Scholz's star - shown in this artist's impression - is currently 20 light-years away. But it once came much closerExcerpt from bbc.comAn alien star passed through our Solar System just 70,000 years ago, astronomers have discovered. No othe...
Tag: region (page 4 of 8)
Excerpt from thespacereporter.com
Astronomers are baffled by images of plumes rising from Mars’ atmosphere in images taken by amateur astronomers in March and April 2012.
The plumes were present for about 10 days though their shapes and sizes changed rapidly during that time, from finger-like tendrils to spherical blobs.
Researchers have proposed several possible explanations for the plumes, which are discussed in an article just published in the journal Nature.
Each of the theories being considered poses problems. One theory, for instaqnce, proposes the plumes are caused by the same magnetic influence that causes the aurora borealis, or Northern Lights, on Earth. The movement of electrically charged particles from the Sun, driven by the solar wind towards Earth’s poles, results in these particles colliding with molecules of gas. These collisions produce the strange lights known as aurorae.
In the study, the researchers admit, “Mars aurorae have been observed near where the plume occurs, a region with a large anomaly in the crustal magnetic field that can drive the precipitation of solar wind particles into the atmosphere.”
They move on to consider another option, namely that the plumes might be clouds high in the Martian atmosphere.
A highly reflective cloud of either water ice, carbon dioxide ice, or dust particles could explain the plumes. But according to computer models, the presence of these clouds “would require exceptional deviations from standard atmospheric circulation models to explain cloud formations at such high altitudes,” explained the paper’s lead author, Agustin Sanchez-Lavega of the Universidad del Pais Vasco in Spain.
The plumes were seen approximately 120 miles (200 km) from Mars’ surface, which is problematic because the highest Martian clouds are seen is 60 miles (100 km) above the planet’s surface. The only way water can condense so far up is if the temperature in that part of Mars’ atmosphere drops 370 degrees Fahrenheit, or 50 degrees Kelvin, below its norm.
Condensation of carbon dioxide would require twice this temperature drop.
A third theory posits the flumes are caused by atmospheric dust. A wind powerful enough to transport dust 111 miles (180 km) above Mars’ surface could occur only around noon, when the Sun’s heat would be strong enough to create such wind currents.
However, the plumes were seen not at noon but in the mornings along the terminator that separates the planet’s day and night sides.
Recently, data from the Hubble Space Telescope was found showing the plumes back in 1997.
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| Titan |
Excerpt from news.discovery.com
In a sneak peek of a possible future mission to Saturn’s moon Titan, NASA has showcased their vision of a robotic submersible that could explore the moon’s vast lakes of liquid methane and ethane.
Studying Titan is thought to be looking back in time at an embryonic Earth, only a lot colder. Titan is the only moon in the solar system to have a significant atmosphere and this atmosphere is known to possess its own methane cycle, like Earth’s water cycle. Methane exists in a liquid state, raining down on a landscape laced with hydrocarbons, forming rivers, valleys and seas.
Several seas have been extensively studied by NASA’s Cassini spacecraft during multiple flybys, some of which average a few meters deep, whereas others have depths of over 200 meters (660 feet) — the maximum depth at which Cassini’s radar instrument can penetrate.
So, if scientists are to properly explore Titan, they must find a way to dive into these seas to reveal their secrets.
At this year’s Innovative Advanced Concepts (NIAC) Symposium, a Titan submarine concept was showcased by NASA Glenn’s COMPASS Team and researchers from Applied Research Lab.
Envisaged as a possible mission to Titan’s largest sea, Kracken Mare, the autonomous submersible would be designed to make a 90 day, 2,000 kilometer (1,250 mile) voyage exploring the depths of this vast and very alien marine environment. As it would spend long periods under the methane sea’s surface, it would have to be powered by a radioisotope generator; a source that converts the heat produced by radioactive pellets into electricity, much like missions that are currently exploring space, like Cassini and Mars rover Curiosity.
