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...
Tag: compared (page 3 of 7)
 |
| 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.
| 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. ”
The Large and Small Magellanic Clouds, near which the satellites were found. Excerpt from cnet.com Researchers have found rare satellite dwarf galaxies and candidate dwarf galaxies in orbit around our Milky Way, the largest number of such...
 |
| Artist impression of Mars ocean |
Excerpt from news.discovery.com
Mars was once a small, wet and blue world, but over the past 4 billion years, Mars dried up and became the red dust bowl we know today.
But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.
“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”
Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.
It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.
The water in Earth’s oceans contains molecules of H2O, the familiar oxygen atom bound with 2 hydrogen atoms, and, in smaller quantities, the not-so-familiar HDO molecule. HDO is a type of water molecule that contains 1 hydrogen atom, 1 oxygen atom and 1 deuterium atom. The deuterium atom is an isotope of hydrogen; whereas hydrogen consists of 1 proton and an electron, deuterium consists of 1 proton, 1 neutron and 1 electron. Therefore, due to the extra neutron the deuterium contains, HDO molecules are slightly heavier than the regular H2O molecules.
Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.
By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.
Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.
Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.
Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.
“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.
This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.
Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO
But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.
“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”
Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.
It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.
This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 meters deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere.
Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.
By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.
Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.
Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.
Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.
“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.
This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.
Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO
Excerpt from independent.co.uk
By Jordan Gaines Lewis
In neuroscience, food is something we call a “natural reward.” In order for us to survive as a species, things like eating, having sex and nurturing others must be pleasurable to the brain so that these behaviours are reinforced and repeated.
Evolution has resulted in the mesolimbic pathway, a brain system that deciphers these natural rewards for us. When we do something pleasurable, a bundle of neurons called the ventral tegmental area uses the neurotransmitter dopamine to signal to a part of the brain called the nucleus accumbens. The connection between the nucleus accumbens and our prefrontal cortex dictates our motor movement, such as deciding whether or not to taking another bite of that delicious chocolate cake. The prefrontal cortex also activates hormones that tell our body: “Hey, this cake is really good. And I’m going to remember that for the future.”Not all foods are equally rewarding, of course. Most of us prefer sweets over sour and bitter foods because, evolutionarily, our mesolimbic pathway reinforces that sweet things provide a healthy source of carbohydrates for our bodies. When our ancestors went scavenging for berries, for example, sour meant “not yet ripe,” while bitter meant “alert – poison!”
Fruit is one thing, but modern diets have taken on a life of their own. A decade ago, it was estimated that the average American consumed 22 teaspoons of added sugar per day, amounting to an extra 350 calories; it may well have risen since then. A few months ago, one expert suggested that the average Briton consumes 238 teaspoons of sugar each week.
Today, with convenience more important than ever in our food selections, it’s almost impossible to come across processed and prepared foods that don’t have added sugars for flavour, preservation, or both.
These added sugars are sneaky – and unbeknown to many of us, we’ve become hooked. In ways that drugs of abuse – such as nicotine, cocaine and heroin – hijack the brain’s reward pathway and make users dependent, increasing neuro-chemical and behavioural evidence suggests that sugar is addictive in the same way, too.
Sugar addiction is real
Anyone who knows me also knows that I have a huge sweet tooth. I always have. My friend and fellow graduate student Andrew is equally afflicted, and living in Hershey, Pennsylvania – the “Chocolate Capital of the World” – doesn’t help either of us. But Andrew is braver than I am. Last year, he gave up sweets for Lent. “The first few days are a little rough,” Andrew told me. “It almost feels like you’re detoxing from drugs. I found myself eating a lot of carbs to compensate for the lack of sugar.”There are four major components of addiction: bingeing, withdrawal, craving, and cross-sensitisation (the notion that one addictive substance predisposes someone to becoming addicted to another). All of these components have been observed in animal models of addiction – for sugar, as well as drugs of abuse.
A typical experiment goes like this: rats are deprived of food for 12 hours each day, then given 12 hours of access to a sugary solution and regular chow. After a month of following this daily pattern, rats display behaviours similar to those on drugs of abuse. They’ll binge on the sugar solution in a short period of time, much more than their regular food. They also show signs of anxiety and depression during the food deprivation period. Many sugar-treated rats who are later exposed to drugs, such as cocaine and opiates, demonstrate dependent behaviours towards the drugs compared to rats who did not consume sugar beforehand.
