht van nabije sterren, ook al bevindt de dichtstbijzijnde zich op zo'n 500 lichtjaar. Bovendien bestaan ze voornamelijk uit waterstof en helium en zijn ze ruim 5 lichtjaar lang. Hun lot is nauw verbonden met de vorming van nieuwe sterren, maar dat niet alleen: voortdurende stellaire winden botsen op deze nevel en eroderen de samenstellende elementen. Het duurt misschien “een paar” miljoen jaar voordat de Pilaren der Creatie ophouden te bestaan, tenminste in deze vorm.

De nieuwe 3D-visualisatie van de Pilaren der Creatie

Greg Bacon, Ralf Crawford, Joseph DePasquale, Leah Hustak, Christian Nieves, Joseph Olmsted, Alyssa Pagan, and Frank Summers (STScI),

NASA's Universe of Learning

Zoals te zien is in de video die door NASA is gedeeld, maakt de nieuwe 3D-visualisatie van de Pilaren der Creatie het mogelijk om deze formaties als nooit tevoren te verkennen. Om tot deze weergave te komen, zijn gegevens van Hubble en James Webb gebruikt om meer detail te verkrijgen. Bovendien wordt in de video ruimte gegeven aan zowel de door Hubble verzamelde reconstructie in zichtbaar licht als de voor de JWST kenmerkende infraroodweergave. Volgens de experts die aan deze prestatie hebben bijgedragen, zullen alle mensen nu de Pilaren der Creatie kunnen verkennen:

We wilden de Pilaren der Creatie al heel lang in 3D nabootsen. Dankzij de Webb-gegevens in combinatie met de Hubble-gegevens konden we de pilaren gedetailleerder bekijken. Door de wetenschap te begrijpen en deze het beste weer te geven, kon ons kleine, getalenteerde team de uitdaging aangaan om deze iconische structuur te visualiseren.

Begrijpen hoe sterren worden gevormd, dankzij de weergave van de Pilaren

De combinatie van gegevens die zijn verkregen door de twee ruimtetelescopen Hubble en James Webb, respectievelijk in 1995 en 2022, heeft het mogelijk gemaakt om de Pilaren der Creatie te reconstrueren zoals niemand ze ooit heeft gezien. Maar dat is nog niet alles. Zoals Mark Clampin van NASA zich herinnert:

Het gebied van de Pilaren der Creatie blijft ons nieuwe inzichten bieden die ons begrip van de vorming van sterren kunnen verscherpen. En nu, met deze nieuwe visualisatie, kan iedereen dit rijke en fascinerende landschap op een nieuwe manier ervaren.

In de video zie je een nieuw gevormde ster, met zijn karakteristieke helderrode gloed in het infrarode licht van de JWST. Bovenaan de linkerpilaar is een diagonale straal te zien van materiaal dat afkomstig is van een andere, eveneens pas ontstane ster. Afgezien van de gegevens die zijn gebruikt voor de 3D-reconstructie, lijdt het geen twijfel dat de inspanning van NASA en alle technici ook en vooral gericht is op het grote publiek. Dankzij de nieuwe visualisatie zal het dus niet alleen mogelijk zijn om te begrijpen hoe sterren worden gevormd, maar ook om nieuwe generaties enthousiastelingen en astronomen te fascineren. Die in de toekomst meer kunnen ontdekken over dit buitengewone en verre spektakel, maar vanaf vandaag iets dichterbij.

{ https://www.curioctopus.nl/ }

26-07-2024 om 17:47 geschreven door peter  

Een team wetenschappers uit China en België heeft een baanbrekende ontdekking gedaan over de interne structuur van Mercurius, de kleinste planeet in ons zonnestelsel. Volgens hun onderzoek zou een laag diamant onder de korst van Mercurius wel 18 km dik kunnen zijn. “Ten eerste is er de kristallisatie van de magma-oceaan, maar dit proces heeft waarschijnlijk alleen een zeer dunne diamantlaag gevormd aan de kern/mantel-grens,” vertelde Olivier Namur, lid van het onderzoeksteam en universitair hoofddocent aan de KU Leuven, aan Space.com. “Ten tweede, en nog belangrijker, de kristallisatie van de metalen kern van Mercurius.” Toen de planeet ongeveer 4,5 miljard jaar geleden werd gevormd, was de metalen kern volledig vloeibaar, die zich in de loop van de tijd geleidelijk kristalliseerde, aldus Namur.

Groeiende diamantlaag

De exacte aard van de vaste fasen in de binnenkern is momenteel niet goed bekend, maar het team gelooft dat deze fasen arm aan koolstof of “koolstofarm” moeten zijn geweest. “De vloeibare kern bevatte vóór kristallisatie enige koolstof; kristallisatie leidt daarom tot koolstofverrijking in het resterende smelt,” vervolgde Namur. “Op een gegeven moment wordt een oplosbaarheidsdrempel bereikt, wat betekent dat de vloeistof geen extra koolstof kan oplossen en dat er diamant wordt gevormd.” Diamant is een dicht mineraal, maar niet zo dicht als metaal. Dit betekent dat tijdens dit proces de diamant naar de top van de kern zou zijn gedreven, tot aan de grens van de kern en de mantel van Mercurius. Dit zou hebben geleid tot de vorming van een ongeveer 1 kilometer dikke diamantlaag die in de loop van de tijd bleef groeien. De wetenschappers suggereren dat de laag wel 18 km dik zou kunnen zijn.

Van koolstof tot diamant

Deze ontdekking benadrukt de verschillen tussen het ontstaan van de planeet die het dichtst bij de zon staat en het ontstaan van andere rotsachtige planeten in het zonnestelsel, zoals Venus, Aarde en Mars. “Mercurius vormde zich veel dichter bij de zon, waarschijnlijk uit een koolstofrijke wolk van stof. Hierdoor bevat Mercurius minder zuurstof en meer koolstof dan andere planeten. Dit leidde tot de vorming van een diamantlaag,” voegde Namur toe. “De kern van de Aarde bevat echter ook koolstof, en de vorming van diamant in de kern van de Aarde is al door verschillende onderzoekers gesuggereerd.”

Belangrijkste bevindingen

• Een team wetenschappers uit China en België heeft een laag diamant ontdekt onder de korst van Mercurius
• De laag is tot 18 km dik en is daarmee een belangrijke ontdekking voor de planeetwetenschap
• Het onderzoek suggereert dat twee processen kunnen hebben bijgedragen aan de vorming van deze diamantlaag: kristallisatie van de magma-oceaan en kristallisatie van de metaalkern.