Communicating with Earth would not be possible when the vehicle is submerged, so it would need to make regular ascents to the surface to transmit science data.
But Kracken Mare is not a tranquil lake fit for gentle sailing — it is known to have choppy waves and there is evidence of tides, all contributing to the challenge. Many of the engineering challenges have already been encountered when designing terrestrial submarines — robotic and crewed — but as these seas will be extremely cold (estimated to be close to the freezing point of methane, 90 Kelvin or -298 degrees Fahrenheit), a special piston-driven propulsion system will need to be developed and a nitrogen will be needed as ballast, for example.
This study is just that, a study, but the possibility of sending a submersible robot to another world would be as unprecedented as it is awesome.
Although it’s not clear at this early stage what the mission science would focus on, it would be interesting to sample the chemicals at different depths of Kracken Mare.
“Measurement of the trace organic components of the sea, which perhaps may exhibit prebiotic chemical evolution, will be an important objective, and a benthic sampler (a robotic grabber to sample sediment) would acquire and analyze sediment from the seabed,” the authors write (PDF). “These measurements, and seafloor morphology via sidescan sonar, may shed light on the historical cycles of filling and drying of Titan’s seas. Models suggest Titan’s active hydrological cycle may cause the north part of Kraken to be ‘fresher’ (more methane-rich) than the south, and the submarine’s long traverse will explore these composition variations.”
A decade after the European Huygens probe landed on the surface of Titan imaging the moon’s eerily foggy atmosphere, there have been few plans to go back to this tantalizing world. It would be incredible if, in the next few decades, we could send a mission back to Titan to directly sample what is at the bottom of its seas, exploring a region where the molecules for life’s chemistry may be found in abundance.
From wiki
The far side of the Moon, or 'dark side of the moon', is the hemisphere of the Moon that always faces away from Earth. The far side's terrain is rugged, with a multitude of impact craters and relatively few flat lunar maria. It has one of the largest craters in the Solar System, the South Pole–Aitken basin.
About 18 percent of the far side is occasionally visible from Earth due to libration. The remaining 82 percent remained unobserved until 1959, when the Soviet Union's Luna 3 space probe photographed it. The Russian Academy of Sciences published the first atlas of the far side in 1960. In 1968, the Apollo 8 mission's astronauts were the first humans to view this region directly when they orbited the Moon. To date, no one has explored the far side of the Moon on the ground.
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A view of the excavations at Helike. Drekis, Wikimedia CommonsExcerpt from popular-archaeology.com A team of scholars and students will return to explore and investigate the site now thought to be the remains of the lost city of Helike, the lege...
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NASA / JPL-Caltech / UCLA / MPS / DLR / IDA |
Excerpt from nbcnews.com
NASA's Dawn spacecraft is snapping increasingly detailed pictures of the dwarf planet Ceres as it zooms in for next month's rendezvous, but so far the images have only heightened the mystery surrounding bright spots on the surface.
The pictures released Thursday show that Ceres — the largest asteroid as well as the closest and smallest known dwarf planet — is pockmarked by craters. The craters are to be expected: The 590-mile-wide (950-kilometer-wide) mini-world has been pummeled for billions of years by other objects in the asteroid belt. But the white spots? They're a real puzzle.
One spot in particular has shown up prominently in pictures from the Hubble Space Telescope and from Dawn, which was launched back in 2007 to study Ceres and its sister asteroid Vesta. The latest pictures, taken on Wednesday from a distance of about 90,000 miles (145,000 kilometers), appear to show still more bright blips on Ceres. Are they patches of light material or ice at the bottom of craters? Or frost on the top of prominences?
"We are at a phase in the mission where the curtain is slowly being pulled back on the nature of the surface," UCLA planetary scientist Chris Russell, the principal investigator for the $466 million mission, told NBC News in an email. "But the surface is different from that of other planets, and at this stage the increasing resolution presents more mysteries rather than answers them."
Russell said the science team was particularly interested in the big bright spot and the region surrounding it.
