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The discovery of tiny salt grains in an asteroid sample provides strong evidence that liquid water may be more common in the solar system’s largest asteroid population than previously thought.
The smattering of tiny salt crystals discovered in a sample from an asteroid has researchers excited, because these crystals can only have formed in the presence of liquid water.
Even more intriguing, according to the research team, is the fact that the sample comes from an S-type asteroid, a category known to mostly lack hydrated, or water-bearing, minerals. The discovery strongly suggests that a large population of asteroids hurtling through the solar system may not be as dry as previously thought. The finding, published in Nature Astronomy, gives renewed push to the hypothesis that most, if not all, water on Earth may have arrived by way of asteroids during the planet’s tumultuous infancy.
“Once these ingredients come together to form asteroids, there is a potential for liquid water to form.”
Tom Zega, the study’s senior author and a professor of planetary sciences at the the University of Arizona Lunar and Planetary Laboratory, and Shaofan Che, lead study author and a postdoctoral fellow at the Lunar and Planetary Laboratory, performed a detailed analysis of samples collected from asteroid Itokawa in 2005 by the Japanese Hayabusa mission and brought to Earth in 2010.
The study is the first to prove that the salt crystals originated on the asteroid’s parent body, ruling out any possibility they might have formed as a consequence of contamination after the sample reached Earth, a question that had plagued previous studies that found sodium chloride in meteorites of a similar origin.
“The grains look exactly like what you would see if you took table salt at home and placed it under an electron microscope,” Zega says. “They’re these nice, square crystals. It was funny, too, because we had many spirited group meeting conversations about them, because it was just so unreal.”
Zega says the samples represent a type of extraterrestrial rock known as an ordinary chondrite. Derived from so-called S-type asteroids such as Itokawa, this type makes up about 87% of meteorites collected on Earth. Very few of them have been found to contain water-bearing minerals.
“It has long been thought that ordinary chondrites are an unlikely source of water on Earth,” says Zega who is the director of the Lunar and Planetary Laboratory’s Kuiper Materials Imaging & Characterization Facility. “Our discovery of sodium chloride tells us this asteroid population could harbor much more water than we thought.”
Today, scientists largely agree that Earth, along with other rocky planets such as Venus and Mars, formed in the inner region of the roiling, swirling cloud of gas and dust around the young sun, known as the solar nebula, where temperatures were very high—too high for water vapor to condense from the gas, according to Che.
“In other words, the water here on Earth had to be delivered from the outer reaches of the solar nebula, where temperatures were much colder and allowed water to exist, most likely in the form of ice,” Che says. “The most likely scenario is that comets or another type of asteroid known as C-type asteroids, which resided farther out in the solar nebula, migrated inward and delivered their watery cargo by impacting the young Earth.”
The discovery that water could have been present in ordinary chondrites, and therefore been sourced from much closer to the sun than their “wetter” kin, has implications for any scenario attempting to explain the delivery of water to the early Earth.
The sample used in the study is a tiny dust particle spanning about 150 micrometers, or roughly twice the diameter of a human hair, from which the team cut a small section about 5 microns wide—just large enough to cover a single yeast cell—for the analysis.
Using a variety of techniques, Che was able to rule out that the sodium chloride was the result of contamination from sources such as human sweat, the sample preparation process, or exposure to laboratory moisture.
Because the sample had been stored for five years, the team took before and after photos and compared them. The photos showed that the distribution of sodium chloride grains inside the sample had not changed, ruling out the possibility that any of the grains were deposited into the sample during that time. In addition, Che performed a control experiment by treating a set of terrestrial rock samples the same as the Itokawa sample and examining them with an electron microscope.
“The terrestrial samples did not contain any sodium chloride, so that convinced us the salt in our sample is native to the asteroid Itokawa,” he says. “We ruled out every possible source of contamination.”
Zega says tons of extraterrestrial matter is raining down on Earth every day, but most of it burns up in the atmosphere and never makes it to the surface.
“You need a large enough rock to survive entry and deliver that water,” he says.
Previous work led by the late Michael Drake, a former director of the Lunar and Planetary Lab, in the 1990s proposed a mechanism by which water molecules in the early solar system could become trapped in asteroid minerals and even survive an impact on Earth.
“Those studies suggest several oceans worth of water could be delivered just by this mechanism,” Zega says. “If it now turns out that the most common asteroids may be much ‘wetter’ than we thought, that will make the water delivery hypothesis by asteroids even more plausible.”