• https://youtu.be/2c-WIPKCGaQ

{ https://businessam.be/ }

26-07-2024 om 17:28 geschreven door peter  

Astronomers Were Looking for a Planet, but They Didn't Expect This One

The Epsilon Indi star system is already pretty weird, but this surprising new planet just made it even weirder.

BY KIONA SMITH

 

A team of astronomers recently used the James Webb Space Telescope (JWST)’s MIRI instrument to capture images of a gas giant orbiting a nearby star. Earlier studies had predicted that the star should have a giant planet, but no one expected the planet astronomer Elisabeth Matthews and her colleagues actually found in JWST’s data: a gargantuan beast of a world, six times the mass of Jupiter and orbiting three times farther from its star than Jupiter does from the Sun.

Matthews (of the Max Planck Institute for Astronomy) and her colleagues published their findings in the journal Nature.

A GIANT SURPRISE

Matthews and her colleagues pointed JWST’s Mid-Infrared Instrument, or MIRI, at the nearby star system Epsilon Indi, which is home to one small orange star, just a little smaller and cooler than our Sun, and a pair of brown dwarfs (objects much too large to be planets, but not quite massive enough to be stars). Other astronomers had previously noticed that Epsilon Indi A, the orange star, had a slight wobble, as if it were being pushed and pulled by the gravity of a giant gas planet in its orbit. But no one had ever actually seen that planet, and the researchers thought JWST would be up to the challenge.

They found the planet, but it wasn’t where all the previous data said it should have been. Instead, it was about four times farther from the star, and about twice as massive, as the researchers had expected. That’s pretty cool, both literally — its about 35 degrees Fahrenheit — but also figuratively, as it is a rare chance to study gas giants in the outer reaches of their star systems.

“To our surprise, the bright spot that appeared in our MIRI images did not match the position we were expecting for the planet,” says Matthews in a recent statement. They’d been looking for a planet about three times the mass of Jupiter, which orbited its star about once every 45 or 50 years. Instead, the bright point of light in MIRI’s images turned out to be a planet about six times more massive than Jupiter, and it’s so far away from its star that it takes around 200 years to finish a single orbit.

For comparison, Jupiter is about five times farther from the Sun than Earth is (that’s five astronomical units, or AU); at that distance, Jupiter takes about 12 years to make a full orbit. Epsilon Eridani Ab, as the new planet is called, is about 15 times farther from its star than Earth is from the Sun, and its orbit is a stretched-out oval, so its actual farthest point from its star is at least 20 AU away.

The earlier studies had drastically underestimated how huge, and how far out, Epsilon Eridani Ab actually was. That’s mostly because those astronomers discovered the planet using what’s called the radial velocity method, which measures how much a star wobbles back and forth as the planet, which exerts a small but noticeable gravitational tug on the star, moves around in its orbit. But astronomers were able to watch those stellar wobbles for just a tiny fraction of the planet’s actual orbit, so it was almost impossible for them to accurately reconstruct the whole thing.

That left Matthews and her colleagues with a huge surprise.

A LITTLE-KNOWN TYPE OF PLANET

Giant gas planets like Jupiter and Epsilon Indi Ab form in the outer reaches of their star systems, where there’s less radiation from the newborn star to blow away the gas that forms these giants. Over time, some of them migrate inward: In our own Solar System, Jupiter did some wandering in its younger days, and in many alien star systems, astronomers have discovered a type of planet called a “hot Jupiter,” a gas giant that’s migrated inward until it’s zipping around its host star once every few days.

Hot Jupiters may be the category of planet we know the most about, even though only about 1 percent of stars actually have a hot Jupiter in their collection of planets. That’s because hot Jupiters are relatively easy to spot: they’re big and close to their stars, so it’s easy to track their radial velocity effects or spot their silhouettes when they pass between their star and Earth.

More distant worlds, even huge gas giants like Epsilon Indi Ab, are harder to find, because their orbits are so long (see above) and because they’re less likely to pass in front of their stars from our point of view, thanks to the angles involved. So the gas giants that don’t end up falling inward into scorching hot orbits are sort of a gap in our knowledge of the universe — and Epsilon Indi Ab is a chance to fill in that blank spot on the cosmic map.

“In the long run, we hope to also observe other nearby planetary systems to hunt for cold gas giants that may have escaped detection,” says the Max Planck Institute for Astronomy’s Thomas Henning, a coauthor of the recent paper, in a statement. “Such a survey would serve as the basis for a better understanding of how gas planets form and evolve.”

Meanwhile, Matthews and her colleagues also hope to get more detailed measurements of the spectrum of light coming from the planet, which could tell them what its atmosphere is made of and whether it’s cloudy, hazy, or clear.

{ https://www.inverse.com/ }

26-07-2024 om 00:08 geschreven door peter  

In this new video, we see a series of images as BepiColombo speeds away from the closest planet to the sun during the 3rd Mercury flyby. The spacecraft captured these images in a span of about 50 minutes.

Video via ESA.

New images of Mercury from BepiColombo flyby

On June 20, 2023, ESA released new images of Mercury after BepiColombo spacecraft flew past the closest planet to the sun the day prior. In these images, we get to see a part of BepiColombo with cratered Mercury in the background. ESA released a trio of images as the spacecraft zoomed away during a gravity assist maneuver. It also released annotated images to point out important surface features.

Reactions from the BepiColombo team

The team involved with the BepiColombo mission were satisfied with the flyby and resulting images. Ignacio Clerigo, ESA’s BepiColombo Spacecraft Operations Manager, said:

Everything went very smoothly with the flyby, and images from the monitoring cameras taken during the close approach phase of the flyby have been transmitted to the ground. While the next Mercury flyby isn’t until September 2024, there are still challenges to tackle in the intervening time: our next long solar electric propulsion ‘thruster arc’ is planned to start early August until mid-September. In combination with the flybys, the thruster arcs are critical in helping BepiColombo brake against the enormous gravitational pull of the sun before we can enter orbit around Mercury.

One of the craters visible in the images is the newly named Manley crater. The International Astronomical Union (IAU) named this crater for Jamaican artist Edna Manley (1900–1987). David Rothery of the BepiColombo team said:

During our image planning for the flyby, we realized this large crater would be in view, but it didn’t yet have a name. It will clearly be of interest for BepiColombo scientists in the future because it has excavated dark ‘low reflectance material’ that may be remnants of Mercury’s early carbon-rich crust. In addition, the basin floor within its interior has been flooded by smooth lava, demonstrative of Mercury’s prolonged history of volcanic activity.

