Posts Tagged ‘science’

What do plants and humans have in common? Actually, more than most people realize.

Plants possess a number of amazing properties and they can “behave” similar to us.

Plants are very much alive. Not only do they dislike human noise but they also posses the capacity to learn and communicate. Perhaps even more astonishing is that plants can also make music and they can sing.

Plants can also sense danger and know exactly how to avoid predators.

In recent years, scientists have uncovered surprising biological connections between humans and other forms of life.Researchers have revealed that plant and human biology is much closer than has ever been understood and the study of these similarities could uncover the biological basis of diseases like cancer as well as other “animal” behaviors.

Not long ago, a group of researchers discovered that although plants are deaf they can feel, see, smell and remember

Now, according to a recent study plants can also be altruistic!

The researchers looked at corn, in which each fertilized seed contained two “siblings” — an embryo and a corresponding bit of tissue known as endosperm that feeds the embryo as the seed grows, said CU-Boulder Professor Pamela Diggle. They compared the growth and behavior of the embryos and endosperm in seeds sharing the same mother and father with the growth and behavior of embryos and endosperm that had genetically different parents.

Plants and humans can behave in a similar way!
“The results indicated embryos with the same mother and father as the endosperm in their seed weighed significantly more than embryos with the same mother but a different father,” said Diggle, a faculty member in CU-Boulder’s ecology and evolutionary biology department. “We found that endosperm that does not share the same father as the embryo does not hand over as much food — it appears to be acting less cooperatively.”

“One of the most fundamental laws of nature is that if you are going to be an altruist, give it up to your closest relatives,” said Friedman.

“Altruism only evolves if the benefactor is a close relative of the beneficiary. When the endosperm gives all of its food to the embryo and then dies, it doesn’t get more altruistic than that.”

In corn reproduction, male flowers at the top of the plants distribute pollen grains two at a time through individual tubes to tiny cobs on the stalks covered by strands known as silks in a process known as double fertilization. When the two pollen grains come in contact with an individual silk, they produce a seed containing an embryo and endosperm. Each embryo results in just a single kernel of corn, said Diggle.

Studies show plants can be altruisti.
The team took advantage of an extremely rare phenomenon in plants called “hetero-fertilization,” in which two different fathers sire individual corn kernels, said Diggle, currently a visiting professor at Harvard. The manipulation of corn plant genes that has been going on for millennia — resulting in the production of multicolored “Indian corn” cobs of various colors like red, purple, blue and yellow — helped the researchers in assessing the parentage of the kernels, she said.

Wu, who cultivated the corn and harvested more than 100 ears over a three-year period, removed, mapped and weighed every individual kernel out of each cob from the harvests. While the majority of kernels had an endosperm and embryo of the same color — an indication they shared the same mother and father — some had different colors for each, such as a purple outer kernel with yellow embryo.

Wu was searching for such rare kernels — far less than one in 100 — that had two different fathers as a way to assess cooperation between the embryo and endosperm.

“It was very challenging and time-consuming research,” said Friedman. “It was like looking for a needle in a haystack, or in this case, a kernel in a silo.”

Endosperm — in the form of corn, rice, wheat and other crops — is critical to humans, providing about 70 percent of calories we consume annually worldwide.

“The tissue in the seeds of flowering plants is what feeds the world,” said Friedman, who also directs the Arnold Arboretum at Harvard.

“If flowering plants weren’t here, humans wouldn’t be here.”

© MessageToEagle.com

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Amazing Phenomenon Of Singing Plants

Posted: December 30, 2012 by phaedrap1 in Science, Spirituality
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Plants are very much alive. Not only do they dislike human noise but they also posses the capacity to learn and communicate.

Perhaps even more astonishing is that plants can also make music.

Have you ever heard the incredible music of the plants? No? Are you waiting for an invitation? Find some cheap airline tickets, hop on a plane and fly down to hear the wonderful sounds these plants can make.

