Archive for April, 2015

Bigger Earthquake Coming on Nepal’s Terrifying Faults

Posted in SCIENCE, GEOLOGY,HEALTH, INVIRONMENT, TECHNOLOGY,ANTHROPOLOGY, ARCHAEOLOGY, with tags on April 28, 2015 by 2eyeswatching

Post 4528

Bigger Earthquake Coming on Nepal’s Terrifying Faults

Nepal faces larger and more deadly earthquakes, even after the magnitude-7.8 temblor that killed more than 4,000 people on Saturday (April 25).

Earthquake experts say Saturday’s Nepal earthquake did not release all of the pent-up seismic pressure in the region near Kathmandu. According to GPS monitoring and geologic studies, some 33 to 50 feet (10 to 15 meters) of motion may need to be released, said Eric Kirby, a geologist at Oregon State University. The earth jumped by about 10 feet (3 m) during the devastating April 25 quake, the U.S. Geological Survey reported.

Nepalese residents gather in an open space at the site of destruction caused after Saturday's earthquake in Bhaktapur, on the outskirts of Kathmandu (27 April 2015)

Tens of thousands of people in Nepal have been forced to live and sleep outside for fear of further aftershocks following Saturday’s earthquake, which killed more than 3,000 people  (http://www.bbc.com/news/world-asia-32476820)

“The earthquakes in this region can be much, much larger,” said Walter Szeliga, a geophysicist at Central Washington University.

Seismologists have extensively studied the possibility of damaging earthquakes in the central Himalayas. Through analyzing written histories, looking for clues from damaged buildings and digging along faults, researchers know of several damaging earthquakes in the past, but not their precise size. [See Photos of This Millennium’s Destructive Earthquakes]

Nepal was overdue for a major earthquake, said Marin Clark, a geophysicist at the University of Michigan. “It has been a long time since the last big rupture, so this is not unexpected,” Clark said.

One of the region’s most devastating recent quakes occurred in 1934, when a magnitude-8.2 earthquake killed over 8,500 people in Kathmandu. Before then, the last time such an immense quake struck Kathmandu was on July 7, 1255. That quake killed about 30 percent of the population. The region west of Kathmandu has been seismically quiet since June 6, 1505, when a great earthquake toppled buildings from Tibet to India.

A member of Nepalese police personnel looks on as an excavator is used to dig through rubble to search for bodies, in the aftermath of Saturdays earthquake in Kathmandu (27 April 2015)

An excavator is used to dig through rubble in search of bodies in Kathmandu (http://www.bbc.com/news/world-asia-32476820)

Crash zone

Nepal is one of the world’s most earthquake-prone regions because it lies at the head-on collision between two tectonic plates. India is slamming into Asia, and neither wants to give. Both India and Asia are continental crust, of the same average density. So instead of one plate sinking beneath the other, such as is happening at the ocean-continent plate collision offshore South America, the Earth’s crust crumples. Slices of India peel off and slowly squeeze under Asia, while Asia is mashed upward, forming the Himalayas.

India and Asia collide at about eight-tenths of an inch (2 centimeters) per year. Most of that energy is loaded onto earthquake faults as elastic strain because the faults are stuck together. Loading a fault is like squeezing a spring; an earthquake releases the built-up energy similar to an uncoiling spring.

The India-Asia plate tectonic collision.
Credit: IRIS

Scientists think earthquakes that are magnitude 7.8 in size can’t release all of the strain between India and Asia. Instead, history suggests most of the stored energy gets uncorked as earthquakes that are magnitude 8 or greater, according to geologic studies. It would take scores of magnitude-7 quakes to accommodate all of the plate motion, but only a handful of midsize, magnitude-8 quakes, or one magnitude 9. (The energy released by a quake increases by a factor of 30 with each additional point in magnitude.) [Video: What Does Earthquake ‘Magnitude’ Mean?]

“It seems likely that the amount of slip in this earthquake probably didn’t make up for the complete deficit,” Kirby said.

Damaged roads are seen after an earthquake on the outskirts of Kathmandu (26 April 2015)

The 7.8 magnitude quake opened up huge cracks in the ground, here in a road on the outskirts of Kathmandu (http://www.bbc.com/news/world-asia-32476820)

The April 25 earthquake struck on one of the many thrust faults that mark the boundary between the two plates. Thrust faults are the most terrifying of all faults because they lie at an angle. This shallow angle means a massive part of the Earth’s crust can lurch during an earthquake. Steeper faults quickly grow too warm and soft to break; as rocks get deeper, they flow like putty, Szeliga said. During the Nepal temblor, a piece of crust roughly 75 miles (120 kilometers) long and 37 miles (60 km) wide jogged 10 feet (3 m) to the south. The fault angled only 10 degrees from the surface, and the quake was only 9 miles (14 km) deep.

