>BOOST O2 >> NASA’s amazing views of Earth

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Space Shuttle separation 

To celebration Earth Day, NASA released some of its most beautiful and surprising images of our planet.
Although the entire collection features dozens of images and photographs of a wide variety of subjects–from hurricanes to volcano eruptions to data visualizations of things like average rainfalls and terrain height–CNET has chosen these 20 images to represent the best of Earth, as seen from high above.
In this incredible image taken from the International Space Station, we see the underside of the Space Shuttle just after the spacecraft completed its post-undocking relative separation on April 17, 2010.

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>O2 VISIONS > Panic over plastics > Facts

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A Shuletvitzian nightmare

“Intuitive Toxicology” and Panicking Over Plastics at The New Republic

Over at The New Republic journalist Judith Shulevitz is wringing her hands over “The Toxicity Panic.” Actually, she seems to be doing her best to fuel the panic. The chief agents of terror are everyday plastics and other products, especially bisphenol-A and phthalates. These synthetic chemicals mimic or interfere with hormones like estrogen and testosterone and are known as endocrine disruptors. A worried Shulevitz suggests that untested modern chemicals are responsible for all kinds of diseases:

By now, you may be asking, if our health is so sensitive and if we live in a total plastic environment, why aren’t we sicker than we are? And sicker than we used to be? The answer is, we’re healthier in some ways and sicker in others. Medical advances mean we’re likelier than ever to survive our illnesses, but all kinds of diseases are on the rise. Childhood cancers are up 20 percent since 1975. Rates of kidney, thyroid, liver, and testicular cancers in adults have been steadily increasing. A woman’s risk of getting breast cancer has gone from one in ten in 1973 to one in eight today. Asthma rates doubled between 1980 and 1995, and have stayed level since. Autism-spectrum disorders have arguably increased tenfold over the past 15 years. According to one large study of men in Boston, testosterone levels are down to a degree that can’t be accounted for by factors such as age, smoking, and obesity. Obesity, of course, has been elevated to the status of an epidemic.

That does sound terrible. But in the next paragraph Shulevitz admits that there could be other factors accounting for the rise in the diseases she mentions:

There are many ways to explain upticks in rates of any particular ailment; for starters, a better-informed populace and better tools for detecting disease mean more diagnoses. Other environmental stressors include Americans’ weirdly terrible eating habits, our sedentary lifestyle, and stress itself.

Well, yes. But let’s take a closer look at the specific diseases she mentions. What about childhood cancer rates? Childhood cancer incidence has indeed increased. In 1975, the rate was 11.5 cases per 100,000 children, ages 0-14. The most recent figure (2007) is 15.5 cases per 100,000. There was a big jump in the rate of childhood cancer between 1975 and 1985, when it was 14.5 cases per 100,000. The National Cancer Institute reports:

The causes of childhood cancers are largely unknown….Environmental causes of childhood cancer have long been suspected by many scientists but have been difficult to pin down, partly because cancer in children is rare and because it is difficult to identify past exposure levels in children, particularly during potentially important periods such as pregnancy or even prior to conception.

What about kidney, thyroid, liver, and testicular cancer rates? Yes, they have been going up too. But Shulevitz is engaging in a bit of cherry picking when it comes to cancer trend data. The latest report from the National Cancer Institute finds that the overall cancer incidence rate in the United States has been declining by about one percent per year for more than a decade. For men, the data for the big three killers, prostate, lung, and colon cancers, show annual declines respectively of -0.3 percent, -1.9 percent, and -3 percent. In fact out of the 17 most common cancers, incidence rates for men declined or remained flat for 11 them. For the record, the incidence rank of kidney, thyroid, liver, and testicular cancer for men is respectively 7, 12, 18, and not even listed.
For women, the overall annual incidence rate of various cancers has also been declining. The breast cancer rate has been going down at -1.2 percent per year since 1998. Colon cancer down by -2.3 percent, and ovarian cancer by -1.8 percent. Out the top 18 cancers that afflict women incidence rates have declined or remained flat for 12 of them. It’s worth noting that decline in breast cancer may well be related to the recent rapid cessation of hormone replacement therapy. Thyroid, kidney, and liver cancers rank 6, 9, and 18 for women.
And what about asthma rates? Asthma rates did about double between 1980 and 1995 and have since leveled off. But roots of the increase are not clear. Many researchers believe that the hygiene hypothesis can explain higher levels of asthma in modern societies. Some research has shown that growing up in relatively sanitized environments prevents a child’s immune system from developing properly which leads to the increased likelihood allergies and asthma. Early exposure to microorganisms may protect against asthma. In fact, asthma rates do go up as countries become richer. Of course, while the environments of people in developing countries are becoming cleaner they are also being exposed to more plastics. In any case, other research suggests that the hygiene hypothesis may not be all there is to the asthma story.
Autism-spectrum disorders certainly do appear to be on the increase. Today about 1 child in 110 is diagnosed with some form of autism. Why the increase? The vaccine/autism hypothesis has been soundly rejected. A 2009 review of autism rate statistics by Eric Fombonne at McGill University notes:

There is evidence that the broadening of the concept, the expansion of diagnostic criteria, the development of services, and improved awareness of the condition have played a major role in explaining this increase, although it cannot be ruled out that other factors might have also contributed to that trend.

Earlier research found that as public schools began to offer more services to children diagnosed as autistic, the diagnosis increased substantially.
And what about that Boston study that found men’s testosterone levels were falling? It is true that study tried to rule out confounders like smoking and obesity, but later research suggests that obesity may well play a role:

Current evidence suggests that body composition changes as expressed by BMI can in part account for the trend in testosterone. More speculative recent findings suggest a potential contributory role for environmental endocrine disruptors, but to date no longitudinal studies have examined this question.

Note that the researchers speculate that endocrine disruptors may be a factor, but have no evidence for it. A recent review of clinical studies finds no deleterious trends in the prevalence of congenital abnormalities in male sexual organs and sperm counts.
Which brings us to obesity. Why are Americans becoming fatter? Could plastics be at fault? Maybe, but here’s a simpler hypothesis: We’re eating too much and exercising too little. The U.S. Department of Agriculture says that

… dietary intake of calories in 2000 [is] at just under 2,700 calories per person per day. [Economic Research Service] ERS data suggest that average daily calorie intake increased by 24.5 percent, or about 530 calories, between 1970 and 2000.

Since 2000 our calorie intake has been stable at this relatively high level.
Interestingly, obesity correlates with a lot of the diseases that Shulevitz is worried about: Kidney cancer, thyroid cancer, liver cancer, breast cancer, and asthma. Obesity apparently protects against testicular cancer (although being tall is a risk factor), but it is negatively correlated with testosterone levels. While there’s no evidence that obesity causes cancer in children, there’s lots of research that suggests that being a fat child increases one’s risk later in life.
As Shulevitz points out tests for the presence of substances in the body have gotten vastly more sensitive so researchers are finding more stuff all the time. A 2009 review of major biomonitoring studies found that average exposures to bisphenol A is about one-thousand times less than the levels determined by the EPA to be safe for daily exposures. Similarly, the study found the average exposures for the general population to phthalates are below levels determined by the EPA to be safe for daily exposures.
In addition, researchers can now see how various compounds affect the operations of thousands of genes at a time, although knowing what health effects they may be causing is still quite murky. In the future toxicogenomics may become a very useful tool for screening compounds for health risks, but the field still has some way to go before being added to the armamentarium of regulatory science. In the meantime, Shulevitz apparently thinks we should rely on our intuitions, which is all very well, but arguably should not be the basis for regulatory decisions.
A couple of final correlations: As our use of plastics has increased so too have our life expectancies, rising from 68 years in 1950 to 78 years now. And we’re not only living longer, we’re living longer with fewer disabilities. And while we’re relying on our intuitions, my intuition is that the hypothesis that trace exposures to endocrine disruptors are responsible for a lot illnesses will prove to be as overblown as the hypothesis that exposures to trace amounts of synthetic chemicals is a major cause of cancer. Panic over plastics? Not me.