Plants can actually sing and compose music and listening to it is truly beautiful and relaxing!

Ever since 1975, researchers at Damanhur, in northern Italy have been experimenting with plants, trying to lean more about their unique properties.

Researchers use devices which they have created to measure the re-activity of the plants to their environment. The devices judge the plants’ capacity to learn and communicate.

Using a simple principle, the researchers used a variation of the Wheatstone bridge, an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component.

Music of the plants is beautiful and relaxing.

This device has 3 fixed resistances and 1 variable one. Electrical differences between the leaves and the roots of the plant are measured. These differences can then be translated into a variety of effects, including music, turning on lights, movement and many others.

There is no danger to the plants as the researchers use very low intensity electrical currents.

Researchers state that every living creature whether animal or plant, produces variations of electrical potential, depending on the emotions being experienced at the time.

The music starts at around 2:11. Credit: www.damanhur.org

 

The plant send impulses to the midi-instruments.
The midi-signal goes to a midi-thru-box and from there to the software

The device that takes the measurements is a tool from damanhur called U1.

 

The plants have the most sensitive variations when they signal the arrival of the person who cares for them, when being watered, when spoken to, during the creation of music, etc.Sensations felt within the plant induce a physiological reaction, which then expresses itself in electrical, conductive and resistance variations.

These variations can be translated in different ways, including into musical scales.

The experiments have shown that plants definitely appear to enjoy learning to use musical scales and also making their own music with the use of a synthesizer.

 

Although there is currently little scientific research conducted on this subject, one cannot deny that listen to these beautiful plants is a joy for the soul.

Messagetoeagle.com

ScienceDaily (Nov. 28, 2012) — Archaeologists from the University of Rhode Island, the Israel Antiquities Authority, and the University of Louisville have discovered the remains of a fleet of early-19th century ships and ancient harbor structures from the Hellenistic period (third to first century B.C.) at the city of Akko, one of the major ancient ports of the eastern Mediterranean. The findings shed light on a period of history that is little known and point to how and where additional remains may be found.

The discoveries were presented on November 15 and 17 in Chicago at the annual meeting of the American Schools of Oriental Research by URI assistant professors Bridget Buxton and William Krieger on behalf of the Israel Coast Exploration project.

According to Buxton, three of the four well-preserved shipwrecks found off the coast south of Akko were first detected using a sub-bottom profiler in 2011. Later, storms stripped off several meters of inshore sediments and temporarily revealed the wrecks, as well as an additional large vessel. The wrecks are now reburied.

During the brief time the shipwrecks were exposed, the Israel Antiquities Authority investigated one of them: a 32 meter vessel which still preserved its brass gudgeon (rudder socket) and many small artifacts, such as plates, a candlestick, and even a cooking pot with bones in it. Laboratory analyses completed this summer by the IAA revealed that the ship’s wood came from Turkey. The team believes these ships may have belonged to the Egyptian navy under Admiral Osman Nurredin Bey, whose ships were severely damaged in his attempt to capture Akko in the Egyptian-Ottoman War of 1831. The town eventually fell to Egyptian land forces under Ibrahim Pasha in 1832.

“These ships have occasionally been exposed and buried again by storms since we found them,” Buxton said. “We’re in a race against time to find other ships in the area and learn from them before storms totally dislodge or destroy them.”

Although shipwrecks from the 1800s are not the highest priorities in a region where civilization goes back thousands of years, Buxton is excited by the discovery for what it tells her about where much older ships may be found.

“Like many underwater archaeologists I’m very interested in finding a well-preserved example of an ancient multi-decked warship from the Hellenistic age,” said Buxton. “These ships were incredible pieces of technology, but we don’t know much about their design because no hulls have been found. However, a combination of unusual environmental and historical factors leads us to believe we have a chance of finding the remains of one of these ships off the northern coast of Israel.”

