Friday, January 23, 2009

Going To Ground The Breakdown -- A Short Circuit On A Large Scale


From Popular Science:

Here's a vivid example of an electrical short circuit in a beautiful natural setting. In brief, a short circuit occurs when the normal path of current is bypassed via an alternate route with very low resistance. Since current likes to take the path of least resistance, most of it will flow through the short circuit. Also, according to Ohm's Law (V = IR), reducing the resistance of the circuit will drive up the current. Large currents result in excessive resistive heating in circuits, and we usually want to avoid them.

In the video an unfortunate tree has fallen onto a high-voltage power line. This provides a direct path for current to go into the ground, rather than travelling the normal route through the electrical grid. The resulting surge of moving charge results in sufficient resistive heating to ignite the tree and potentially start a forest fire.

Read more ....

Thursday, January 22, 2009

Mating Game Is A Waiting Game


From Live Science:

How long do you wait before having sex with a new sweetie? Three dates? 10?

A new study suggests that both males and females benefit from extended courtships in which mating is delayed: By holding out, females can more accurately screen for potential providers, while waiting males can prove they're suitable mates.

The study, published this month in the Journal of Theoretical Biology and conducted by researchers at University College London, University of Warwick, and London School of Economics and Political Science, invoked game theory to examine the strategies used by potential partners of various species, including humans; the game ended when either the male or female quit, or when the female accepted the male as a mating partner. Scientists used a mathematical model dependent upon evolutionarily stable equilibrium behaviors, in which both males and females are doing as well as possible against the other's actions.

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Did You Know A Solar Flare Can Make Your Toilet Stop Working?

Auroras over Blair, Nebraska, during a geomagnetic storm in May 2005. Photo credit: Mike Hollingshead/Spaceweather.com.

From NASA:

That's the surprising conclusion of a NASA-funded study by the National Academy of Sciences entitled Severe Space Weather Events—Understanding Societal and Economic Impacts. In the 132-page report, experts detailed what might happen to our modern, high-tech society in the event of a "super solar flare" followed by an extreme geomagnetic storm. They found that almost nothing is immune from space weather—not even the water in your bathroom.

The problem begins with the electric power grid. "Electric power is modern society's cornerstone technology on which virtually all other infrastructures and services depend," the report notes. Yet it is particularly vulnerable to bad space weather. Ground currents induced during geomagnetic storms can actually melt the copper windings of transformers at the heart of many power distribution systems. Sprawling power lines act like antennas, picking up the currents and spreading the problem over a wide area. The most famous geomagnetic power outage happened during a space storm in March 1989 when six million people in Quebec lost power for 9 hours: image.

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Do Naked Singularities Break the Rules of Physics?

Image: Kenn brown Mondolithic Studios

From Scientific American:

The black hole has a troublesome sibling, the naked singularity. Physicists have long thought--hoped--it could never exist. But could it?

* Conventional wisdom has it that a large star eventually collapses to a black hole, but some theoretical models suggest it might instead become a so-called naked singularity. Sorting out what happens is one of the most important unresolved problems in astrophysics.
* The discovery of naked singularities would transform the search for a unified theory of physics, not least by providing direct observational tests of such a theory.

Modern science has introduced the world to plenty of strange ideas, but surely one of the strangest is the fate of a massive star that has reached the end of its life. Having exhausted the fuel that sustained it for millions of years, the star is no longer able to hold itself up under its own weight, and it starts collapsing catastrophically. Modest stars like the sun also collapse, but they stabilize again at a smaller size. Whereas if a star is massive enough, its gravity overwhelms all the forces that might halt the collapse. From a size of millions of kilometers across, the star crumples to a pinprick smaller than the dot on an "i."

Read more ....

Wednesday, January 21, 2009

Dark Matter Filaments Stoked Star Birth In Early Galaxies

From The New Scientist:

Tendrils of dark matter channelled gas deep into the hearts of some of the universe's earliest galaxies, a new computer simulation suggests. The result could explain how some massive galaxies created vast numbers of stars without gobbling up their neighbours.