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>O2 VISIONS >What do we want to be when we grow up? (video)

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Puberty on the Scale of a Planet

As I put together the post on  the role of boosted intelligence in meshing infinite human aspirations with a finite planet, it brought to mind a theme that has been tugging at me for years now. It’s the question of how to blend data, uncertainty and values to produce a worldview and way of life in a time of great change, risk, opportunity and complexity.
As an introduction to this question, I offer below a version of a talk I’ve been giving of late, named after this blog. It may be the only time you’ll see the word puberty in a discussion of environmental sustainability. To a modest extent, I’m trying to take the approach Murray Gell-Mann has extolled in discussing the value of taking a “ crude look at the whole.”
The answers are starting to emerge, in large part thanks to the ongoing discussion here (in other words, largely thanks to you). But for now, here’s a framing of the question…



9 Billion People + 1 Planet = ?

At a quickening pace, humanity is etching its signature across the Earth, diverting waterways and downing forests, spreading  pythons to the Everglades and American  bullfrogs to Bordeaux, extracting minerals used in cellphones from a last patch of gorilla habitat, altering the atmosphere,  knitting the land with roadways and the sky with contrails. For two generations, the nascent environmental movement railed against this process. Like many, I was weaned on that scary sensibility. Population was a ticking bomb. Spring threatened to be silent. I still admire those who led the call for cleaning up the mess people had created in the rise and spread of industrialized, consumptive living.
But lately I’ve come to see those recent dirty decades less as malfeasance (mind you, there have been plenty of dubious actors) and more as an inevitable phase, a transition as natural — and volatile — as puberty.
The real question is, what comes next? As its moment on Earth has arrived, H. sapiens, one of nature’s great experiments, has necessarily had to have a selfish, muscle-flexing, exuberant adolescence. It is only natural for a young person to break things, burn things, kill things, to be mean and even nasty sometimes, if only to learn how that attitude can bite back. In a youth’s life, mistakes are not only inevitable; they are vital.
In fact, by one measure we truly are a teenage species at this moment. There are currently about 1.2 billion humans between the ages of 10 and 19. Some demographers have recently concluded that this so-called “ youth bulge” could well constitute the largest single generation that will ever exist (as long as humans are restricted to this planet, at least). This pulse of youth is not only intensifying pressures on resources, but also providing fodder for extremist movements and contributing to social unrest as employment fails to keep up. If provided with education and opportunity, however — perhaps as simple as a micro-loan of $200 to buy some tools — those in this generation can be a force for progress.

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A group of youths danced around a car they had set on fire in a Paris working-class district Wednesday night, the seventh night of clashes.
Continue on to nytimes.com 

There comes a time in almost everyone’s youth when those remarkable human traits, self-awareness and empathy, catch up with potency, when you pause and reflect, when you first look back at the muddy tracks you just left across a floor and conclude that you are the person who needs to mop things up. Most people go through this transition successfully and become responsible citizens. Most of us would not leave the scene of an accident.
Now it may be humanity’s turn to go through  the same kind of transition. All species that have preceded people as planetary powerhouses never had to worry about such a coming of age because, as far as we can tell, they had no inner mirror or global view. They pressed on like bacteria on agar or rust on iron, pushing out to peripheral zones where only the absence of essentials prevented them from advancing. People have eternally pressed outward as well, but with a difference. Through the rise of human civilizations, individual communities came to the realization that they could not be perpetually wanton, that they had to store seed for spring, that if they stole from their neighbors they would probably be robbed in kind, that if they stained a river and sickened those downstream, there was nothing to prevent the next upriver village from fouling their waters. Over time, norms evolved. Neighboring countries followed suit, entering peace pacts and economic agreements. And most recently came global treaties, first to establish mutually beneficial rulebooks for issues like the treatment of prisoners of war, more recently to foster fairness in trade and enact shared standards for protecting the globe’s commons –- its atmosphere, biological veneer and seas.
But, so far at least, these have just been baby steps. That is not surprising. After all, one could argue that it has just been 40 years since we really got our first good look at ourselves.
Some have even put a date on that epiphany, December 24, 1968, which happens to be right around the time I shot that little bird. If there ever was a moment in human history that put all of our travails and disputes in context, it came on that day, when Frank Borman, Jim Lovell and Bill Anders, the three astronauts on Apollo 8, became the first humans to orbit the Moon. Anders had spent nearly an hour photographing craters and other features on the surface, charting possible landing sites for subsequent flights. When he was done, Borman began adjusting the spacecraft’s attitude, tilting the nose back up in line with the horizon. As he did so, an object came into view floating in space just above the blazingly bright pocked moonscape.
It was the first “Earthrise” ever witnessed by human eyes.