Buxton believes that the ships they are looking for are likely buried in the coastal sediment, which has built up over the centuries through natural processes. However, time is not on their side. “That protective silt is now being stripped away,” she said. “And it’s being stripped away a lot faster than it was originally dumped, by a combination of development, environmental changes, and the effects of the Aswan Dam.” The Nile River has historically deposited large quantities of silt in the area, but the dam has significantly reduced the flow of silt.

The archaeologists found the ships and another early modern vessel within Akko’s modern harbor while testing their equipment in preparation for an ongoing survey out in deeper water. The sub-bottom profiler detects anomalies below the sea floor. “It’s the gift that keeps on giving,” Buxton said. “We found so many targets to explore that we didn’t have time to check all of them, but even just having information about where things are helps Koby (Jacob Sharvit, director of the IAA Maritime Antiquities Unit) know where to look after any big storms.”

One line of buried targets detected off the southern seawall of old Akko is particularly suggestive. Continuing excavations in this area over the summer revealed an alignment between these targets and a newly-discovered slipway and shipshed structure, which continued out under the sea floor 25 meters from the Ottoman city wall. The feature resembles other naval shipsheds found in places such as Athens where they were used to haul up ancient warships. The excavation project was initially undertaken to strengthen the eroding sea wall, but it also revealed Hellenistic masonry, pottery vessels, an ancient mooring stone, and a stone quay 1.3 meters below the modern sea level. The possibility that much more of the Hellenistic port lies well-preserved under the sea floor is exciting for the archaeologists, because it means that shipwrecks from earlier centuries that have so far not been found at Akko may simply be buried deeper down in the sediment.

“We’ve got fragmentary historic records for this area in the Hellenistic period, and now we’ve found a very important feature from the ancient harbor. Ancient shipwrecks are another piece of the puzzle that will help us to rewrite the story of this region at a critical time in Mediterranean history,” she said.

Located on the northern coast of Israel, the UNESCO World Heritage Site of Akko is one of the few cities in the Mediterranean with more than 5,000 years of maritime history. Also known as Acre, Ake and Ptolemais, its port was an important waypoint for the Phoenicians, Romans, Crusaders, Ottomans and other ancient maritime empires. In the Hellenistic period, it was bitterly fought over by the rival empires of Egypt and Syria.

“Understanding the history and archaeology of Akko’s port is crucial to understanding the broader issues of maritime connectivity and the great power struggles that defined the history of the Eastern Mediterranean during the Hellenistic Age,” Buxton said.

Black Hole Blast Biggest Ever Recorded

Posted: November 29, 2012 by phaedrap1 in News, Science
Tags: ,
Explosion is at least five times more powerful than previously observed events.

An illustration of a powerful burst of material ejected from a quasar.

Material is ejected near a supermassive black hole in the quasar SDSS J1106+1939 in an illustration.

Illustration courtesy L. Calçada, ESO

Andrew Fazekas

for National Geographic News

Published November 28, 2012

Astronomers have witnessed a record-breaking blast of gas and dust flowing out of a monster black hole more than 11.5 billion light-years away.

The supermassive gravity well, with a mass of one to three billion suns, lurks at the core of a quasar—a class of extremely bright and energetic galaxies—dubbed SDSS J1106 1939. (See “Black Hole Blasts Superheated Early Universe.”)

“We discovered the most energetic quasar outflow ever seen, at least five times more powerful than any that have been observed to date,” said Nahum Arav, an astronomer at Virginia Tech and co-author of the study to be published in The Astrophysical Journal.

Using the powerful telescopes of the European Southern Observatory in Chile, Arav and his team were able to clock the speed and other properties of the outflow.

Belching out material as much as 400 times the weight of our sun every year, the blast is located nearly a thousand light-years from the quasar and has a velocity of roughly 18 million miles (29 million kilometers) per hour.

“We were hoping to see something like this, but the sheer power of this outflow still took us by surprise,” said Arav.

The central black hole in this quasar is true giant dynamo. It’s estimated to be upward of a thousand times more massive than the one in the Milky Way, producing energy at rates about a hundred times higher than the total power output of our galaxy. (See black hole pictures.)

