Although geologists and seismologists have known and understood the basics of plate tectonics since the concept was put forth and proved, they are still baffled by many aspects, including the nature of the “boundary” between Earth’s two outermost layers: the lithosphere and asthenosphere.

Just this week, however, seismologist and NASA Postdoctoral Program Fellow Dr. Nicholas Schmerr, who is stationed at NASA Goddard Spaceflight Center in Greenbelt, Maryland, has found an actual layer between the two aforementioned layers that effects the movement of plate tectonics and seismic waves.

Plate tectonics describes the movement of the seven broken plates of the Earth’s crust. These movements are a result of the magma churning in the mantle and cause continental drifts (i.e. the continents move toward or away from one another), earthquakes, and volcanic activity.

The lithosphere (the crust) is the outermost layer of the Earth. The asthenosphere lies between the lithosphere and the mantle and contains viscous magma. This thin layer – thinner than the lithosphere – acts as the transition from cold, solid rock to hot, liquid rock.

The imaginary boundary between the lithosphere and asthenosphere is called the LAB, where the abrupt change in temperature occurs. For many years, there has been a mystery as to what causes the continents to slide over the asthenosphere. Recently, it has been speculated that there is a layer at the LAB that is designated the ‘Gutenberg discontinuity,’ which provides lubricant for the plates to move with ease. The Gutenberg discontinuity is composed of partially molten rock.

“This melt-rich layer is actually quite spotty under the Pacific Ocean basin and surrounding areas, as revealed by my analysis of seismometer data,” Dr. Schmerr said in the NASA press release. He hypothesized that the existence of the Gutenberg discontinuity is the result of decompressed hot rock, or hot mantle, plumes that cause the lower portion of the lithosphere to melt.

“Most of the melt layers are where you would expect to find them, like under volcanic regions like Hawaii and various active undersea volcanoes, or around subduction zones – areas at the edge of a continental plate where the oceanic plate is sinking into the deep interior and producing melt,” he continued. Essentially, the Gutenberg discontinuity is located in only certain areas, mainly in parts as deep as the LAB and where there has been recent volcanic activity.

“However, the interesting result is that this layer does not exist everywhere, suggesting something other than melt is needed to explain the properties of the asthenosphere.”

To find an answer, Dr. Schmerr analyzed shear waves (S-waves) with a seismometer. S-waves, which are a type of wave produced by earthquakes, bounce off different interfaces inside the Earth and arrive at certain locations and times depending on the type of interface. Dr. Schmerr measured their arrival times, heights, and shapes.

From his data, he determined that S-waves having longer paths travel all the way up to the surface without being reflected on any interface. Meanwhile, S-waves with shorter paths are reflected from the melt layers right at the LAB, causing them to travel faster. After comparing the arrival times, he was then able to ascertain the seismic properties and depth of the layers under the Pacific Ocean basin.

Dr. Schmerr will continue his study to see if he can find a presence of the melt layers in other oceans. If he and others are able to determine the exact nature of plate tectonics, the discovery would allow scientists to understand the evolution of the Earth and those of other rocky planets in the solar system.

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The year 2012 is looking like a good one for fans of heavy metal, with releases of new albums from Lamb of God, Woods of Ypres, and Swallow the Sun already out, and Earth, Drudkh, Meshuggah, and Cynic set for new releases in the next few months.

If you are a big fan of the doom, technical, and post-metal genres, keep checking in with Toonari Post as we will cover these niches over the coming months. First up, let’s talk about Lamb of God’s new album, Resolution.

The best way to describe the sound of this new album is momentum: the marriage of speed and heaviness. “Straight for the Sun” opens up slow and sludgey, but by the end of this the second briefest track on the album, a sick and pounding drum rhythm picks up, dropping you into the next track with the momentum of a cannonball skipping across the surface of the sea.

Not for the first time, the atmosphere of the album switches from the sea to the desert for the track “Ghost Walking”, the current single from the album. The track is somewhat more narrative than is typical for Lamb of God, and starts off with a few seconds of acoustic guitar, referencing the often personal or especially heartfelt nature of songs set to acoustic guitar.

The acoustic facade quickly drops, however, and the vocals growl the struggle of a soldier returning from war. Lines like “There’s no one left to save” might sound a bit contrived, but “Desolation never looked so divine” elevate it almost to poetry.

“The Undertow” is a guitar-driven, rhythmic, shifting, pulling composition reminiscent of Icon-era Paradise Lost, with lyrical references to past Lamb of God albums and even references Metallica lyrics, paraphrasing “The empty can rattles the most” from “My Friend of Misery.” This is the first inkling of the flood of inspiration from past masters present on this album.

On the next track, “The Number Six”, Lamb of God starts out wholly within their own unique sound, then shifts the tone into atmospheric, Tool-like tension building, finally crushing it in the post-metal spirit of Isis or Pelican.

The two best examples on this album of Lamb of God’s willingness to experiment and stick their toes in other bands’ pools are “Insurrection” and the ending track “King Me.” “Insurrection” incorporates elements of prog metal into the mix and a complete change of vocal styles for part of the song. “King Me” actually features keyboards and symphonic metal stylings, which you would hardly expect from a groove/thrash metal band.

But the most impressive part about Lamb of God’s picking bits and pieces from other genres and subgenres is that it all still sounds like Lamb of God — they move seamlessly and logically between styles to create something melodic, compelling, and transfixing, like a hybrid beast of ancient myth staring back at you between trees in a forest. But there’s nothing ancient about the sound of the album; it’s this chimerism itself that constantly breathes new life into the band, nearly 20 years old, that has never lost its stride.