Japan’s space agency and NHK broadcasting company filmed a new view of the lunar “earthrise” last year. (Credit: Copyright JAXA/NHK ) UPDATE, 12/25 : The Genesis reading by the Apollo 8 astronauts, and Christmas in Deadhorse (Alaska).] Forty years ago today, the Apollo 8 astronauts, the first…

The reactions of Borman and the others were captured in a tape recording. “Oh my God,” Anders exclaimed. “Look at that picture over there! Here’s the Earth coming up!”
One of the resulting photographs set Earth in sobering isolation in a way that its inhabitants had perhaps never appreciated before. Interestingly, while the mission planners at NASA had anticipated virtually every activity of the astronauts, hour by hour, minute by minute, they had not foreseen the simple emotional power of looking back at the fertile home planet over the barren shoulder of its sterile moon.
From that point on, our worldview has been steadily enriched, as ever more expeditions, satellites, and sensors have been lofted into space or deposited in the oceans to study, photograph, and measure everything from plankton blooms to urban sprawl. Observations in real time are only one facet of the self-awareness revolution. Ever-expanding understanding of the planet’s distant and recent geophysical and biological past has helped put the human impact on the planet in context, and opened our eyes to natural perils that have only been hinted at in the blink of an eye we call history.
Some of our actions are the equivalent of faint static behind the stronger signal of natural variations in droughts, storms and the like. But other research has shown that human actions have put us in the planetary driver’s seat even though we have not yet passed driver’s ed. Scientists have recently concluded that people are the dominant force shaping ecosystems. We have up-ended the oceans’ web of life,  removing 90 percent of the mass of great predatory fishes that were there a century ago. And, through the use of pesticides, genetic manipulation and antibiotics, humans are  now said to be the dominant influence on natural selection, the engine of evolution.
Perhaps most consequentially in the long run, we are altering the insulating power of the atmosphere by raising the concentration of a trace, but influential, greenhouse gas, carbon dioxide, more than a third in 150 years. We are well on the way at least to doubling its concentration compared to levels that were the norm for more than 800,000 years and likely far longer. A century of science has built a robust understanding that  this trend is nudging the planet’s thermostat in ways that are already perceptible and could be disruptive both for us and for ecosystems from the tropics to the poles.
The view ahead is afforded by the newest scientific tool: simulation. For three centuries, science relied on two practices to advance: observation of the world and experimentation to test hypotheses about what made things work. But because there is only one Earth, and it is already in the midst of a planet-size experiment – the buildup of greenhouse gases – the only way to test various outcomes is to build mockups of the planet using equations.
The ongoing explosion of computer power has allowed geophysicists to construct ever more detailed  mathematical “stunt planets” that can be subjected to all kinds of abuses that could not be done safely or responsibly on the real Earth. Integrated with lessons from the past and observations of current changes, the models — while still highly imperfect — have created a picture of a planet that will be increasingly under our sway for generations, indeed centuries, to come.
Not only is knowledge exploding in volume, but it is also spreading around the world as satellites, fiber-optic cables, and other communication links knit communities and the global knowledge base. This is happening at every level of society. Governments have initiated the first  Global Earth Observation System of Systems, an attempt to link satellites and other environmental monitoring technologies into a single database. Squatters in shantytowns in Africa and Asia now are linked by the Internet through a network of “ Shack Dweller” associations, through which they trade information on common issues. Cell phones allow Kenyan farmers, still lacking a lamp at home, to get the price of corn before heading to market. Hundreds of millions of computer users have downloaded their own personal worldview, Google Earth.
There was a Russian geochemist,  Vladimir Vernadsky, who in the 1930’s foresaw a day when the globe evolved from simply being a common habitat for myriad species to being what he called a “ noosphere,” a planet of the mind, a place where ecology and enlightened human intelligence meld.
We’re nowhere near anything like that. But the turbulence of our times, reflected in everything from terrorism to the thawing of the iconic frozen seascape of the Arctic, hint that a great transformation, for better or worse, is in the offing.

