Excerpt from eaglecurrent.com NASA is joining in an effort to have an understanding of the presence of a methane hotspot over the 4 corners area of the United States. How severe is the atmospheric feature?A methane hotspot hovering over t...
Tag: chance (page 2 of 10)
 |
| Dutch national women's field hockey team |
Excerpt from news.sciencemag.org
ByMartin Enserink
AMSTERDAM—Insecure about your height? You may want to avoid this tiny country by the North Sea, whose population has gained an impressive 20 centimeters in the past 150 years and is now officially the tallest on the planet. Scientists chalk up most of that increase to rising wealth, a rich diet, and good health care, but a new study suggests something else is going on as well: The Dutch growth spurt may be an example of human evolution in action.
The study, published online today in the Proceedings of the Royal Society B, shows that tall Dutch men on average have more children than their shorter counterparts, and that more of their children survive. That suggests genes that help make people tall are becoming more frequent among the Dutch, says behavioral biologist and lead author Gert Stulp of the London School of Hygiene & Tropical Medicine.
"This study drives home the message that the human population is still subject to natural selection," says Stephen Stearns, an evolutionary biologist at Yale University who wasn't involved in the study. "It strikes at the core of our understanding of human nature, and how malleable it is." It also confirms what Stearns knows from personal experience about the population in the northern Netherlands, where the study took place: "Boy, they are tall."
For many years, the U.S. population was the tallest in the world. In the 18th century, American men were 5 to 8 centimeters taller than those in the Netherlands. Today, Americans are the fattest, but they lost the race for height to northern Europeans—including Danes, Norwegians, Swedes, and Estonians—sometime in the 20th century.
Just how these peoples became so tall isn't clear, however. Genetics has an important effect on body height: Scientists have found at least 180 genes that influence how tall you become. Each one has only a small effect, but together, they may explain up to 80% of the variation in height within a population. Yet environmental factors play a huge role as well. The children of Japanese immigrants to Hawaii, for instance, grew much taller than their parents. Scientists assume that a diet rich in milk and meat played a major role.
The Dutch have become so much taller in such a short period that scientists chalk most of it up to their changing environment. As the Netherlands developed, it became one of the world's largest producers and consumers of cheese and milk. An increasingly egalitarian distribution of wealth and universal access to health care may also have helped.
Still, scientists wonder whether natural selection has played a role as well. For men, being tall is associated with better health, attractiveness to the opposite sex, a better education, and higher income—all of which could lead to more reproductive success, Stulp says.
Yet studies in the United States don't show this. Stulp's own research among Wisconsinites born between 1937 and 1940, for instance, showed that average-sized men had more children than shorter and taller men, and shorter women had more children than those of average height. Taken together, Stulp says, this suggests natural selection in the United States pulls in the opposite direction of environmental factors like diet, making people shorter instead of taller. That may explain why the growth in average American height has leveled off.
Stulp—who says his towering 2-meter frame did not influence his research interest—wondered if the same was true in his native country. To find out, he and his colleagues turned to a database tracking key life data for almost 100,000 people in the country's three northern provinces. The researchers included only people over 45 who were born in the Netherlands to Dutch-born parents. This way, they had a relatively accurate number of total children per subject (most people stop having children after 45) and they also avoided the effects of immigration.
In the remaining sample of 42,616 people, taller men had more children on average, despite the fact that they had their first child at a higher age. The effect was small—an extra 0.24 children at most for taller men—but highly significant. (Taller men also had a smaller chance of remaining childless, and a higher chance of having a partner.) The same effect wasn't seen in women, who had the highest reproductive success when they were of average height. The study suggests this may be because taller women had a smaller chance of finding a mate, while shorter women were at higher risk of losing a child.
Because tall men are likely to pass on the genes that made them tall, the outcome suggests that—in contrast to Americans—the Dutch population is evolving to become taller, Stulp says. "This is not what we've seen in other studies—that's what makes it exciting," says evolutionary biologist Simon Verhulst of the University of Groningen in the Netherlands, who was Stulp's Ph.D. adviser but wasn't involved in the current study. Verhulst points out that the team can't be certain that genes involved in height are actually becoming more frequent, however, as the authors acknowledge.