Dramatic bursts of star formation are thought to occur when galaxies merge and their gas collides and heats up. Evidence of these smash-ups is fairly easy to spot, since they leave behind mangled pairs of galaxies that eventually merge, their gas settling into a bright, compact centre.

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Spring Is Arriving 'Two Days Earlier Than Half A Century Ago' As Global Temperatures Rise



From Daily Mail Online:

Spring is arriving earlier than it was half a century ago, a definitive new study has shown.

After analysing temperature records from across the northern hemisphere since 1850, researchers say the seasons have shifted by at least two days.

They also found that the difference between summer and winter temperatures has become less extreme.

The new research adds to the growing evidence that plants, insects, birds and mammals are waking up from winter earlier each decade.

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First Americans Arrived As Two Separate Migrations, According To New Genetic Evidence

Bering Strait. After the Last Glacial Maximum some 15,000 to 17,000 years ago, one group entered North America from Beringia following the ice-free Pacific coastline, while another traversed an open land corridor between two ice sheets to arrive directly into the region east of the Rocky Mountains. (Beringia is the landmass that connected northeast Siberia to Alaska during the last ice age.) (Credit: NOAA, NPO)

From Science Daily:

ScienceDaily (Jan. 21, 2009) — The first people to arrive in America traveled as at least two separate groups to arrive in their new home at about the same time, according to new genetic evidence published online in Current Biology.

After the Last Glacial Maximum some 15,000 to 17,000 years ago, one group entered North America from Beringia following the ice-free Pacific coastline, while another traversed an open land corridor between two ice sheets to arrive directly into the region east of the Rocky Mountains. (Beringia is the landmass that connected northeast Siberia to Alaska during the last ice age.) Those first Americans later gave rise to almost all modern Native American groups of North, Central, and South America, with the important exceptions of the Na-Dene and the Eskimos-Aleuts of northern North America, the researchers said.

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From George Washington To Barack Obama: All 44 US Presidents



This is cool.

It’s Official: La Niña Is Back

(Click the Image to Enlarge)

From Watts Up With That?:

UPDATE: There’s some question about NCEP’s communications intent with this paper. While they cite “La Niña conditions” in the language, and the visual imagery lends itself to that, the numerical threshold of ONI hasn’t been reached, as has been pointed out in comments. Yet NCEP made no mention in the summary that the threshold had not been reached. I’ll see if I can locate the authors and get a clarification. - Anthony

In a document published January 19th, NOAA’s Climate Prediction Center (NCEP) has officially put the stamp on the cold water conditions we’ve seen growing in the equatorial mid and eastern Pacific. I first reported on this on December 4th, 2008. This does not bode well for California’s drought conditions, which are likely to continue due to this renewed La Niña event.

Read more ....

Antarctica Is Warming: Climate Picture Clears Up

This illustration depicts the warming that scientists have determined has occurred in West Antarctica during the last 50 years, with the dark red showing the area that has warmed the most. Credit: NASA

From Live Science:

The frozen desert interior of Antarctica was thought to be the lone holdout resisting the man-made warming affecting the rest of the globe, with some areas even showing signs of cooling.

Some global warming contrarians liked to point to inner Antarctica as a counter-example. But climate researchers have now turned this notion on its head, with the first study to show that the entire continent is warming, and has been for the past 50 years.

"Antarctica is warming, and it's warming at the same rate as the rest of the planet," said study co-author Michael Mann of Penn State University.

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Quotas For Women In Science?

In ‘Geek Chic’ And Obama, New Hope For Lifting Women In Science -- New York Times

With the inauguration of an administration avowedly committed to Science as the grand elixir for the nation’s economic, environmental and psycho-reputational woes, a number of scientists say that now is the time to tackle a chronic conundrum of their beloved enterprise: how to attract more women into the fold, and keep them once they are there.