You can learn more about these new images here.

BepiColombo 3rd Mercury flyby June 19, 2023

BepiColombo made its third flyby of the planet Mercury on June 19, 2023. The spacecraft swept closest to Mercury at 19:34 UTC (2:34 p.m. CDT).

BepiColombo is a joint Mercury mission, launched in October 2018 by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). For the past several years, our sun’s inner planets have been giving BepiColombo gravity assists, needed to enable the spacecraft to achieve a stable orbit around Mercury.

BepiColombo is due to enter Mercury’s orbit on December 5, 2025. In the meantime, there will be three more flybys after Monday’s close approach.

Why the gravity assists?

Why can’t BepiColombo just shoot on over to Mercury and go into orbit around it? It can’t because Mercury is so near the sun.

The flyby maneuvers will keep the craft from being pulled into the sun’s gravity well. With one Earth flyby, two Venus flybys, and six eventual Mercury flybys, the spacecraft will lose enough energy that Mercury will capture it in its orbit. That’s right, we said “lose.” We typically think of a gravity assist as a way to boost a spacecraft’s energy. But a gravity assist can either speed up or slow down a spacecraft. Or it can simply change a craft’s direction.

ESA flight dynamics expert Frank Budnik explained more about this 3rd flyby:

As BepiColombo starts feeling Mercury’s gravitational pull, it will be traveling at 3.6 km/s [2.2 mi/s] with respect to the planet. That’s just over half the speed it approached with during the previous two Mercury flybys.

And this is exactly what the point of such events is. Our spacecraft began with far too much energy because it launched from Earth and, like our planet, is orbiting the sun. To be captured by Mercury, we need to slow down, and we’re using the gravity of Earth, Venus and Mercury to do just that.

Tricky maneuvering

Even though BepiColombo’s flight to Mercury was meticulously mapped in advance, controllers will have to make corrections during the seven years it’ll take the spacecraft to get there. In May, mission control performed a course correction that otherwise would have put BepiColombo 15,000 miles (24,000 km) too far from Mercury and on the wrong side of the planet.

Santa Martinez Sanmartin, ESA’s BepiColombo mission manager, explained more about the methods used to get BepiColombo in orbit:

This is the first time scientists are using the complex solar electric propulsion method to get a spacecraft to Mercury. And it represents a big challenge during the remaining part of the cruise phase. We have already adapted our operations concept to have additional communications passes with our ground stations, enabling us to recover faster from thruster interruptions and to improve orbit determination.

And all the while this is working with communications delays of more than 10 minutes due to the time it currently takes light signals to travel between Earth and the spacecraft.

As ESA said, the most demanding part of its journey is still to come:

After this flyby, the mission will enter a very challenging part of its journey to Mercury, gradually increasing the use of solar electric propulsion through additional propulsion periods called ‘thrust arcs’ to continually brake against the enormous gravitational pull of the sun. These thrust arcs can last from a few days up to two months, with the longer arcs interrupted periodically for navigation and maneuver optimization.

This challenging journey is one of the reasons that Mercury is one of the least explored planets in our solar system.

The images from the 3rd Mercury flby

BepiColombo got as close as 146 miles (235 km) from Mercury’s surface during this flyby. However, closest approach was past the unlit portion of Mercury, so scientists didn’t capture any images until a bit later. At about 13 minutes past closest approach, when the spacecraft was 1,143 miles (1,840 km) away, it reached the illuminated part of Mercury. Then it began sending back black-and-white images, including part of the craft itself. A Mercurial selfie, if you will.

You can follow along with the #MercuryFlyby at these Twitter accounts: @esaoperations, @BepiColombo, @ESA_Bepi, @ESA_MTM and @JAXA_MMO.

Testing the instruments

The team uses these flybys as a chance to test some of the instruments. During Monday’s flyby, the magnetic, plasma and particle monitoring instruments sampled the environment. Johannes Benkhoff, project scientist, said:

Collecting data during flybys is extremely valuable for the science teams to check their instruments are functioning correctly ahead of the main mission. It also provides a novel opportunity to compare with data collected by NASA’s MESSENGER spacecraft during its 2011–2015 mission at Mercury from complementary locations around the planet not usually accessible from orbit. We are delighted to already have data published based on our previous flybys that generated new science results, which makes us even more excited to get into orbit!

Bottom line: BepiColombo had its 3rd flyby of Mercury on June 19, 2023. The spacecraft will eventually go into orbit around the closest planet to the sun. ESA released three new images of Mercury taken during the encounter.

• Via ESA

{ https://earthsky.org/ }

25-07-2024 om 16:10 geschreven door peter  

Mercury has a layer of diamond 10 miles thick, NASA spacecraft finds

• https://youtu.be/nRyTUI423kY

The same process would have also led to the formation of a carbon-rich mantle beneath the surface. The team behind these findings thinks that this mantle isn't graphene, as previously suspected, but is composed of another much more precious allotrope of carbon: diamond. 

"We calculate that, given the new estimate of the pressure at the mantle-core boundary, and knowing that Mercury is a carbon-rich planet, the carbon-bearing mineral that would form at the interface between mantle and core is diamond and not graphite," team member Olivier Namur, an associate professor at KU Leuven, told Space.com. "Our study uses geophysical data collected by the NASA MESSENGER spacecraft."

MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) launched in Aug. 2004 and became the first spacecraft to orbit Mercury. The mission, which ended in 2015, mapped the entire tiny world, discovering abundant water ice in shadows at the poles and gathering crucial data about Mercury's geology and magnetic field.

Related: 

• Mercury was shrinking for at least 3 billion years — and it still might be today

Under pressure!

This new study also relates to a major surprise that came a few years ago when scientists re-evaluated the distribution of mass on Mercury, discovering the mantle of this tiny planet is thicker than previously thought.

"We directly thought that this must have a huge implication for the speciation [the distribution of an element or an allotrope amongst chemical species in a system] of carbon, diamond vs graphite, on Mercury," Namur said.

The team investigated this here on Earth by using a large-volume press to replicate the pressures and temperatures that exist within the interior of Mercury. They applied incredible amounts of pressure, over seven gigapascals, to a synthetic silicate acting as a proxy for the material found in the mantle of Mercury, achieving temperatures of up to 3,950 degrees Fahrenheit (2,177 degrees Celsius).

This allowed them to study how minerals like those that would have been found in Mercury's mantle in its early existence changed under these conditions. They also used computer modeling to assess data about Mercury's interior, which gave them clues to how the diamond mantle of Mercury could have been created.