The study suggests that sexual selection is at work in the Dutch population, Stearns says: Dutch women may prefer taller men because they expect them to have more resources to invest in their children. But there are also other possibilities. It could be that taller men are more resistant to disease, Stearns says, or that they are more likely to divorce and start a second family. "It will be a difficult question to answer.”
Another question is why tall men in Holland are at a reproductive advantage but those in the United States are not. Stulp says he can only speculate. One reason may be that humans often choose a partner who's not much shorter or taller than they are themselves. Because shorter women in the United States have more children, tall men may do worse than those of average height because they're less likely to partner with a short woman.
In the end, Stearns says, the advantage of tall Dutchmen may be only temporary. Often in evolution, natural selection will favor one trend for a number of generations, followed by a stabilization or even a return to the opposite trend. In the United States, selection for height appears to have occurred several centuries ago, leading to taller men, and then it stopped. "Perhaps the Dutch caught up and actually overshot the American men," he says.
The study, published online today in the Proceedings of the Royal Society B, shows that tall Dutch men on average have more children than their shorter counterparts, and that more of their children survive. That suggests genes that help make people tall are becoming more frequent among the Dutch, says behavioral biologist and lead author Gert Stulp of the London School of Hygiene & Tropical Medicine.
"This study drives home the message that the human population is still subject to natural selection," says Stephen Stearns, an evolutionary biologist at Yale University who wasn't involved in the study. "It strikes at the core of our understanding of human nature, and how malleable it is." It also confirms what Stearns knows from personal experience about the population in the northern Netherlands, where the study took place: "Boy, they are tall."
For many years, the U.S. population was the tallest in the world. In the 18th century, American men were 5 to 8 centimeters taller than those in the Netherlands. Today, Americans are the fattest, but they lost the race for height to northern Europeans—including Danes, Norwegians, Swedes, and Estonians—sometime in the 20th century.
Just how these peoples became so tall isn't clear, however. Genetics has an important effect on body height: Scientists have found at least 180 genes that influence how tall you become. Each one has only a small effect, but together, they may explain up to 80% of the variation in height within a population. Yet environmental factors play a huge role as well. The children of Japanese immigrants to Hawaii, for instance, grew much taller than their parents. Scientists assume that a diet rich in milk and meat played a major role.
The Dutch have become so much taller in such a short period that scientists chalk most of it up to their changing environment. As the Netherlands developed, it became one of the world's largest producers and consumers of cheese and milk. An increasingly egalitarian distribution of wealth and universal access to health care may also have helped.
Still, scientists wonder whether natural selection has played a role as well. For men, being tall is associated with better health, attractiveness to the opposite sex, a better education, and higher income—all of which could lead to more reproductive success, Stulp says.
Yet studies in the United States don't show this. Stulp's own research among Wisconsinites born between 1937 and 1940, for instance, showed that average-sized men had more children than shorter and taller men, and shorter women had more children than those of average height. Taken together, Stulp says, this suggests natural selection in the United States pulls in the opposite direction of environmental factors like diet, making people shorter instead of taller. That may explain why the growth in average American height has leveled off.
Stulp—who says his towering 2-meter frame did not influence his research interest—wondered if the same was true in his native country. To find out, he and his colleagues turned to a database tracking key life data for almost 100,000 people in the country's three northern provinces. The researchers included only people over 45 who were born in the Netherlands to Dutch-born parents. This way, they had a relatively accurate number of total children per subject (most people stop having children after 45) and they also avoided the effects of immigration.
In the remaining sample of 42,616 people, taller men had more children on average, despite the fact that they had their first child at a higher age. The effect was small—an extra 0.24 children at most for taller men—but highly significant. (Taller men also had a smaller chance of remaining childless, and a higher chance of having a partner.) The same effect wasn't seen in women, who had the highest reproductive success when they were of average height. The study suggests this may be because taller women had a smaller chance of finding a mate, while shorter women were at higher risk of losing a child.
