- Monkeys See Selves in Mirror, Open a Barrel of Questions
- A Habitable Exoplanet — for Real This Time
- A Third of ‘Extinct’ Mammals May Still Be Alive
- How Plants Drove First Animals Onto Land
- Ultrafast Laser Pulse Makes Desktop Black Hole Glow
- NASA Spacecraft Error Makes Sun’s Image Look Like Jupiter
- Tiny Plankton Could Steer Giant Hurricanes
- Great Digs: Finalists Vie to Live in Museum for a Month
Posted: 29 Sep 2010 03:25 PM PDT
Monkeys may possess cognitive abilities once thought unique to humans, raising questions about the nature of animal awareness and our ability to measure it.
In the lab of University of Wisconsin neuroscientist Luis Populin, five rhesus macaques seem to recognize their own reflections in a mirror. Monkeys weren't supposed to do this.
"We thought these subjects didn't have this ability. The indications are that if you fail the mark test, you're not self-aware. This opens up a whole field of possibilities," Populin said.
Populin doesn't usually study monkey self-awareness. The macaques described in this study, published Sept. 29 in Public Library of Science One, were originally part of his work on attention deficit disorder. But during that experiment, study co-author Abigail Rajala noticed the monkeys using mirrors to study themselves.
So-called mirror self-recognition is thought to indicate self-awareness, which is required to understand selfhood in others, and ultimately to be empathic. Researchers measure this with the "mark test." They paint or ink a mark on unconscious animals, then see if they use mirrors to discover the marks.
It was once thought that only humans could pass the mark test. Then chimpanzees did, followed by dolphins and elephants. These successes challenged the notions that humans were alone on one side of a cognitive divide. Many researchers think the notion of a divide is itself mistaken. Instead, they propose a gradual spectrum of cognitive powers, a spectrum crudely measured by mirrors.
Indeed, macaques — including those in Populin's study — have repeatedly failed the mark test. But after Rajala called attention to their strange behaviors, the researchers paid closer attention. The highly social monkeys only rarely tried to interact with the reflections. They used mirrors to study otherwise-hidden parts of their bodies, such as their genitals and the implants in their heads. Mark tests not withstanding, they seemed quite self-aware.
"I think that these findings show that self-awareness is not an all-or-nothing phenomenon," said Lori Marino, an Emory University evolutionary neurobiologist who was not involved in the study. "There may be much more of a continuum in self-awareness than we thought before,"
According to Emory University primatologist Frans de Waal, the new findings fit with his work on capuchin monkeys who don't quite recognize themselves in mirrors, but don't treat the reflections as belonging to strangers. "As a result, we proposed a gradual scale of self awareness. The piece of intriguing information presented here may support this view," he said.
However, de Waal cautioned that "many scientists would want more tests and more controls" — a warning especially salient in light of a high-profile controversy involving Marc Hauser, a Harvard University evolutionary biologist who appears to have overstated the cognitive powers of his own monkeys.
"What you're seeing in the videos is subject to all kinds of interpretations," said Gordon Gallup, a State University of New York at Albany psychologist who invented the mirror test, and has administered it with negative results to rhesus monkeys. "I don't think these findings in any way demonstrate that rhesus monkeys are capable of recognizing themselves in mirrors."
Populin said his monkeys may have developed an unusual familiarity with mirrors, which are given to them as toys during infancy. The presence of saltshaker-sized implants screwed into their skulls may also have captured their interest more readily than an inked mark.
Marino, who helped demonstrate self-recognition in bottlenose dolphins, disagreed with Gallup. "The videos are absolutely convincing," she said. "I have been trying to find an alternative explanation for the results – and haven't come up with one yet."
Marino said the findings fit with other research on monkey cognition, including a since-replicated Journal of Experimental Psychology study in which macaques displayed unexpectedly sophisticated math skills and passed other, non-mirror-based tests of self-awareness.
"There are many ways to look at animals. Mirror tests are not the end-all and be-all," said Diana Reiss, a mammal cognition specialist at the City University of New York.