Clues to Galaxy Evolution

Supermassive black holes are large enough to swallow our entire solar system and are notorious for ripping apart and swallowing stars. But they also power distant quasars and spew out material at high speeds.

(See “Monster Black Holes Gobble Binary Stars to Grow?”)

The outflows have been suspected to play a key role in the evolution of galaxies, explained Arav, but questions have persisted for years in the astronomical community as to whether they were powerful enough.

This newly discovered super outflow could solve major cosmic mysteries, including how the mass of a galaxy is linked to its central black hole mass and why there is a relative scarcity of large galaxies across the universe.

“I believe this is the smoking gun for several theoretical ideas that use the mechanical energy output of quasars to solve several important problems in the formation of galaxies and cluster of galaxies,” said Arav.

While Kirk Korista, an astronomer not connected to the study, believes these claims may be a bit premature, the research is expected to shed new light on the most powerful and least understood portions of typical quasar outflows.

“The superb spectroscopic data of this quasar have allowed for a breakthrough in quantifying the energetics of what is probably a typical quasar outflow,” said Korista, an astronomy professor at Western Michigan University.

“This definitely is an important step in piecing together the story of galaxy evolution, and in elucidating the role of quasars in that story.”

Animals Are Moral Creatures, Scientist Argues

Posted: November 17, 2012 by phaedrap1 in News, Science
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Animal behavior research suggests that animals have moral emotions. One study found that rhesus monkeys will forgo food if they had to push a lever that would electrically shock their companions to get it.
CREDIT: jinterwas | Flickr.com

Does Mr. Whiskers really love you or is he just angling for treats?

Until recently, scientists would have said your cat was snuggling up to you only as a means to get tasty treats. But many animals have a moral compass, and feel emotions such as love, grief, outrage and empathy, a new book argues.

The book, “Can Animals Be Moral?” (Oxford University Press, October 2012), suggests social mammals such as rats, dogs and chimpanzees can choose to be good or bad. And because they have morality, we have moral obligations to them, said author Mark Rowlands, a University of Miami philosopher.

 

“Animals are owed a certain kind of respect that they wouldn’t be owed if they couldn’t act morally,” Rowlands told LiveScience.

But while some animals have complex emotions, they don’t necessarily have true morality, other researchers argue. [5 Animals With a Moral Compass]

Moral behavior?

Some research suggests animals have a sense of outrage when social codes are violated. Chimpanzees may punish other chimps for violating certain rules of the social order, said Marc Bekoff, an evolutionary biologist at the University of Colorado, Boulder, and co-author of “Wild Justice: The Moral Lives of Animals” (University Of Chicago Press, 2012).

Male bluebirds that catch their female partners stepping out may beat the female, said Hal Herzog, a psychologist at Western Carolina University who studies how humans think about animals.

And there are many examples of animals demonstrating ostensibly compassionate or empathetic behaviors toward other animals, including humans. In one experiment, hungry rhesus monkeys refused to electrically shock their fellow monkeys, even when it meant getting food for themselves. In another study, a female gorilla named Binti Jua rescued an unconscious 3-year-old (human) boy who had fallen into her enclosure at the Brookline Zoo in Illinois, protecting the child from other gorillas and even calling for human help. And when a car hit and injured a dog on a busy Chilean freeway several years ago, its canine compatriot dodged traffic, risking its life to drag the unconscious dog to safety.

All those examples suggest that animals have some sense of right and wrong, Rowlands said.

“I think what’s at the heart of following morality is the emotions,” Rowlands said. “Evidence suggests that animals can act on those sorts of emotions.”

Instinct, not morals?

Not everyone agrees these behaviors equal morality, however.

One of the most obvious examples — the guilty look of a dog that has just eaten a forbidden food — may not be true remorse, but simply the dog responding appropriately to its owner’s disappointment, according to a study published in the journal Behavioural Processes in 2009.