Lyrics from the song “The Number Six” on the album hint towards the mentality behind Lamb of God’s willingness and success in expanding their sound: “Sloth is the enemy of greatness / Reflection a scalpel to my mind / We strive as you leisurely criticize / A free ride till you find that you’ve dug your own grave”.

They could churn out album after album of the same old thing and ride the success of a few good early albums, but they have artistic curiosity that pushes them forward. The willingness of headline acts like Lamb of God to take the time and experiment is one of the things making metal a fascinating genre to be a fan of.

Rating: 8.5/10

Image Courtesy of   https://www.facebook.com/lambofgod

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A team of chemistry researchers in the United Kingdom has discovered a molecule that could potentially halt global warming and its effects by cleaning the atmosphere of pollutants and producing clouds.

In the 1950s, German chemist Rudolph Criegee postulated the existence of these molecules, which are known as the Criegee biradicals or Criegee intermediates. Criegee biradicals were confirmed only recently because the means to observe had not been developed until now. They are extremely reactive and elusive: once they form, they immediately bond with other chemicals.

The researchers, from the Universities of Manchester and Bristol and the Sandia National Laboratories, accidentally detected the molecule while performing an experiment with a synchrotron, which used light from the Lawrence Berkeley National Laboratory’s Advanced Light Source.

The intense light allowed the researchers to discern the Criegee biradicals’ formation and eliminate those of similarly arranged molecules. Upon detecting them, the team further observed the Criegee biradicals reacting in atmospheric conditions in the synchrotron. They learned that the molecules formed rapidly – faster than imagined – and accelerated in formation when in the presence of pollutants.

“Criegee radicals have been impossible to measure until this work carried out at the Advanced Light Source,” says Dr. Carl Percival, Reader in Atmospheric Chemistry at the University of Manchester and co-author of the team’s paper, in the University of Manchester’s media release. “We have been able to quantify how fast Criegee radicals react for the first time.”

Criegee biradicals oxidize pollutants such as nitrogen dioxide and sulphur dioxide into nitrates and sulfates. These compounds initiate the development of aerosols, tiny particles that deflect solar radiation into space. Aerosol formation ultimately leads to cloud formation, which cools the Earth by blocking sunlight.

These reactions can occur anytime. According to Dr. Percival, “The main source of these Criegee biradicals does not depend on sunlight and so these processes take place throughout the day and night.”

“But the fact is that these [intermediates] haven’t been studied before,” George Marston tells LiveScience.com, “so it’s difficult to know what you would really expect.” Marston, who did not partake in the research, is a chemist at the University of Reading in the United Kingdom.

The Criegee biradicals have not yet been observed in action in the atmosphere, so the idea of the molecules controlling the Earth’s climate remains hypothetical. Initiating the formation of Criegee biradicals and controlling their reactions at such a large scale would be a difficult task for scientists to undertake.

Furthermore, the geoengingeering project may backfire; the atmosphere is still complex and not well understood. ”This is very much the beginning of a much more extensive systematic study,” Marston adds.

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NASA is planning to use a “laser broom” to clean up the cloud of space trash that is currently orbiting around our planet. While the pieces floating around the earth are only fragments and often very small, they than cause a terrible problem for astronauts if they hit the weak points of a space shuttle – just as they are capable of taking out important satellites and break down communication here on earth.

The situation is as following: close to ten million human-made objects are at present time floating around our planet, approximately 800-2.000 kilometers above the surface where commercial and military satellites also move around.

This ‘cloud’ consists of around 20.000 piece of space-junk larger than five centimeters and can be spotted through telescopes from earth. The largest fragments come from space collisions, old satellites and wasted rocket fuel-tanks. Half a million fragments are only more than a centimeter big but they are capable of causing huge damage if they collide with other objects because of the high speeds that occurs when moving in such a low orbit.

For this reason, NASA has just announced the approval of funding for a new project that will test the idea of “sweeping” the space-junk out of the earth’s close orbit by directing relatively weak laser beams at the fragments to change their direction or speed. The goal is to reduce the risk of collisions. “It actually doesn’t sound completely implausible that it will work on smaller object” Peter Davidsen, a system engineer from the Danish company Terma, says to the Danish daily Berlingske Tidende. “The volume of space-junk will continue to grow in the future and at the moment we don’t have many option other than keeping our fingers crossed that it won’t hit anything important.”

Around this time last year, Davidsen was in fact sitting in the control room at Terma, who produce aerospace, defense and security applications, crossing his fingers that a large piece of Russian space-junk would pass by the Danish research satellite ‘Oersted’ – a project he had worked on for 18 years. This was the first time that a Danish project had been warned by the US of a ‘near miss’ in space and the case received a lot of attention at the time. “Since then, we have actually received more warnings like it – usually a couple of them every three months” Davidsen explains.

Other examples have not been so fortunate. In February 2009, the old Russian military satellite Kosmos 2251 collided with a satellite owned by the American company Iridium. To put the damage in perspective, Iridium makes some of the satellite phones that are used to pass on information in and out of Libya at the moment, where ordinary communication systems have been paralyzed.

The NASA “laser broom” is expected to be situated near the poles where most of the trash accumulates. They will be connected with grand telescopes which will guide the laser beams in the sky. The project is not expected to be too expensive since construction takes place on earth and will only use relatively weak lasers which will not require any specialized equipment.

Engineers at the Ames research centre in California, assigned to develop the project, have calculated that the “broom” will be able to sweep enough space-junk aside to significantly decrease the risk of the so-called Kessler syndrome – a domino effect of collisions already predicted back in 1978 which could cause the destruction of virtually all satellites with unimaginable consequences for the earth’s communication systems.

The current way of avoiding this situation has been to install a type of control system in newer satellites. This way, some are able to change course in orbit while eventually, they will fall down to earth after use.

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