Icelandic volcano eruption: Researchers gather extensive dataset - Video

A team of researchers from Cambridge's Department of Earth Sciences have recently returned from Iceland where, thanks to a bit of luck, they have gathered the most extensive dataset ever from a volcanic eruption, which will likely yield considerable new insights into how molten rock moves underground, and whether or not it erupts.

The team, led by Professor Bob White, has been monitoring activity near the Bárðarbunga and Holuhraun volcanoes since 2006, using up to 70 broadband seismometers.

Luckily, the seismometers and field researchers were still in Iceland at the time that this most recent volcanic activity began, as the team had recently finished recovering 25 seismometers from the Vatnajökull ice cap where they had been used for a study of small quakes caused by ice cracking.

Here, White and PhD student Tim Greenfield discuss their work, and what it's like to be up close to such a spectacular eruption.

Scottish Researchers build acoustic tractor beam

(a) Nonconservative pushing force exerted on an object by a plane wave as a result of strong backscattering. 

(b) Decreasing of the pushing force due to an enhanced forward scattering in a nonparaxial beam. 

(c) The authors used a target designed to maximize the forward scattering of acoustic radiation, leading to a pulling nonconservative force towards the source: an acoustic tractor beam. 

Credit: APS/Alan Stonebraker

A team of researchers with members from the U.K., Scotland and the U.S. has built a functioning acoustic tractor beam in a lab, one that is able to pull objects of centimeter size.

In their paper published in the journal Physical Review Letters, the team describes how they built their device, why it works and to what applications it might be put.

Tractor beams, as we all know are a staple of science fiction, a beam is emitted from a spaceship that can be used to lock on to other objects, such as another space ship, and then used to move that other object in any direction, most interestingly, in the same direction from which the beam is being emitted, pulling it in.

Tractor beams seem counterintuitive as beams of light tend to push objects away, rather than attract them—but, as prior research has shown, optical tractor beams can be created at the nanoparticle level, e.g. optical tweezers.

In this new effort, the research team has extended the abilities of a tractor beam by using one based on acoustics, rather than optics.

Sending a beam (wave) at an object and having it pull the object closer rather than push it can work because of the scattering of the wave that occurs when it collides with the object and if the wave is sent at an angle to the object.

If the scattering and angle are controlled just right, a low pressure zone can be created in front of the object, in effect, pushing it back towards the origin of the beam.

In the lab, the researchers used ultrasonic sound waves in a tank of water.

They put an array of ultrasound emitters at the bottom of the tank and used a hollow isosceles triangular prism as the object to be pulled.

Using an array of emitters allowed for very precisely controlling the wave, which allowed for directing energy onto the outer surface of the object, causing backscattering that led to the frontal low pressure zone, which in turn led to pushing the object back towards the wave source.

An analogy would be squeezing a chocolate chip with your fingers, forcing it to move in whatever direction you choose.

Experimental configuration to demonstrate negative radiation forces with a planar ultrasonic array.

(a) Scaled cross-sectional geometry of the 550 kHz planar matrix array source and hollow, prism-shaped targets suspended above the array. Linear phase gradients applied to the array elements produce wave fronts steered at θ=50.6° towards the array center line.

Active subapertures, forming a hollow core with diameter Δxn, are stepped towards the center line by the array element pitch, with a corresponding lateral (±x) shift in the transmitted local wave fronts and an axial (−z) shift of the intersection with the axis.

(b), (c) Normalised maps of simulated instantaneous pressure field and

(d),(e) measured magnitude of the pressure field produced by the transmitting subapertures illustrated under the field maps. 

Credit: (c) PRL, DOI: 10.1103/PhysRevLett.112.174302

Because of the stipulations required to make it work, applications that could make use of such a tractor beam are clearly limited, though the researchers suggest it might prove useful in some medical situations.

More information: Acoustic Tractor Beam, Phys. Rev. Lett. 112, 174302 – Published 30 April 2014. dx.doi.org/10.1103/PhysRevLett.112.174302

ESA’s Planck satellite capture the Milky Way's magnetic fingerprint

The magnetic field of our Milky Way Galaxy as seen by ESA’s Planck satellite. 

This image was compiled from the first all-sky observations of polarised light emitted by interstellar dust in the Milky Way. 

The magnetic field is displayed using a visualisation technique called line integral convolution (LIC). 

Credit: ESA Planck Collaboration

Our Galaxy's magnetic field is revealed in a new image from ESA’s Planck satellite. This image was compiled from the first all-sky observations of 'polarised' light emitted by interstellar dust in the Milky Way.

