Tag Archive: Earth


Earthquake scars Earth’s gravity

Earth’s gravity scarred by earthquake

ESA’s GOCE satellite has revealed that the devastating Japanese earthquake of 2011 left its mark in Earth’s gravity – yet another example of this extraordinary mission surpassing its original scope.

GOCE mapped Earth’s gravity with unrivalled precision for over four years, but nobody really expected the data to show changes over time.

Now, careful analysis shows the effects of the 9.0 earthquake that struck east of Japan’s Honshu Island on 11 March 2011 are clearly visible in GOCE’s gravity data.

Large earthquakes not only deform Earth’s crust, but can also cause tiny changes in local gravity.

The strength of gravity varies from place to place on our planet’s surface and it was GOCE’s task to map these variations very precisely.

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Racing high over the Sahara at 5 miles per second, protected from the desert’s parched endlessness and soaking in its sere beauty, I saw Khartoum, the city where the White and Blue Nile rivers meet. I turned my head left and followed the river downstream to Cairo and the Mediterranean. Twisting weightlessly back to my right, I could pick out sunlight glinting off the waters of Lake Tana and Lake Victoria, the Nile’s headwaters. Explorers from the early Greeks to Queen Victoria’s David Livingstone had toiled and failed to find what I could see at a glance. Impressive on its own—even more so since I had been over Winnipeg, on the edge of the Canadian prairies, just 20 minutes earlier.

Circling Earth so fast makes you think. When you look out the window of a space­ship, you see entire countries, vast swaths of continents. One turn of the head covers what once took thousands of years to traverse at ground level. Historians and archaeologists estimate that human beings started migrating from Africa to Asia about 70,000 years ago, and to Australia 20,000 years after that. We went to the New World of the Americas about 30,000 years ago. All told, from the first dissatisfied teenager’s steps away from home, it took about 50,000 years to walk to the far corners of the planet.

Technology helped us pick up the pace. By the 1870s, new railways across the US and India and the opening of the Suez Canal made it seem completely plau­sible that the fictional Phileas Fogg and his valet could circle the world in 80 days. In 1911, Roald Amundsen reached the farthest end of Earth and stood atop the South Pole; 50 years later, the Soviet Union sent Yuri Gagarin around that same world in a ­little more than 80 minutes. And since November 2000, astronauts on the International Space Station have circled our planet 16 times a day—that’s about 75,000 times around and counting.

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A Terra Satellite image of the Earth

Europe next week will launch a trio of hi-tech satellites to explore something that may seem utterly mundane: Earth’s magnetic field.

After all, magnetism has been with us for billions of years.

We harness it in innumerable ways, in navigation and electrical devices. What’s new?

Well, plenty, actually.

If all goes well, the 230-million-euro ($276-million) Swarm mission will explain some of the weird things happening to the planet’s magnetism.

And they are more than just curiosities.

“Earth’s magnetic field is a very important thing. It makes life possible on Earth by providing shelter against radiation from space,” said Albert Zaglauer, project manager at Astrium, which made the three satellites.

The field is fickle, he said.

“The magnetic pole is changing, and the magnetic field is changing too. Why?”

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Planet Earth

Two contradictory ideas shape UK politics. First, the argument for austerity, that the nation cannot and should not live beyond its financial means. Second, the notion that we can and must, in effect, live beyond our environmental means. That is why any increase in our spending and consumption is hailed as economic success.

Today, the world goes into ecological debt, or “overshoot” – an estimate of the moment in the year when humanity has consumed more natural resources and created more waste than our biosphere can replace and safely absorb over a 12-month period.

Since the 1970s we’ve been living beyond our means, going into ecological deficit before the end of each year. And, the day when we hit “overshoot” has been creeping ever earlier. This year it falls two days earlier than in 2012. It now takes about 18 months for the biosphere to compensate for a year’s worth of human consumption and waste. Conservatively, here in the UK we’re using the equivalent of three and a half times the natural resources we have as a nation. For a country like Japan the figure is seven times. Many low-consuming countries in Africa are ecological creditors. Indonesia has been a creditor, but rising consumption and deforestation are running down its natural assets and pushing it over the brink.

