Laboratory experiments have lead to new information about the chemical composition of the mysterious dark material in the long, dark fractures on the surface of Europa, a large moon of Jupiter. Researchers at NASA’s Jet Propulsion Laboratory (JPL) mimicked conditions on Europa’s surface. They now say that the dark material is discolored salt, likely sea salt from below the moon’s icy crust. The journal Geological Research Letters published their study on May 15, 2015.
The scientists say this new insight is important in considering whether this icy moon might be hospitable for extraterrestrial life. The life question is a key one for Europa, since this world is believed to have a liquid ocean beneath its crust. The presence of sea salt on Europa’s surface suggests the ocean is interacting with its rocky seafloor.
Scientists have been intensely curious about Europa since Galileo discovered it in 1610. In recent years, they’ve puzzled over the dark material coating the long, linear fractures on Europa’s observable surface. The material was associated with young terrain on this moon of Jupiter, suggesting that it had erupted from within Europa. However, the chemical composition of the dark material remained elusive, until now. Planetary scientist Kevin Hand at JPL led the new study. He said in a statement:
If it’s just salt from the ocean below, that would be a simple and elegant solution for what the dark, mysterious material is.
Europa is immersed radiation from Jupiter’s powerful magnetic field, causing high-powered electrons to slam into the moon’s surface. Hand and his team created a laboratory test that mimicked the conditions of Europa’s temperature, pressure, and radiation exposure. They tested a variety of samples including common salt – sodium chloride – and salt water in a vacuum chamber at Europa’s chilly surface temperature of minus 280 degrees Fahrenheit (minus 173 Celsius). They also bombarded the samples with an electron beam to imitate Jupiter’s influence.
After several hours – a time period corresponding to over a century on Europa, the researchers said – the salt samples were observed to go from white to a yellowish brown, the color similar to the features on the icy moon. Hand said:
This work tells us the chemical signature of radiation-baked sodium chloride is a compelling match to spacecraft data for Europa’s mystery material.
A “Europa-in-a-can” laboratory setup at NASA-JPL mimics conditions of temperature, near vacuum and heavy radiation on the surface of Jupiter’s icy moon. Image via NASA/JPL-Caltech
Close-up of salt grains discolored by radiation following exposure in a “Europa-in-a-can” test setup at JPL. Image via NASA/JPL-Caltech
Until now, telescopic observations have only shown glimpses of irradiated salts. No telescope on Earth can observe Europa’s surface with enough resolution to identify them with certainty. Researchers suggest additional spacecraft observation to gather more evidence. A visit to this icy world would help answer the most tantalizing questions about Europa. Long believed to have a liquid ocean of salt water below its icy surface, this moon continues to display promising conditions for extraterrestrial life.
As Europa orbits Jupiter, it experiences strong tidal forces similar to Earth and the Moon. These forces from Jupiter and the other Jovian moons cause Europa to flex and stretch, which creates heat, and results in Europa having a warm internal temperature than it would with just the heat from the Sun alone.
Recent observable geological activity also creates strong evidence that the subsurface ocean interacts directly with Europa’s rocky interior, making geothermal vents, like those in Earth’s oceans, a strong possibility as well.
These hydrothermal vent ecosystems on Earth thrive with no energy from the sun. Bacteria, shrimp and crustaceans have all been observed in these extreme environments, surviving on what researchers have deemed chemosythesis.
With Europa’s enormous amount of liquid salt water, essential chemical elements and geological activity, this long discovered icy moon appears to be one of the solar systems most promising locations for habitable requirements for life.
However, until a devoted spacecraft visit’s, nothing beyond hopeful speculation can be proven, the researchers say.
Bottom line: Researchers at NASA’s Jet Propulsion Laboratory created laboratory conditions that mimicked those on Jupiter’s large moon Europa, to learn the chemical compositions of the material in long, dark fractures in the moon’s surface. They now believe this material is sea salt, which has emerged to Europa’s surface from its liquid ocean below.
Excerpt from huffingtonpost.comHighly advanced aliens seem MIA, according to a recent study by astronomers at Penn State University. These researchers checked out a huge gob of cosmic real estate -- roughly 100,000 galaxies -- and failed to find cl...