If research continues to find that monkeys possess higher-than-expected awareness, it could influence how researchers and the public think about biomedical research on monkeys. Macaques were critical in the development of a polio vaccine during the 20th century and, more recently, the refinement of embryonic stem cell techniques.
"I would absolutely hope that we do not stop using them now. Their contributions have been immense," said Populin, who studies how ritalin affects the brain's prefrontal cortex.
"There are decisions I would make with a monkey, that I would not feel comfortable making with a chimpanzee," said University of Wisconsin psychologist Chris Coe, who was not involved in the study. "Some of the other cognitive abilities that monkeys would have to show, I don't believe they do. I don't believe they sit and ponder their fate, or reflect on the past, or fret about the future, because they are able to see themselves in a mirror," he said.
"We don't know whether they have a sense of past or future," said Marino, who called Coe's research distinction an ethical non-sequitur. "Whether an animal has a sense of the past or future is irrelevant to the issue of whether they can suffer in the present."
Even if Coe accepts human-benefiting research involving contagious diseases or invasive procedures in monkeys that he wouldn't in chimps, however, he said the findings underscore the importance of improving research animal conditions. The macaques' unexpected self-awareness certainly influences the equations by which society must continually balance the harms and benefits of research.
"A study such as this one, that pushes our own awareness of what monkeys can and can't do, challenges us," Coe said. "I'm not going to argue that having animals live in small cages is so wonderful. One has to reflect on that."
A more accurate understanding of animal awareness may ultimately require better tools. Many researchers are skeptical of the mirror test, which Marino said "is shaped more by the cognitive limitations of human researchers than anything else."
Wrote Marino in an e-mail, "Other animals may be more deeply contemplative than humans – we just don't know. That's really the bottom line. Any scientist who tells you they know that other animals don't think as richly or as complexly as humans — is, well, not being scientific."
Image & Videos: 1) Rhesus macaques. Paul Asman and Jill Lenoble, Flickr. 2) Rhesus macaque using a mirror to inspect parts of himself that cannot typically be seen./University of Wisconsin. 3) Rhesus macaque using a mirror to study the implant in his head./University of Wisconsin.
Note: From the study: "All efforts were made to ameliorate suffering of the animals. Specifically, all procedures were approved by the University of Wisconsin Animal Care Committee and were in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals."
Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on an ecological tipping point project.
Posted: 29 Sep 2010 02:16 PM PDT
After years of saying habitable exoplanets are just around the corner, planet hunters have finally found one. Gliese 581g is the first planet found to lie squarely in its star's habitable zone, where the conditions are right for liquid water.
"The threshold has now been crossed," said astronomer R. Paul Butler of the Carnegie Institution of Washington, one of the planet's discoverers, in a press briefing Sept. 29. "The data says this planet is at the right distance for liquid water, and the right mass to hold on to a substantial atmosphere."
The discovery is both "incremental and monumental," comments exoplanet expert Sara Seager of MIT, who was not involved in the new study. When a recent study predicted the first habitable world should show up by next May, Seager rightly said the real answer was more like "any day now."
"We've found smaller and smaller planets that got closer and closer to the habitable zone," she said. "But this is the first that's in the habitable zone."
The new planet is one of six orbiting the star Gliese 581, a red dwarf 20 light-years from Earth. Two of the planet's siblings, dubbed planets C and D, have also been hailed as potentially habitable worlds. The two planets straddle the region around the star where liquid water could exist — 581c is too hot, and 581d is too cold. But 581g is just right. The discovery will be published in the Astrophysical Journal and online at arxiv.org.
The new planet is about three times the mass of Earth, which indicates it is probably rocky and has enough surface gravity to sustain a stable atmosphere. It orbits its star once every 36.6 Earth days at a distance of just 13 million miles.
The surface of a planet that close to our sun would be scorching hot. But because the star Gliese 581 is only about 1 percent as bright as the sun, temperatures on the new planet should be much more comfortable. Taking into account the presence of an atmosphere and how much starlight the planet probably reflects, astronomers calculated the average temperature ranges from minus 24 degrees to 10 degrees above zero Fahrenheit.