Itokawa is a peanut-shaped near-Earth asteroid about 2,000 feet long and 750 feet in diameter and is believed to have broken off from a much larger parent body. According to Che and Zega, it is conceivable that frozen water and frozen hydrogen chloride could have accumulated there, and that naturally occurring decay of radioactive elements and frequent bombardment by meteorites during the solar system’s early days could have provided enough heat to sustain hydrothermal processes involving liquid water. Ultimately, the parent body would have succumbed to the pummeling and broken up into smaller fragments, leading to the formation of Itokawa.
“Once these ingredients come together to form asteroids, there is a potential for liquid water to form,” Zega says. “And once you have liquids form, you can think of them as occupying cavities in the asteroid, and potentially do water chemistry.”
The evidence pointing at the salt crystals in the Itokawa sample as being there since the beginning of the solar system does not end here, however. The researchers found a vein of plagioclase, a sodium-rich silicate mineral, running through the sample, enriched with sodium chloride.
“When we see such alteration veins in terrestrial samples, we know they formed by aqueous alteration, which means it must involve water,” Che says. “The fact that we see that texture associated with sodium and chlorine is another strong piece of evidence that this happened on the asteroid as water was coursing through this sodium-bearing silicate.”
Source: University of Arizona
The post Salt on Itokawa asteroid suggests liquid water appeared first on Futurity.
This morning I was flipping through my copy of the Bicycle Sentences Journal that illustrator Betsy Streeter sent me and I was quite taken with this final paragraph by Grant Petersen. (I’m a big fan of his blog and Just Ride.)
He touches on why I keep a diary, why I keep it on paper, and the magic of keeping a logbook. The mundane details can bring back sublime memories, and what you think is boring now may be interesting in the future: “What seems bland when you write it down… will seem epic in thirty years.”
I have a new studio routine where when I’m unsure of what to write about, I revisit my notebooks each year on today’s date. (I have notebooks going back 20 years, daily logbooks going back 15, but I’ve kept a daily diary for 5 years now. That’s where a lot of gems are buried.)
Flipping through these notebooks will usually yield something worth writing about. (This morning, it was William Burroughs on language.)
Reading my diary this way, which I first learned from reading Thoreau’s diary, also shows me the cycles and patterns of my life.
(For example: Cocteau Twins and the beginning of spring are somehow intertwined in my life. What does that mean? And what does the fact that their lyrics are barely understandable mean when matched with the Burroughs? Spring is a season of rebirth… When babies are new, they babble and make noise without language… do they sound like spring to me for this reason? You can see how these thoughts, none of which I had when I woke up this morning, come forth from just reading myself.)
Another way to think about it: Keeping a diary is being a good research assistant to your future self.
This is the advice that art critic Jerry Saltz has tweeted over the years:
Be a good assistant to yourself. Prepare and gather, make notations and sketches in your head or phone. When you work, all that mapping, architecture, research & preparation will be your past self giving a gift to the future self that you are now. That is the sacred.
I’ve never had an assistant. I am my own best assistant. My assistant-self is my past self loving my future self who’ll need this previous research when I reach for something in my work. My assistant-self has gotten ideas for whole articles, essays from minutes of research online.
Artists: The beautiful thing about giving yourself a little break & not working – those are the times when new ideas flood in from the cosmos & set your “assistant self” in motion, the self that will be there for your “future-self.” Curiosity and obsession always fill the vacuum.
Artists: Be your own best assistant. Do your research. Get your tools and materials in order. These will be the ancestors, spirit guides and self-replicating imagination of your work. This will allow art to reproduce itself in you. You’ll thank yourself during & afterwards.
I have my many moments of self-loathing at my own lack of progress, but one thing I have done right, at least in the past half decade or so: I have been a good assistant to my future self.
Joan Didion said of re-reading notebooks, “I think we are well advised to keep on nodding terms with the people we used to be.” This is especially true if they have bothered to preserve themselves so we can visit them later.
Yes, a diary is a good spaceship for time travel: for meditating on the present, flinging ourselves into the future, and visiting ourselves in the past.
A new substance created in a lab on Earth could form at the surface and bottom of Europa’s deep oceans, say researchers.
The red streaks crossing the surface of Jupiter’s moon are thought to be a frozen mixture of water and salts, but its chemical signature matches no known substance on Earth.
The researchers may have solved the puzzle with the discovery of a new type of solid crystal that forms when water and table salt combine in cold and high-pressure conditions.