Excerpt from cnet.comEnceladus may have a warm ocean beneath its icy surface, but it may also be shooting through that crust in big sheets, perhaps filled with sea monkeys. We already know that Saturn's ...
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This artist's impression of the interior of Saturn's moon Enceladus shows that interactions between hot water and rock occur at the floor of the subsurface ocean -- the type of environment that might be friendly to life, scientists say. (NASA/JPL-Caltech)
Scientists say they’ve discovered evidence of a watery ocean with warm spots hiding beneath the surface of Saturn’s icy moon Enceladus. The findings, described in the journal Nature, are the first signs of hydrothermal activity on another world outside of Earth – and raise the chances that Enceladus has the potential to host microbial life.
Scientists have wondered about what lies within Enceladus at least since NASA’s Cassini spacecraft caught the moon spewing salty water vapor out from cracks in its frozen surface. Last year, a study of its gravitational field hinted at a 10-kilometer-thick regional ocean around the south pole lying under an ice crust some 30 to 40 kilometers deep.
Another hint also emerged about a decade ago, when Cassini discovered tiny dust particles escaping Saturn’s system that were nanometer-sized and rich in silicon.
“It’s a peculiar thing to find particles enriched with silicon,” said lead author Hsiang-Wen Hsu, a planetary scientist at the University of Colorado, Boulder. In Saturn’s moons and among its rings, water ice dominates, so these odd particles clearly stood out.
The scientists traced these particles’ origin to Saturn’s E-ring, which lies between the orbits of the moons Mimas and Titan and whose icy particles are known to come from Enceladus. So Hsu and colleagues studied the grains to understand what was going on inside the gas giant’s frigid satellite. Rather than coming in a range of sizes, these particles were all uniformly tiny – just a few nanometers across. Studying the spectra of these grains, the scientists found that they were made of silicon dioxide, or silica. That’s not common in space, but it’s easily found on Earth because it’s a product of water interacting with rock.
Knowing how silica interacts in given conditions such as temperature, salinity and alkalinity, the scientists could work backward to determine what kind of environment creates these unusual particles.
A scientist could do the same thing with a cup of warm coffee, Hsu said.
“You put in the sugar and as the coffee gets cold, if you know the relation of the solubility of sugar as a function of temperature, you will know how hot your coffee was,” Hsu said. “And applying this to Enceladus’s ocean, we can derive a minimum [temperature] required to form these particles.”
The scientists then ran experiments in the lab to determine how such silica particles came to be. With the particles’ particular makeup and size distribution, they could only have formed under very specific circumstances, the study authors found, determining that the silica particles must have formed in water that had less than 4% salinity and that was slightly alkaline (with a pH of about 8.5 to 10.5) and at temperatures of at least 90 degrees Celsius (roughly 190 degrees Fahrenheit).
The heat was likely being generated in part by tidal forces as Saturn’s gravity kneads its icy moon. (The tidal forces are also probably what open the cracks in its surface that vent the water vapor into space.) Somewhere inside the icy body, there was hydrothermal activity – salty warm water interacting with rocks. It’s the kind of environment that, on Earth, is very friendly to life.
“It’s kind of obvious, the connection between hydrothermal interactions and finding life,” Hsu said. “These hydrothermal activities will provide the basic activities to sustain life: the water, the energy source and of course the nutrients that water can leach from the rocks.”
Enceladus, Hsu said, is now likely the “second-top object for astrobiology interest” – the first being Jupiter’s icy moon and fellow water-world, Europa. This activity is in all likelihood going on right now, Hsu said – over time, these tiny grains should glom together into larger and larger particles, and because they haven’t yet, they must have been recently expelled from Enceladus, within the last few months or few years at most.
Gabriel Tobie of the University of Nantes in France, who was not involved in the research, compared the conditions that created these silica particles to a hydrothermal field in the Atlantic Ocean known as Lost City.
“Because it is relatively cold, Lost City has been posited as a potential analogue of hydrothermal systems in active icy moons. The current findings confirm this,” Tobie wrote in a commentary on the paper. “What is more, alkaline hydrothermal vents might have been the birthplace of the first living organisms on the early Earth, and so the discovery of similar environments on Enceladus opens fresh perspectives on the search for life elsewhere in the Solar System.”