But the actual temperature range is even wider, says astronomer Steven Vogt of the University of California, Santa Cruz, who designed some of the instruments that helped find the planet. Gravity dictates that such a close-in planet would keep the same side facing the star at all times, the same way the moon always shows the same face to Earth.
That means the planet has a blazing-hot daytime side, a frigid nighttime side, and a band of eternal sunrise or sunset where water — and perhaps life — could subsist comfortably. Any life on this exotic world would be confined to this perpetual twilight zone, Vogt says, but there's room for a lot of diversity.
"You can get any temperature you want on this planet, you just have to move around on its surface," Vogt said. "There's a great range of eco-longitudes that will create a lot of different niches for different kinds of life to evolve stably."
Another advantage for potential life on Gliese 581g is that its star is "effectively immortal," Butler said. "Our sun will go 10 billion years before it goes nova, and life here ceases to exist. But M dwarfs live for tens, hundreds of billions of years, many times the current age of the universe. So life has a long time to get a toehold."
The discovery is based on 11 years of observations using the HIRES spectrometer at the Keck Telescope in Hawaii, combined with data from the HARPS (High-Accuracy Radial-velocity Planet Searcher) instrument at the European Southern Observatory in La Silla, Chile.
Both instruments looks for the small wobbles stars make as their planets' gravity tugs them back and forth. The HIRES project started looking for planets 25 years ago, back "when looking for planets made you look like a nut," Butler said. At first the instruments could detect changes in a star's velocity that were 300 meters per second or larger. That's why the first extrasolar planets discovered were almost exclusively hot Jupiters: These monstrous planets that sit roastingly close to their stars will exert a bigger gravitational pull.
Since then, techniques have improved so that changes as small as 3 meters per second can be seen. That wouldn't be enough to see Earth from 20 light-years away, Butler says. Because red dwarfs are so small and their habitable zones so close, though, Earth-sized planets have enough gravitational oomph to make a difference.
"The excitement here is that by looking at stars that are small it's much easier to find small planets," said exoplanet expert David Charbonneau of Harvard, who is hunting for small planets that cross in front of dwarf stars. "I think it's great news for those of us looking for this kind of thing around this kind of star."
But finding them takes a long time. In all, 238 measurements of the star's wobbles, went into the discovery, and each measurement took a full night of observing.
For Butler and Vogt, though, 11 years wasn't so long to wait. He's actually surprised that a potentially habitable planet showed up so quickly and so nearby.
"The fact that we found one so close and so early on in the search suggests there's a lot of these things," Butler says. Only about 100 other stars are as close to Earth as Gliese 581, and only 9 of them have been closely examined for planets. Odds are good that 10 to 20 percent of stars in the Milky Way have habitable planets, Vogt says.
Finding them won't take a huge advance in technology, he adds. It will just take more telescope time.
"I have suggested that we build a dedicated automated planet finder to do this kind of work 365 nights a year," he said. "If we had something equivalent to Keck that we could use every night, these things would be pouring out of the sky."
Image: 1) Lynette Cook. 2) The planetary orbits of the Gliese 581 system compared to those of our own solar system. Zina Deretsky/National Science Foundation.
Posted: 29 Sep 2010 11:47 AM PDT
There may be many more "extinct" mammals waiting to be rediscovered than conservation biologists previously thought.
Categorizing a mammal species as extinct has rested upon two criteria: It has not been seen for more than 50 years, or an exhaustive search has come up empty. But "extinct" species occasionally turn up again, and some species have disappeared more than once. Australia's desert rat kangaroo, for example, was rediscovered in 1931 after having gone missing for almost a century, only to disappear again in 1935 when invasive red foxes moved into the area of the remaining survivors.
In order to determine how often extinct species had been rediscovered, University of Queensland scientists Diana Fisher and Simon Blomberg created a dataset of 187 mammal species that have been reported extinct, extinct in the wild, or probably extinct since 1500, as well as those which have been rediscovered. They also looked at historical data on the threats that caused species to become extinct — or brought them close to it — including habitat loss, introduced species and overkill by humans.