Light is a very familiar form of energy and yet some of its properties are all but hidden to everyday human experience.

One of these, polarisation, carries a wealth of information about what happened along a light ray's path, and can be exploited by astronomers.

Light can be described as a series of waves of electric and magnetic fields that vibrate in directions that are at right angles to each other and to their direction of travel.

Usually, these fields can vibrate at all orientations. However, if they happen to vibrate preferentially in certain directions, we say the light is 'polarised'.

This can happen, for example, when light bounces off a reflective surface like a mirror or the sea.

Special filters can be used to absorb this polarised light, which is how polarised sunglasses eliminate glare.

In space, the light emitted by stars, gas and dust can also be polarised in various ways.

By measuring the amount of polarisation in this light, astronomers can study the physical processes that caused the polarisation.

In particular, polarisation may reveal the existence and properties of magnetic fields in the medium light has travelled through.

The map presented here was obtained using detectors on Planck that acted as the astronomical equivalent of polarised sunglasses.

Swirls, loops and arches in this new image trace the structure of the magnetic field in our home galaxy, the Milky Way.

In addition to its hundreds of billions of stars, our Galaxy is filled with a mixture of gas and dust, the raw material from which stars are born.

Even though the tiny dust grains are very cold, they do emit light but at very long wavelengths – from the infrared to the microwave domain.

If the grains are not symmetrical, more of that light comes out vibrating parallel to the longest axis of the grain, making the light polarised.

If the orientations of a whole cloud of dust grains were random, no net polarisation would be seen.

However, cosmic dust grains are almost always spinning rapidly, tens of millions of times per second, due to collisions with photons and rapidly moving atoms.

ESA Herschel Observatory: Researchers discover young galaxies not behaving as predicted

The young galaxy SDSS090122.37+181432.3. It is distorted because of gravitational lensing. 

Credit: NASA/STScI; S. Allam and team; and the Master Lens Database (masterlens.org), L. A. Moustakas, K. Stewart, et al (2014).

New Herschel Space Observatory findings have given scientists a remarkable insight into the internal dynamics of two young galaxies.

Surprisingly, they have shown that just a few billion years after the big bang, some galaxies were rotating in a mature way, seemingly having completed the accumulation of their gas reservoirs.

When galaxies form, they accumulate mass by gravitationally attracting vast, external gas clouds. As the gas clouds are consumed by the galaxy, they fall into haphazard orbits.

These disordered paths cause turbulence in the host galaxies, which can drive star formation.

James Rhoads

To investigate the internal conditions of forming galaxies, James Rhoads and Sangeeta Malhotra, both from Arizona State University, and colleagues targeted two young galaxies, known as SDSS0901 and the Clone.

The light from both galaxies has taken 10 billion years to reach us across space. Thus, we are seeing them when they were comparatively young.

Rhoads studies galaxy formation, galaxy evolution and the reionization of intergalactic hydrogen by early galaxies.

Malhotra's research ranges from properties of dust and gas in the (relatively nearby) interstellar medium to some of the farthest known galaxies.

Sangeeta Malhotra

In recent years they have also collaborated on finding and characterizing galaxies in the cosmic dawn, when the universe was less than a billion years old.

The current project focuses on a somewhat later time, the high noon of star formation in the universe – a time when the universe was about 3 billion years old, and when star birth in galaxies was much more active than it is today.

"The purpose of this project is to study the physical conditions of gas in those galaxies. We wanted to know: 'Are they similar to the galaxies around us, or is there some difference in their physical conditions?'" says Rhoads.

The two galaxies they choose to study are average galaxies for that time in cosmic history. This means that they are about 10 to 20 percent the size of our Milky Way, which is considered an average galaxy in the present-day universe.

Studying galaxies so far away is usually challenging because they appear too dim to study effectively, but in this case, the researchers were helped by a cosmic mirage known as a gravitational lens.

The two galaxies both sit behind intervening groups of galaxies, whose gravity warps space.

As described by Albert Einstein's General Theory of Relativity, this warping acts like a lens.

Although it distorts the images of the young galaxies, it helps by magnifying their light, thus bringing them within reach of ESA Herschel's HIFI instrument.

Read the full article here

Combustion continues to draw researchers to International Space Station (ISS)

Astronaut Chris Cassidy installs the right glove on the Microgravity Science Glovebox just before starting a BASS investigation experiment run. 