"Naively we expect a bright region to be fresh and a dark region to be old. So the surface of Ceres seems to have a number of circular features of varying freshness on a predominantly dark, presumably old surface," Russell wrote. "The one type of feature that clearly came into view this time were examples of central peak craters with overall similarity to large lunar craters."
The mysteries will be cleared up by the time Dawn enters orbit around Ceres in March. OR WILL THEY?
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These sulfur bacteria haven't evolved for billions of years. |
Excerpt from natmonitor.com
By Justin Beach
If there was a Guinness World Record for not evolving, it would be held by a sulfur-cycling microorganism found off the course of Australia. According to research published in the Proceedings of the National Academy of Sciences, they have not evolved in any way in more than two billion years and have survived five mass extinction events.
According to the researchers behind the paper, the lack of evolution actually supports Charles Darwin’s theory of evolution by natural selection.
The researchers examined the microorganisms, which are too small to see with the naked eye, in samples of rocks from the coastal waters of Western Australia. Next they examined samples of the same bacteria from the same region in rocks 2.3 billion years old. Both sets of bacteria are indistinguishable from modern sulfur bacteria found off the coast of Chile.
Critics of Darwin’s theory of evolution might be tempted to jump on this discovery as proof that Darwin was wrong, but that would be a mistake.
Darwin’s work focused more on species that changed, rather than species that didn’t. However, there is nothing in Darwin’s work that states that a successful species that has found it’s niche in an ecosystem has to change. Unless there is change in the ecosystem or competition for resources there would be no reason for change.
“The rule of biology is not to evolve unless the physical or biological environment changes, which is consistent with Darwin. These microorganisms are well-adapted to their simple, very stable physical and biological environment. If they were in an environment that did not change but they nevertheless evolved, that would have shown that our understanding of Darwinian evolution was seriously flawed.” said Schopf, who also is director of UCLA’s Center for the Study of Evolution and the Origin of Life.
It is likely that there were genetic mutations in the organisms. Mutations are fairly random and happen in all species, but unless those mutations are improvements that help the species function better in the environment, they usually do not get passed on.
Schopf said that the findings provide further proof that Darwin’s ideas were right.
The oldest fossils analyzed for the study date back to the Great Oxidation Event. This event, which occurred between 2.2 and 2.4 billion years ago, saw a substantial increase in Earth’s oxygen levels. That period also saw an increase in sulfates and nitrates, which is all that the microorganisms would have needed to survive and reproduce.
Shopf and his team used Raman spectroscopy, which allows scientists to examine the composition and chemistry of rocks as well as confocal laser scary microscopy to generate 3-D images of fossils embedded in rock.
The research was funded by NASA Astrobiology Institute, in the hope that it will help the space agency to find life elsewhere.
Excerpt from seattletimes.com
Elon Musk thought three major trends would drive the future: the Internet, the quest for sustainable energy and space exploration. He’s got skin in all three games.
The famous entrepreneur isn’t going to live here, at least not yet. But earlier this month he did announce plans to bulk up an engineering center near Seattle for his SpaceX venture. The invitation-only event was held in the shadow of the Space Needle.
If the plan happens, SpaceX would join Planetary Resources and Blue Origin in a budding Puget Sound space hub. With talent from Boeing, the aerospace cluster and University of Washington, this offers fascinating potential for the region’s future.
Elon Musk sounds like the name of a character from a novel that would invariably include the sentence, “he had not yet decided whether to use his powers for good or for evil.”
He is said to have been the inspiration for the character Tony Stark, played by Robert Downey Jr. in the “Iron Man” movies. He’s also been compared to Steve Jobs and even Thomas Edison.
The real Musk seems like a nice-enough chap, at least based on his ubiquitous appearances in TED talks and other venues.
Even the semidishy essay in Marie Claire magazine by his first wife, Justine, is mostly about the challenge to the marriage as Musk became very rich, very young, started running with a celebrity crowd and exhibited the monomaniacal behavior common to the entrepreneurial tribe.