And animals don’t seem to develop or follow rules that serve no purpose for them or their species, suggesting they don’t reason about morality.

Humans, in contrast, have a grab bag of moral taboos, such as prohibitions on eating certain foods, committing blasphemy, or marrying distant cousins.

“What I think is interesting about human morality is that often times there’s this wacky, arbitrary feature of it,” Herzog said.

Instead, animal emotions may be rooted in instinct and hard-wiring, rather than conscious choice, Herzog said.

“They look to us like moral behaviors, but they’re not rooted in the same mire of intellect and culture and language that human morality is,” he said.

Hard-wired morality

But Rowlands argues that such hair-splitting is over thinking things.

In the case of the child-rescuing gorilla Binti Jua, for instance, “what sort of instinct is involved there? Do gorillas have an instinct to help unconscious boys in enclosures?” he said.

And even if instinct is involved, human parents have an instinctive desire to help their children, but that makes the desire no less moral, he said.

Being able to reason about morality isn’t required to have a moral compass, he added. A 3-year-old child, for instance, may not consciously articulate a system of right and wrong, but will (hopefully) still feel guilty for stealing his playmate’s toy. (Scientists continue to debate whether or not babies have moral compasses.)

If one accepts that animals have moral compasses, Rowlands argues, we have the responsibility to treat them with respect, Rowlands said.

“If the animal is capable of acting morally, I don’t think it’s problematic to be friends with your pets,” he said. “If you have a cat or a dog and you make it do tricks, I am not sure that’s respect. If you insist on dressing them up, I’m not sure I’m onboard with that either.”

Tia Ghose, LiveScience Staff Writer

 

For centuries scientists have studied how both instinct and intellect figure into the decision-making process.

A new study has shown that forced to choose between two options based on instinct alone, participants made the right call up to 90 percent of the time.

Professor Marius Usher of Tel Aviv University’s School of Psychological Sciences and his fellow researchers say their findings show that intuition was a surprisingly powerful and accurate tool.

The team say that following your gut and doing what you want is usually the best optionThe team say that following your gut and doing what you want is usually the best option

Even at the intuitive level, an important part of the decision-making process is the integration of value – that is, taking into account the strengths and weaknesses of each option to come up with an overall picture, explained Prof Usher.

He said: ‘The study demonstrates that humans have a remarkable ability to integrate value when they do so intuitively, pointing to the possibility that the brain has a system that specialises in averaging value.

‘This could be the operational system on which common decision-making processes are built.

‘In order to get to the core of this system, Prof Usher designed an experiment to put participants through a controlled decision-making process.

On a computer screen, participants were shown sequences of pairs of numbers in quick succession. All numbers that appeared on the right of the screen and all on the left were considered a group; each group represented returns on the stock market.

Participants were asked to choose which of the two groups of numbers had the highest average.

Because the numbers changed so quickly – two to four pairs every second – the participants were unable to memorise the numbers or do proper mathematical calculations.

To determine the highest average of either group, they had to rely on intuitive arithmetic.
Their accuracy increased when more date was presented.

When shown six pairs of numbers the participants chose accurately 65 percent of the time.

But when they were shown 24 pairs, the accuracy rate grew to about 90 percent.

‘Intuitively, the human brain has the capacity to take in many pieces of information and decide on an overall value,’ said Prof Usher.

‘Gut reactions can be trusted to make a quality decision.’

The results of their study were published in the journal Proceedings of the National Academy of Sciences.

By Mark Prigg
Mail Online

Tsunamis in the Alps?

Posted: November 1, 2012 by phaedrap1 in News, Science, Uncategorized
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A killer wave slammed medieval Geneva, a new study says. And it could happen again.

Chateau de Chillon on Lake Geneva, Switzerland.

The circa A.D. 1000 Chateau de Chillon on Lake Geneva, Switzerland.