About Dot Earth

Andrew C. Revkin on Climate Change

By 2050 or so, the world population is expected to reach nine billion, essentially adding two Chinas to the number of people alive today. Those billions will be seeking food, water and other resources on a planet where, scientists say, humans are already shaping climate and the web of life. In Dot Earth, which recently moved from the news side of The Times to the Opinion section, Andrew C. Revkin examines efforts to balance human affairs with the planet’s limits. Conceived in part with support from a John Simon Guggenheim Fellowship, Dot Earth tracks relevant developments from suburbia to Siberia. The blog is an interactive exploration of trends and ideas with readers and experts.


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>O2 VISIONS > Humans, the assailant, Earth the avenger? (video)

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Humanity as Assailant, Earth as Avenger?

It’s not enough to think of Earth as an impotent casualty of humanity’s predations.  It is also a complex organic system with many potent defenses against alien intervention — defenses it is already wielding to devastating effect when it comes to human societies. And keep this in mind: we are only at the beginning of this process.

Humans, the assailant, Earth the avenger?

We are a young species with a short memory and only slowly-dawning awareness of three vital pieces of the challenge of meshing our aspirations with life on Earth: the planet’s dynamics, our capacity to jog the system and — perhaps most importantly — the distorting mix of rational, emotional and instinctual processes in our brains that shape our perceptions and actions.

About Dot Earth

Andrew C. Revkin on Climate Change

By 2050 or so, the world population is expected to reach nine billion, essentially adding two Chinas to the number of people alive today. Those billions will be seeking food, water and other resources on a planet where, scientists say, humans are already shaping climate and the web of life. In Dot Earth, which recently moved from the news side of The Times to the Opinion section, Andrew C. Revkin examines efforts to balance human affairs with the planet’s limits. Conceived in part with support from a John Simon Guggenheim Fellowship, Dot Earth tracks relevant developments from suburbia to Siberia. The blog is an interactive exploration of trends and ideas with readers and experts.
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>O2 > rare clouds on Planet Earth (photos)

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Clouds fill the skies above us and are part of our every day lives, often going unnoticed. However, there are some clouds that are so rare that you will be very lucky to see them in your lifetime.
amazing cloud formations01 Amazing Cloud Formations
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amazing cloud formations09 Amazing Cloud Formations
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>O2 VISIONS >> WHY IS THE MOON SHRINKING? (video)

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Dave Scott's space suit on display at the NASM.  

Young Fault Scarps on the Moon

CEPS Contact: Dr. Tom Watters

NASA

Lobate Scarp - Thrust Fault Illustration
Smithsonian Institution Photo
WEB11574-2010

The lobate scarps were formed when the lunar crust was pushed together as the Moon contracted. This causes the near-surface materials to break forming a thrust fault. The thrust fault carries crustal materials up and sometimes over adjacent crustal materials.

Gregory Scarp
Smithsonian Institution Photo
WEB11565-2010

Over recent geologic time, as the lunar interior cooled and contracted the entire Moon shrank by about 100 meters (328 feet). As a result its brittle crust ruptured and thrust faults (compression) formed distinctive landforms known as lobate scarps. In a particularly dramatic example, a thrust fault pushed crustal materials (arrows) up the side of the farside impact crater named Gregory (2.1°N, 128.1°E). By mapping the distribution and determining the size of all lobate scarps, the tectonic and thermal history of the Moon can be reconstructed over the past billion years. Credit: NASA/GSFC/Arizona State University/Smithsonian
The most well known tectonic landforms on the Moon are found in and around the nearside mare basins. Wrinkle ridges, formed by contraction, and rilles or troughs, formed by extension, deform the mare basalt-filled impact basins and the adjacent highlands. The wrinkle ridges and extensional troughs are the result of loading from mare basalts that causes downward flexure of the lunar lithosphere, resulting in contraction in the interior of the basin and extension near the margins.

Tectonic landforms on the Moon not directly associated with the mare basins are lobate scarps. Lobate scarps look like stair-steps in the landscape; they are one-sided and often have lobate fronts. These landforms are the surface express of thrust faults. Thrust faults are a break in the near-surface materials formed when crustal materials are contracted or pushed together. Crustal material is thrust upward along the fault forming a scarp.