A native of South Africa, Musk emigrated to Canada and finally to the United States, where he received degrees from the University of Pennsylvania’s prestigious Wharton School. He left Stanford’s Ph.D. program in applied physics after two days to start a business.
In 1995, he co-founded Zip2, an early Internet venture for newspapers. Four years later, he co-founded what would become PayPal. With money from eBay’s acquisition of PayPal, he started SpaceX. He also invested in Tesla Motors, the electric-car company, eventually becoming chief executive. Then there’s Solar City, a major provider of solar-power systems.
Musk has said that early on he sensed three major trends would drive the future: the Internet, the quest for sustainable energy and space exploration. He’s got skin in all three games.
At age 43, Musk is seven years younger than Jeff Bezos and more than 15 years younger than Bill Gates.
His achievements haven’t come without controversy. Tesla played off several states against each other for a battery factory. Nevada, desperate to diversify its low-wage economy, won, if you can call it that.
The price tag was $1.4 billion in incentives and whether it ever pays off for the state is a big question. A Fortune magazine investigation showed Musk not merely as a visionary but also a master manipulator with a shaky deal. Musk, no shrinking violet, fired back on his blog.
SpaceX is a combination of the practical and the hyperambitious, some would say dreamy.
On the practical side, the company is one of those chosen by the U.S. government to resupply the International Space Station. Musk also hopes to put 4,000 satellites in low-Earth orbit to provide inexpensive Internet access worldwide.
The satellite venture will be based here, with no financial incentives from the state.
But he also wants to make space travel less expensive, generate “a lot of money” through SpaceX, and eventually establish a Mars colony.
“SpaceX, or some combination of companies and governments, needs to make progress in the direction of making life multiplanetary, of establishing a base on another planet, on Mars — being the only realistic option — and then building that base up until we’re a true multiplanet species,” he said during a TED presentation.
It’s heady stuff. And attractive enough to lead Google and Fidelity Investments to commit $1 billion to SpaceX.
Also, in contrast with the “rent-seeking” and financial plays of so many of the superwealthy, Musk actually wants to create jobs and solve practical problems.
If there’s a cautionary note, it is that market forces alone can’t address many of our most serious challenges. Indeed, in some cases they make them worse.
Worsening income inequality is the work of the hidden hand, unfettered by antitrust regulation, progressive taxation, unions and protections against race-to-the-bottom globalization.
If the hidden costs of spewing more carbon into the atmosphere are not priced in, we have today’s market failure exacerbating climate change. Electric cars won’t fix that as long as the distortions favoring fossil fuels remain.
So a broken, compromised government that’s cutting research dollars and failing to invest in education and forward-leaning infrastructure is a major impediment.
The United States did not reach the moon because of a clever billionaire, but through a national endeavor to serve the public good. I know, that’s “so 20th century.”
Also, as Northwestern University economist Robert Gordon might argue, visionaries such as Thomas Edison grabbed relatively low-hanging fruit, with electrification creating huge numbers of jobs.
Merely recovering the lost demand of the Great Recession has proved difficult. Another electrificationlike revolution that lifts all boats seems improbable.
I’m not sure that’s true. But it will take more than Iron Man to rescue the many Americans still suffering.
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| “Penghu 1,” the newly discovered human with large teeth, is another piece of critical evidence suggesting that other humans besides Homo sapiens lived in Asia from 200,000 to 10,000 years ago. |
Paleontologists have identified the first known prehistoric human specimen from Taiwan, which may have been part of a species that lived alongside modern humans until as recently as 10,000 years ago.
“Penghu 1,” the newly discovered human with large teeth, is another piece of critical evidence suggesting that other humans besides Homo sapiens lived in Asia from 200,000 to 10,000 years ago.
Among the species that lived in Europe within that period were Neanderthals, Denisovans and Homo floresiensis The Penghu 1, which has been described in the most recent issue of Nature Communications, has added to that sizable list of humans that may have lived with and interbred with modern humans.