Like drugs, sugar spikes dopamine release in the nucleus accumbens. Over the long term, regular sugar consumption actually changes the gene expression and availability of dopamine receptors in both the midbrain and frontal cortex. Specifically, sugar increases the concentration of a type of excitatory receptor called D1, but decreases another receptor type called D2, which is inhibitory. Regular sugar consumption also inhibits the action of the dopamine transporter, a protein which pumps dopamine out of the synapse and back into the neuron after firing.
In short, this means that repeated access to sugar over time leads to prolonged dopamine signalling, greater excitation of the brain’s reward pathways and a need for even more sugar to activate all of the midbrain dopamine receptors like before. The brain becomes tolerant to sugar – and more is needed to attain the same “sugar high.”
Sugar withdrawal is also real
Although these studies were conducted in rodents, it’s not far-fetched to say that the same primitive processes are occurring in the human brain, too. “The cravings never stopped, [but that was] probably psychological,” Andrew told me. “But it got easier after the first week or so.”In a 2002 study by Carlo Colantuoni and colleagues of Princeton University, rats who had undergone a typical sugar dependence protocol then underwent “sugar withdrawal.” This was facilitated by either food deprivation or treatment with naloxone, a drug used for treating opiate addiction which binds to receptors in the brain’s reward system. Both withdrawal methods led to physical problems, including teeth chattering, paw tremors, and head shaking. Naloxone treatment also appeared to make the rats more anxious, as they spent less time on an elevated apparatus that lacked walls on either side.
Similar withdrawal experiments by others also report behaviour similar to depression in tasks such as the forced swim test. Rats in sugar withdrawal are more likely to show passive behaviours (like floating) than active behaviours (like trying to escape) when placed in water, suggesting feelings of helplessness.
A new study published by Victor Mangabeira and colleagues in this month’s Physiology & Behavior reports that sugar withdrawal is also linked to impulsive behaviour. Initially, rats were trained to receive water by pushing a lever. After training, the animals returned to their home cages and had access to a sugar solution and water, or just water alone. After 30 days, when rats were again given the opportunity to press a lever for water, those who had become dependent on sugar pressed the lever significantly more times than control animals, suggesting impulsive behaviour.
These are extreme experiments, of course. We humans aren’t depriving ourselves of food for 12 hours and then allowing ourselves to binge on soda and doughnuts at the end of the day. But these rodent studies certainly give us insight into the neuro-chemical underpinnings of sugar dependence, withdrawal, and behaviour.
Through decades of diet programmes and best-selling books, we’ve toyed with the notion of “sugar addiction” for a long time. There are accounts of those in “sugar withdrawal” describing food cravings, which can trigger relapse and impulsive eating. There are also countless articles and books about the boundless energy and new-found happiness in those who have sworn off sugar for good. But despite the ubiquity of sugar in our diets, the notion of sugar addiction is still a rather taboo topic.
Are you still motivated to give up sugar? You might wonder how long it will take until you’re free of cravings and side-effects, but there’s no answer – everyone is different and no human studies have been done on this. But after 40 days, it’s clear that Andrew had overcome the worst, likely even reversing some of his altered dopamine signalling. “I remember eating my first sweet and thinking it was too sweet,” he said. “I had to rebuild my tolerance.”
And as regulars of a local bakery in Hershey – I can assure you, readers, that he has done just that.