Because tall men are likely to pass on the genes that made them tall, the outcome suggests that—in contrast to Americans—the Dutch population is evolving to become taller, Stulp says. "This is not what we've seen in other studies—that's what makes it exciting," says evolutionary biologist Simon Verhulst of the University of Groningen in the Netherlands, who was Stulp's Ph.D. adviser but wasn't involved in the current study. Verhulst points out that the team can't be certain that genes involved in height are actually becoming more frequent, however, as the authors acknowledge.
The study suggests that sexual selection is at work in the Dutch population, Stearns says: Dutch women may prefer taller men because they expect them to have more resources to invest in their children. But there are also other possibilities. It could be that taller men are more resistant to disease, Stearns says, or that they are more likely to divorce and start a second family. "It will be a difficult question to answer.”
Another question is why tall men in Holland are at a reproductive advantage but those in the United States are not. Stulp says he can only speculate. One reason may be that humans often choose a partner who's not much shorter or taller than they are themselves. Because shorter women in the United States have more children, tall men may do worse than those of average height because they're less likely to partner with a short woman.
In the end, Stearns says, the advantage of tall Dutchmen may be only temporary. Often in evolution, natural selection will favor one trend for a number of generations, followed by a stabilization or even a return to the opposite trend. In the United States, selection for height appears to have occurred several centuries ago, leading to taller men, and then it stopped. "Perhaps the Dutch caught up and actually overshot the American men," he says.
Artist impression of the protoplanetary disk surrounding the young star MWC 480. ALMA has detected the complex organic molecule methyl cyanide in the outer reaches of the disk in the region where comets are believed to form. This is another indication that complex organic chemistry, and potentially the conditions necessary for life, is universal. (B. Saxton/NRAO/AUI/NSF)
Excerpt from washingtonpost.com
We're not special. Or our complex organic molecules aren't, anyway. And that's good news in the hunt for extraterrestrial life.
In a new study published Wednesday in Nature, astronomers found the first signs of the complex, carbon-based molecules that make life possible on Earth in a protoplanetary disk; the region where cosmic building blocks gather to create planets in a brand-new star system. The cyanides found there are essential to life as we know it: without them, there would be no proteins.
"We know when our own solar system was very young, it was rich in water and complex organics. We know that from observing comets," explained study author Karin Öberg, an assistant professor of astronomy at Harvard. Comets have kept the molecules of our solar system's early days locked up tight ever since, which is why scientists are so eager to study them for clues about Earth's formation. These comets show us that certain organic molecules were common in our solar system's pre-planetary days.
But this is the first time we've seen evidence of such molecules ready to seed another star system with planets that could support life.
"We're finding that we're not that special," Öberg said. "Other young solar systems in the making are also rich in the same volatiles, and in similar proportions."
And in this case, she said, being not-special is a great thing: If other solar systems formed just the way ours did, we can hope that they formed some kind of life, too.
Öberg and her colleagues found the molecules using the Atacama Large Millimeter/submillimeter Array (ALMA), a radio telescope with some pretty sweet resolution. They spotted the complex organics as much as 15 billion kilometers from the star itself, which they believe is right smack dab in the middle of the system's comet-forming region. That means the organics could get locked away in comets, just as the ones in our solar system were, and go out to seed future planets with them (as some believe was the case with Earth).
"It was kind of a chance discovery, because we weren't targeting this specific molecule," Öberg said. So she and her team need to go back and look more systematically. She also hopes they'll be able to find more systems to look at. The star they've observed -- MWC 480, located some 455 light-years away in the Taurus star-forming region -- is twice the mass of the sun, so they also hope to find some that are more similar to our host star.
"We of course want to know whether this is a really common thing or if we just lucked out on this one," Öberg said.
 |
| It now seems more probable that a collision between two planets of similar composition led to the formation of the Moon. |
Excerpt from nature.com
A nagging problem at the heart of the leading theory of how the Moon formed seems to have been explained away.