It turns out that rumors of the extinction of more than a third of these species have turned out to be premature, the scientists report in Proceedings of the Royal Society B Sept. 29. At least 67 species — a little more than a third of those presumed to be extinct — were later found again. And in most cases, these were animals that had been hardest hit by habitat loss.
Humans and invasive species have been significantly more efficient killers. It's rare that a species reported extinct due to one of these causes has been seen again.
"If you think that a missing species is extinct and the main cause of decline was introduced predators such as feral foxes, cats or rats, then you are very likely to be right," Fisher said. But, she added, "If the main cause of decline was habitat loss, you are quite likely to be wrong if you say that it's extinct, unless it was restricted to a very small area."
As an example, Fisher cites the Malabar civet, which was thought to be extinct due to habitat loss in 1929 but survived in marginal areas at least until 1987 when it was last seen on a cashew plantation. Unfortunately, that animal was killed by villagers, and no more have been seen since.
The team found species that were relatively sparsely distributed over a larger range were more likely to turn up again. But mammals of any particular evolutionary group or body size weren't more likely to be rediscovered.
"I was a little bit surprised that body size was not important," Fisher said. "I thought that small species might not be found so often, because they don't attract much attention, but that wasn't the case."
With these findings in hand, conservation biologists may be better able to target species that are more likely to still be out there somewhere. While species hunted into extinction — such as the Stellar's sea cow — are almost certainly gone forever, individuals of other species may still exist. Whether we find them again or not seems to be directly influenced by how hard we look.
According to Fisher and Blomberg, one or two searches for a missing species aren't likely to succeed, but missing species that were the subject of three to six searches have often been rediscovered. Chances do not continue to get better past this point, though. Species that have been the subject of more than 11 searches, such as the Tasmanian tiger and the Yangtze dolphin, have not been found.
We may hope for the rediscovery of such charismatic species, but the chances of finding some of the lesser-known species that haven't been looked for yet are significantly better. Among the good candidates for rediscovery Fisher lists are the Montane monkey-faced bat of the Solomon Islands, last seen on Guadalcanal in 1990, and Alcom's pocket gopher, which was abundant in a high-elevation forest in Mexico in the late 1990's but hasn't been seen since.
"We should be trying to protect the habitat of recently extinct species," Fisher said. "But this is not easy, because we don't know where they might be rediscovered. It is not necessarily near where the species was last seen."
Gilbert's potoroo, for example, disappeared sometime around 1879 but was rediscovered in 1994 at Two People's Bay in Australia in a reserve that had been set up to protect an endangered bird. Because many rediscovered species had populations that were spread over a wide area, ecologists have a lot of ground to cover in their search for "extinct" mammals.
Images: 1) Desert rat kangaroo. John Gould/Wikimedia Commons. 2) Tasmanian tiger. Smithsonian Institution/Wikimedia Commons. 3) Gilbert's potoroo. John Gould/Wikimedia Commons.
Posted: 29 Sep 2010 10:40 AM PDT
About 350 million years ago, evolution took one small step for fish, and a giant leap for every terrestrial animal since. According to a new study, it was all made possible by plants.
Prehistoric oxygen levels extrapolated from ancient mineral sediments suggest aquatic life went into overdrive after plants boosted atmospheric oxygen levels. Oceans became so fiercely competitive that some fish sought safe haven outside them.
Some scientists have proposed as much, but the new research, published Sept. 28 in the Proceedings of the National Academy of Sciences, provides the first solid evidence.
"Before this paper, there was essentially no experimental evidence for how oxygen accumulated through animal history. It was only predicted by theory," said Tais Dahl, an evolutionary biologist at the University of Southern Denmark's Nordic Center for Earth Evolution.
Dahl and study co-author Donald Canfield analyzed prehistoric seafloor samples gathered from around the world and dating to between 1.7 billion to 400 million years past. They were especially interested in molybdenum, a mineral widespread in Earth's soil and carried off by erosion. At sea, the particles circulate for about one million years before coming to sedimentary rest.