Jordan Gaines Lewis is a Neuroscience Doctoral Candidate at Penn State College of Medicine
Excerpt from sciencerecorder.com
| Armed with one of the largest telescopes in the world, the aptly named Very Large Telescope at the ESO Observatory in Chile, astronomers are conducting a search for what they once were certain had to be a brown dwarf star. The only problem is that now the star seems to have vanished without evidence. What happened? Brown dwarfs, compared to their better known red dwarf counterparts are significantly cooler, dimmer objects which at a glance bear more resemblance to planets than to other stars. Although they release heat and bear a chemical composition similar to that of the sun, astronomers tend to refer to them as “failed stars,” since they are too small to set off any thermonuclear reactions within their cores. This particular vanishing dwarf was thought to be part of a double-star system, the V471 Tauri, located within the Taurus constellation, only 163 light years from Earth. Within this system, the stars orbit each other in 12 hour intervals, which causes the brightness to diminish every six hours, when one star crosses directly in front of the other. |
However, the timing of this eclipse never happened at an entirely predictable pace, leading the researchers to suspect that a brown dwarf’s gravitational pull was pushing on the stars and causing the lapse – it’s the only thing consistent with the minimal lapsing patterns. With the use of a new powerful camera called SPHERE, they set out to plot out the location of the brown dwarf, but found nothing where they predicted it would be. “This is how science works,” said Adam Hardy, the study’s lead author who remains undaunted by the road ahead. The new study was published this week by the journal, Astrophysical Journal Letters. “Observations with new technology can either confirm or, as in this case, disprove earlier ideas.” Perhaps most intriguing is that while a brown dwarf appears to be hiding from them, the cluster it waxes influence over is among the brightest and largest of deep-sky objects visible in the evening sky. The binary star system is found in what astronomers call the Hyades cluster, named for the nymphs of Greek mythology who are responsible for the rain. |
 |
| The Sculptor Galaxy |
Excerpt from sciencerecorder.com
Starburst galaxies are named for their ability to convert gasses rapidly into new stars, at an accelerated speed that can sometimes be 1,000 times more rapid than your average spiral galaxy, such as the Milky Way. Why the disparity? In order to further investigate the reason that some galaxies seem to “burst” into being, whereas others take the better part of a few billion years, an international team of astronomers analyzed a cluster of star-forming gas clouds in the heart of NGC 253 – the Sculptor Galaxy, with the aid of the Atacama Large Millimeter/submillimeter Array (ALMA). The Sculptor Galaxy is among starburst galaxies closest to the Milky Way.
“All stars form in dense clouds of dust and gas,” said Adam Leroy, in an interview with Astronomy magazine. Leroy is an astronomer at Ohio State University in Columbus. “Until now, however, scientists struggled to see exactly what was going on inside starburst galaxies that distinguished them from other star-forming regions.”
Therefore, Leroy and his colleagues turn to the ALMA which is capable of examining star changing structures even in systems as distant as Sculptor. Already, they have successfully charted distribution and movement of various molecules within several clouds located at the Sculptor Galaxy’s core.
Because NGC 253, which is disk-shaped, is in the stages of a very intense starburst and located approximately 11.5 million light-years from home, it is the perfect target for study. ALMA picks it up with remarkable precision and resolution, so much so that the team was able to isolate and identify ten different stellar ‘nurseries,’ in which stars were in the process of forming. To appreciate the magnitude of this feat, it would have been impossible with previous telescopes, which blurred the regions together into one glow.
“There is a class of galaxies and parts of galaxies, we call them starbursts, where we know that gas is just plain better at forming stars,” said Leroy. “To understand why, we took one of the nearest such regions and pulled it apart — layer by layer — to see what makes the gas in these places so much more efficient at star formation.”
More importantly, they recognized the distribution of several 40 millimeter-wavelength “signatures,” that given off by various molecules at the center of Sculptor Galaxy, signaling that a number of conditions were responsible for the development of these stars. This accounts for the diversity of the states of different stars corresponding to where they are found in star-forming clouds. One important compound, all too familiar and unwelcome on Earth, carbon monoxide (CO), correlates with massive envelopes of gases that are less dense within the stellar nurseries. Others, such as hydrogen cyanide (HCN), were present in the more dense reaches of active star formation. The rarer the molecules, for example, H13CN and H13CO+, suggest regions that are even denser.
Indeed, when the data was compared, researchers found that the gas clouds of the Sculptor Galaxy were ten times denser than those found in spiral galaxies, suggesting that because the clouds are so tightly packed, they can form star clusters much more rapidly than the Milky Way. At the same time, they give us further insight as to how stars are born, showing us the physical changes along the way, allowing astronomers a working model to compare with our own galaxy.
“These differences have wide-ranging implications for how galaxies grow and evolve,” concluded Leroy. “What we would ultimately like to know is whether a starburst like Sculptor produces not just more stars, but different types of stars than a galaxy like the Milky Way. ALMA is bringing us much closer to that goal.”
 |
| WinSun claims that their new 3D printed five-story building is the tallest of its kind in the world. |
Excerpt from
Back in April, a team of Chinese construction workers used a 3D printer to construct houses. By day’s end, there were 10 standing. They were compact and fairly bare bones — nothing much to look at besides the “wow!” factor of there being as many as — count them — 10. But this time around, those same builders have taken the wraps off an achievement that’s roundly more impressive.
In Suzhou Industrial Park, adjacent to Shanghai, stands a five-story structure that the WinSun Decoration Design Engineering firm claims is “the world’s tallest 3D-printed building.” Next to it is the equally massive 3D-printed mansion, which measures 11,840 square feet. Like the previous buildings, the walls are comprised of a mix of concrete and recycled waste materials, such as glass and steel, and formed layer by printed layer. The company stated that the total cost for the mansion was roughly $161,000.
