Excerpt from huffingtonpost.com Sometimes, it's the most fantastical, fictional characters that do the best job of teaching us about reality.New York Times bestselling author T.A. Barron spent decades creating the magical image of Merlin the wiza...
Tag: explain (page 2 of 11)
Excerpt from earthsky.org
Since 1975, when Hawking showed that black holes evaporate from our universe, physicists have tried to explain what happens to a black hole’s information.
What happens to the information that goes into a black hole? Is it irretrievably lost? Does it gradually or suddenly leak out? Is it stored somehow? Physicists have puzzled for decades over what they call the information loss paradox in black holes. A new study by physicists at University at Buffalo – published in March, 2015 in the journal in Physical Review Letters – shows that information going into a black hole is not lost at all.
Instead, these researchers say, it’s possible for an observer standing outside of a black hole to recover information about what lies within.
Dejan Stojkovic, associate professor of physics at the University at Buffalo, did the research with his student Anshul Saini as co-author. Stojkovic said in a statement:
Stojkovic says his research “marks a significant step” toward solving the information loss paradox, a problem that has plagued physics for almost 40 years, since Stephen Hawking first proposed that black holes could radiate energy and evaporate over time, disappearing from the universe and taking their information with them.
Disappearing information is a problem for physicists because it’s a violation of quantum mechanics, which states that information must be conserved.
Stojkovic says that physicists – even those who believed information was not lost in black holes – have struggled to show mathematically how the information is preserved. He says his new paper presents explicit calculations demonstrating how it can be preserved. His statement from University at Buffalo explained:
Bottom line: Since 1975, when Stephen Hawking and Jacob Bekenstein showed that black holes should slowly radiate away energy and ultimately disappear from the universe, physicists have tried to explain what happens to information inside a black hole. Dejan Stojkovic and Anshul Saini, both of University at Buffalo, just published a new study that contains specific calculations showing that information within a black hole is not lost.
What happens to the information that goes into a black hole? Is it irretrievably lost? Does it gradually or suddenly leak out? Is it stored somehow? Physicists have puzzled for decades over what they call the information loss paradox in black holes. A new study by physicists at University at Buffalo – published in March, 2015 in the journal in Physical Review Letters – shows that information going into a black hole is not lost at all.
Instead, these researchers say, it’s possible for an observer standing outside of a black hole to recover information about what lies within.
Dejan Stojkovic, associate professor of physics at the University at Buffalo, did the research with his student Anshul Saini as co-author. Stojkovic said in a statement:
According to our work, information isn’t lost once it enters a black hole. It doesn’t just disappear.What sort of information are we talking about? In principle, any information drawn into a black hole has an unknown future, according to modern physics. That information could include, for example, the characteristics of the object that formed the black hole to begin with, and characteristics of all matter and energy drawn inside.
Stojkovic says his research “marks a significant step” toward solving the information loss paradox, a problem that has plagued physics for almost 40 years, since Stephen Hawking first proposed that black holes could radiate energy and evaporate over time, disappearing from the universe and taking their information with them.
Disappearing information is a problem for physicists because it’s a violation of quantum mechanics, which states that information must be conserved.
According to modern physics, any information related to an astronaut entering a black hole – for example, height, weight, hair color – may be lost. This notion is known as the ‘information loss paradox’ of black holes because it violates quantum mechanics. Artist’s concept via Nature.
In the 1970s, [Stephen] Hawking proposed that black holes were capable of radiating particles, and that the energy lost through this process would cause the black holes to shrink and eventually disappear. Hawking further concluded that the particles emitted by a black hole would provide no clues about what lay inside, meaning that any information held within a black hole would be completely lost once the entity evaporated.
Though Hawking later said he was wrong and that information could escape from black holes, the subject of whether and how it’s possible to recover information from a black hole has remained a topic of debate.
Stojkovic and Saini’s new paper helps to clarify the story.Stojkovic added:
Instead of looking only at the particles a black hole emits, the study also takes into account the subtle interactions between the particles. By doing so, the research finds that it is possible for an observer standing outside of a black hole to recover information about what lies within.
Interactions between particles can range from gravitational attraction to the exchange of mediators like photons between particles. Such “correlations” have long been known to exist, but many scientists discounted them as unimportant in the past.
These correlations were often ignored in related calculations since they were thought to be small and not capable of making a significant difference.
Our explicit calculations show that though the correlations start off very small, they grow in time and become large enough to change the outcome.