As they circulate, the particles' atomic configurations are subtly changed by concentrations of atmospheric and aquatic oxygen, making their stratified deposits a record of Earth's oxygen composition. According to Dahl, it's a far more detailed record than can be read in carbon, the traditional source of oxygen extrapolation.
"As you walk back in time, the uncertainty of those models becomes larger and larger," he said. "If you're off by a little bit at a given time, you end up being completely off." Indeterminate carbon records have given rise to two competing interpretations of Earth's prehistoric oxygen levels, and thus the evolution of its life.
Each accepts that planetary oxygen levels first spiked about 550 million years ago, coincident with the first mobile, symmetrical life forms — a benchmark in animal complexity, set until then by sponges. But after that, the interpretations diverge.
The first, traditional view holds that planetary oxygen levels continued to rise steadily, reaching near-contemporary levels well before Earth's life diversified again, some 400 million years ago. In this narrative, it was only a matter of time — another 50 million years, give or take — before a few lagoon-dwelling creatures ventured onto land. Terrestrial life was a clockwork eventuality. Plants provided more oxygen, but weren't essential.
According to the other interpretation, oxygen levels stayed steady from 550 million to 400 million years ago, when the forerunners of modern plants evolved and flourished. Only then did oxygen jump, allowing fish — until then a small, relatively insignificant part of the animal kingdom — to take large, highly predatory forms.
This is the interpretation supported by Dahl and Canfield's molybdenum patterns. Plants, which release oxygen both while they live and as they decompose, are the key.
"The low oxygen level early in animal history limited evolution for fish. After this second oxygenation event, we begin to see large, predatory fish up to 30 feet long," said Dahl. "When land animals walked out of water in the first place, it was to escape predation. It's oxygen that drove the evolution of large predators in the ocean. It's plants that caused oxygen to rise. In principle, you could connect this all."
Images: 1) Dunkleosteus, a 30-foot-long fish with some of history's most powerful jaws, lived just before the first land animals./University of Texas, Arlington. 2) Tiktaalik, considered to be a bridge between aquatic and terrestrial vertebrates./Zina Deretsky, National Science Foundation. 3) A leaf from a gingko tree, remarkably little-changed in 350 million years./Flickr, Geishaboy500.
Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on an ecological tipping point project.
Posted: 29 Sep 2010 10:21 AM PDT
A desktop black hole created in a lab in Italy has been shown to emit light, a discovery that could seal one of the biggest holes in theoretical physics and pave the way for physicist Stephen Hawking to win a Nobel Prize.
The eerie glow is called Hawking radiation, and physicists have been hunting it for decades. Hawking calculated in 1974 that, rather than gobbling up everything in their path and giving nothing back, black holes can radiate like the heating element in a toaster.
But astrophysical black holes, the ultradense gobs of mass that lurk at the centers of galaxies and are left behind when stars collapse, radiate too dimly to be seen. So instead of looking at real black holes, a group of physicists led by laser physicist Daniele Faccio of Heriot-Watt University in Scotland, created a miniature analog by shooting short pulses of intense laser light into a chip of glass. The results will appear in Physical Review Letters.
"This is an extremely important paper," said physicist Ulf Leonhardt of the University of St Andrews in Scotland, who built an artificial black hole in a phone line in 2008. "The experiment confirms that Hawking radiation can exist in principle."
The basic idea behind Hawking radiation is that the quantum vacuum is not actually empty. Instead, it is a roiling mess of virtual particles and anti-particles that constantly pop into existence and eliminate each other when they meet. If one member of the particle–anti-particle pair is created on the wrong side of an event horizon — the edge of a black hole beyond which not even light can escape — the particles can never meet to destroy each other. An observer outside the black hole would see a perpetual stream of real particles.
But until now, no one had seen any evidence of these particles. Radiation from a black hole the mass of our sun would be 10 million times colder than the cosmic microwave background radiation, the ambient temperature of the universe left over from the Big Bang, which itself is only a few degrees warmer than absolute zero. Larger black holes would be colder still.