“This one was relatively shallow, which intensifies the surface shaking,” Clark said.

A Nepalese policeman tries to clear the rubble with his hands while looking for survivors at the compound of a collapsed temple in Kathmandu (27 April 2015)

A Nepalese policeman tries to clear the rubble with his hands while looking for survivors at the site of a collapsed temple in Kathmandu (http://www.bbc.com/news/world-asia-32476820)

From seismic readings, many scientists suspect the fault did not break all the way to the surface, like the 1994 Northridge earthquake in Los Angeles. That’s another indication that the earthquake did not unleash all of the stored strain in the region, Kirby said. The seismic instruments can detect where the strongest motion occurred on the fault.

However, even without a surface trace, GPS instruments and InSAR (radar from satellites) will provide precise tracking of how the ground shifted during the earthquake, Szeliga said. The data will help ground-truth scientist’s models of Himalayan tectonics.

People pray before cremating the body of a victim of Saturdays earthquake, alongside a river in Kathmandu, Nepal (27 April 2015)

People pray before cremating the body of a victim in Kathmandu (http://www.bbc.com/news/world-asia-32476820)

“Now’s the chance to see who made predictions that were even remotely testable, and if they stand up,” Szeliga said.

Follow Becky Oskin @beckyoskin. Follow Live Science @livescience,Facebook &Google+. Originally published on Live Science.

 

Advertisements

Thin ‘Bubble’ Coatings Could Hide Submarines from Sonar

Posted in World Military Corner with tags on April 28, 2015 by 2eyeswatching

Post 4527

Thin ‘Bubble’ Coatings Could Hide Submarines from Sonar

Bubble-filled rubbery coatings may one day help make submarines virtually undetectable to sonar, researchers say.

To avoid detection by sonar,military submarines are often covered with sound-absorbing tiles called anechoic coatings. These perforated rubber tiles are typically about 1 inch (2.5 centimeters) thick.

In the past decade, research has suggested that the same degree of stealth could be provided by much thinner coatings filled with vacant cavities. When hit by sound waves, empty spaces in an elastic material can oscillate in size, “so it will dissipate a lot of energy,” said lead study author Valentin Leroy, a physicist at the Université  Paris Diderot in France. [7 Technologies That Transformed Warfare]

However, figuring out how to optimize such materials for stealth applications previously involved time-consuming simulations. To simplify the problem, Leroy and his colleagues modeled the empty spaces in the elastic material as spherical bubbles, with each giving off a springy response to a sound wave that depended on its size and the elasticity of the surrounding material. This simplification helped them derive an equation that could optimize the material’s sound absorption to a given sound frequency.

The researchers designed a “bubble meta-screen,” a soft layer of silicone rubber that is only 230 microns thick, which is a little more than twice the average width of a human hair. The bubbles inside were cylinders measuring 13 microns high and 24 microns wide, and separated from each other by 50 microns.

In underwater experiments, the scientists bombarded a meta-screen placed on a slab of steel with ultrasonic frequencies of sound. They found that the meta-screen dissipated more than 91 percent of the incoming sound energy and reflected less than 3 percent of the sound energy. For comparison, the bare steel block reflected 88 percent of the sound energy.

“We have a simple analytical expression whose predictions are in a very good agreement with numerical simulations and real experiments,” Leroy told Live Science. “I find it exciting and beautiful.”

To make submarines invisible to the sound frequencies used in sonar, larger bubbles are needed. Still, the researchers predicted that a 0.16-inch-thick (4 millimeters) film with 0.08-inch (2 millimeters) bubbles could absorb more than 99 percent of the energy from sonar, cutting down reflected sound waves by more than 10,000-fold, or about 100 times better than was previously assumed possible.

However, despite the possibilities, “making these samples will probably be tough,” Leroy cautioned.

The scientists detailed their findings online Jan. 6 in the journal Physical Review B.

Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

Woman Finds 3.69-Carat White Diamond at Arkansas State Park, Names It ‘Hallelujah Diamond’

Posted in News with tags , on April 28, 2015 by 2eyeswatching

Post 4526

Woman Finds 3.69-Carat White Diamond at Arkansas State Park, Names It ‘Hallelujah Diamond’

Good Morning America

https://gma.yahoo.com/woman-finds-3-69-carat-white-diamond-arkansas-121328920.html

Susie Clark and her husband spent days hunting diamonds at Crater of Diamonds State Park in Murfreesboro, Arkansas, and on the last day she said a prayer.