But the theory also implies that the Moon is made up mostly of impactor material. Since lunar and Earth rocks have such similar compositions, this suggests that Earth and the planet that smacked into it resembled each other too. They would have needed to be sister planets, with a relationship much closer than that of any other planetary bodies we have studied in our Solar System. The odds of this being possible were thought to be around a 1% chance, or “uncomfortably rare”, according to Robin Canup, a planetary researcher at the Southwest Research Institute in Boulder, Colorado1.
Better odds
Now it seems that the scenario is not so far-fetched, says Hagai Perets, an astrophysicist at the Israel Institute of Technology in Haifa. He and his colleagues performed simulations of the Solar System’s formation, to investigate how similar planets tend to be to their last giant impactor. They estimated that for 20% to 40% of collisions, the two bodies would be sufficiently similar to explain the Moon’s composition — considerably better odds. The findings are published in Nature2.The planets would have closely resembled each other because of their similar distance from the Sun, meaning that they would have formed from the same kind of orbiting proto-planetary material. “The Earth and the Moon are not twins born from the same planet, but they are sisters in the sense that they grew up in the same environment,” says Perets.
Excerpt from foxnews.com
Eleven fast radio bursts from space seem to follow a strange mathematical pattern, according to a new study – and it has researchers scratching their heads.
According to study co–authors Michael Hippke of the Institute of Data Analysis in Neukirchen-Vluyn, Germany, and John Learned of the University of Hawaii in Manoa, the bursts– which were first detected in 2001 – all had dispersion measures that were integer multiples of the same number: 187.5. “The astronomers that found [the bursts] have not seen such things before and do not understand them,” Learned told FoxNews.com.
Nobody knows what causes fast radio bursts, known as FRBs. They only last a few milliseconds, and only one so far has been captured live (by the Parkes Telescope in Australia last year). Though the bursts release just as much energy in a few milliseconds as the sun does in a month, their brevity indicates that the source must be small, with estimates being several hundred miles across at most.
Researchers use dispersion measures, which records how much “space gunk” the burst has passed through, to estimate the distance an FRB has travelled. For instance, a low frequency FRB will have more gunk on it, indicating a longer trip, whereas a high frequency FRB will be cleaner, indicating it came from closer to Earth.
The fact that all of the FRBs’ dispersion measures are integer multiples of 187.5 has, according to Hippke and Learned’s team’s calculations, a 5 in 10,000 chance of being coincidental. The dispersion measures also indicate that their origin is relatively close to Earth, but unlikely from within our own galaxy.
There are numerous theories on where these bursts came from, including speculation that the messages are from extraterrestrial intelligence. To the scientific community, however, this theory doesn’t really hold water, and is seen as more of a last resort only after all other avenues have been exhausted.
“We think these are likely from some very energetic process, like a burst from a high magnetic field neutron star or energy released [when] two neutron stars merge,” Professor Maura McLaughlin of the West Virginia University Center for Astrophysics explained. “The thing that made people think they were possibly from ETs was a recent paper that showed that one fundamental property is quantized in a way that wouldn't be expected if the signals were naturally occurring. However, I imagine that correlation will totally go away once more are discovered.”
Learned himself is dubious of an alien source as well, noting that he and Hippke only noted the dispersion measures’ “peculiar” pattern, and that they may even be coming from Earth. “We are now leaning more towards a terrestrial, anthropogenic interpretation,” he said. “At this point I would place my money on some sort of governmental satellite, not a natural phenomena, but I would not bet much. More data, which reportedly [is] being analyzed but which we have no insider information about yet, will be most interesting and refute or confirm our hypotheses.” He also noted that he’d only look to an ETI interpretation once all other possibilities have been eliminated.
As for McLaughlin, she believes there’s no way the FRBs could be messages from aliens, as the signals are very broadband and emitted over a wide range of radio frequencies. “It would take a LOT of energy for an alien civilization to produce these bursts - they'd need to harness the energy of many, many suns - and there's no real advantage for communication to send a signal over such a large bandwidth.”