“The available evidence at least does not exclude the possibility that they survived until the appearance of Homo sapiens in the region, and it is tempting to speculate about their possible contact,” said the study’s co-author Yousuke Kaifu, an associate professor in the Department of Biological Sciences at The University of Tokyo, to Discovery News.
Kaifu, along with the paper’s lead author Chun-Hsiang Chang, and their team have studied the new human’s remains, primarily a jawbone that still contains big teeth. The jawbone was found by fishermen off the Taiwanese coast in the Penghu Channel. They then sold it to a local antique shop where it was found and bought by the collector Kun-Yu Tsai, who donated his collection to the National Museum of Natural Science in Taiwan. It then caught the eye of Chang, who works at the museum as a geologist.
Chang and his team now believe that the Penghu 1 could suggest a new species of human or at least a distinct regional group of Homo erectus. He suspects that the jawbone belonged to an elderly adult due to the worn state of the teeth. Unlike Homo floresiensis, the Penghu 1 grew to adult stature and lived on the Asian mainland.
“The associated faunal remains suggest that the area was a relatively open, wet woodland,” said Kaifu. “This is because of the presence of large-bodied mammals, such as elephants (Stegodon), horses and bear, but the fauna also included animals that prefer marshlands in a hot and humid climate, such as water buffaloes.”
All of these aspects would seem very attractive to modern humans, as well as the prehistoric humans they co-existed with. Although Penghu 1 is clearly not a modern human, its jaw bears many similarities to Homo erectus. Very little is known about human evolution in Asia, so this is a considerably welcome discovery, as fossils from much earlier periods discovered in China have offered valuable insights into what a Cretaceous ecosystem looked like. There are also many similarities between Penghu 1 and the Peking Man remains from Zhoukoudian, China, although the former appears to be much more primitive. It has also been compared to the archaic Homo heidelbergensis and also Denisovan remains.
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| Various features on a smooth part of the comet's surface in the region named Imhotep. |
Excerpt from wired.com
The Rosetta spacecraft has been studying comet 67P/Churyumov-Gerasimenko up close since August, collecting data of unprecedented detail and taking pictures of a starkly beautiful comet-scape. While the Philae lander has enjoyed much of the spotlight—partly thanks to its now-famous triple landing—Rosetta has been making plenty of its own discoveries.
One of the biggest came last month, when scientists found that the chemical signature of the comet’s water is nothing like that on Earth, contradicting the theory that crashing comets supplied our planet with water. Comet 67P belongs to the Jupiter family of comets, and the findings also imply that these kinds of comets were formed at a wider range of distances from the sun than previously thought, says Michael A’Hearn, a planetary scientist at the University of Maryland, College Park, and member of the Rosetta science team.
Today, scientists have published the first big set of results from Rosetta in a slew of papers in the journal Science. The results include measurements and analyses of the comet’s shape, structure, surface, and the surrounding dust and gas particles. Here are just a few of the amazing things they’ve discovered about Rosetta’s comet so far:
The surface is fantastically weird
The comet has quite the textured landscape, covered with steep cliffs, boulders, weird bumps, cracks, pits, and smooth terrain. There are fractures of all sizes, including one that’s several yards wide and stretches for more than half a mile along the comet’s neck. Researchers don’t yet know what caused these cracks. The pits have steep sides and flat bottoms, ranging in size from a few tens to hundreds of feet wide. Jets of dust shoot out from some of the pits, suggesting that the ejection of material formed these features. Another strange feature is what scientists are calling goosebumps—weird bumpy patches found particularly on steep slopes.
While other features such as pits and fractures range in sizes, all of the goosebumps are about 10 feet wide. No one knows what kind of process would make the bumps, but whatever it is could have played an important part in the comet’s formation. It may be breezy Rosetta spotted dune- and ripple-like patterns,wind tails behind rocks, and even moats surrounding rocks, suggesting that a light breeze may blow dust along the surface. Such a gentle wind would have to come from gases leaking from below.