Credit: NASA

The mesmerizing power of fire keeps researchers returning to the lab to understand the fundamental combustion science behind it.

Combustion has powered our world and consumed scientific attention for years, both on Earth and in space.

Fire continues as the focus with the Burning and Suppression of Solids-II (BASS-II) experiments, which recently launched to the International Space Station aboard the Orbital 1 cargo resupply mission.

Designed by researchers at NASA's Glenn Research Center in Cleveland, BASS-II is scheduled to operate through August 2014.

Through a series of experiments, scientists will investigate the combustion of a variety of solid materials, including plastic and fabric samples with different geometries.

Fabric sheets and plastic slabs, cylinders and spheres will be burned in the station's Microgravity Science Glovebox (MSG), provided by ESA.

This contained facility provides an environment that allows astronauts to burn open flames safely aboard station for scientific investigation.

An earlier BASS study, which used the MSG and ran on the space station in 2012, provided an initial look at burning materials with different shapes.

Researchers used that investigation to assess the effectiveness of nitrogen in suppressing microgravity fires.

BASS-II takes that research even further with five separate investigations overseen by five different research teams.

While each investigation has its own goal (flammability, flame spread, extinguishment, etc.), they share the same objective: a better understanding flame behaviour in space and on Earth.

"These are the thickest samples we've flown to date," said Sandra Olson, spacecraft fire safety researcher and BASS-II principal investigator at Glenn.

"We're looking to see how long it takes to reach a steady-state flame. How long it takes them to extinguish."

"We want to learn how to screen materials for future flights. A primary goal of BASS-II is improved spacecraft fire safety, improved understanding of combustion in space and how to avoid it."

"If you're on a mission far from Earth, a fire can be catastrophic. We want to select the safest materials."

These two candle flame images from BASS (side by side, left) show air flow from bottom to top, as compared with how a flame appears on Earth (right). Credit: NASA

The aim is to better understand the basic structure of flames and fires.

The results of BASS-II should help researchers refine computational models and theories about flame behaviour.

To produce better models, scientists need reliable data. Earth-based flame studies are greatly affected by gravity.

Buoyancy, which makes hot gasses rise, usually causes flame flickering even in a still environment.

If researchers can reduce buoyancy to near zero, they have the opportunity to study a range of flame behaviour that may be concealed by the influence of gravity.

Read the full article here

Researchers find phosphate in more soluble form on Mars

Synthetic crystals of the calcium phosphate mineral whitlockite similar to those used to produce the extraterrestrial mineral merrillite. 

If life ever arose on Mars, merrillite may have been a major source of biologically required phosphate. Largest crystal are ~1mm. 

Credit: C. T. Adcock / University of Nevada Las Vegas 

A trio of researchers at the University of Nevada has found that phosphate found in minerals on Mars, is far more soluble than it is in natural Earth minerals.

In their paper published in the journal Nature Geoscience, the researchers describe how they synthesized mineral types found on Mars and then tested how well they dissolved in water releasing phosphate as compared to samples from natural Earth minerals.

Most scientists agree that phosphate is a key ingredient for life. Put another way, they believe that life couldn't have evolved without it.

For that reason, scientists have been studying ways in which minerals that contain phosphate could have broken down to allow the phosphate to escape.

Such studies have thus far found that minerals that hold phosphate on Earth are not very soluble—they don't break down easily when soaked in sea water.

That has led to what Earth scientists call "the phosphate problem." How did life get started on Earth if there wasn't enough phosphate around when life was first beginning?

Some have suggested the answer is that it didn't, instead, it started on another planet, such as Mars, and made its way here via meteorites.

Prior research has already shown that Mars has much more phosphate than does Earth. In this new effort, the team in Nevada looked at minerals that exist on Mars to see if they might be more soluble in water as well.

Lacking samples from Mars to test, the researchers synthesized chlorapatite and merrillite in their lab—two common phosphate bearing minerals found on the Red Planet.

They then soaked samples in several tubs, each with a different pH level for varying amounts of time. As they did so, they measured how much phosphate made its way into the water and how long it took.

In analyzing their results, the researchers found that more phosphate made its way into the water with both types of minerals and they did so at a faster rate than minerals that contain phosphate found naturally on Earth.

In some cases, they report that the Mars rocks released phosphate up to 45 percent faster than Earth rocks.

The findings by the team don't prove that life began on Mars and migrated to Earth—after all, scientists have yet to prove life ever existed Mars. But it does add some credence to the argument that perhaps life did start somewhere other than our home planet, which if true, might mean it's still out there waiting for us to discover it.