“Are you going to bless me and let me find a diamond today?” Clark, from Evening Shade, Arkansas, prayed, according to a park news release.

Her prayer was answered shortly after with a 3.69-carat white diamond, which she saw “sticking out of a furrow ridge in the plowed dirt,” the release said.

Arkansasstateparks.com

Clark has named the teardrop-shaped rock “the Hallelujah Diamond” because it was an answer to her prayer, the release said.

Park Interpreter Waymon Cox described the stone as frosted white with a pearlescent shine.

Oklahoma Teenager Finds 3.85-Carat Canary Diamond

Man Finds 6-Carat Diamond in Park, Doesn’t Plan to Keep It

According to the park, Clark’s find is the largest of this year, though other park-goers have found 121 other diamonds. A visitor found a 6.19-carat white diamond — named the Limitless Diamond — on April 16, 2014. Other diamonds of note found by the park’s visitors include a 16.37-carat white diamond and a 3.85-carat canary diamond.

Arkansasstateparks.com

Clark had first visited the Crater of Diamonds State Park 33 years ago with her mother and grandmother from Germany. ABC News could not reach Clark for comment, but the release said that she plans to keep the diamond.

According to Cox, rainfall in recent weeks, combined with park staffers’ plowing the 37.5-acre search field — eroded the surface of a diamond-bearing deposit, helping to bring more of the stones to the surface and increasing visitors’ chances of finding them.

“Diamonds are a bit heavy for their size, and they lack static electricity, so rainfall slides the dirt off diamonds that are on the surface of the search area, leaving them exposed. And when the sun comes out, they’ll sparkle and be noticed,” he said in the release.

Crater of Diamonds is the world’s only diamond-producing site that is open to the public, according to the park. Visitors who find diamonds are allowed to keep them.

Photos: Shimmering Shades May Help Animals Survive

Posted in SCIENCE, GEOLOGY,HEALTH, INVIRONMENT, TECHNOLOGY,ANTHROPOLOGY, ARCHAEOLOGY, with tags on April 28, 2015 by 2eyeswatching

Post 4525

Photos: Shimmering Shades May Help Animals Survive

In Photos: Beautiful Cactus Flowers Signal Spring Is Here

Posted in SCIENCE, GEOLOGY,HEALTH, INVIRONMENT, TECHNOLOGY,ANTHROPOLOGY, ARCHAEOLOGY, with tags on April 28, 2015 by 2eyeswatching

Post 4524

In Photos: Beautiful Cactus Flowers Signal Spring Is Here

25 Years of the Hubble Space Telescope: A Story of Redemption

Posted in THE UNIVERSE & SPACE SCIENCE with tags on April 26, 2015 by 2eyeswatching

Post 4522

25 Years of the Hubble Space Telescope: A Story of Redemption

This week, NASA and the space science community celebrated 25 years since the launch and deployment of the Hubble Space Telescope, an instrument with one of the greatest redemption stories in science history.

Throughout its quarter-century in space, the iconic telescope — which launched on April 24, 1990 — has provided spectacular views of the cosmos and revealed exceptional insights about the universe. But there were also moments when it looked as though decades of work, plus billions of taxpayer dollars, might suddenly slip down the drain, and there were worries that the project might fail completely.

But Hubble overcame those obstacles to become one of the most successful telescopes ever built, both in terms of its scientific return and its impact on the public. And after 25 years of operation, Hubble’s best days may still be ahead of it, astronomers say. [The Hubble Space Telescope: A 25th Anniversary Photo Celebration]

Infographic: Find out how the Hubble Space Telescope works.

 

Find out how Hubble has stayed on the cutting edge of deep-space astronomy for the past 20 years here.
Credit: Karl Tate, SPACE.com Infographics Artist

On Thursday (April 23), NASA unveiled its official anniversary image for the Hubble 25-year celebration. It’s a cosmic landscape featuring multicolored gas clouds and dazzling, jewel-like stars — a breathtaking image of a region in space that can teach astronomers about how star clusters form in the universe. When it comes to this equation of beauty plus science, there really isn’t another scientific instrument on Earth, or in orbit, that can compete with the Hubble telescope.

“Even the most optimistic person to whom you could have spoken back in 1990 couldn’t have predicted the degree to which Hubble would rewrite our astrophysics and planetary science textbooks,” NASA Administrator Charles Bolden said at the image-unveiling event. “A quarter-century later, Hubble has fundamentally changed our understanding of our universe, and our place in it.”