"We believe that diamond could have been formed by two processes. First is the crystallization of the magma ocean, but this process likely contributed to forming only a very thin diamond layer at the core/mantle interface," Namur explained. "Secondly, and most importantly, the crystallization of the metal core of Mercury."

Namur said that when Mercury formed around 4.5 billion years ago, the core of the planet was fully liquid, progressively crystallizing over time. The exact nature of the solid phases forming in the inner core is not currently well known, but the team believes that these phases must have been low in carbon or "carbon-poor."

"The liquid core before crystallization contained some carbon; crystallization, therefore, leads to carbon enrichment in the residual melt," he continued. "At some point, a solubility threshold is reached, meaning the liquid cannot dissolve more carbon, and diamond forms."

Diamond is a dense mineral but not as dense as metal, meaning that during this process, it would have floated to the top of the core, stopping at the boundary of Mercury's core and its mantle. This would have resulted in the formation of an around 0.62-mile (1 km) thick diamond layer that then continued to grow over time. 

The discovery highlights the differences between the birth of the closest planet to the sun when compared with the creation of the solar system's other rocky planets, Venus, Earth, and Mars.

"Mercury formed much closer to the sun, likely from a carbon-rich cloud of dust. As a consequence, Mercury contains less oxygen and more carbon than other planets, which led to the formation of a diamond layer," Namur added. "However, Earth's core also contains carbon, and diamond formation in the Earth's core has already been suggested by various researchers."

The researcher hopes that this discovery could help reveal clues to some of the other mysteries surrounding the solar system's smallest planet, including why its volcanic phase was cut short around 3.5 billion years ago.

"A major question that I have about Mercury's evolution is why the major phase of volcanism lasted only a few hundred million years, much shorter than other rocky planets. This must mean that the planet cooled down very fast," Namur said. "This is partly related to the small size of the planet, but we are now working with physicists to try to understand if a diamond layer could have contributed to very fast heat removal, therefore terminating major volcanism very early."

Namur said that the team's next step will be to investigate the thermal effect of a diamond layer at the mantle/core boundary. This study could be supported by data from a mission that will follow in the footsteps of MESSENGER.

"We are also eagerly waiting for the first data collected by BepiColombo, hopefully in 2026, to refine our understanding of Mercury's internal structure and evolution," Namur concluded.

• The team's research was published in the journal Nature Communications. 

{ https://www.space.com/ }

25-07-2024 om 15:48 geschreven door peter  

However, in reduced gravity, the bubbles either take much longer to detach or don’t do so at all. This creates a buffer layer along the electrode’s length that decreases the electrolysis process’s efficiency, sometimes stalling it out entirely. Electrolysis isn’t the only fluidic process that has difficulty operating in reduced gravity environments – many ISS experiments also have trouble. This is partly due to a lack of complete understanding of how liquids operate in these environments – and that in itself is partly driven by a dearth of experimental data. 

Which is where the modeling comes in. Dr. Burke and his colleagues use a technique known as Computational Fluid Dynamics to attempt to mimic the forces the fluids will undergo in a reduced gravity environment while also understanding bubble formation.

Electrolysis on Earth is typically done with water, but why stop there? The team used their CFD to model two other liquids that might be used in electrolyzers – molten salt (MSE) and molten regolith (MRE). Molten salt is used on Earth, but less commonly than regular water, and has successfully produced oxygen. However, molten regolith electrolysis is still somewhat of a novel use case and has yet to be thoroughly tested. MOXIE, the experiment that famously created oxygen on Mars in 2021, used the carbon dioxide in Mars’ atmosphere and a solid-state electrode – neither representative of molten regolith.

Dr. Burke and his team found that, computationally, at least, MRE has the most challenging conditions in reduced gravity. It has also never been tested in any reduced gravity environment, so for now; these simulations are all engineers have to go on with if they are going to design a system.

There were a few key takeaways from the modeling, though. First, engineers should design horizontal electrodes into MRE systems, as the longer a bubble spreads across an electrode (i.e., as it goes “up” it), the longer it takes for that bubble to detach. In a horizontal configuration, the electrode has less surface area to attach to, making it more likely for the bubbles to detach and float to the surface.

Additionally, the amount of time bubbles remain attached to an electrode scales exponentially with decreasing gravity. That means bubbles on the Moon will take longer to detach than those on Mars, which will take longer than those on Earth. Consequently, electrolysis on the Moon will be less efficient than that on Mars, which will again be less efficient than that on Earth, and mission planners will need to account for these discrepancies if they plan on getting something as mission-critical as oxygen from this process. The smoothness of the electrodes also seems to matter, with rougher electrodes more likely to hold onto their bubbles and, therefore, end up less efficient.

Other engineering solutions can overcome all these challenges, such as a vibratory mechanism on the electrode to shake the bubbles loose. However, it’s a good idea to consider all the additional complications operations in a reduced gravity environment have before launching a mission. That’s why modeling is so important, but humanity will ultimately have to experimentally test these systems, perhaps on the Moon itself, if we plan to utilize its local resources to sustain our presence there.

Learn More:

• Burke et al. – Modeling electrolysis in reduced gravity: producing oxygen from in-situ resources at the moon and beyond
  
• UT – NASA Wants to Learn to Live Off the Land on the Moon
• UT – What is ISRU, and How Will it Help Human Space Exploration?
• UT – A Robotic Chemist Could Whip up the Perfect Batch of Oxygen on Mars

Lead Image:

• Graphic showing the difference in bubble accumulation in low and high gravities.
• Credit – Burke et al.

{ https://www.universetoday.com/ }

24-07-2024 om 23:45 geschreven door peter  

In a new article in Nature, science journalist Sarah Wild looked at how researchers are using astronomical methods to uncover deepfakes. Adejumoke Owolabi is a student at the University of Hull in the UK who studies data science and computer vision. Her Master’s Thesis focused on how light reflected in eyeballs should be consistent, though not identical, between left and right. Owolabi used a high-quality dataset of human faces from Flickr and then used an image generator to create fake faces. She then compared the two using two different astronomical measurement systems called the CAS system and the Gini index to compare the light reflected in the eyeballs and to determine which were deepfakes.

CAS stands for concentration, asymmetry, and smoothness, and astronomers have used it for decades to study and quantify the light from extragalactic stars. It’s also used to quantify the light from entire galaxies and has made its way into biology and other areas where images need to be carefully examined. Noted astrophysicist Christopher J. Conselice was a key proponent of using CAS in astronomy.