More information: Readily available phosphate from minerals in early aqueous environments on Mars, Nature Geoscience (2013) DOI: 10.1038/ngeo1923

Researchers calculate radiation exposure associated with journey to Mars

The RAD instrument measures radiation dose using silicon detector and plastic scintillator technology.

The latter has a composition somewhat similar to tissue and is more sensitive to neutrons than are the silicon detectors.

This illustration of RAD shows the silicon detectors (A, B & C) that measure charged particles and the plastic detectors (D, E & F) that measure both charged and neutral particles.

Credit: Hassler et al., 2012. Space Science Reviews, 170, 503.

On November 26, 2011, the Mars Science Laboratory began a 253-day, 560-million-kilometer journey to deliver the Curiosity rover to the Red Planet.

Radiation Assessment Detector

En route, the Southwest Research Institute (SwRI) Radiation Assessment Detector (RAD) made detailed measurements of the energetic particle radiation environment inside the spacecraft, providing important insights for future human missions to Mars.

Cary Zeitlin

"In terms of accumulated dose, it's like getting a whole-body CT scan once every five or six days," said Dr. Cary Zeitlin, a principal scientist in SwRI's Space Science and Engineering Division and lead author of Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory, scheduled for publication in the journal Science on May 31.

"Understanding the radiation environment inside a spacecraft carrying humans to Mars or other deep space destinations is critical for planning future crewed missions," Zeitlin said.

"Based on RAD measurements, unless propulsion systems advance rapidly, a large share of mission radiation exposure will be during outbound and return travel, when the spacecraft and its inhabitants will be exposed to the radiation environment in interplanetary space, shielded only by the spacecraft itself."

Two forms of radiation pose potential health risks to astronauts in deep space: a chronic low dose of galactic cosmic rays (GCRs) and the possibility of short-term exposures to the solar energetic particles (SEPs) associated with solar flares and coronal mass ejections.

Radiation dose is measured in units of Sievert (Sv) or milliSievert (1/1000 Sv). Long-term population studies have shown that exposure to radiation increases a person's lifetime cancer risk; exposure to a dose of 1 Sv is associated with a 5 percent increase in fatal cancer risk.

GCRs tend to be highly energetic, highly penetrating particles that are not stopped by the modest shielding provided by a typical spacecraft.

These high-energy particles include a small percentage of so-called heavy ions, which are atomic nuclei without their usual complement of electrons.

Heavy ions are known to cause more biological damage than other types of particles.

Energetic protons constitute about 85 percent of the primary galactic cosmic ray flux and easily traverse even the most shielded paths (reds) inside the MSL spacecraft.

Heavy ions tend to break up into lighter ions in thick shielding, but can survive traversal of thin shielding (blues) intact.

The solar particles of concern for astronaut safety are typically protons with kinetic energies up to a few hundred MeV (one MeV is a million electron volts).

Solar events typically produce very large fluxes of these particles, as well as helium and heavier ions, but rarely produce higher-energy fluxes similar to GCRs.

The comparatively low energy of typical SEPs means that spacecraft shielding is much more effective against SEPs than GCRs.

"A vehicle carrying humans into deep space would likely have a 'storm shelter' to protect against solar particles. But the GCRs are harder to stop and, even an aluminum hull a foot thick wouldn't change the dose very much," said Zeitlin.

"The RAD data show an average GCR dose equivalent rate of 1.8 milliSieverts per day in cruise. The total during just the transit phases of a Mars mission would be approximately .66 Sv for a round trip with current propulsion systems," said Zeitlin.

Time spent on the surface of Mars might add considerably to the total dose equivalent, depending on shielding conditions and the duration of the stay.

Exposure values that ensure crews will not exceed the various space agencies standards are less than 1 Sv.

More Information here

Moore's Law used to calculate that life began Before Earth existed

Richard Gordon

Geneticists Richard Gordon of the Gulf Specimen Marine Laboratory in Florida and Alexei Sharov of the National Institute on Aging in Baltimore have proposed, in a paper uploaded to the preprint server arXiv, that if the evolution of life follows Moore's Law, then it predates the existence of planet Earth.

Moore's Law, of course, famously suggests that the complexity of computers grows at a rate of double the transistors per circuit every two years, resulting in exponential growth.

Looking at the complexity of computers today and working Moore's Law backwards shows that the first microchips came about during the 1960s, which is when they were actually invented.