Researchers who have long promoted the cause of women in science view the incoming administration with a mix of optimism and we’ll-see-ism. On the one hand, they said, the new president’s apparent enthusiasm for science, and the concomitant rise of “geek chic” and “smart is the new cool” memes, can only redound to the benefit of all scientists, particularly if the enthusiasm is followed by a bolus of new research funds. On the other hand, they said, how about appointing a woman to the president’s personal Poindexter club, the President’s Council of Advisers on Science and Technology? The designated leaders so far include superstars like Harold Varmus, a Nobel laureate, and Eric Lander, genome meister.

Read more ....

Why People Fake Their Deaths


From Live Science:

When people die, sometimes it's hard to believe they are really gone — and for good reason.

Rumors of faked deaths have followed many famous people, including comedian Andy Kaufman, Elvis Presley, John F. Kennedy, and (up until October 2008) pilot Steve Fossett. Rumors and conspiracy theories aside, faked deaths are a perpetually popular subject in fiction, from Mark Twain's Tom Sawyer and Huckleberry Finn to today's soap operas.

And, of course, it happens in real life. Last week, Wall Street investor Marcus Schrenker disappeared while flying his plane over Alabama. He radioed a distress call, and his plane was found — without him — in a swamp. He was later discovered in a campground and arrested.

Read more ....

Source Of Moon's Magnetism Found


From Yahoo News/Space.com:

Moon rocks delivered to Earth by Apollo astronauts held a mystery that has plagued scientists since the 1970s: Why were the lunar rocks magnetic?

Earth's rotating, iron core produces the planet's magnetic field. But the moon does not have such a setup.

Now, scientists at MIT think they have a solution. Some 4.2 billion years ago, the moon had a liquid core with a dynamo (like Earth's core today) that produced a strong magnetic field. The moon's magnetic field would have been about 1-50th as strong as Earth's is today, the researchers say.

Read more ....

Tuesday, January 20, 2009

The 'Toxic' Web Generation: Children Spend Six Hours A Day In Front Of Screens

From The Daily Mail:

Youngsters are shunning books and outdoor games to spend up to six hours a day in front of a screen, a survey has revealed.

Children as young as five are turning their bedrooms into multi-media 'hubs' with TVs, computers, games consoles, MP3 players and mobile phones all within easy reach.

The trend triggered warnings that the next generation will struggle to compete in the adult world because they lack reading and writing skills.

At the same time their mastery of technology is not widely appreciated by their parents.

The market research involving 1,800 children aged five to 16 found that they spend an average of 2.7 hours a day watching TV, 1.5 on the internet and 1.3 playing on games consoles, although in some cases these activities are simultaneous, such as watching TV while playing on a console.

In contrast, youngsters spend just over half an hour reading books, according to the survey by ChildWise.

Almost a third take a games console to bed rather than a book, while a quarter never read in their own time.

Read more ....

Monday, January 19, 2009

What Went Right: Flight 1549 Airbus A-320's Ditch Into The Hudson

US Airways A320 N106US, the same aircraft that landed in the Hudson River, is seen here approaching LAX on a better day. (Photograph by code20photog, via Flickr)

From Popular Mechanics:

Miraculous. That’s the descriptor that continues to pop up in many accounts of the successful landing of US Air Flight 1549 in the Hudson River on Thursday. Aviation experts see the events a little differently. What happened to captain Chesley Sullenberger III and his crew was a piece of tremendously bad luck, mitigated by a few turns of equally stunning good fortune and a sequence of smart decisions by the captain and his crew. Here’s a pilot’s eye view of what went right during the emergency, the landing and the rescue that saw all 150 passengers rescued safely from the plane. –Allen St. John

Read more ....

Heavy Rains Damage Peru's Nazca Lines


From Yahoo News/AP:

LIMA, Peru – Heavy rains have damaged part of one of Peru's top tourist destination, depositing clay and sand on mysterious figures etched in the desert sand by indigenous groups centuries ago, an archaeologist said Monday.