At its current pace, the Hubble telescope produces 10TB of new data per year — enough to fill the entire collection of the Library of Congress, Bolden said. At that same event, Kathy Flanagan, interim director of the Space Telescope Science Institute in Baltimore, which operates Hubble’s science program, said scientists using data from the telescope have produced “nearly 13,000″ science papers.

This week, NASA hosted a Hubble symposium to discuss major science results from the telescope. The space agency also has hosted Hubble-themed events for the press and the general public, as well as a Friday night (April 24) gala to honor many of the people who made Hubble what it is today. Few, if any other, NASA projects have garnered such an ovation.

The climb to success

The Hubble telescope climbed to its current position at the peak of accomplishment from some deep valleys of near-failure.

In his book, “The Universe a Mirror: The Saga of the Hubble Space Telescope and the Visionaries Who Built it,” (Princeton University Press, 2008), science writer Robert Zimmerman chronicled the decades-long slogto get the Hubble telescope to where it is today. First, there was the chore of convincing the astronomy community to agree to invest in such a costly project, and then to get Congress to fund it, and to keep funding it during construction. It wasn’t just the telescope that suffered during those years; Zimmerman also wrote about people who dedicated themselves to Hubble at the expense of their careers or even their personal lives.

Planetary Nebula NGC 5189
A dying star expels is outer layers of material out into space, forming what’s known as a planetary nebula. Shown here, nebula NGC 5189, imaged by the Hubble telecope.
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

The Hubble Space Telescope was originally scheduled to blast off in 1983 but didn’t get off the ground until 1990. Shortly after the telescope’s launch, the scientific team realized the images they were receiving were blurry. It turned out that the telescope’s mirror was ground ever so slightly to the wrong thickness. (The flaw arose because of a mistake with the testing equipment used during the mirror’s construction.)

In 1993, the first Hubble servicing mission installed hardware that could adjust for the flaw in the mirror, and the telescope quickly blossomed to its full potential. Itrevealed new information at every size scale, from the solar system to the entire observable universe. Hubble has found four new moons around Pluto, demonstrated that galaxies frequently collide and merge together, drastically improved measurements of the age of the universe, and showed that space is not only expanding but spreading out faster and faster.

By 2003, Hubble had provided more than a decade of valuable science and beautiful images. At that point, it could have retired and still been labeled a success. But plans were in the works to add two new instruments to Hubble and repair two instruments that had stopped working. [Photos: NASA’s Hubble Space Telescope Servicing Missions]

The fifth and thus-far final crewed repair mission to Hubble took place in 2009. That mission is a microcosm of Hubble’s life story: full of close callsthat nearly spelled disaster for the telescope, like when a bolt holding down a handrail wouldn’t come loose and nearly prevented the astronauts from getting to one of the instruments that needed fixing.

In the end, the mission was a complete success. The astronauts installed two new instruments, fixed two broken instruments, and installed new batteries, new gyroscopes and a new scientific computer, to prolong Hubble’s life. Today, it continues to be one of the most powerful, most in-demand telescopes in the world.

What the future holds

So, what’s next for the Hubble Space Telescope?

“Frankly, we never even thought that the telescope would last this long,” Bolden said at the image-unveiling event. “The original plan for Hubble, we were told, wasmaybe 15 years. The fact that we are still going strong a quarter-century later is thanks to the Hubble heroes […] many of whom you will never know.”

Hubble will stop taking data someday, but right now, NASA has no firm decommissioning date because the observatory is operating better than anyone expected more than five years after its last servicing. [Hubble Space Telescope: Kill Or Save It? (Video)]

Right now, the Hubble team members aim to keep the telescope running through at least 2020. If Hubble can reach that goal, it should overlap with NASA’s James Webb Space Telescope, which is set to launch into space in 2018.

The Horsehead Nebula in 2013
The Horsehead Nebula, which can be found in the constellation Orion, was discovered over a century ago. But few images of the nebula compare to this one taken by the Hubble telescope in 2013.
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

While the Hubble telescope sees mostly optical and ultraviolet light, the $8.8 billion James Webb Space Telescope sees infrared light, and it will peer even deeper into the universe than Hubble has. The James Webb telescope has a larger mirror — 21.3 feet (6.5 meters) wide, compared to Hubble’s 7.9-foot (2.4 m) mirror — and will have a more powerful camera. And yet, it’s hard to think how any future telescopes will fill the shoes Hubble leaves behind.