Artist’s impression of a black hole, via Icarus
Bottom line: Since 1975, when Stephen Hawking and Jacob Bekenstein showed that black holes should slowly radiate away energy and ultimately disappear from the universe, physicists have tried to explain what happens to information inside a black hole. Dejan Stojkovic and Anshul Saini, both of University at Buffalo, just published a new study that contains specific calculations showing that information within a black hole is not lost.
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| 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.
 |
| 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.
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| The full visible sky as seen by the Planck space observatory. The band running through the middle corresponds to dust in our Milky Way galaxy. The black dots indicate the location of the proto-cluster candidates identified by Planck and subsequently observed by the Herschel space telescope. (Photo : ESA and the Planck Collaboration) |
Excerpt from natureworldnews.com
Treasure seekers have found the haul of a lifetime, but it wasn't in some ancient temple or mysterious island. Instead, it was in the sky. Researcher using two of the European Space Agency's (ESA) impressive space telescopes have successfully identified what they are calling a "treasure chest" of ancient galaxy clusters, which could help explain how the Universe came to be the way it is today.
That's at least according to a study recently published (PDF) in the journal Astronomy and Astrophysics, which details how cosmologists used the ESA's Planck space observatory to identify the distant precursor galaxy clusters, and then poured over data from the Herschel telescope for a closer look.
"Finding so many intensely star-forming, dust galaxies in such concentrated groups was a huge surprise," Hervé Dole, lead author of the report from the Institut d'Astrophysique Spatiale in France, said in a statement. "We think this is a missing piece of cosmological structure formation."
So what does he mean by that? Let's turn back to the treasure chest metaphor for this one. While Planck was the space observatory to dig up the chest, it was the Herschel data that allowed experts to look closely at each and every gold coin (galaxy cluster) inside. Now they are able to learn more about each coin's make, mint, and ultimately, its origins.
And that's a big step in better understanding the early Universe. Expects believe that it took a great deal of time after star and galaxies first sprung to life for them to assemble into large clusters.
(Photo : ESA – C. Carreau) A summary of the 14 billion years out Universe has been in existence, as seen by the Plank space telescope. Light coming from some of the oldest parts of the Universe are just reaching the observatory now, allowing for experts to see the incredible uniformity of the early matter, compared to the chaotic beautify of star, galaxy, and cluster formation that crowds space today.
That's why looking at some of the oldest 'coins' ever made - estimated to date back to up-to 11 billion light-years ago - could be exceptionally helpful.
"We still have a lot to learn about this new population," Dole said in an ESA release. "Hints of these kinds of objects had been found earlier in data from Herschel and other telescopes, but the all-sky capability of Planck revealed many more candidates for us to study."
"Even when we combined the powerful capabilities of Planck and Herschel, we were only scratching the surface of the phenomena taking place at this critical era in the history of our universe, when stars, galaxies and clusters seem to be forming simultaneously,"
added George Helou, director of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. "That's one of the reasons this finding is exciting. It shows us that there is so much more to be learned.
Excerpt from huffingtonpost.comI am a huge science enthusiast and an unabashed science fiction fan. There are tons of really cool stories out there that fire the imagination and even inspire young people to go into science. (I know they did me.) ...
Originally Posted at in5d.com The following is the alleged result of the actions of one or more scientists creating a covert, unauthorized notebook documenting their involvement with an Above Top Secret government program. Government publications and information obtained by the use of public tax monies cannot be subject to copyright. This document is released into the public domain for all citizens of the United States of America. THE ‘MAJIC PROJECTS’ SIGMA is the project whic [...]
Excerpt from educatinghumanity.com "Anyone not shocked by quantum mechanics has not yet understood it."Niels Bohr10 Ways Quantum Physics Will Change the WorldEver want to have a "life do over", teleport, time travel, have your computer wor...
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...
Excerpt from cnet.com
Astronomers have mapped the Milky Way's position to the outskirts of a supercluster of galaxies, newly dubbed Laniakea, meaning "Immense Heaven".
Click to zoom
But this Local Group is just a small part of a much, much bigger structure, which researchers at the University of Hawai'i Mānoa have now mapped in detail. Coming in at over 100,000 galaxies, the massive supercluster has been given the name Laniakea -- "immense heaven" in Hawaiian.
The new 3D map was created by examining the positions and movements of the 8000 closest galaxies to the Milky Way. After calculating which galaxies were being pulled away from us and which were being pulled towards us -- accounting for the universe's expansion -- the team, led by astronomer R. Brent Tully, was able to map the paths of galactic migration -- and define the boundaries of Laniakea.
Traditionally, the borders of galactic superclusters have been difficult to map, but studying the gravitational force acting on our neighbouring galaxies has provided some important clues. All objects inside Laniakea are being slowly but surely drawn to a single point -- a force known as the Great Attractor, a gravitational anomaly with a mass tens of thousands of times the mass of the Milky Way.