However, Hsu pointed out, it’s not enough to have the right conditions for life – they have to have been around for long enough that life would have a fighting chance to emerge.
“The other factor that is also very important is the time.… For Enceladus, we don’t know how long this activity has been or how stable it is,” Hsu said. “And so that’s a big uncertainty here.”
One way to get at this question? Send another mission to Enceladus, Tobie said.
“Cassini will fly through the moon’s plume again later this year,” he wrote, “but only future missions that can undertake improved in situ investigations, and possibly even return samples to Earth, will be able to confirm Enceladus’ astrobiological potential and fully reveal the secrets of its hot springs. ”
Long before they shared the landscape with modern humans, Neanderthals in Europe developed a sharp sense of style, wearing eagle claws as jewelry, new evidence suggests.
Researchers identified eight talons from white-tailed eagles — including four that had distinct notches and cut marks — from a 130,000-year-old Neanderthal cave in Croatia. They suspect the claws were once strung together as part of a necklace or bracelet.
"It really is absolutely stunning," study author David Frayer, an anthropology professor at the University of Kansas, told LiveScience. "It fits in with this general picture that's emerging that Neanderthals were much more modern in their behavior."
The talons were first excavated more than 100 years ago at a famous sandstone rock-shelter site called Krapina in Croatia. There, archaeologists found more than 900 Neanderthal bones dating back to a relatively warm, interglacial period about 120,000 to 130,000 years ago. They also found Mousterian stone tools (a telltale sign of Neanderthal occupation), a hearth, and the bones of rhinos and cave bears — but no signs of modern human occupation. Homo sapiens didn't spread into Europe until about 40,000 years ago.
The eagle talons were all found in the same archaeological layer, Frayer said, and they had been studied a few times before. But no one noticed the cut marks until last year, when Davorka Radovcic, curator of the Croatian Natural History Museum, was reassessing some of the Krapina objects in the collection.
The researchers don't know exactly how the talons would have been assembled into jewelry. But Frayer said some facets on the claws look quite polished — perhaps made smooth from being wrapped in some kind of fiber, or from rubbing against the surface of the other talons. There were also nicks in three of the talons that wouldn't have been created during an eagle's life, Frayer said.
The findings were published March 11 in the journal PLOS ONE.
Excerpt from todayifoundout.com Determining exactly when humans began wearing clothes is a challenge, largely because early clothes would have been things like animal hides, which degrade rapidly. Therefore, there’s very little archaeological evidence that can be used to determine the date that clothing started being worn.
There have been several different theories based on what archaeologists have been able to find. For instance, based on genetic skin-coloration research, humans lost body hair around one million years ago—an ideal time to start wearing clothes for warmth. The first tools used to scrape hides date back to 780,000 years ago, but animal hides served other uses, such as providing shelter, and it’s thought that those tools were used to prepare hides for that, rather than clothing. Eyed needles started appearing around 40,000 years ago, but those tools point to more complex clothing, meaning clothes had probably already been around for a while. All that being said, scientists have started gathering alternative data that might help solve the mystery of when we humans started covering our bits.
A recent University of Florida study concluded that humans started wearing clothes some 170,000 years ago, lining up with the end of the second-to-last ice age. How did they figure that date out? By studying the evolution of lice.
Scientists observed that clothing lice are, well, extremely well-adapted to clothing. They hypothesized that body lice must have evolved to live in clothing, which meant that they weren’t around before humans started wearing clothes. The study used DNA sequencing of lice to calculate when clothing lice started to genetically split from head lice.
The findings of the study are significant because they show that clothes appeared some 70,000 years before humans started to migrate north from Africa into cooler climates. The invention of clothing was probably one factor that made migration possible. This timing also makes sense due to known climate factors in that era. As Ian Gilligan, a lecturer at the Australian National University, said that the study gave “an unexpectedly early date for clothing, much earlier than the earliest solid archaeological evidence, but it makes sense. It means modern humans probably started wearing clothes on a regular basis to keep warm when they were first exposed to Ice Age conditions.”