The rains, which are uncommon on Peru's dry coastal desert, washed off the nearby Panamerican highway and pushed sand on top of three fingers of a geoglyph in the famed Nazca lines, said Mario Olaechea of Peru's National Culture Institute. The fingers form part of a pair of hands.

Olaechea told The Associated Press that the damage is minor and the institute plans to clear the material and restore the geoglyph.

Read more ....

If There IS Life On Mars, This Is Where It Lives

Plumes of up to 19,000 tons of methane, pictured red,
were detected in Mars' northern hemisphere


From The Daily Mail:

If there is life on Mars as NASA scientists claim, this is where it lives.

This extraordinarily detailed picture shows exactly where the most methane, taken as an indication of life, can be found.

Appropriately enough for the sphere dubbed the Red Planet , the scarlet areas are the places where scientists have detected the most of the gas.

The picture was released by NASA just days after the U.S. space agency confirmed the presence of methane on Mars.

It is the first 'definitive proof' of plumes of the gas seeping from the planet's northern hemisphere.

And it is the strongest hint yet that alien microbes could be thriving deep below the red, dusty surface.

On Earth, 90 per cent of the methane produced is released by living organisms far beneath the soil.

'It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon,' said NASA scientist Professor Michael Mumma.

Read more ....

Sunspot Lapse Exceeds 95% of Normal

Above: The solar cycle, 1995-2015. The "noisy" curve traces measured sunspot numbers; the smoothed curves are predictions. Credit: D. Hathaway/NASA/MSFC.

From Watts Up With That:

Well John Christy gave me a lot to think about in satellite temp trends as far as an improved correction over my last post. Steve McIntyre pitched in some comments as well. It is going to take a bit to work out the details of that for me but I think I can produce an improved accuracy slope over my last posts. In the meantime, I downloaded sunspot numbers from the NASA.

Cycles are interesting things. There are endless cycles in nature, orbits, ocean temp shifts, solar cycles, magnetic cycles the examples are everywhere. What makes a cycle unusual is also an interesting topic. Some solar scientists have claimed that our current solar cycle is not unusual by the record. They are certainly the experts but recently the experts have been forced to update their predictions for the next solar cycle.

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Scientists To Solve Astronomical Riddle Using Galileo DNA

NASA image shows hot blue stars deep inside an elliptical galaxy. Italian scientists are trying to get Galileo's DNA in order to figure out how the astronomer forged groundbreaking theories on the universe while gradually becoming blind, a historian said Monday. (AFP/NASA/File)

From Yahoo News/AFP:

ROME (AFP) – Italian scientists are trying to get Galileo's DNA in order to figure out how the astronomer forged groundbreaking theories on the universe while gradually becoming blind, a historian said Monday.

Scientists at Florence's Institute and Museum of the History of Science want to exhume the body of 17th Century astronomer Galileo Galilei to find out exactly what he could see through his telescope.

The Italian astronomer -- who built on the work of predecessor Nicolaus Copernicus to develop modern astronomy with the sun as the centre of the universe -- had a degenerative eye disease that eventually left him blind.

Read more ....

DNA Testing May Unlock Secrets Of Medieval Manuscripts

From E! Science News:

Thousands of painstakingly handwritten books produced in medieval Europe still exist today, but scholars have long struggled with questions about when and where the majority of these works originated. Now a researcher from North Carolina State University is using modern advances in genetics to develop techniques that will shed light on the origins of these important cultural artifacts. Many medieval manuscripts were written on parchment made from animal skin, and NC State Assistant Professor of English Timothy Stinson is working to perfect techniques for extracting and analyzing the DNA contained in these skins with the long-term goal of creating a genetic database that can be used to determine when and where a manuscript was written. "Dating and localizing manuscripts have historically presented persistent problems," Stinson says, "because they have largely been based on the handwriting and dialect of the scribes who created the manuscripts – techniques that have proven unreliable for a number of reasons."

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