Luckily, conceptual counterparts to black holes and their event horizons are not hard to come by. Two physicists in the 1980s independently suggested this thought experiment: Picture a black hole as a river that flows faster and faster as it approaches a waterfall. Fleet-finned fish headed upstream can escape the falls, but at a certain point the water flows faster than the fish can swim. Any hapless fish caught behind that point are doomed to flop backwards over the falls. Replacing fish with light and the river with gravity yields a good simulation of a black hole.
Replace the fish with any other wave and the river with any fluid moving faster than that wave, and the likeness goes deeper. Physicists have found that the math describing light moving in the warped space-time geometry around a black hole is exactly the same as the math describing waves flowing through moving fluids. The analogy works for white holes, theoretical objects where nothing can get in rather than out, as well. And mathematically, Hawking radiation doesn't need gravity or curved space-time at all. It just needs an event horizon.
In the new study, Faccio and colleagues created an event horizon with two quick pulses of laser light inside a piece of glass.
"Your piece of glass, which is equivalent to the river, you can't think of making this travel at velocities that are faster than the speed of light," Faccio said. "But you can create a perturbation inside it."
Light always moves through a vacuum at the same speed, but it gets slowed down by a factor called the refractive index in a medium like water or glass. A pulse of laser light traveling through the glass can change the refractive index, slowing light down even further.
The physicists sent two pulses of infrared laser light into a small rod of silica glass. The first pulse warped the glass, and the second pulse bumped up against this warp, eventually slowing to a standstill. This is exactly what happens to light trying to enter a white hole, Leonhardt says.
A light detector perpendicular to the laser beam picked up one extra photon for every 100 laser pulses on average, Faccio said. The light was extremely dim, invisible to human eyes, but it was there.
"It was pretty amazing," Faccio said. "My first reaction was, it has to be something else, it can't be so easy."
To make sure the photons weren't coming from somewhere else — particularly the fluorescent glow of the glass itself — Faccio and colleagues changed the velocity at which the warp moved through the glass. Theory predicted that changing the warp velocity should alter the wavelength, and therefore the color, of the extra photons.
"We changed the velocity and saw that the color was changing, and then we changed it again and saw it was still changing, and the original colors disappeared and it had shifted to this new wavelength," Faccio said. "There's no other physical mechanism out there that can give the same effect. Hawking radiation is the only physical model known which can give rise to something like this."
Understanding Hawking radiation could help physicists toward a unified theory of physics that works on the scales of stars and galaxies, which are described by Einstein's general relativity, and on the scales of electrons and quarks, described by quantum mechanics.
"These laboratory analogs are important, because they literally shed light on a mysterious phenomenon that seems to connect three areas of physics: gravity, quantum physics and thermodynamics," Leonhardt said. "They show first of all that Hawking radiation is not a mere theoretical dream, but something real."
"While this measurement can't actually tell you anything about quantum gravity," Faccio said, "it does tell you that some of the simple approaches in this direction do work, and they do give you correct predictions. This means that if you develop a quantum theory of gravity, you have something to test this theory on."
There are a few problems with this particular model black hole, Faccio points out. The biggest is that physicists can see only one photon of the pair supposedly created at the event horizon. That means there's no way to tell whether the two photons are quantum-entangled, a key feature of Hawking radiation. Leonhardt and his colleagues are working on making a radiating black hole in an optical fiber that would show whether or not the photons are entangled.
Physicist Dentcho Genov of Louisiana Tech University, who also makes lab-bench–scale black holes using a class of materials called metamaterials, points out that this is only an indirect proof of Hawking radiation. A direct proof would have to come from observing a tiny black hole radiating away in space.
"To have a direct proof is very difficult. I don't know if in my lifetime or in my kids' or grandkids' lifetime that's going to happen," Genov said. "The actual full-scale experimental validation of Hawking radiation is still far away in the future. But this one I think is sufficient."
Correction: The original version of this story said the team of physicists was led by Franco Belgiorno of the University of Milan. Belgiorno is the first author of the paper, but the lab leader was Daniele Faccio.