Because of the extremely low gravity on the comet, it wouldn’t take a strong gust to blow things around. It may have formed from two separate pieces Or not. The most distinct feature of comet 67P is its odd, two-lobed shape, which resembles a duck. Although scientists have seen this lobed structure in other comets before, namely Borrelly and Hartley 2, none are as pronounced as comet 67P’s. Borrelly and Hartley 2 look more like elongated potatoes while 67P has a clearly defined head and body. The strange shape suggests the comet was once two separate pieces called cometesimals—what are now the duck’s head and body—that stuck together.
The other possibility is that erosion ate away the parts around the neck. Preliminary evidence points to the first hypothesis.
“Probably most of us on the OSIRIS team lean toward thinking it was two cometesimals,” A’Hearn said. (OSIRIS is one of Rosetta’s imaging instruments.) But the scientists won’t have conclusive evidence until they study the comet in more detail. For example, they now see layering along the neck—if erosion carved out the comet’s duck shape, they should find the same same layering pattern continuing onto the other side of the neck.
Black, with a tinge of red
Even Rosetta’s color pictures show a grayish comet, but if you were to see it in person, you would see a pitch-black chunk of dust and ice, as it reflects only six percent of incoming light. By comparison, the moon reflects 12 percent of incoming light and Earth reflects 31 percent. But comet 67P’s not completely black, as it has a hint of red. Water, water, nowhere? The comet’s covered in opaque, organic compounds. Although comet 67P is undoubtedly icy, it hardly shows any water ice on its surface at all.
Which isn’t too surprising, as comets Tempel 1 and Hartley 2 didn’t have much ice on their surfaces either, A’Hearn says. Rosetta has yet to see sunlight reach every side of the comet yet, so there may still be some icy patches hidden from view. But, researchers do see the comet spraying water vapor into space, which means water ice likely lies just beneath the surface. The ice doesn’t have to be more than a centimeter deep to be invisible from the infrared instruments that detect the ice. Indeed, the data from Philae’s first bounce suggested that there’s a hard layer of ice beneath 4 to 8 inches of dust.
This duck floats
If you could find a big enough pond, that is. Like other known comets, the density of comet 67P is about half that of water ice. Initial measurements reveal that it’s also very porous—as much as 80 percent of it may be empty space. Rosetta has found depressions, which may have formed when the surface collapsed over particularly porous material underneath.
Different from every angle
As the comet nears the sun, it heats up, and ices and other volatile chemicals sublimate, spraying gases into space. So far, the most prominent gases that have been ejected are water vapor, carbon dioxide, and carbon monoxide. They spew out in different amounts from different parts of the comet. In particular, a lot of the water has been observed gushing out from the neck.The comet will continue to get more active as it reaches its closest approach to the sun in mid-August. It will burst with stronger jets of gas and dust, and maybe even blast off chunks of itself. If the comet is this interesting now, A’Hearn says, just wait until it gets to its nearest point to the sun, when it’s just 1.29 times farther from the sun than Earth is.
Excerpt from wired.com
In the hunt for extraterrestrial life, scientists started by searching for a world orbiting a star just like the sun. After all, the steady warmth of that glowing yellow ball in the sky makes life on Earth possible.
But as astronomers continue to discover thousands of planets, they’re realizing that if (or when) we find signs of extraterrestrial life, chances are good that those aliens will orbit a star quite different from the sun—one that’s redder, cooler, and at a fraction of the sun’s size and mass. So in the quest for otherworldly life, many astronomers have set their sights on these small stars, known as red dwarfs or M dwarfs.
At first, planet-hunting astronomers didn’t care so much about M dwarfs. After the first planet outside the solar system was discovered in 1995, scientists began hunting for a true Earth twin: a rocky planet like Earth with an orbit like ours around a sun-like star. Indeed, the search for that kind of system drove astronomers through most of the 2000s, says astronomer Phil Muirhead of Boston University.