As to when humans moved on from animal hides and into textiles, the first fabric is thought to have been an early ancestor of felt. From there, early humans took up weaving some 27,000 years ago, based on impressions of baskets and textiles on clay. Around 25,000 years ago, the first Venus figurines—little statues of women—appeared wearing a variety of different clothes that pointed to weaving technology being in place by this time. From there, more recent ancient civilizations discovered many materials they could fashion into clothing. For instance, Ancient Egyptians produced linen around 5500 BC, while the Chinese likely started producing silk around 4000 B.C.
As for clothing for fashion, instead of just keeping warm, it is thought that this occurred relatively early on. The first example of dyed flax fibers were found in a cave in the Republic of Georgia and date back to 36,000 years ago. That being said, while they may have added colour, early clothes seem to have been much simpler than the clothing we wear today—mostly cloth draped over the shoulder and pinned at the waist.
Around the mid-1300s in certain regions of the world, with some technological advances in previous century, clothing fashion began to change drastically from what it was before. For instance, clothing started to be made to form fit the human body, with curved seams, laces, and buttons. Contrasting colours and fabrics also became popular in England. From this time, fashion in the West began to change at an alarming rate, largely based on aesthetics, whereas in other cultures fashion typically changed only with great political upheaval, meaning changes came more slowly in most other cultures.
The Industrial Revolution, of course, had a huge impact on the clothing industry. Clothes could now be made en mass in factories rather than just in the home and could be transported from factory to market in record time. As a result, clothes became drastically cheaper, leading to people having significantly larger wardrobes and contributing to the constant change in fashion that we still see today.
After six years of planetary observations, scientists at NASA say they have found convincing new evidence that ancient Mars had an ocean.
It was probably the size of the Arctic Ocean, larger than previously estimated, the researchers reported on Thursday. The body of water spread across the low-lying plain of the planet’s northern hemisphere for millions of years, they said.
If confirmed, the findings would add significantly to scientists’ understanding of the planet’s history and lend new weight to the view that ancient Mars had everything needed for life to emerge.
“The existence of a northern ocean has been debated for decades, but this is the first time we have such a strong collection of data from around the globe,” said Michael Mumma, principal investigator at NASA’s Goddard Center for Astrobiology and an author of the report, published in the journal Science. “Our results tell us there had to be a northern ocean.”
But other experts said the question was hardly resolved. The ocean remains “a hypothesis,” said Ashwin Vasavada, project scientist of the Curiosity rover mission at the Jet Propulsion Laboratory in Pasadena, Calif.
Dr. Mumma and Geronimo Villanueva, a planetary scientist at NASA, measured two slightly different forms of water in Mars’ atmosphere. One is the familiar H2O, which consists of two hydrogen atoms and one oxygen atom.
The other is a slightly “heavier” version of water, HDO, in which the nucleus of one hydrogen atom contains a neutron. The atom is called deuterium.
The two forms exist in predictable ratios on Earth, and both have been found in meteorites from Mars. A high level of heavier water today would indicate that there was once a lot more of the “lighter” water, somehow lost as the planet changed.
The scientists found eight times as much deuterium in the Martian atmosphere than is found in water on Earth. Dr. Villanueva said the findings “provide a solid estimate of how much water Mars once had by determining how much water was lost to space.”
He said the measurements pointed to an ancient Mars that had enough water to cover the planet to a depth of at least 137 meters, or about 450 feet. Except for assessments based on the size of the northern basin, this is the highest estimate of the amount of water on early Mars that scientists have ever made.
The water on Mars mostly would have pooled in the northern hemisphere, which lies one to three kilometers — 0.6 to 1.8 miles — below the bedrock surface of the south, the scientists said.
At one time, the researchers estimated, a northern ocean would have covered about 19 percent of the Martian surface. In comparison, the Atlantic Ocean covers about 17 percent of Earth’s surface.
The new findings come at a time when the possibility of a northern ocean on Mars has gained renewed attention.
The Curiosity rover measured lighter and heavier water molecules in the Gale Crater, and the data also indicated that Mars once had substantial amounts of water, although not as much as Dr. Mumma and Dr. Villanueva suggest.
“The more water was present — and especially if it was a large body of water that lasted for a longer period of time — the better the chances are for life to emerge and to be sustained,” said Paul Mahaffy, chief of the atmospheric experiments laboratory at the Goddard Space Flight Center.