The Gini index, or Gini coefficient, is also used to study galaxies. It’s named after the Italian statistician Corrado Gini, who developed it in 1912 to measure income inequality. Astronomers use it to measure how light is spread throughout a galaxy and whether it’s uniform or concentrated. It’s a tool that helps astronomers determine a galaxy’s morphology and classification.

In her research, Owolabi successfully determined which images were fake 70% of the time.

For her article, Wild spoke with Kevin Pimbblet, director of the Centre of Excellence for Data Science, Artificial Intelligence and Modelling at the University of Hull in the UK. Pimblett presented the research at the UK Royal Astronomical Society’s National Astronomy Meeting on July 15th.

“It’s not a silver bullet, because we do have false positives and false negatives,” said Pimbblet. “But this research provides a potential method, an important way forward, perhaps to add to the battery of tests that one can apply to try to figure out if an image is real or fake.”

This is a promising development. Open democratic societies are prone to disinformation attacks from enemies without and within. Public figures are prone to similar attacks. Disturbingly, the majority of deepfakes are pornographic and can depict public figures in private and sometimes degrading situations. Anything that can help combat it and bolster civil society is a welcome tool.

But as we know from history, arms races have no endpoint. They go on and on in an escalating series of countermeasures. Look at how the USA and the USSR kept one-upping each other during their nuclear arms race as warhead sizes reached absurd levels of destructive power. So, inasmuch as this work shows promise, the purveyors of deepfakes will learn from it and improve their AI deepfake methods.

Wild also spoke to Brant Robertson in her article. Robertson is an astrophysicist at the University of California, Santa Cruz, who studies astrophysics and astronomy, including big data and machine learning. “However, if you can calculate a metric that quantifies how realistic a deepfake image may appear, you can also train the AI model to produce even better deepfakes by optimizing that metric,” he said, confirming what many can predict.

This isn’t the first time that astronomical methods have intersected with Earthly issues. When the Hubble Space Telescope was developed, it contained a powerful CCD (charge-coupled device.) That technology made its way into a digital mammography biopsy system. The system allowed doctors to take better images of breast tissue and identify suspicious tissue without a physical biopsy. Now, CCDs are at the heart of all of our digital cameras, including on our mobile phones.

Might our internet browsers one day contain a deepfake detector based on Gini and CAS? How would that work? Would hostile actors unleash attacks on those detectors and then flood our media with deepfake images in an attempt to weaken our democratic societies? It’s the nature of an arms race.

It’s also in our nature to use deception to sway events. History shows that rulers with malevolent intent can more easily deceive populations that are in the grip of powerful emotions. AI deepfakes are just the newest tool at their disposal.

We all know that AI has downsides, and deepfakes are one of them. While their legality is fuzzy, as with many new technologies, we’re starting to see efforts to combat them. The United States government acknowledges the problem, and several laws have been proposed to deal with it. The “DEEPFAKES Accountability Act” was introduced in the US House of Representatives in September 2023. The “Protecting Consumers from Deceptive AI Act” is another related proposal. Both are floundering in the sometimes murky world of subcommittees for now, but they might breach the surface and become law eventually. Other countries and the EU are wrestling with the same issue.

But in the absence of a comprehensive legal framework dealing with AI deepfakes, and even after one is established, detection is still key.

Astronomy and astrophysics could be an unlikely ally in combatting them.

{https://www.universetoday.com/ ,}

24-07-2024 om 23:31 geschreven door peter  

Curiosity’s Peregrinations

At the moment, the Curiosity rover is making its way through the Gediz Vallis. That’s a flow channel winding its way down a section of Mount Sharp (aka Aeolis Mons). That’s the central peak of Gale Crater. The rover has been heading up since 2014, charting different surface layers as it goes. Each layer was put down during a different era of Mars’s history. They could contain clues to the planet’s habitability in the past.

Fast-moving liquid water raged over the surface and carved Gediz. The floods carried a lot of rocks and sand and deposited them all along the way. Other piles of flood debris lie around the region, bearing witness to other ancient floods and landslides. “This was not a quiet period on Mars,” said Becky Williams, a scientist with the Planetary Science Institute in Tucson, Arizona, and the deputy principal investigator of the Mast Camera, or Mastcam on Curiosity. “There was an exciting amount of activity here. We’re looking at multiple flows down the channel, including energetic floods and boulder-rich flows.”

Understanding Sulfur’s Presence

The surface materials in Gediz contain high amounts of sulfates. Those are sulfur-bearing salts that appear as water evaporates. They are a chemical clue that water existed in the region. Judging by some parts of the surface, it also appears the water ponded at some times, in addition to the floods that scoured the landscape and then deposited debris.

Now the planetary science team has to explain how a pure form of elemental sulfur got stuck in the middle of rocks, according to project scientist Ashwin Vasavada. “Finding a field of stones made of pure sulfur is like finding an oasis in the desert,” said Vasavada. “It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”

Putting Sulfur in Context

Sulfur, of course, exists on Earth, which helps scientists understand its behavior and the environments where it’s found. The presence of sulfur can be a result of various geological processes. The sulfur “cycle” includes the flow of sulfur from the core to the surface through volcanism. That’s not unusual. Sulfur commonly appears around volcanic vents. Mt Ijen in Indonesia is a good example. It sports extensive elemental sulfur deposits that are mined.

The volcanic moon Io in the Jupiter system features patches of different allotropes of sulfur. They’re also volcanic in origin, spewed out along with widespread lava flows. This moon has more than 400 volcanic features, making it the most volcanically active (and sulfurous) place in the Solar System.

The pure sulfur in the Mars rock most likely came from volcanic processes. They occurred sometime in the past, but that doesn’t answer how the crystals got inside the rock it crushed. Scientists have known for years that Mars was extremely volcanically active in the past. For a long time, they also thought it was dead, or at least dormant. The planet has no plate tectonics like we see on Earth, either. However, the Mars InSight mission found evidence of some seismic activity on the planet in 2021.

In 2023, planetary scientists at the University of Arizona offered up evidence of a giant mantle plume under Elysium Planitia that drove some kinds of activity in the more recent past. Gale Crater lies in this region and could well have experienced related volcanic and seismic activity during the recent geologic past. If so, that could help explain the presence not only of pure sulfur but also the flood-related sulfates deposited on the surface.