For how long we can get away with not balancing the ecological books is a question that exercises many scientific minds, if unfortunately few political and economic ones. It’s a bit like Jenga, the game with the tower of wooden blocks; you can keep taking them away for a while until, with a suspenseful amount of uncertainty, the whole thing collapses.

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OUR home galaxy has been weighed, and it is surprisingly lean. The latest gauge of the dark matter mass of the Milky Way suggests it weighs only a quarter to a third of the amount previously estimated.

This could explain the dearth of smaller galaxies buzzing around the Milky Way. But it also means we may live in a cosmic anomaly.

It is thought the first galaxies were born as normal matter coalesced around globs of dark matter, the invisible stuff thought to make up about 80 per cent of the matter in the universe. We can’t see dark matter itself, but we can trace its effects in the motions of stars in modern galaxies.

Stars on the edges of large spirals like the Milky Way are orbiting so fast that they should fly off, so something must be holding on to them. That thing is thought to be a halo of dark matter encircling the visible disc.

Knowing our galaxy’s total mass will tell us a lot about it. “Is our Milky Way typical, or is it actually quite weird?” asks Alis Deason of the University of California, Santa Cruz.

A smattering of stars live in the Milky Way’s dark matter halo, and previous studies have used their motion to figure out the halo’s mass. But we are embedded in a spiral arm, which means dust and gas blocks much of our view of our relatively flat galaxy, so those models had to make assumptions about the parts we can’t see.

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We all know that as the seasons change on Earth, temperatures rise and fall, plants grow or die, ice forms or melts away. Perhaps nobody is more aware of this than NASA’s Visible Earth team who provide a vast catalog of images of our home planet as seen from space. Last month designer, cartographer, and dataviz expert John Nelson download a sequence of twelve cloud-free satellite imagery mosaics of Earth, one from each month, and then created a number of vivid animated gifs showing the seasonal changes in vegetation and land ice around the world.

Despite having encountered numerous seasonal timelapse videos shot here on Earth, this is the first time I’ve ever seen anything like this visualized on such a large scale from space. It really looks like a heartbeat or the action of breathing.

Earth’s Van Allen belts rocket electrons around the Earth at near light speed. One scientist just figured out how it’s done.

As the Sun’s churning surface lets loose a belch of white-hot flame, it sends out a storm of radiation that washes over the solar system. Luckily for us, Earth’s magnetic field shields us from most of these deadly rays. But overhead, something strange and lethal is happening when the solar wind bombards the Earth. A band of radioactive particles circling the planet, called the outer Van Allen belt, starts to charge up like a rail gun. It whips electrons along on its circular racetrack at a breakneck pace—near light speed. The powerful band ebbs and flows with solar radiation, but until today, nobody could be sure how it was creating such swift and energetic particles.

“This is like watching a natural particle accelerator in space,” says Geoffrey Reeves, a magnetic field researcher at Los Alamos National Laboratory.

Reeves and a team of scientists published research today in the journal Science describing the bizarre way the outer Van Allen belt—which orbits around the Earth like a giant doughnut—accelerates electrons to more than 99.9 percent of the speed of light. Discounting light itself, Reeves says, “these electrons are the fastest things the Earth creates naturally.” And they aren’t simply a high-velocity curiosity: They pose a threat to the International Space Station and to commercial satellites. The particles can burst through the protective shielding—causing temporary computer failures—and cause degradation to vital onboard equipment such as solar panels.

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NASA published a new photograph taken on July 19, 2013, by a wide-angle camera on the Cassini spacecraft that shows a view of Earth from the dark side of Saturn. In the photo Earth is 898 million miles away and the moon appears as just a tiny protrusion off to the right. According to NASA this is only the third time that Earth has ever been photographed from the outer solar system.