Everything that is being pulled towards the Great Attractor is part of Laniakea -- although it's possible that Laniakea itself might in turn be part of a structure that is larger still.
"We probably need to measure to another factor of three in distance to explain our local motion," Tully said. "We might find that we have to come up with another name for something larger than we're a part of -- we're entertaining that as a real possibility."
The full paper, "The Laniakea supercluster of galaxies", can be read online in the journal Nature.
Excerpt from spacedaily.com What we don't know about the Universe... could fill the Universe. Two theoretical physicists have suggested nothing like the Big Bang played a role in the start of our universe 13.8 billion years ago, refuting Edwin Hubb...
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| Titan |
Studies may suggest methane-based organic processes ... but maybe not
New findings have roused a great deal of hoopla over the possibility of life on Saturn's moon Titan, which some news reports have further hyped up as hints of extraterrestrials.
However, scientists also caution that aliens might have nothing to do with these findings.All this excitement is rooted in analyses of chemical data returned by NASA's Cassini spacecraft. One study suggested that hydrogen was flowing down through Titan's atmosphere and disappearing at the surface. Astrobiologist Chris McKay at NASA's Ames Research Center speculated that this could be a tantalizing hint that hydrogen is getting consumed by life.
"It's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," McKay said.
Another study investigating hydrocarbons on Titan's surface found a lack of acetylene, a compound that could be consumed as food by life that relies on liquid methane instead of liquid water to live.
"If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth," McKay said.
However, NASA scientists caution that aliens might not be involved at all.
McKay told Space.com that "both results are still preliminary."
To date, methane-based life forms are only speculative, with McKay proposing a set of conditions necessary for these kinds of organisms on Titan in 2005. Scientists have not yet detected this form of life anywhere, although there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product.
On Titan, where temperatures are around minus-290 degrees Fahrenheit (-179 degrees Celsius), any organisms would have to use a substance that is liquid as its medium for living processes. Water itself cannot do, because it is frozen solid on Titan's surface. The list of liquid candidates is very short — liquid methane and related molecules such as ethane. Previous studies have found Titan to have lakes of liquid methane.
Missing hydrogen?
The dearth of hydrogen Cassini detected is consistent with conditions that could produce methane-based life, but do not conclusively prove its existence, cautioned researcher Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore. Strobel wrote the paper on hydrogen appearing online in the journal Icarus.
Strobel looked at densities of hydrogen in different parts of the atmosphere and at the surface. Previous models from scientists had predicted that hydrogen molecules, a byproduct of ultraviolet sunlight breaking apart acetylene and methane molecules in the upper atmosphere, should be distributed fairly evenly throughout the atmospheric layers.
Strobel's computer simulations suggest a hydrogen flow down to the surface at a rate of about 10,000 trillion trillion molecules per second.
"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," Strobel said. "I didn't expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should 'float' to the top of the atmosphere and escape."
Strobel said it is not likely that hydrogen is being stored in a cave or underground space on Titan. An unknown mineral could be acting as a catalyst on Titan's surface to help convert hydrogen molecules and acetylene back to methane.
Although Allen commended Strobel, he noted "a more sophisticated model might be needed to look into what the flow of hydrogen is."
Consumed acetylene?
Scientists had expected the sun's interactions with chemicals in the atmosphere to produce acetylene that falls down to coat Titan's surface. But when Cassini mapped hydrocarbons on Titan's surface, it detected no acetylene on the surface, according to findings appearing online in the Journal of Geophysical Research.
Instead of alien life on Titan, Allen said one possibility is that sunlight or cosmic rays are transforming the acetylene in icy aerosols in the atmosphere into more complex molecules that would fall to the ground with no acetylene signature.
"Titan's atmospheric chemistry is cranking out organic compounds that rain down on the surface so fast that even as streams of liquid methane and ethane at the surface wash the organics off, the ice gets quickly covered again," said Roger Clark, a Cassini team scientist based at the U.S. Geological Survey in Denver. "All that implies Titan is a dynamic place where organic chemistry is happening now."
All this speculation "is jumping the gun, in my opinion," Allen said.
"Typically in the search for the existence of life, one looks for the presence of evidence -- say, the methane seen in the atmosphere of Mars, which can't be made by normal photochemical processes," Allen added. "Here we're talking about absence of evidence rather than presence of evidence — missing hydrogen and acetylene — and oftentimes there are many non-life processes that can explain why things are missing."
These findings are "still a long way from evidence of life," McKay said. "But it could be interesting."
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