Photograph from ADS/Alamy

Daniel Stone

National Geographic News

Published October 31, 2012

Nearly 1,500 years ago a massive flood in Geneva reportedly swept away everything in its pathmills, houses, cattle, even entire churches.

Now researchers believe they’ve found the unlikely sounding culprit: a tsunami-like killer wave in the Alps. The threat, they add, may still be very much alive.  

Spurred by a huge landslide, the medieval Lake Geneva “tsunami” (technically defined as a seismic ocean wave) swamped the city, which was already a trading hub, according to a new study.

Far from any ocean, the massive wave was likely generated by a massive landslide into the Rhône River, which feeds and flows through Lake Geneva, according to a group of Swiss researchers.

The team analyzed a massive sediment deposit at the bottom of the lake’s easternmost corner and determined that the material had once sat above the lake and had slid all at once into the Rhône, near where the river flows into the eastern end of Lake Geneva (map).

The sudden splash sent a tsunami barreling down the length of the 225-square-mile (580-square-kilometer) lake toward Geneva, at the western end of the lake, the study suggests. Researchers estimate the wave was between 9 and 26 feet (3 and 8 meters) tall, depending on how quickly the rockfall occurred, which they were unable to measure.

(From National Geographic magazine: Where and when will the next tsunami hit?)

Geneva in the Crosshairs

The Alpine tsunami, the researchers caution, isn’t just a thing of the past.

A similar event at Lake Geneva could affect the modern-day Swiss cities of Lausanne, Nyon, and Thonon-les-Bains—but Geneva itself may be at greatest risk.

The city is home to major financial and international organizations as well as nearly 200,000 people, many of whom live in low-lying areas near the lake. Unfortunately for them, the lake narrows as it approaches Geneva, creating a funnel effect that would amplify an approaching wave.

For now, there’s little indication that another Geneva tsunami is imminent, researchers have said. But the new study found evidence of several large flooding events in Geneva since the last glacier retreated from the city’s site.

“If this has happened five to six times since the last glaciation, there’s reason to believe it could happen again in the future,” said University of Geneva geologist Guy Simpson, who study team’s modeler.

“A three-meter [ten-foot] wave that hit Geneva today would be a scary wave.”

The Geneva-tsunami study appears this week in the journal Nature Geoscience.

Earth is undergoing true polar wander, scientists say

Posted: October 2, 2012 by phaedrap1 in Science
Tags: ,
earth_nasa_300
Scientists developed a computer model to identify four possible instances of true polar wander in the past. And, they say, true polar wander is happening now.

Scientists based in Germany and Norway today published new results about a geophysical theory known as true polar wander. That is a drifting of Earth’s solid exterior – an actual change in latitude for some land masses – relative to our planet’s rotation axis. These scientists used hotspots in Earth’s mantle as part of a computer model, which they say is accurate for the past 120 million years, to identify four possible instances of true polar wander in the past. And, they say, true polar wander is happening now. These scientists published their results in the Journal for Geophysical Research today (October 1, 2012).

The scientists – including Pavel V. Doubrovine and Trond H. Torsvik of the University of Oslo, and Bernhard Steinberger of the Helmholtz Center in Potsdam, Germany – established what they believe is a stable reference frame for tracking true polar wander. Based on this reference frame, they say that twice – from 90 to 40 million years ago – the solid Earth traveled back and forth by nearly 9 degrees with respect to our planet’s axis of rotation. What’s more, for the past 40 million years, the Earth’s solid outer layers have been slowly rotating at a rate of 0.2 degrees every million years, according to these scientists.

Diagram showing solid-body rotation of the Earth with respect to a stationary spin axis due to true polar wander. This diagram is greatly exaggerated. According to Doubrovine and his team, Earth’s solid outer layers have been slowly rotating at a rate of 0.2 degrees every million years. Diagram via Wikimedia Commons.