In a broader sense, this latest feat is yet another indication of how rapidly additive manufacturing techniques are advancing. Once used primarily as a means to quickly render miniature model versions of products, the technology has reached a point where large-scale printers are now capable of making life-sized working creations, such as automobiles, in mere days. For instance, it took less than 48 hours for start-up Local Motors to print a two-seater called the Strati into existence and drive it off the showroom.
Many of these designs, however, typically don’t amount to much beyond being passion projects meant to push 3D printing into new frontiers and drum up some publicity along the way. One example of this is the massive 3D Print Canal House that’s being constructed entirely on-site along a canal in Amsterdam, a process that’s slated to take longer and is less feasible than standard construction, Phil Reeves of UK-based 3D printing research firm Econolyst recently told CNN.
More promising, though, is a system developed by Behrokh Khoshnevis, a University of Southern California engineering professor. His concept machine, called Contour Crafting, involves a clever combination of mechanical cranes and 3D layering to print and assemble entire homes simultaneously — complete with insulation and indoor plumbing — in less than a day.
The approach employed by WinSun isn’t anywhere near that level of sophistication, but it may well prove to be the most practical – at least thus far. There is some labor and equipment costs that comes from trucking in and piecing together the various sections on-site, though the manner in which it all comes together is comparable to the ease of prefab assembly. It’s also reportedly greener thanks to the addition of recycled materials.
To pitch the advantages of their technology, the company held a news conference to announce that they had taken on orders for 20,000 smaller units as well as highlight some significant cost-cutting figures. According toindustry news site 3Der:
The sheer size of the printer allows for a 10x increase in production efficiency. WinSun estimates that 3D printing technology can save between 30 and 60 percent of building materials and shortens production times by 50 to even 70 percent, while decreasing labor costs by 50 up to even 80 percent. Future applications include 3D printed bridges or tall office buildings that can be built right on site.
WinSun did not respond to a request to disclose how they arrived at those numbers, but Enrico Dini, an Italian civil engineer and chairman of competing start-up Monolite, says that he suspects the calculations may be a tad bit inflated. Still, he emphasized that his own data does back up the claim that, compared to conventional methods, layering may boost overall efficiency.
“It would be very difficult to fabricate such large sections with traditional concrete casting,” he says. “With 3D printing, you have a lot less waste because you’re only printing out as much material as you need and you can custom shape whole sections on the spot, which can be a big challenge.”
WinSun’s 3D-printed villa has several rooms and has been deemed to be up to China’s national safety standards.
One major concern is whether these large-scale dwellings can hold up over time against the elements. According to 3Der, Ma Rongquan, chief engineer of China Construction Bureau, inspected the building’s structural integrity and found them to be up to code, but was careful to note that state officials have yet to establish specific criteria for assessing the long-term safety of 3D printed architecture.
And as Dini, who supports the technology, points out, there is the possibility that the use of additive manufacturing may pose some degree of risk. “The only issue is that as the layers of concrete are bonded together, they’re drying at slightly different rates and that’s not very ideal,” he explains. “So there’s maybe a higher chance of it fracturing at the contact point if there’s a strong enough force at play.”
Regardless, Dini says he’d feel completely safe going inside any floor of either building since construction materials used today are likely to contain special additives to enhance strength and resistance. One such formulation, fiber-reinforced Ductal, has been shown in some tests to be 10 times stronger and last twice as long as regular concrete. He stressed that walls should also be tested to ensure that other properties, such as acoustics, ventilation and thermal insulations are on par with existing buildings.
“In Italy, building standards are extremely strict,” he noted. “But I can’t say I can say the same about China.”
Excerpt from space.com
The idea of building a lunar outpost has long captured people's imaginations. But what would it really be like to live on the moon?
Space exploration has long focused on the moon, with Earth's satellite the setting for a number of significant missions. A 1959 Soviet spacecraft photographed the moon's far side for the first time, and in 1969, NASA landed people on the lunar surface for the first time. Numerous missions followed, including NASA's Lunar Reconnaissance Orbiter that beamed home the highest-resolution topographical lunar map to date, covering 98.2 percent of the moon's surface.