Lobate scarps were first found in the highest resolution images and photographs taken by the Lunar Orbiters and the Panoramic Cameras flow on the Apollo 15, 16, and 17 missions. Because these high resolution images and photographs covered only a small area of the surface confined mostly to the lunar equatorial zone, it was not known how widely distributed lobate scarps were on the Moon.

The Lunar Reconnaissance Orbiter, launch in June, 2009, is returning the highest resolution images of the Moon ever obtained from orbit. These images, taken by the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Cameras (NACs), have a resolution of 0.5 to 2 meter per pixel. The new NAC images are being used to search for previously unknown lobate scarps.

Newly discovered lobate scarps are being found in the LROC images. Many of the previously undetected fault scarps are located at high lunar latitudes and some have been found near the lunar poles.1 Lunar scarps found well outside the equatorial zone indicate that they are globally distributed.

Global map of fault scarps
Smithsonian Institution Photo
WEB11575-2010

A plot of the locations of newly detected and previously known lobate scarps shows that the faults are globally distributed. The newly discovered lobate scarps are shown by the white dots and the previously known scarps are shown by black dots. Most of the previously known lobate scarps were found in Apollo Panoramic Camera photographs that covered only part of the lunar equatorial region. The locations of the lobate scarps are plotted on the Lunar Orbiter Laser Altimeter (LOLA) global topographic model of the Moon. Credit: NASA/GSFC/Arizona State University/Smithsonian

The most likely reason for the formation of the lobate scarps is global contraction caused by interior cooling. The loss of heat from the Moon’s interior results in contraction. Although the lobate scarps indicate contraction, the Moon has not contracted by much in the recent past. The total radial contraction or decrease in the Moon’s radius is estimated to be only about 100 meters.

The age of lobate scarps is also being investigated. Examining the crosscutting relations between the fault scarps and small diameter impact craters, their age is estimated to be no more than 1 billion year old. An even younger age for the scarps is suggested by the lack of superimposed, large-diameter impact craters. Also, the scarps are very pristine and undegraded. The young age of the fault scarps indicates that the Moon has contracted very recently.

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>O2 THINKING AHEAD >> PLANET FORWARD > ENERGY (video)

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Are there any new energy innovations out there to help us kick our petroleum habit?

The answer might lie in a microscopic single-cell plant, a landfill or an iconic building.

http://www-tc.pbs.org/video/media/swf/PBSPlayer.swf

Watch the full episode. See more Planet Forward.

>O2 VISIONS >> Are we living in the age of UPHEAVALS ? >> GIANT EARTHQUAKES?

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Valdivia's Casino 

Searching for patterns in the occurrence of large magnitude earthquakes after a succession of large tremors — surpassed by the recent magnitude-9.0 quake in Japan — has researchers wondering if the amount of big quakes is on the rise…


   Are we living in an age of giant quakes?

Street scene from Valdivia, Chile, after the 1960 magnitude-9.5 earthquake — the largest ever recorded. Credit: NOAA | Pierre St. Arnand

The devastating 2004 Indonesian tsunami, with its death toll of as many as 250,000 people, was caused by the first magnitude-9.0 since 1967. A succession of smaller but still destructive tremors in Haiti, Chile, and New Zealand — surpassed by this year’s magnitude-9.0 quake in Japan — has some researchers wondering whether the number of large earthquakes is on the rise.
An earthquake represents the abrupt release of seismic strain that has built up over the years as plates of the Earth’s crust slowly grind and catch against each other. Giant earthquakes live up to their fearsome name. The biggest ever recorded was the magnitude-9.5 Chile earthquake of 1960. It accounts for about a quarter of the total seismic strain released worldwide since 1900. In just three minutes, the recent quake in Japan unleashed one-twentieth of that global total according to geophysicist Richard Aster at the New Mexico Institute of Mining and Technology in Socorro.
The Indonesian quake “reinvigorated interest in these giants,” said Aster, who is also president of the Seismological Society of America. The Chile and Japan earthquakes — along with a magnitude-9.2 quake in Alaska in 1964 — also triggered catastrophic tsunamis.
After a lull in large quakes in the 1980s and 1990s, we may now be in the middle of a new age of large earthquakes, Aster added.
Records from the past century reveal some periods that have seen an unusual number of giant earthquakes, defined as those with magnitude 8.0 or higher. For example, global show a dramatic spike in the rate of large earthquakes from 1950-67. But there have also been quiet periods with fewer large quakes. And with only 100 years worth of records to consult, researchers aren’t sure what these patterns of large quakes might mean — or whether they mean anything at all.
Are we living in an age of giant quakes?