True polar wander is not:

  • A geomagnetic reversal, or reversal of Earth’s magnetic field, known to have happened before in Earth history.
  • Plate tectonics, which describes the large-scale motions of great land plates on Earth and is thought to be driven by the circulation of Earth’s mantle.
  • Precession of the Earth, whereby our world’s axis of rotation slowly moves, tracing out a circle among the stars, causing the identity of our North Star changes over time.

True polar wander is a geophysical theory, a way of thinking about Earth processes that might happen and that these scientists believe do happen. The theory suggests that if an object of sufficient weight on Earth – for example, a supersized volcano or other weighty land mass – formed far from Earth’s equator, the force of Earth’s rotation would gradually pull the object away from the axis around which Earth spins. A supersized volcano far from Earth’s equator would create an imbalance, in other words. As explained at Princeton.edu:

If the volcanoes, land and other masses that exist within the spinning Earth ever became sufficiently imbalanced, the planet would tilt and rotate itself until this extra weight was relocated to a point along the equator.

That’s the theory of true polar wander. It would cause a movement of Earth’s land masses, but for a different reason than the reason the continents drift in the theory of plate tectonics (formerly called “continental drift”). In the theory of plate tectonics, the continents drift because Earth’s the layer of Earth underlying our planet’s crust, called the mantle, is convective. That is, it circulates, slowly – like water about to boil. In true polar wander, on the other hand, a similar-seeming movement of land masses on Earth’s crust happens in order to correct an imbalance of weight with respect to Earth’s spin.

Scientists’ understanding of true polar wander overlaps with their understanding of plate tectonics in various ways. That’s understandable, since it’s all the same Earth.

Scientists delving into true polar wander want to know when, in which direction, and at what rate the Earth’s solid exterior might be rotating due to true polar wander. To sort it out, they say, you would need a stable frame of reference to which observations of relative motion might be compared. Doubrovine and his team say they found one: volcanic hotspots.

Hotspot forming an island chain. As land plates drift, a successive of volcanoes form over the hotspot. Image via Wikimedia Commons.

In geology, hotspots are volcanic regions fed by Earth’s underlying mantle. For example, the Hawaiian islands are believed to have formed over a hotspot in the mantle. The hotspot created a volcano, but then – as that land plate drifted over time, as described by the theory of plate tectonics – the volcano drifted, too, and was eventually cut off from the hotspot. Gradually, another volcano begins to form over the hotspot, right next to the first one. And then it moves on … and another one forms … and so on … and so on. Earth’s crust produces first one, then another volcano over the hotspot until a long chain of volcanoes forms, such as in Hawaii. Hotspots have long been used to understand the motion of tectonic plates.

Doubrovine and colleagues went a step further in order to understand true polar wander. Instead of treating the hot spots as static – frozen in place at one spot above Earth’s mantle – their computer model let the hotspots’ positions drift slowly. According to these scientists, this drifting is what produced a model of a stable reference frame, which in turn let them draw conclusions about true polar wander.

They say their model does a good job of matching observations of real hotspot tracks on Earth – the path drawn by each hotspot’s island chain – which gives them confidence their results about true polar wander are accurate.

The Hawaiian islands are believed to have formed over a hotspot – a particularly hot place in Earth’s underlying mantle. Scientists expanded on previous thinking about hotspots to suggest that Earth’s solid surface is drifting, minutely, with respect to our planet’s rotation axis.

Bottom line: German and Norwegian scientists have incorporated hotspots in Earth’s mantle into a computer model being used to study true polar wander. They say their work established a stable reference frame for this study that lets them conclude Earth is undergoing true polar wander today.