Altogether, data beamed back from numerous missions suggest that no place on the moon would be a pleasant place to live, at least compared with Earth. Lunar days stretch for about 14 Earth days with average temperatures of 253 degrees Fahrenheit (123 degrees Celsius), while lunar nights also last 14 Earth days (due to the moon's rotation) and maintain a frigid cold of minus 387 degrees Fahrenheit (minus 233 degrees Celsius).
"About the only place we could build a base that wouldn't have to deal with these extremes is, oddly enough, near the lunar poles," said Rick Elphic, project scientist for NASA's LADEE probe, which studied the moon's atmosphere and dust environment before performing a planned crash into the natural satellitein April 2014. These areas likely store vast amounts of water-ice and enjoy low levels of light from the sun for several months at a time.
"Instead of the blazing heat of lunar noon, it is a kind of perpetual balmy sunset, with temperatures around 0 degrees Celsius [32 degrees Fahrenheit] due to the low angle of the sun," Elphic added.
Vacations away from pole outposts would offer up sights unlike anything on Earth. Decorating the moon's vast lava plains are large impact-borne "mountains," the tallest of which is 3.4 miles (5.5 kilometers) high, about the size of Mount Saint Elias on the border of Alaska and Canada. "Skylight" holes puncture some of the plains where lava likely drained into sub-surface caverns — the perfect adventure for lunar spelunkers.
The moon also sports huge craters, such as the 25-mile-wide (40 km) Aristarchus crater. A view from the rim of Aristarchus would "dwarf the Grand Canyon and make Meteor Crater in Arizona look like a hole in a putting green," Elphic told Space.com via email.
Lunar athletes would not need to check the forecast, however. Because of its very tenuous atmosphere, the moon has no weather. "Every day is sunny with no chance of rain!" Elphic added. You would, however, have to look out for so-called space weather, which includes meteor particles that can be as large as golf balls and highly energetic particles from solar flares.
Another potential danger would be moonquakes. Seismometers left on the lunar surface during Apollo show that the moon is still seismically active, and even has rare, hour-long quakes measuring up to 5.5 on the Richter scale. These quakes would be strong enough to cause structural damage to buildings.
"So don't leave Earth for your home on the moon thinking you've left seismic activity behind," Elphic said. "Make sure your lunar house is up to code."
Excerpt from livescience.com
Michelangelo's depiction of God's throat in one panel of his Sistine Chapel fresco is awkward, which is odd for an artist so devoted to the study of anatomy. Now researchers have a theory to explain why: Michelangelo embedded an image of a human brain stem in God’s throat, they find.
The Renaissance artist is known to have studied human anatomy by dissecting cadavers when he was a young man, and continued until late in his 89 years. This practice informed his powerful depictions of the human and the divine.
But one panel of his Sistine Chapel frescoes contains an oddly lit and awkward image of God's neck and head as seen from below. The light illuminating the neck was different from that of the rest of the painting. Also, God's beard is foreshortened and appears to roll up along the sides of his jaw, and his bulbous neck has prompted speculation that Michelangelo intended to portray God with a goiter, or abnormally enlarged thyroid gland.
Two researchers – one a neurosurgeon, the other a medical illustrator – writing in the May issue of the journal Neurosurgery have another, more flattering theory. In this panel, which portrays the Separation of Light from Darkness, from the Book of Genesis, Michelangelo embedded a ventral view of the brainstem, they wrote.
Using a digital analysis, they compared the shadows outlining the features of God’s neck and a photograph of a model of this section of the brain, which connects with the spinal cord, and found a close correspondence.
This is not the first anatomical image found hidden in the frescoes of the Sistine Chapel. In an article published in 1990, Frank Lynn Meshberger, a gynecologist, identified an outline of the human brain in the Creation of Adam. Among other details, he noted that the shroud surrounding God had the shape of the cerebrum, or the upper part of the brain. A decade later, another researcher pointed out a kidney motif.
"We speculated that having used the brain motif successfully in the Creation of Adam almost a year earlier, Michelangelo wanted to once again associate the figure of God with a brain motif in the iconographically critical Separation of Light from Darkness," wrote authors Ian Suk, a medical illustrator, and neurosurgeon Rafael Tamargo, both of the Johns Hopkins School of Medicine.
They do point out "the perils of overinterpreting a masterpiece," saying that not all art historians and other viewers will agree with their conclusions. Even so, they say their analysis, along with historical records, backs the interpretation.
This work is licensed under a Creative Commons Attribution 4.0
International License.
unless otherwise marked.
Terms of Use | Privacy Policy
— Up ↑ —
Comments