The study, published in the Proceedings of the National Academy of Sciences, announces a new combination for two of Earth’s most common substances: water and sodium chloride, or table salt.
“Salt and water are very well known at Earth conditions. But beyond that, we’re totally in the dark.”
“It’s rare nowadays to have fundamental discoveries in science,” says lead author Baptiste Journaux, an acting assistant professor of earth and space sciences at the University of Washington.
“Salt and water are very well known at Earth conditions. But beyond that, we’re totally in the dark. And now we have these planetary objects that probably have compounds that are very familiar to us, but at very exotic conditions. We have to redo all the fundamental mineralogical science that people did in the 1800s, but at high pressure and low temperature. It is an exciting time.”
At cold temperatures, water and salts combine to form a rigid salted icy lattice, known as a hydrate, held in place by hydrogen bonds. The only previously known hydrate for sodium chloride was a simple structure with one salt molecule for every two water molecules.
But the two new hydrates, found at moderate pressures and low temperatures, are strikingly different. One has two sodium chlorides for every 17 water molecules; the other has one sodium chloride for every 13 water molecules. This would explain why the signatures from the surface of Jupiter’s moons are more “watery” than expected.
“It has the structure that planetary scientists have been waiting for,” Journaux says.
The discovery of new types of salty ice has importance not just for planetary science, but for physical chemistry and even energy research, which uses hydrates for energy storage, Journaux says.
The experiment involved compressing a tiny bit of salty water at synchrotron facilities in France, Germany and the US between two diamonds about the size of a grain of sand, squeezing the liquid up to 25,000 times the standard atmospheric pressure. The transparent diamonds allowed the team to watch the process through a microscope.
“We were trying to measure how adding salt would change the amount of ice we could get, since salt acts as an antifreeze,” Baptiste says. “Surprisingly, when we put the pressure on, what we saw is that these crystals that we were not expecting started growing. It was a very serendipitous discovery.”
These planetary bodies “are, in my opinion, the best place in our solar system to discover extraterrestrial life…”
Such cold, high-pressure conditions created in the lab would be common on Jupiter’s moons, where scientists think 5 to 10 kilometers (3 to 6 miles) of ice would cover oceans up to several hundred kilometers thick, with even denser forms of ice possible at the bottom.
“Pressure just gets the molecules closer together, so their interaction changes—that is the main engine for diversity in the crystal structures we found,” Journaux says.
Once the newly discovered hydrates had formed, one of the two structures remained stable even after the pressure was released.
“We determined that it remains stable at standard pressure up to about minus 50 C. So if you have a very briny lake, for example in Antarctica, that could be exposed to these temperatures, this newly discovered hydrate could be present there,” Journaux says.
The team hopes to either make or collect a larger sample to allow more thorough analysis and verify whether the signatures from icy moons match the signatures from the newly discovered hydrates.
Two upcoming missions will explore Jupiter’s icy moons: The European Space Agency’s Jupiter Icy Moons Explorer mission, launching in April, and NASA’s Europa Clipper mission, launching for October 2024. NASA’s Dragonfly mission launches to Saturn’s moon Titan in 2026. Knowing what chemicals these missions will encounter will help to better target their search for signatures of life.
“These are the only planetary bodies, other than Earth, where liquid water is stable at geological timescales, which is crucial for the emergence and development of life,” Journaux says.
“They are, in my opinion, the best place in our solar system to discover extraterrestrial life, so we need to study their exotic oceans and interiors to better understand how they formed, evolved and can retain liquid water in cold regions of the solar system, so far away from the sun.”
NASA funded the work. Additional coauthors are from the German Electron Synchrotron in Hamburg; the European Synchrotron Facility in France; the Institute of Geochemistry and Petrology in Switzerland; the Bavarian Geoinstitute for Experimental Geochemistry and Geophysics in Germany; NASA’s Jet Propulsion Laboratory; and the University of Chicago.
Source: University of Washington
The post Are Europa’s streaks a frozen mix of water and salt? appeared first on Futurity.
The City of Madison, Wisconsin just announced the winners of the Wisconsin Salt Wise naming contest for the various vehicles in Madison's snow removal fleet—and they do not disappoint! WMTV NBC15 reports:
— Read the restThe people have spoken, and they have chosen wisely, with the names Saltimus Prime, Snowbi Wan Kenobi, Seymour Pavement, and Dolly Plowton floating to the top.
Sugar and salt will now be limited in school meals at the same time foods with whole grains will be increased according to new guidelines by the Biden administration.
FreshRSS 