Read the original paper: Absolute plate motions in a reference frame defined by moving hot spots in the Pacific, Atlantic and Indian oceans

Deborah Byrd/EarthSky

The point of no return: In astronomy, it’s known as a black hole—a region in space where the pull of gravity is so strong that nothing, not even light, can escape. Black holes that can be billions of times more massive than our sun may reside at the heart of most galaxies. Such supermassive black holes are so powerful that activity at their boundaries can ripple throughout their host galaxies. Now, an international team, led by researchers at MIT’s Haystack Observatory, has for the first time measured the radius of a black hole at the center of a distant galaxy—the closest distance at which matter can approach before being irretrievably pulled into the black hole. The scientists linked together radio dishes in Hawaii, Arizona and California to create a telescope array called the “Event Horizon Telescope” (EHT) that can see details 2,000 times finer than what’s visible to the Hubble Space Telescope. These radio dishes were trained on M87, a galaxy some 50 million light years from the Milky Way. M87 harbors a black hole 6 billion times more massive than our sun; using this array, the team observed the glow of matter near the edge of this black hole—a region known as the “event horizon.” “Once objects fall through the event horizon, they’re lost forever,” says Shep Doeleman, assistant director at the MIT Haystack Observatory and research associate at the Smithsonian Astrophysical Observatory. “It’s an exit door from our universe. You walk through that door, you’re not coming back.” Doeleman and his colleagues have published the results of their study this week in the journal Science.
Jets at the edge of a black hole
Supermassive black holes are the most extreme objects predicted by Albert Einstein’s theory of gravity—where, according to Doeleman, “gravity completely goes haywire and crushes an enormous mass into an incredibly close space.” At the edge of a black hole, the gravitational force is so strong that it pulls in everything from its surroundings. However, not everything can cross the event horizon to squeeze into a black hole. The result is a “cosmic traffic jam” in which gas and dust build up, creating a flat pancake of matter known as an accretion disk. This disk of matter orbits the black hole at nearly the speed of light, feeding the black hole a steady diet of superheated material. Over time, this disk can cause the black hole to spin in the same direction as the orbiting material.  Caught up in this spiraling flow are magnetic fields, which accelerate hot material along powerful beams above the accretion disk The resulting high-speed jet, launched by the black hole and the disk, shoots out across the galaxy, extending for hundreds of thousands of light-years. These jets can influence many galactic processes, including how fast stars form.
‘Is Einstein right?’
A jet’s trajectory may help scientists understand the dynamics of black holes in the region where their gravity is the dominant force. Doeleman says such an extreme environment is perfect for confirming Einstein’s theory of general relativity—today’s definitive description of gravitation. “Einstein’s theories have been verified in low-gravitational field cases, like on Earth or in the solar system,” Doeleman says. “But they have not been verified precisely in the only place in the universe where Einstein’s theories might break down—which is right at the edge of a black hole.” According to Einstein’s theory, a black hole’s mass and its spin determine how closely material can orbit before becoming unstable and falling in toward the event horizon. Because M87’s jet is magnetically launched from this smallest orbit, astronomers can estimate the black hole’s spin through careful measurement of the jet’s size as it leaves the black hole. Until now, no telescope has had the magnifying power required for this kind of observation. “We are now in a position to ask the question, ‘Is Einstein right?'” Doeleman says. “We can identify features and signatures predicted by his theories, in this very strong gravitational field.” The team used a technique called Very Long Baseline Interferometry, or VLBI, which links data from radio dishes located thousands of miles apart. Signals from the various dishes, taken together, create a “virtual telescope” with the resolving power of a single telescope as big as the space between the disparate dishes. The technique enables scientists to view extremely precise details in faraway galaxies. Using the technique, Doeleman and his team measured the innermost orbit of the accretion disk to be only 5.5 times the size of the black hole event horizon. According to the laws of physics, this size suggests that the accretion disk is spinning in the same direction as the black hole—the first direct observation to confirm theories of how black holes power jets from the centers of galaxies. The team plans to expand its telescope array, adding radio dishes in Chile, Europe, Mexico, Greenland and Antarctica, in order to obtain even more detailed pictures of black holes in the future.
By Jennifer Chu / Physorg.com
September 27, 2012
Ref. “Jet Launching Structure Resolved Near the Supermassive Black Hole in M87,” by S.S. Doeleman et al., Science, 2012.
Journal reference: Science
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