NASA Releases Photo of Earth Taken from the Dark Side of Saturn by the Cassini Spacecraft space Saturn NASA Earth

NASA Releases Photo of Earth Taken from the Dark Side of Saturn by the Cassini Spacecraft space Saturn NASA Earth

Numerous satellites in orbit around Earth are collecting data constantly of many different facets of the forces of air and water we all live around and in.

The video “Hyper Earth: the New World in 4k UHD, has put together some of the most stunning animations and visualizations that have been created from the NASA Scientific Visualization Studio, NASA Goddard Space Flight Center Global Modeling and Assimilation Office and the Image Science and Analysis Laboratory at NASA Johnson Space Center.

The youtube channel SpaceRip has uploaded a dramatically narrated video that ties these visualizations together. Take a look.

plasmaspheric-wind-leak-loop

Earth looks like such a solid and stable blue marble from outer space. But looks can be deceiving. Our planet is actually quietly leaking the equivalent of about 90 metric tons of plasma into outer space every day, according to new data collected by the European Space Agency’s Cluster mission. Plasma is an invisible, electrically charged gas that forms in the upper atmosphere when air particles are heated by the Sun’s ultraviolet rays. These particles travel along Earth’s magnetic field lines and are able to escape Earth’s gravity, but most remain trapped in an enormous bubble around the Earth known as the plasmasphere that ends about 16,000 miles outward from the planet.

Scientists observed that some plasma was escaping even further beyond this point in sporadic bursts of sudden activity known as plumes, which were first recored in the 1990s. But now the new data from ESA’s Cluster missions suggests the process of plasma escape is actually more regular, supporting a theory first proposed in 1992. “Now we have finally found proof of a permanent and continuous leakage of material from the plasmasphere outwards,” said Iannis Dandouras, a French scientist involved in the research, in a statement published online.

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Earth’s center is out of sync

Earth’s centre is out of sync

We all know that the Earth rotates beneath our feet, but new research from ANU has revealed that the center of the Earth is out of sync with the rest of the planet, frequently speeding up and slowing down. Associate Professor Hrvoje Tkalcic from the ANU College of Physical and Mathematical Sciences and his team used earthquake doublets to measure the rotation speed of Earth’s inner core over the last 50 years. They discovered that not only did the inner core rotate at a different rate to the mantle– the layer between the core and the crust that makes up most of the planet’s interior – but its rotation speed was variable.

“This is the first experimental evidence that the inner core has rotated at a variety of different speeds,” Associate Professor Tkalcic said. “We found that, compared with the mantle, the inner core was rotating more quickly in the 1970s and 1990s, but slowed down in the 80s. The most dramatic acceleration has possibly occurred in the last few years, although further tests are needed to confirm that observation. “Interestingly, Edmund Halley, namesake of Halley’s Comet, speculated that the inner shells of the Earth rotate with a different speed back in 1692.”

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The Earth from space

The Earth could be closer than previously thought to the inner edge of the Sun’s habitable zone, according to a new study by planetary scientists in the US and France. The research also suggests that if our planet moved out of the habitable zone, it could lead to a “moist greenhouse” climate that could kick-start further drastic changes to the atmosphere.

A star’s habitable zone is the set of orbits within which a planet could have liquid water on its surface – and being within this zone is considered to be an important prerequisite for the development of life.

The current consensus is that the Sun’s habitable zone begins at about 0.95 astronomical units (AU), a comfortable distance from the Earth’s orbit at 1 AU. However, this latest work by James Kasting and colleagues at Penn State University, NASA and the University of Bordeaux suggests that that inner edge of the zone is much further out at 0.99 AU.

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Scientists have tentatively identified several particles lurking deep inside the Earth’s mantle that could reveal how much heat the planet produces and confirm that the Earth formed from materials from the sun.

The wacky particles are called geoneutrinos, or the antimatter partners of neutrinos (exotic fundamental particles that can pass right through Earth), that form deep within the Earth’s mantle. Every matter particle has an antimatter partner particle that has an opposite charge, and when the two meet they annihilate each other. The findings were detailed described March 11 in the preprint journal arXiv.org.