For More Information

• NASA’s Curiosity Rover Discovers a Surprise in a Martian Rock
  
• Recent Volcanism on Mars Reveals a Planet More Active than Previously Thought
  
• Sulfur on Mars from the Atmosphere to the Core

{ https://www.universetoday.com/ }

24-07-2024 om 23:18 geschreven door peter  

Chandra Marks 25 Years in Space with Collection of 25 Stunning Images

To celebrate the 25th anniversary of NASA’s Chandra X-ray Observatory, the Chandra team has released a set of 25 new images of cosmic objects and phenomena.

This collection of images was released to commemorate the 25th anniversary of Chandra.

Image credit: NASA / CXC / SAO.

On July 23, 1999, the space shuttle Columbia launched into orbit carrying Chandra, which was then the heaviest payload ever carried by the shuttle.

With Commander Eileen Collins at the helm, the astronauts aboard Columbia successfully deployed Chandra into its highly elliptical orbit that takes it nearly one-third of the distance to the Moon.

“For a quarter century, Chandra has made discovery after amazing discovery,” said Dr. Pat Slane, director of the Chandra X-ray Center located at the Smithsonian Astrophysical Observatory.

“Astronomers have used Chandra to investigate mysteries that we didn’t even know about when we were building the telescope — including exoplanets and dark energy.”

“Chandra has been a great success story for humanity and its pursuit of knowledge,” said Dr. Andrew Schnell, acting project manager of Chandra at NASA’s Marshall Space Flight Center.

“The telescope’s incredible accomplishments are made possible by the team’s hard work and dedication.”

The new set of images is a sample of almost 25,000 observations Chandra has taken during its quarter century in space.

In 1976, Riccardo Giacconi and Harvey Tananbaum first proposed to NASA the mission that would one day become Chandra.

Eventually, Chandra was selected to become one of NASA’s Great Observatories, along with the Hubble Space Telescope and the now-retired Compton Gamma Ray Observatory and Spitzer Space Telescope, each looking at different types of light.

In 2002, Giacconi was awarded the Nobel Prize in physics for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources, laying the foundation for the development and launch of Chandra.

Today, astronomers continue to use Chandra data in conjunction with other powerful telescopes including the NASA/ESA/CSA James Webb Space Telescope, NASA’s Imaging X-ray Polarimetry Explorer (IXPE), and many more.

“On behalf of the STS-93 crew, we are tremendously proud of the Chandra X-ray Observatory and its brilliant team that built and launched this astronomical treasure,” said Eileen Collins, commander of the space shuttle Columbia mission that launched Chandra into space in 1999.

“Chandra’s discoveries have continually astounded and impressed us over the past 25 years.”

• This article is a version of a press-release provided by NASA.
  

Top 10 Facts About Chandra

10. Chandra flies 200 times higher than Hubble - more than 1/3 of the way to the moon!

Explanation: For the planned operational orbit of Chandra, the closest approach to Earth and the most distant point from Earth will be as follows:
Altitude at Perigee (closest approach) = 10,000 km = 6,214 (statute) mile = 5,400 nautical mile
Altitude at Apogee (most distant point from Earth) = 140,000 km = 86,992 (statute) mile = 75,594
nautical mile
For reference, Mean radius of Earth = 6,371 km = 3,959 (statute) mile = 3,440 nautical mile

9. Chandra can observe X-rays from clouds of gas so vast that it takes light five million years to go from one side to the other!

Explanation: If we assume conservatively that a cluster extends out to a radius of 1 Mpc, then it has a diameter of 2 Mpc, or 6 million light years.

8. During maneuvers from one target to the next, Chandra slews more slowly than the minute hand on a clock.

Explanation: According the CXC Observatory Guide, it takes Chandra 31 minutes to slew 90 degrees. It takes the minute hand on a clock 15 minutes to slew 90 degrees.

7. At 45 feet long, Chandra is the largest satellite the shuttle has ever launched. See also: Top 10 Facts Infographic

Explanation: For comparison, the Hubble Space Telescope was just over 43 feet long.

6. If Colorado were as smooth as Chandra's mirrors, Pikes Peak would be less than one inch tall!

Explanation: Numbers:
Assume optics size = 84 cm
Assume rms low frequency figure errors are < 100a = 1e-6 cm
Assume size of Colorado= 600 km = 6 E7 cm
Then the ratio of the (rms errors)/(optics size) < 1.2 e-8
Assuming that there will be one 3 sigma peak in 1000 trials (the approx. number of measurements of the figure), then the ratio is < 3.6e-8.
Then the largest mountain (which is not Pikes Peak, but is not much taller than Pikes Peak) in Colorado would be < 2.2 cm < 1 inch.

5. Chandra's resolving power is equivalent to the ability to read a stop sign at a distance of twelve miles.

Explanation: The letters on a stop sign are 25 cm high. Assuming that we need a 5 x 5 pixel square, then the resolution element is 5 cm high, which would subtend an angle = 0.5 arcsec at a distance D = 5/2.5E-6 = 2 E6 cm = 20 km = 12 miles.

4. The electrical power required to operate the Chandra spacecraft and instruments is 2 kilowatts, about the same power as a hair dryer.

Explanation: A standard hair dryer uses 1600-1800 watts (slightly less than 2 kilowatts) on its high setting.

3. The light from some of the quasars observed by Chandra will have been traveling through space for ten billion years.

Explanation: If we take a Hubble constant of 60 km/sec-Mpc, then the Hubble time is approx 16 billion years, so for a quasar at z > 3, the look back time, depending on Omega, is greater than 10 billion years.

2. STS-93, the space mission that deployed Chandra, was the first NASA shuttle mission commanded by a woman.

Explanation: Commander Eileen Collins was the first woman to command a NASA shuttle mission.

Chandra can observe X-rays from particles up to the last second before they fall into a black hole!!!

Explanation: The last stable orbit for a Schwarzchild metric is 6GM/c^2 ~ 10^7 cm for a 10 solar mass black hole. The time to fall in from this point on is ~ 0.001-.01 seconds, depending on the details of the orbit of the infalling particle.

{ https://www.sci.news/ }

24-07-2024 om 22:24 geschreven door peter  

Curiosity Finds Pure Sulfur on Mars

Yellow crystals of elemental sulfur were revealed after NASA’s Curiosity rover happened to drive over a rock and crack it open on May 30, 2024, according to the Curiosity team.

Yellow crystals of elemental sulfur on Mars.

Image credit: NASA.

While people associate sulfur with the odor from rotten eggs, elemental sulfur is odorless.

It forms in only a narrow range of conditions that scientists haven’t associated with the history of this location.

And Curiosity found a lot of it — an entire field of bright rocks that look similar to the one the rover crushed.