The Hubble telescope cannot maintain its orbit forever — if left alone, it will fall to Earth and be destroyed, likely in the mid- to late 2030s. NASA officials have said they won’t let an uncontrolled re-entry happen, because people on the ground could be hurt by falling Hubble parts. So the agency has two options: Either steer Hubble to a safe destruction over the Pacific Ocean, or boost the telescope to a higher orbit (and possibly refurbish it one more time).

The time frame of Hubble’s ultimate fate remains up in the air, because no one knows for sure how much longer Hubble will keep producing good science. (Zimmerman said he’ll bet that if the Hubble telescope is still working when the time comes to capture it, NASA will find a way to put it back into a steady orbit.)

Twenty-five years after the Hubble Space Telescope’s deployment, the iconic observatory’s birthday celebration is not a memorial. Hubble is currently performing better than when it started, and shows no signs of slowing down. In fact, the telescope that has ascended to such great heights may not yet have reached the pinnacle of its accomplishments.

Follow Calla Cofield @callacofield. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

 

What Is a Geosynchronous Orbit?

Posted in THE UNIVERSE & SPACE SCIENCE with tags on April 26, 2015 by 2eyeswatching

Post 4521

What Is a Geosynchronous Orbit?

A geosynchronous orbit is a high Earth orbit that allows satellites to match Earth’s rotation. Located at 22,236 miles (35,786 kilometers) above Earth’s equator, this position is a valuable spot for monitoring weather, communications and surveillance.

“Because the satellite orbits at the same speed that the Earth is turning, the satellite seems to stay in place over a single longitude, though it may drift north to south,” NASA wrote on its Earth Observatory website.

Satellites are designed to orbit Earth in one of three basic orbits defined by their distance from the planet: low Earth orbit, medium Earth orbit or high Earth orbit. The higher a satellite is above Earth (or any other world for that matter), the slower it moves. This is because of the effect of Earth’s gravity; it pulls more strongly at satellites that are closer to its center than satellites that are farther away.

So a satellite at low Earth orbit — such as the International Space Station, at roughly 250 miles (400 km) — will move over the surface, seeing different regions at different times of day. Those at medium Earth orbit (between about 2,000 and 35,780 km, or 1,242 and 22,232 miles) move more slowly, allowing for more detailed studies of a region. At geosynchronous orbit, however, the orbital period of the satellite matches the orbit of the Earth (roughly 24 hours), and the satellite appears virtually still over one spot; it stays at the same longitude, but its orbit may be tilted, or inclined, a few degrees north or south.

geostationary, geo-satellites, geosynchronous orbit, geostationary orbit, geosynchronous orbit altitude, altitude of geosynchronous orbit
This image depicts the geostationary equatorial orbit in which most communications and weather satellites are located.
Credit: Smithsonian National Air and Space Museum

Benefits

A satellite in geosynchronous orbit can see one spot of the planet almost all of the time. For Earth observation, this allows the satellite to look at how much a region changes over months or years. The drawback is the satellite is limited to a small parcel of ground; if a natural disaster happens elsewhere, for example, the satellite won’t be able to move there due to fuel requirements.

This is a large benefit for the military. If, for example, the United States is concerned about activities in a certain region of the world — or it wants to see how its troops are doing — a geosynchronous orbit allows constant pictures and other surveillance of one particular region. An example of this is the United States’ Wideband Global SATCOM 5, which launched in 2013. Joining a “constellation” of four other WGS satellites, it extends the military’s communications system to provide blanket coverage over virtually the entire planet. The network serves troops, ships, drones and civilian leaders and is supposed to provide communications for ground personnel.

Communications for civilians also benefit from geosynchronous orbit. There are numerous companies that provide telephone, Internet, television and other services from satellites in that orbital slot. Because the satellite is constantly hovering over one spot on the ground, communications from that location are reliable as long as the satellite is well connected to the location you want to communicate with.

Orbital competition

According to Satellite Signals, there are 402 satellites in geosynchronous orbit. At geosynchronous orbit, the “ring” around Earth can accommodate a number of satellites — 1,800 altogether, according to one analysis by Lawrence Roberts, published in the Berkeley Technology Law Review. However, there are obvious space and technological limitations.

Specifically, satellites must remain in a very confined area and not drift too far from their assigned “slot” above Earth; otherwise they may pose a threat to other satellites. The International Telecommunication Union assigns slots for geosynchronous orbit and settles disputes between countries about slots.

Similarly, it is considered good practice to move almost-dead satellites into a “graveyard” orbit above geosynchronous orbit before they run out of fuel, to clear the way for the next generation.

The satellites must also be located far enough away from each other so their communications don’t interfere with each other, which could mean a separation of anything between 1 and 3 degrees. As technology has improved, it’s possible to pack more satellites into a smaller spot.