Geoneutrinos aren’t the only particles scientists are hoping to find inside Earth.  An experiment using the Earth as a source of electrons recently narrowed down the search for a new force-bearing particle, possibly the so-called unparticle, placing tighter limits on the force it carries.

When Earth formed, the radioactive elements thorium and uranium were distributed in Earth’s interior at different concentrations within the crust (the planet’s outer layer) and mantle. As these elements within the mantle radioactively decay, they give off heat and also form subatomic particles known as geoneutrinos, said study co-author Aldo Ianni, a physicist at the Gran Sasso National Laboratory in Italy.

The heat formed from this decay is the engine that drives the motion of the viscous, oozing material that forms the Earth’s mantle. That, in turn can shift the tectonic plates, causing earthquakes. Whereas researchers have models to predict how much heat is generated inside the Earth, measuring it has proved tricky.

That’s partly because mantle lies miles beneath the Earth’s surface, so “if you want to understand how much heat is produced by these radioactive elements, the only way today to understand how much is this so-called radiogenic heat is through the geoneutrinos,” Ianni said.

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High above Earth’s surface float two rings of energetic charged particles, and for about four weeks in September, they were joined by a third. The temporary ring may have formed in response to a solar shock wave that passed by Earth, researchers report online February 28 inScience.

The discovery could force scientists to revisit decades of ideas about the structure of the Van Allen belts, donut-shaped rings of radiation trapped in orbit by the planet’s magnetic field. Those revisions could improve predictions of space weather and scientists’ understanding of the space environment near Earth, resulting in better protection for manned and unmanned spacecraft that navigate those areas.

“It’s a very important discovery,” says Yuri Shprits of the University of California, Los Angeles, who wasn’t involved in the study. “Over half a century after the discovery of the radiation belts, this most important region of space where most of the satellites operate presents us with new puzzles.”

Until the discovery, researchers thought the Van Allen belts always contained two zones of high-energy particles: an inner zone made mostly of protons and some electrons, and an outer zone dominated by electrons. A sparsely populated area separates the zones. The belts run from the top of the atmosphere, some 1,000 kilometers above Earth’s surface, to as far as five or six Earth radii from the planet’s surface.

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If ET phones home today, his long distance charge might not be as much as people believed when Steven Spielberg’s classic film came out three decades ago.

That’s because recent data from NASA’s Kepler space telescope suggests that billions of Earth-like planets are much closer than ever before imagined.

“The information we presented today will excite the general public because we now know that the nearest potentially Earth-like world is likely within 13 light years of the sun,” astronomer Courtney Dressing said in an email to The Huffington Post.

“Astronomically speaking, 13 light years is practically next door.”

While we don’t know if intelligent life exists on any of these planets, it raises the chances of that possibility.

The scientific team studied the huge number of red dwarf stars in our galaxy — stars that are smaller and have a longer life span than our own sun.

Just doing the math, the odds of Earth-like planets in our galaxy are, well, astronomical.

Scientists estimate 6 percent of the 75 billion red dwarf stars may have Earth-size planets orbiting them at a possible habitable distance. That works out to approximately 4.5 billion Earths out there.

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According to a new study conducted by German astronomers Dr Valeri Hambaryan and Dr Ralph Neuhauser, an intense blast of high-energy radiation that struck our planet in the 8th century may have been caused by a nearby short gamma-ray burst, emitted by two merging stellar remnants – black holes, neutron stars or white dwarfs.

In 2012, cosmic-ray physicist Prof Fusa Miyake from Nagoya University in Japan announced the detection of high levels of the isotope carbon-14 and beryllium-10 in tree rings formed in 775 CE, suggesting that a burst of radiation struck the Earth in the year 774 or 775.

Carbon-14 and beryllium-10 form when radiation from space collides with nitrogen atoms, which then decay to these heavier forms of carbon and beryllium. The earlier research ruled out the nearby explosion of a massive star as nothing was recorded in observations at the time and no remnant has been found.