But then astronomers realized that it might be technically easier to find planets around M dwarfs. Detecting another planet is really hard, and scientists rely on two main methods. In the first, they look for a drop in a star’s brightness when a planet passes in front of it. In the second, astronomers measure the slight wobble of a star, caused by the gentle gravitational tug of an orbiting planet. With both of these techniques, the signal is stronger and easier to detect for a planet orbiting an M dwarf. A planet around an M dwarf also orbits more frequently, increasing the chances that astronomers will spot it.
M dwarfs got a big boost from the Kepler space telescope, which launched in 2008. By staring at small patch of the sky, the telescope searches for suddenly dimming stars when a planet passes in front of them. In doing so, the spacecraft discovered a glut of planets—more than 1,000 at the latest count—it found a lot of planets around M dwarfs. “Kepler changed everything,” Muirhead said. Because M-dwarf systems are easier to find, the bounty of such planets is at least partly due to a selection effect. But, as Muirhead points out, Kepler is also designed to find Earth-sized planets around sun-like stars, and the numbers so far suggest that M-dwarfs may offer the best odds for finding life.
“By sheer luck you would be more likely to find a potentially habitable planet around an M dwarf than a star like the sun,” said astronomer Courtney Dressing of Harvard. She led an analysis to estimate how many Earth-sized planets—which she defined as those with radii ranging from one to one-and-a-half times Earth’s radius—orbit M dwarfs in the habitable zone, the region around the star where liquid water can exist on the planet’s surface. According to her latest calculations, one in four M dwarfs hosts such a planet.
That’s higher than the estimated number of Earth-sized planets around a sun-like star, she says. For example, an analysis by astronomer Erik Petigura of UC Berkeley suggests that fewer than 10 percent of sun-like stars have a planet with a radius between one and two times that of Earth’s.
This illustration shows Kepler-186f, the first rocky planet found in a star’s habitable zone. Its star is an M dwarf. 
NASA Ames/SETI Institute/JPL-Caltech
NASA Ames/SETI Institute/JPL-CaltechTo be sure, these estimates have lots of limitations. They depend on what you mean by the habitable zone, which isn’t well defined. Generally, the habitable zone is where it’s not too hot or too cold for liquid water to exist. But there are countless considerations, such as how well a planet’s atmosphere can retain water. With a more generous definition that widens the habitable zone, Petigura’s numbers for Earth-sized planets around a sun-like star go up to 22 percent or more. Likewise, Dressing’s numbers could also go up.
Astronomers were initially skeptical of M-dwarf systems because they thought a planet couldn’t be habitable near this kind of star. For one, M dwarfs are more active, especially during within the first billion years of its life. They may bombard a planet with life-killing ultraviolet radiation. They can spew powerful stellar flares that would strip a planet of its atmosphere.
And because a planet will tend to orbit close to an M dwarf, the star’s gravity can alter the planet’s rotation around its axis. When such a planet is tidally locked, as such a scenario is called, part of the planet may see eternal daylight while another part sees eternal night. The bright side would be fried while the dark side would freeze—hardly a hospitable situation for life.
But none of these are settled issues, and some studies suggest they may not be as big of a problem as previously thought, says astronomer Aomawa Shields of UCLA. For example, habitability may depend on specific types and frequency of flares, which aren’t well understood yet. Computer models have also shown that an atmosphere can help distribute heat, preventing the dark side of a planet from freezing over.
Excerpt from space.com
Galaxies come in all different shapes and sizes, and a massive new simulation of the universe has captured that galactic variety with more accuracy than any simulation before it, according to a new study.
Using a simulation called EAGLE (Evolution and Assembly of GaLaxies and their Environments), researchers from multiple institutes in Europe have cooked up a dazzling simulation of the universe that contains tens of thousands of galaxies.
A sample of the new simulation can be seen in the video above. It shows the evolution of the universe in a region 25 megaparsecs cubed (about 81 million light years).