Tsunami damage along the waterfront of Kodiak, Alaska, after the 1964 magnitude-9.2 quake. Credit: USGS

Even if clusters of giant earthquakes are a real phenomenon, Aster noted, researchers don’t have any good ideas on how one big quake can trigger another big one in a different part of the world.

Earthquakes are well known to generate smaller aftershocks, including some at great distance. The Japan quake spawned small tremors as far away as Nebraska.
But Andrew Michael, a geophysicist at the U.S. Geological Survey in Menlo Park, Calif., has studied the patterns in large earthquake occurrences that remain once aftershocks are removed from the picture. “Overall, the pattern is random,” he said. Apparent clusters of large quakes can be explained simply as statistical flukes.
“Random doesn’t mean evenly spaced out,” Michael added. That’s why quakes can seem to bunch together in the historical record. He cautioned that such clusters may not mean anything for predicting future earthquakes, or for explaining how a cluster of quakes might occur.
He compared the pattern to a baseball player’s hitting slump. “It could mean that he needs to change something in his game. Or it could just be a random streak,” Michael said.
Further evidence against the significance of apparent clustering came in a recent study by Don Parsons of the U.S. Geological Survey in Menlo Park and Aaron Velasco of the University of Texas at El Paso, published in Nature Geosciences. They found that large earthquakes do not generate other large quakes on a global scale.
Aster acknowledged that the rarity of large earthquakes means that questions about possible connections between them are difficult to answer. “We see magnitude-7 earthquakes only 15 or so times a year and magnitude-9 earthquakes only a few times a century,” he said.
Michael said that until researchers know more about why the rate of large earthquakes varies over time “we shouldn’t be worrying less, but there’s no need for panic either.”
The recent spate of giant earthquakes may not signal more to come, but Aster said that “it’s undeniable that we’re becoming more and more vulnerable to the effects of earthquakes in general.”
Aster added that many rapidly growing cities around the world aren’t prepared for a large , while at the same time coastal communities are expanding into tsunami-prone areas. “We just have more people in precarious places,” he said.

Source: Inside Science News Service (news : web)

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>O2 VISIONS >> The Milky Way as you’ve never seen it before!!!

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Digital fusion: Amateur astronomer Juan Carlos Casado stitched together this extraordinary shot from nine photos of the night sky 

Digital fusion: Amateur astronomer Juan Carlos Casado stitched together this extraordinary shot from nine photos of the night sky

The Milky Way as you’ve never seen it before: Incredible 360-degree panorama reveals the majesty of our galaxy

  Daily Mail

This breathtaking composite image shows just how huge the Milky Way really is.
Amateur astronomer Juan Carlos Casado stitched together this extraordinary shot from nine photos of the night sky.
All were taken in a national park in the Canary Islands away from light pollution, resulting in images of astounding clarity.

Viewed as one digitally-fused image, as they are here, and the result is a 360-degree panorama.
The faint band of light that stretches across the sky is the disc of our spiral galaxy. It appears to encircle Earth – this is because we are inside the disc.

Also visible is Tenerife‘s Teide Volcano near the centre of the image, behind a volcanic landscape that includes many huge boulders.

But far behind these Earthly structures are many sky wonders that are invisible to the unaided eye, such as the bright waxing moon inside the arch.
Also visible are the Pleiades open star cluster and Barnard’s Loop, which can be seen as the half red ring below the Milky Way band.
The stars that the human eye can distinguish in the night sky are relatively near and are all part of the Milky Way.
Our galaxy contains between 100billion and 400billion stars, as well as an estimated 50 billion planets.

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