Image: 1) Artist's conception of the black hole at the center of the Milky Way. Gallery of Space Time Travel. 2) Laser setup at Faccio's lab. Reproduced courtesy of Daniele Faccio.
Posted: 28 Sep 2010 01:18 PM PDT
The Earth's shadow painted what looks like a silhouette of Jupiter on top of the sun in a new image from NASA's Solar Dynamics Observatory.
"Now we know what it would look like if Jupiter and the sun had a child," joked engineer Ralph Seguin of the Lockheed-Martin Solar and Astrophysics Lab in a writeup on spaceweather.com.
SDO sits in a geosynchronous orbit directly above a research station near La Cruces, New Mexico, and transmits data on our local star non-stop to two large dishes on the ground. Usually, this position gives SDO a stellar view (so to speak). But near the spring and autumn equinoxes, Earth gets in the way. Once a day for about an hour, the spacecraft, Earth and the sun line up perfectly, and SDO is briefly blind.
The "Sunpiter" image is a composite of images through multiple color filters and a black-and-white magnetogram taken just as the sun was emerging from blackout. Magnetograms, visual representations of the sun's magnetic field, are compiled from a series of images spread out in time. The Jupiter-esque ribbons of color come from Earth's shadow moving across the sun.
"Errors can be beautiful sometimes," @NASA_SDO tweeted earlier today.
Eclipse season doesn't end until October 6, so we may have a full week of bizarre sun photos to look forward to.
UPDATE: Ralph Seguin wrote in to point out that the image is not the result of a spacecraft or processing error; it's more like a side effect of the spacecraft acting normally.
Posted: 28 Sep 2010 11:59 AM PDT
By Duncan Geere, Wired UK
Microscopic plants less than half a centimeter across may be able to change the paths of 300-mile-wide tropical storms, due to their ability to change the color of the surface of the sea.
Phytoplankton is as common in the oceans as grass is on land, and blooms when cold, nutrient-rich water upwells from the depths. That bloom turns the ocean surface from a deep dark blue to a murky turquoise, henceforth known as murkquoise.
The murkquoise stops the sun from penetrating as far as it normally does into the surface of the sea, making the surface layer much warmer, and the depths cooler. As a result, hurricanes tend to be stronger and last longer.
While these results haven't been isolated in the real world, and there are plenty of other factors affecting hurricane formation too, results from numerical models suggest that reducing the amount of phytoplankton could also keep hurricanes weaker and confine them to equatorial latitudes.
At the Geophysical Fluid Dynamics Laboratory at the U.S. National Oceanic and Atmospheric Administration, researchers simulated a large-scale "phytocide" in the Pacific Ocean and observed the effects on the sea surface and atmosphere. The results were clear — a 15 percent drop in the number of hurricanes that formed each year.
Those that did form didn't track as far north, either. Instead, they wobbled along the equator before fizzling out. Hurricane activity in the subtropical north-west of the Pacific dropped a whopping 70 percent.
But why? Well, removing the murkquoise and allowing the sun deeper into the ocean cools the surface. That in turn cools the air above the surface of the sea, allowing more cool dry air to descend from above. When the hurricane moves into this large-scale cool, dry, air-descending area, its moist, warm upwelling air is countered by it, and so it weakens.
The sinking air is also carried along the surface to the equator, where it rises again, strengthening the already-powerful western winds in the upper atmosphere in the tropics. These winds, if strong enough, can behead storm systems that are beginning to organize into a hurricane by literally blowing them away.
But before you dig out the industrial-strength herbicide to dump into the ocean and reduce the risk of hurricanes, it might be wise to consider the implications. Killing off phytoplankton would be like removing all grass from land. Grazing herbivores would be deprived of their food source and die, depriving carnivores of their food source too.
Before too long, the oceans would be barren and sterile. Probably too great a price to pay for a slightly lowered risk of hurricanes.
Source Link: Wired.co.uk
Posted: 28 Sep 2010 08:45 AM PDT
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