“Finding a field of stones made of pure sulfur is like finding an oasis in the desert,” said Curiosity’s project scientist Dr. Ashwin Vasavada, a researcher at NASA’s Jet Propulsion Laboratory.

“It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”

It’s one of several discoveries Curiosity has made while off-roading within Gediz Vallis channel, a groove that winds down part of the 5-km-tall (3-mile-tall) Mount Sharp, the base of which the rover has been ascending since 2014.

Spotted from space years before the rover’s launch, the channel is one of the primary reasons the science team wanted to visit this part of Mars.

They think that the channel was carved by flows of liquid water and debris that left a ridge of boulders and sediment extending 3.2 km (2 miles) down the mountainside below the channel.

The goal has been to develop a better understanding of how this landscape changed billions of years ago, and while recent clues have helped, there’s still much to learn from the dramatic landscape.

Since Curiosity’s arrival at the channel earlier this year, scientists have studied whether ancient floodwaters or landslides built up the large mounds of debris that rise up from the channel’s floor here.

The latest clues from the rover suggest both played a role: some piles were likely left by violent flows of water and debris, while others appear to be the result of more local landslides.

hose conclusions are based on rocks found in the debris mounds: whereas stones carried by water flows become rounded like river rocks, some of the debris mounds are riddled with more angular rocks that may have been deposited by dry avalanches.

Finally, water soaked into all the material that settled here.

Chemical reactions caused by the water bleached white ‘halo’ shapes into some of the rocks.

Erosion from wind and sand has revealed these halo shapes over time.

“This was not a quiet period on Mars,” said Dr. Becky Williams, a scientist with the Planetary Science Institute in Tucson, Arizona, and the deputy principal investigator of Curiosity’s Mast Camera.

“There was an exciting amount of activity here. We’re looking at multiple flows down the channel, including energetic floods and boulder-rich flows.”

• This article is a version of a press-release provided by NASA.

{ https://www.sci.news/ }

24-07-2024 om 18:39 geschreven door peter  

NASA's Curiosity rover ontdekt iets dat nog nooit eerder op Mars is gezien, verborgen in een rots

Door Janine

Jet Propulsion Laboratory / NASA/JPL-Caltech - Wikimedia commons - Public domain

Nooit eerder geziene gele kristallen van pure zwavel op Mars

NASA/JPL-CALTECH/MSSS

De verrassing van de wetenschappers, zoals NASA aankondigde, was onbeschrijflijk: sulfaten, zouten die zwavel bevatten, komen veel voor in het gebied van de krater Gale waar Curiosity zich momenteel bevindt, maar het gesteente dat de rover vond heeft een andere bijzonderheid: “Waar eerdere waarnemingen betrekking hadden op zwavelhoudende mineralen, oftewel een mix van zwavel en andere materialen, is het gesteente dat Curiosity onlangs heeft gevonden samengesteld uit elementaire, oftewel pure zwavel”, verklaarde de Amerikaanse ruimtevaartorganisatie.

In tegenstelling tot de zwavel waar wij aan denken, ruikt elementaire zwavel echter niet naar “rotte eieren”. Het is gewoon reukloos. Maar dit lijkt niet de enige rots te zijn die zuivere zwavel bevat op de rode planeet: de rover identificeerde een veld met zeer vergelijkbare, lichtgekleurde rotsblokken, waarin andere gele kristallen te vinden waren.

Ashwin Vasavada van het Jet Propulsion Laboratory, een wetenschapper van het project Curiosity, zei: "Het vinden van een veld met rotsen bestaande uit pure zwavel is als het vinden van een oase in de woestijn. Het zou er niet moeten zijn, dus nu moeten we het verklaren." Andrew Good, woordvoerder van JPL, voegde eraan toe dat "er geen reden is om pure zwavel te verwachten in deze specifieke regio, dus we zijn behoorlijk verrast."

Curiosity, op een missie om de geschiedenis van water op Mars te bestuderen

Hoewel Curiosity in alle opzichten een bewegend laboratorium is dat kan boren en graven, zijn de gele kristallen te klein om ze te kunnen onderzoeken. Wetenschappers zijn echter van plan uit te zoeken waarom en hoe ze zijn gevormd. Good brengt een hypothese naar voren: "Een idee zou kunnen zijn dat zoiets als warmwaterbronnen deze zwavel hebben gevormd,  maar we hebben geen bewijs gezien dat wijst op hun aanwezigheid in dit gebied.

Om meer te weten te komen, zullen we moeten wachten tot onderzoekers de elementen kunnen onderzoeken die zijn verzameld door de zeswielige rover, die twaalf jaar geleden landde op Mount Sharp, de gigantische berg in het midden van de krater Gale. Onlangs richtte Curiosity zich op het Gediz Vallis kanaal, waar mogelijk ooit een rivier was. De missie van de rover is juist om de geschiedenis van het water op Mars te ontdekken en daarmee ook bewijs voor mogelijk microbieel leven in het verleden.

INFO PETER2011

{ https://www.curioctopus.nl/ }

24-07-2024 om 17:26 geschreven door peter  

Evidence of Alien Life May Lie on the Surface of Europa and Enceladus, A New Study Reveals

Chemicals that hint at the presence of life, like amino acids, aren't destroyed by cosmic radiation nearly as quickly as we thought, and that's good news.

BY KIONA SMITH

 

All About Space Magazine/Future/Getty Images

According to recent experiments at NASA’s Goddard Space Flight Center, evidence of alien life could be preserved on the surface of Enceladus, and just a few inches below the surface of Europa, despite the heavy bombardment of radiation that scours the surface of both moons.

Planetary scientist Alexander Pavlov, of NASA Goddard, and his colleagues published their work in the journal Astrobiology.

SIMULATING AN IRRADIATED ICY WASTELAND

In their lab at Goddard, Pavlov and his colleagues mixed up several simulated versions of the slush — laden with organic matter — that ends up smeared and spattered across the ice atop Enceladus and Europa’s oceans, all chilled to -321 degrees Fahrenheit. Then they bombarded the chilly cocktails with gamma radiation, to simulate the radiation that constantly blasts the surfaces of Enceladus and Europa. And it turns out that most of the evidence of life survived higher doses of radiation than the researchers had expected.

High-energy radiation can trigger chains of chemical reactions, which eventually break down the molecules associated with life including DNA, amino acids, and proteins, among others. Amino acids are the building blocks of proteins (which are the building blocks of pretty much everything that makes life actually work). Some amino acids can form through chemical reactions that have nothing to do with life, but others are what scientists call biosignatures: If you see these particular chemicals, especially if you see them along with other biosignatures, they probably came from a living cell at some point.