Prof Miyake also considered whether a solar flare could have been responsible, but these are not powerful enough to cause the observed excess of carbon-14. Large flares are likely to be accompanied by ejections of material from the Sun’s corona, leading to vivid displays of the northern and southern lights, but again no historical records suggest these took place.

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Earth as Art

In 1960, the United States put its first Earth-observing environmental satellite into orbit around the planet. Over the decades, these satellites have provided invaluable information, and the vantage point of space has provided new perspectives on Earth. This book celebrates Earth’s aesthetic beauty in the patterns, shapes, colors, and textures of the land, oceans, ice, and atmosphere. The book features 75 stunning images of Earth from the Terra, Landsat 5, Landsat 7, EO-1, and Aqua satellites. Sensors on these satellites can measure light outside of the visible range, so the images show more than what is visible to the naked eye. The images are intended for viewing enjoyment rather than scientific interpretation. The beauty of Earth is clear, and the artistry ranges from the surreal to the sublime.

Download: PDF

Download the Accompanying iPad App

UrtheCast is launching the world’s first ever high definition, streaming video platform of planet Earth. The camera will be installed on the outside of the International Space Station through a joint effort with the Russian Space Agency. The camera will provide a 40 km wide, high resolution, color image down to as close as 1.1 metres.

For more info go here.

Did a massive comet explode over Canada 12,900 years ago, wiping out both beast and man in North America and propelling the earth back into an ice age?

That’s a question that has been hotly debated by scientists since 2007, with the University of South Carolina’s Topper archaeological site right in the middle of the comet impact controversy. However, a new study published today in the Proceedings of the National Academy of Sciences (PNAS) provides further evidence that it may not be such a far-fetched notion.

Albert Goodyear, an archaeologist in USC’s College of Arts and Sciences, is a co-author on the study that upholds a 2007 PNAS study by Richard Firestone, a staff scientist at the Department of Energy’s Lawrence Berkeley National Laboratory.

Firestone found concentrations of spherules (micro-sized balls) of metals and nano-sized diamonds in a layer of sediment dating 12,900 years ago at 10 of 12 archaeological sites that his team examined. The mix of particles is thought to be the result of an extraterrestrial object, such as a comet or meteorite, exploding in the earth’s atmosphere. Among the sites examined was USC’s Topper, one of the most pristine U.S. sites for research on Clovis, one of the earliest ancient peoples.

“This independent study is yet another example of how the Topper site with its various interdisciplinary studies has connected ancient human archaeology with significant studies of the Pleistocene,” said Goodyear, who began excavating Clovis artifacts in 1984 at the Topper site in Allendale, S.C. “It’s both exciting and gratifying.”

Younger-Dryas is what scientists refer to as the period of extreme cooling that began around 12,900 years ago and lasted 1,300 years. While that brief ice age has been well-documented – occurring during a period of progressive solar warming after the last ice age – the reasons for it have long remained unclear. The extreme rapid cooling that took place can be likened to the 2004 sci-fi blockbuster movie “The Day After Tomorrow.”

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This is the Earth’s song, pinging out contended chirrups into deep space.

The haunting sounds have been captured by Nasa’s twin Radiation Belt Storm Probe (RBSP) satellite, which launched on August 30 this year.

The satellites captured the chirping and whistling radio waves emitted by Earth’s magnetosphere on September 5.

The sound is known as ‘Earth’s chorus’ and can be heard by human ears – that is, assuming you could take your helmet off while floating in space.

Craig Kletzing, from the University of Iowa, is the principal investigator of the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instruments on-board the satellites.

The sounds of Earth: As charged solar particles hit the inner and outer radiation belts around our planet, they get caught and whipped around, emitting the sounds which you can hear below

He said: ‘People have known about chorus for decades.

‘Radio receivers are used to pick it up, and it sounds a lot like birds chirping.

‘It was often more easily picked up in the mornings, which along with the chirping sound is why it’s sometimes referred to as “dawn chorus”.’

The radio waves are at frequencies which can be heard from the human ear, but sadly you might need to be in space and without a helmet – which is not medically advisable.

You might also encounter the tricky problem of sound not travelling through the vacuum.

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