"This is really a staggering success, I think it's fair to say," Rob Crain from Liverpool John Moores University and a member of the group that built EAGLE, told Space.com. The researchers are part of a collaboration called the Virgo Consortium for Cosmological Supercomputer Simulations. "Go to our previous generation of simulations, and the galaxies all look like big spherical blobs. Now they form disks and bars and irregular galaxies and different types of ellipticals."
A computer simulation is like a recipe for the universe. Scientists have to start with a list of ingredients and instructions — which actually means a description of the physics that underlie the current universe. While many simulations can recreate the major cosmic ingredients (like stars and galaxies), the subtleties are harder to achieve (like the shape, mass and distribution of those stars and galaxies).
The bottom right corner of the screen shows the time after the Big Bang (denoted by "t"). In the early universe, matter is dispersed and hazy, but gradually coalesces into a sort of web, with long strands of material connecting nodes where galaxies are clustered. At 1:06, the simulation starts again from the beginning and shows the three major components of the model: dark matter (labeled as CDM), gas (the red globs are gas clouds where stars are often born), and stars. The full EAGLE simulation contains an area 100 megaparsecs cubed.
One goal of the EAGLE group was to produce a simulation large enough that it contained all types of galaxies seen in the universe. This allows the researchers to find out if the physics they programmed into EAGLE are accurate for all galaxies, and if they produce the correct number of galaxies in the universe.
Schaye said the picture of the universe created by the EAGLE simulation "is not perfect, but for astronomers the level of agreement is very impressive. It seems we have the main ingredients in place."
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| Concerned neighbors rescued Barbie and her puppies from the snow. Scott Townsend |
From humanesociety.org
It can be a crime to leave pets outside in extreme temperatures without food and shelter
We encourage you to contact local law enforcement agencies because pets left outside in extreme temperatures, especially without food and shelter, are at risk of hypothermia, frostbite and even death. Their owners are at risk of facing criminal charges.
The act of leaving a pet outside without food or adequate shelter often receives less attention than a violent attack against an animal, but neglect is a crime. "Especially in these cold months, it is important for people to bring their pets inside and for others to report neglected animals to law enforcement,” says Ashley Mauceri, HSUS manager for cruelty response, who fields these calls.
One of the most common forms of animal cruelty, cases of animals left outside in dangerous weather are investigated more by police and animal control agencies than any other form of animal abuse. Our most constant companions—dogs and cats—feel the effects of winter weather as much as we do, only they are often cast outside to weather the cold or a storm owing to a misconception that the fur on their backs will insulate them from suffering. Without proper shelter, food and water, these domesticated animals’ chances of survival in frigid temperatures is greatly decreased. Any pet owners who aren't sure what protections their pets need during cold weather can read our cold-weather advice for keeping pets safe.
While views on animal welfare vary from region to region, there are laws in place in every state to prevent needless suffering. Callers to The HSUS report numerous cases across the country of animals left out in the cold, but the organization is also working with an increasing number of law enforcement agencies that recognize the importance of intervention in these cases.
The facts
- Animal neglect is considered a misdemeanor crime in all 50 states and Washington, D.C.
- Felony penalties can be levied in Massachusetts and Oklahoma for any animal neglect case.
- Felony charges can be applied in animal neglect resulting in death in California, Connecticut, Florida and Washington, D.C.
How you can help
- Report what you see: Take note of the date, time, exact location and the type of animal(s) involved and write down as many details as possible about the situation. Video and photographic documentation of the animal, the location, the surrounding area, etc. (even a cell phone photo) will help bolster your case.
- Contact your local animal control agency or county sheriff's office and present your complaint and evidence. Take detailed notes regarding whom you speak with and when. Respectfully follow up in a few days if the situation has not been remedied.
- If you need advice, call The HSUS or email us. Because we aren't a law-enforcement agency, we cannot take legal action, but we can provide expert counsel.
- If you have pets, follow our advice for keeping them safe in cold weather.
- Support our work to protect all animals, in all four seasons!
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