Pavlov and his colleagues wanted to know how long it would take the harsh radiation to break amino acids down into something useless to astrobiologists — a molecule that wouldn’t clearly point back to alien life as its source. They also wanted to know how deep future missions would have to drill into the ice to find signs of life, if they exist at all.

That’s something astrobiologists, planetary scientists, and mission planners have been trying to figure out for both Europa and Enceladus. Some studies suggest that the tremendous geysers of Enceladus could blast whole microbes out into space, where a passing spacecraft could just scoop them up. At the other end of the spectrum, some researchers predict that landers might have to drill all way through Europa’s ice to the ocean beneath.

But thanks to cryovolcanism — a phenomenon that happens in very cold places like Europa and Enceladus, where water or partially-frozen slush behaves like magma here on Earth, so it either oozes out of cracks in the ice or erupts in geysers — there’s organic material splattered across the moon’s frozen surface. The only question is whether it’s too damaged by radiation to actually reveal anything about whether there’s life beneath the ice.

The answer, it turns out, is probably good news for future missions.

RIGHT THERE ON THE SURFACE

Once Pavlov and his colleagues had calculated how quickly their amino acids broke down under different radiation doses, they combined that with everything we know about how much radiation hits different regions of Europa and Enceladus, along with how old the ice is in those regions. That information let the researchers predict where future missions would stand the best chance of finding evidence of life — and how deep they would need to drill.

On Europa, future missions should find intact, recognizable amino acids about eight inches beneath the surface, especially in the high latitudes near the north and south poles of the moon. And on Enceladus, future missions will just need to scrape away the top fraction of an inch of ice to find usable samples.

That could make it much easier for eventual landers — which could reach Europa sometime in the 2040s, if NASA’s planned Europa Clipper mission finds anything interesting when it arrives in orbit around Europa in a few years — to get samples that might (or, alas, might not) contain evidence of alien life swimming in the dark water beneath the icy crust.

{ https://www.inverse.com/ }

24-07-2024 om 16:53 geschreven door peter  

The largest storm in the Solar System is shrinking and planetary scientists think they have an explanation. It could be related to a reduction in the number of smaller storms that feed it and may be starving Jupiter’s centuries-old Great Red Spot (GRS).

This storm has intrigued observers from its perch in the Jovian southern hemisphere since it was first seen in the mid-1600s. Continuous observations of it began in the late 1800s, which allowed scientists to chart a constant parade of changes. In the process, they’ve learned quite a bit about the spot. It’s a high-pressure region that generates a 16,000 km-wide anticyclonic storm with winds clocking in at more than 321 km per hour. The storm extends down through the atmosphere to a depth of about 250 km below the mainly ammonia cloud tops.

Modeling a Shrinking and Growing Great Red Spot

Over the past century, scientists noticed the GRS shrinking, leaving them with a puzzle on their hands. Yale Ph.D. student Caleb Keaveney had the idea that perhaps smaller storms that feed the GRS could play a role in starving it. He and a team of researchers focused on their influence and conducted a series of 3D simulations of the Spot. They used a model called the Explicit Planetary Isentropic-Coordinate (EPIC) model, which is used in studying planetary atmospheres. The result was a suite of computer models that simulated interactions between the Great Red Spot and smaller storms of varying frequency and intensity.

A separate control group of simulations left out the small storms. Then, the team compared the simulations. They saw that the smaller storms seemed to strengthen the Great Red Spot and make it grow. “We found through numerical simulations that by feeding the Great Red Spot a diet of smaller storms, as has been known to occur on Jupiter, we could modulate its size,” Keaveney said.

If that’s true, then the presence (or lack thereof) of those smaller storms could be what’s changing the spot’s size. Essentially, a lot of smaller spots cause it to grow larger. Fewer little ones cause it to shrink. Furthermore, the team’s modeling supports an interesting idea. Without forced interactions with these smaller vortices, the Spot can shrink over a period of about 2.6 Earth years.

Using Earth Storms as a Comparison

The Great Red Spot isn’t the only place in the Solar System that sports such a long-lived high-pressure system. Earth experiences plenty of them, usually called “heat domes” or “blocks.” Most of us are familiar with heat domes because we experience them during the summer months. They happen frequently in the upper atmosphere jet stream that circulates across our planet’s mid-latitudes. We can blame them for some of the extreme weather people experience—such as heat waves and extended droughts. They tend to last a long time, and they are linked to interactions with smaller transient weather such as high-pressure eddies and anticyclones.

Given that the Great Red Spot is an anticyclonic feature, it has interesting implications for similar atmospheric structures on both planets, according to Keaveney. “Interactions with nearby weather systems have been shown to sustain and amplify heat domes, which motivated our hypothesis that similar interactions on Jupiter could sustain the Great Red Spot,” he said. “In validating that hypothesis, we provide additional support to this understanding of heat domes on Earth.”

The Ever-changing Great Red Spot

In addition to the changing size of the Great Red Spot, observers also notice shifts in its color. It’s mainly reddish-orange but has been known to fade to a pinkish-orange hue. The colors suggest some complex chemistry occurring in the region spurred by solar radiation. It has an effect on a chemical compound called ammonium hydrosulfide as well as the organic compound acetylene. That creates a substance called a tholin, which gives a reddish color wherever it exists.

At times the spot has nearly disappeared altogether due to some complex interaction with a feature called the Southern Equatorial Belt (SEB). The SEB is where the spot is located, and when it is bright and white, the spot goes dark. At other times, the reverse color change happens. In some cases, the SEB itself has disappeared at various times. No one is quite sure why this is happening, but it’s one more piece of the Jovian atmospheric puzzle.

Changes to the Great Red Spot have been studied extensively not just from the ground, but also by spacecraft missions, beginning with Voyager and extending through the Galileo, Cassini, and Juno missions. Each spacecraft used specialized instruments to probe the spot, measure its windspeeds and temperatures, and sample the gas and compounds in the upper atmosphere. All of that data feeds models like the ones used at Yale to model the smaller storms’ contributions to the Great Red Spot’s growth and shrinkage.

For More Information

• A New Explanation for Jupiter’s Great, Shrinking “Spot”
  
• Effect of Transient Vortex Interactions on the Size and Strength of Jupiter’s Great Red Spot
  
• Juno and the Great Red Spot

Graphical abstract

{ https://www.universetoday.com/ }

23-07-2024 om 18:10 geschreven door peter