Excerpt from bulletinstandard.com A pair of pictures of a young star, produced 18 years apart, has revealed a dramatic distinction that is giving astronomers with a exclusive, "real-time" appear at how enormous stars create in the e...
Excerpt from wired.com
It sounds almost like a late ’90s sci-fi flick: NASA sends a spacecraft to an asteroid, plucks a boulder off its surface with a robotic claw, and brings it back in orbit around the moon. Then, brave astronaut heroes go and study the space rock up close—and bring samples back to Earth.
Except it’s not a movie: That’s the real-life idea for the Asteroid Redirect Mission, which NASA announced today. Other than simply being an awesome space version of the claw arcade game (you know you really wanted that stuffed Pikachu), the mission will let NASA test technology and practice techniques needed for going to Mars.
The mission, which will cost up to $1.25 billion, is slated to launch in December 2020. It will take about two years to reach the asteroid (the most likely candidate is a quarter-mile-wide rock called 2008 EV5). The spacecraft will spend up to 400 days there, looking for a good boulder. After picking one—maybe around 13 feet in diameter—it will bring the rock over to the moon. In 2025, astronauts will fly NASA’s still-to-be-built Orion to dock with the asteroid-carrying spacecraft and study the rock up close.
Although the mission would certainly give scientists an up-close opportunity to look at an asteroid, its main purpose is as a testing ground for a Mars mission. The spacecraft will test a solar electronic propulsion system, which uses the power from solar panels to pump out charged particles to provide thrust. It’s slower than conventional rockets, but a lot more efficient. You can’t lug a lot of rocket fuel to Mars.
Overall, the mission gives NASA a chance at practicing precise navigation and maneuvering techniques that they’ll need to master for a Mars mission. Such a trip will also require a lot more cargo, so grabbing and maneuvering a big space rock is good practice. Entering lunar orbit and docking with another spacecraft would also be helpful, as the orbit might be a place for a deep-space habitat, a rendezvous point for astronauts to pick up cargo or stop on their way to Mars.
And—you knew this part was coming, Armageddon fans—the mission might teach NASA something about preventing an asteroid from striking Earth. After grabbing the boulder, the spacecraft will orbit the asteroid. With the added heft from the rock, the spacecraft’s extra gravity would nudge the asteroid, creating a slight change in trajectory that NASA could measure from Earth. “We’re not talking about a large deflection here,” says Robert Lightfoot, an associate administrator at NASA. But the idea is that a similar technique could push a threatening asteroid off a collision course with Earth.
NASA chose this mission concept over one that would’ve bagged an entire asteroid. In that plan, the spacecraft would’ve captured the space rock by enclosing it in a giant, flexible container. The claw concept won out because its rendezvous and soft-landing on the asteroid will allow NASA to test and practice more capabilities in preparation for a Mars mission, Lightfoot says. The claw would’ve also given more chances at grabbing a space rock, whereas it was all or nothing with the bag idea. “It’s a one-shot deal,” he says. “It is what it is when we get there.” But the claw concept offers some choices. “I’ve got three to five opportunities to pull one of the boulders off,” he says. Not bad odds. Better than winning that Pikachu
Excerpt from esbtrib.com
Imagine the distinct possibility that among the billions of stars located in our vast Milky Way Galaxy, there might be a habitable zone where water probably exists and life as we know it as well.
Scientists have studied more than 150 exoplanetary systems with more than one planet circling the host star, thru the Kepler space telescope of NASA.
The new research, published in Monthly Notices of the Royal Astronomical Society, revealed the thousands of planets orbiting stars in our Milky Way galaxy. Researchers were able to compute that the stars in the Milky Way have one to three planets orbiting the habitable zone.
PhD student in the research group Astrophysics and Planetary Science at the Niels Bohr Institute at the University of Copenhagen, Steffen Kjær Jacobsen said, “In these 31 planetary systems located near the habitable zone, our calculations showed that there was an average of two planets in the habitable zone. According to statistics and the indications we have, a good share of the planets in the habitable zone will be solid planets where there might be liquid water and where life could exist.”