Just last month, the science team running the Curiosity rover held its first formal discussion about the possibility of such an ocean and what it would have meant for the rest of Mars.
Scientists generally agree that lakes must have existed for millions of years in Gale Crater and elsewhere. But it is not clear how they were sustained and replenished.
“For open lakes to remain relatively stable for millions of years — it’s hard to figure how to do that without an ocean,” Dr. Vasavada said. “Unless there was a large body of water supplying humidity to the planet, the water in an open lake would quickly evaporate and be carried to the polar caps or frozen out.”
Yet climate modelers have had difficulty understanding how Mars could have been warm enough in its early days to keep water from freezing. Greenhouse gases could have made the planet much warmer at some point, but byproducts of those gases have yet to be found on the surface.
James Head, a professor of geological sciences at Brown University, said in an email that the new paper had “profound implications for the total volume of water” on ancient Mars.
But, he added, “climate models have great difficulty in reconstructing an early Mars with temperatures high enough to permit surface melting and liquid water.”
Also missing are clear signs of the topographic and geological features associated with large bodies of water on Earth, such as sea cliffs and shorelines.
Based on low-resolution images sent back by the Viking landers, the geologist Timothy Parker and his colleagues at the NASA Jet Propulsion Lab reported in 1989 the discovery of ancient shorelines. But later high-resolution images undermined their conclusions.
Still, Dr. Parker and his colleagues have kept looking for — and finding, they say — some visible signs of a northern ocean. The new data “certainly encourages me to do more,” he said in an interview.
Other researchers have also been looking for signs of an ancient ocean.
In 2013, Roman DiBiase, then a postdoctoral student at the California Institute of Technology, and Michael Lamb, an assistant professor of geology there, identified what might have been a system of channels on Mars that originated in the southern hemisphere and emptied steeply into the northern basin — perhaps, they said, water flowing through a delta to an ocean.
This image, taken 147,000 miles from Ceres by NASA's Dawn spacecraft, is part of a series of views representing the best look so far at the dwarf planet. The spacecraft is set to enter orbit March 6. (NASA)
Eat your heart out, Hubble! NASA’s Dawn spacecraft is in the home stretch of its journey to Ceres and has snapped the best images yet of the dwarf planet. Grainy as they are, the new views of the 590-mile-wide world are already turning up unexpected features on the surface.
“What we expect at Ceres is to be surprised, so it’s getting off to a good start,” said deputy principal investigator Carol Raymond. The images, taken 147,000 miles from Ceres on Jan. 25, are 30% higher-resolution than the images taken by NASA’s Hubble Space Telescope in 2003 and 2004. They measure 43 pixels wide, a significant improvement over Dawn’s images from earlier this month, which were 27 pixels across. The images show significant brightness and darkness variations over the surface – particularly a bright spot gleaming in the northern hemisphere and darker spots in the southern hemisphere. While the scientists were aware of those major spots, they weren’t expecting to see quite so much texture on the surface, said Raymond, a geophysicist at the Jet Propulsion Laboratory.
Ceres is fairly warm by ice-world standards; temperatures generally range from 180 to 240 Kelvin (or minus-136 degrees Fahrenheit to minus-28 degrees Fahrenheit), Raymond said. Theoretically, the ice on Ceres’ surface should start to flow as it warms up, smoothing out any bumps such as those from impact craters. But the brightness variations across the surface make it appear very rough, she said. “This is just starting to illuminate the fact that Ceres is one of these unique bodies that has astrobiological potential ... and it’s just continued to become more intriguing as we’ve been marching inexorably closer,” she added.
Ceres was not the first stop in Dawn’s 3-billion-mile journey. The first was the protoplanet Vesta, which is vastly different from its fellow mega-asteroid, Ceres. Where Vesta is dry and lumpy, Ceres is icy and round, massive enough to have been pulled into a planet-like shape. Scientists want to find out why these two space-fossils from the early solar system ended up with such different geophysical life stories. At least with Vesta, there were meteorites linked to the asteroid that planetary scientists can study, Raymond pointed out. For Ceres, there are no such space rocks found on Earth – so the researchers have somewhat less of an idea of what to expect.
“I am excited,” Raymond said. “Just having had the wild ride at Vesta, I’m also just in awe of what’s going to happen. It’s going to be amazing.”