He added, “In 124 of the planetary systems, the Titius-Bode law fit with the position of the planets as good as or better than our own solar system. Using Titus-Bode’s law we tried to predict where there could be more planets further out in the planetary systems. But we only made calculations for planets where there is a good chance you can see them with the Kepler satellite,”
Researchers urged other scientist to look further into the records from the Kepler satellite again for more signs of the planetary systems they have predicted, as a number of them should be quite apparent.
Will this change our perception of religion? That we are not God’s only living creation?
Excerpt from robertlanza.com
By Robert Lanza
Recent discoveries require us to rethink our understanding of history. “The histories of the universe,” said renowned physicist Stephen Hawking “depend on what is being measured, contrary to the usual idea that the universe has an objective observer-independent history.”
Is it possible we live and die in a world of illusions? Physics tells us that objects exist in a suspended state until observed, when they collapse in to just one outcome. Paradoxically, whether events happened in the past may not be determined until sometime in your future – and may even depend on actions that you haven’t taken yet.
In 2002, scientists carried out an amazing experiment, which showed that particles of light “photons” knew — in advance — what their distant twins would do in the future. They tested the communication between pairs of photons — whether to be either a wave or a particle. Researchers stretched the distance one of the photons had to take to reach its detector, so that the other photon would hit its own detector first. The photons taking this path already finished their journeys — they either collapse into a particle or don’t before their twin encounters a scrambling device.
Somehow, the particles acted on this information before it happened, and across distances instantaneously as if there was no space or time between them. They decided not to become particles before their twin ever encountered the scrambler. It doesn’t matter how we set up the experiment. Our mind and its knowledge is the only thing that determines how they behave. Experiments consistently confirm these observer-dependent effects.
More recently (Science 315, 966, 2007), scientists in France shot photons into an apparatus, and showed that what they did could retroactively change something that had already happened. As the photons passed a fork in the apparatus, they had to decide whether to behave like particles or waves when they hit a beam splitter.
Later on – well after the photons passed the fork – the experimenter could randomly switch a second beam splitter on and off. It turns out that what the observer decided at that point, determined what the particle actually did at the fork in the past. At that moment, the experimenter chose his history.
Of course, we live in the same world. Particles have a range of possible states, and it’s not until observed that they take on properties. So until the present is determined, how can there be a past? According to visionary physicist John Wheeler (who coined the word “black hole”), “The quantum principle shows that there is a sense in which what an observer will do in the future defines what happens in the past.” Part of the past is locked in when you observe things and the “probability waves collapse.” But there’s still uncertainty, for instance, as to what’s underneath your feet. If you dig a hole, there’s a probability you’ll find a boulder. Say you hit a boulder, the glacial movements of the past that account for the rock being in exactly that spot will change as described in the Science experiment.
But what about dinosaur fossils? Fossils are really no different than anything else in nature. For instance, the carbon atoms in your body are “fossils” created in the heart of exploding supernova stars.
Bottom line: reality begins and ends with the observer. “We are participators,” Wheeler said “in bringing about something of the universe in the distant past.” Before his death, he stated that when observing light from a quasar, we set up a quantum observation on an enormously large scale. It means, he said, the measurements made on the light now, determines the path it took billions of years ago.
Like the light from Wheeler’s quasar, historical events such as who killed JFK, might also depend on events that haven’t occurred yet. There’s enough uncertainty that it could be one person in one set of circumstances, or another person in another. Although JFK was assassinated, you only possess fragments of information about the event. But as you investigate, you collapse more and more reality. According to biocentrism, space and time are relative to the individual observer – we each carry them around like turtles with shells.
History is a biological phenomenon — it’s the logic of what you, the animal observer experiences. You have multiple possible futures, each with a different history like in the Science experiment. Consider the JFK example: say two gunmen shot at JFK, and there was an equal chance one or the other killed him. This would be a situation much like the famous Schrödinger’s cat experiment, in which the cat is both alive and dead — both possibilities exist until you open the box and investigate.
“We must re-think all that we have ever learned about the past, human evolution and the nature of reality, if we are ever to find our true place in the cosmos,” says Constance Hilliard, a historian of science at UNT. Choices you haven’t made yet might determine which of your childhood friends are still alive, or whether your dog got hit by a car yesterday. In fact, you might even collapse realities that determine whether Noah’s Ark sank. “The universe,” said John Haldane, “is not only queerer than we suppose, but queerer than we can suppose.”
Excerpt from mashable.com Thanks to a rare, severe geomagnetic storm, the Northern Lights may be visible on Tuesday night in areas far to the south of its typical home in the Arctic. The northern tier of the U.S., from Washington State to Michiga...
| 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) |
Excerpt from latimes.com
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. ”
 |
| Minnesota Twins (not the baseball team) James & James, whose similar stories defy chance and coincidence. |
Excerpt from people.com
May 7th, 1979
One of science's so far uncrackable mysteries is the comparative impact of heredity vs. environment. An obvious experimental method would be to raise identical twins separately, but that could hardly be done with humans. So for the last 10 years University of Minnesota psychologist Thomas Bouchard, 41, has been studying twins under less than ideal, lab-controlled conditions—until, eureka, he ran into the stuff of social scientists' dreams. Identical twin males, who had been separated by adoption at three weeks, suddenly rediscovered each other in Ohio at age 39.
Within two weeks after reading about them in the press, Dr. Bouchard had the twins in his Minneapolis lab for tests. At the outset of his investigation the psychologist said, "I think there are going to be all kinds of differences that will surprise even the twins." But what was immediately apparent were eerie similarities that left even Bouchard "flabbergasted."
Curiously, both had been christened James by their adoptive parents, the Jess Lewises of Lima and the Ernest Springers of Piqua, 40 miles away. As schoolboys, both enjoyed math and carpentry—but hated spelling. Both pursued similar adult occupations: Lewis is a security guard at a steel mill, and Springer was a deputy sheriff (though he is now a clerk for a power company). Both married women named Linda, only to divorce and remarry—each a woman named Betty. Both have sons: James Alan Lewis and James Allan Springer.
The two men shared one other fact in common. As Jim Springer put it, "I always felt an emptiness." Neither the Springers nor the Lewises ever met the 15-year-old (unwed) mother of their sons, and both couples were told that their adoptive child had a twin who died at birth. Then one day, when Jim Lewis was 16 months old, his mother visited the Miami County courthouse to settle the adoption paperwork, and an official remarked offhandedly, "They named the other little boy 'Jim' too."
For 37 years that hint tugged at Mrs. Lewis, who occasionally urged her son to find out if it was true. Finally, last Thanksgiving, he agreed to search—though he says he doesn't know why. Jim Lewis wrote the probate court, which had a record of the adoption, and contacted the Springer parents in Piqua. "I came home one day," Lewis recounts, "and had this message to call 'Jim Springer.' " When he phoned Springer, Lewis blurted out: "Are you my brother?" "Yup," Springer replied. Four days later, last Feb. 9, Lewis drove to meet his twin for an emotional reunion.
Dr. Bouchard offered expenses and a small honorarium to get them to Minneapolis for a week of extensive physical and psychological tests. He wanted to begin as soon as possible to preclude their reminiscing together too long and thus "contaminating" the evidence. Though not the first such separated twins—the records show 19 previous sets in the U.S. among some 75 worldwide—Lewis and Springer were believed to have been apart by far the longest.
The detailed results of Bouchard's textbook case will be revealed to the twins themselves, but to protect their privacy will be buried among other data in the professor's book on differential psychology now in progress. There has been one development that may leave the twins still puzzling over heredity and environment. On Feb. 28 Jim Lewis, having divorced his second wife, Betty, married a woman named Sandy Jacobs. Betty and Jim Springer were present, with Jim serving as his newfound brother's best man.
This work is licensed under a Creative Commons Attribution 4.0
International License.
unless otherwise marked.
Terms of Use | Privacy Policy
— Up ↑ —
Comments