In their paper, Gordon and Sharov take the same approach, only they apply it to biological complexity.

Alexei Sharov

The two researchers acknowledge their ideas are more of a "thought exercise" than a theory proposal, but at the same time suggest their calculations ought to be taken seriously.

They start with the idea of genetic complexity doubling every 376 million years—working backwards, they say, means that life first came about almost 10 billion years ago, which of course predates the creation of Earth itself.

Most scientists agree the Earth formed just 4.5 billion years ago. Assuming that Moore's Law does apply to biological complexity, this would suggest that life began somewhere other than on Earth and migrated here.

Of course there are other possibilities to explain what happened, as the two acknowledge, life could have evolved following Moore's Law during certain periods but not at others, a deep freeze could have temporarily halted changes in complexity, for example, or cataclysmic events could have periodically killed off the more advanced biotic life forms.

There is also the possibility that the development of life had to reach a certain stage of development before it began to conform to Moore's Law.

Then of course, there is the very real possibility that the beginnings and evolution of life don't conform to Moore's Law at all.

Gordon and Sharov's paper is likely to set off multiple rounds of discussion regarding not just the origin of life on Earth, but in the galaxy as well.

If life truly predates our planet, and it can be proved, what impact might that have on religious thought and what might it mean to those looking for meaning in its very existence?

More information: Life Before Earth, arXiv:1304.3381 [physics.gen-ph] arxiv.org/abs/1304.3381

Major Breathrough in TB Research: Questions answered!

After three decades of searching, the random screening of a group of compounds against the bacterium that causes pulmonary tuberculosis has led scientists to a eureka discovery that breaks through the fortress that protects the bacterium and allows it to survive and persist against treatments.

The two findings, which occurred at Colorado State University, are published today in Nature Chemical Biology.

The article describes the discovery of an important cell function in the mycobacterium that causes tuberculosis which allows the mycobacterium to survive. The researchers also discovered a compound that prevents this cell function.

The bacterium that causes tuberculosis is extremely difficult to kill and current tuberculosis drugs on the market don’t do well to treat it. Six months of multiple antibiotics are generally required to treat tuberculosis in most people, and many current drugs no longer work because of resistant strains of the bacterium that causes tuberculosis. Scientists hope that finding new drugs to kill the bacteria in ways different than current drugs will help tackle those strains.

Cell envelopes form a virtually impenetrable bubble around the bacterium cell and protect it. Mycolic acids are key portions of this bacterium’s cell envelope. They are made inside the cell, but have to cross the cell membrane, with the help of a transporter, to reach their final location in the cell envelope.

“Without mycolic acids in the cell envelope, the bacteria die,” said Mary Jackson, one of the leading researchers on the project. Jackson is a professor in the Department of Microbiology, Immunology and Pathology.

“While randomly testing a group of compounds against the bacterium in the lab, we found one class of compounds that powerfully stops the growth of the bacterium, a significant finding on its own.

When we looked closer, we found that the compounds stopped a transporter from moving mycolic acids from inside to outside the cell, which also means this discovery identified a new method of killing the bacterium.

Scientists have been trying to find the transporter of mycolic acids for decades, knowing that understanding how to stop mycolic acids from reaching the surface of the cell could lead to new tuberculosis treatments.

“If mycolic acids cannot be transported, the tuberculosis bacterium cannot grow,” said Mike McNeil, co-researcher on the project with Jackson and also a professor in the Department of Microbiology, Immunology and Pathology at CSU.

“It is like a factory making bricks and no way to get them to the construction site. It is a long, hard road to develop new, badly-needed tuberculosis drugs. Still, we are optimistic that this research will strongly contribute to the worldwide crusade to diminish suffering and death caused by tuberculosis.”

Jackson, McNeil and partner researchers from CSU and St. Jude Children’s Hospital in Memphis also note that there are other potential transporters in the bacterium that resemble the one just found.

“We hope that our work also will pave the way to understanding what those transporters do in the cell and finding how to target them to kill the mycobacteria,” Jackson said.

Tuberculosis causes the death of more than 1.5 million people around the globe each year.

Kuiper Belt Researchers Study Object During A Stellar Occultation

First Team To Study A Kuiper Belt Object During A Stellar Occultation

Until now, astronomers have used telescopes to find Kuiper Belt objects (KBOs), moon-sized bodies, and obtain their spectra to determine what types of ices are on their surface.

They have also used thermal-imaging techniques to get a rough idea of the size of KBOs, but other details have been difficult to glean.

While astronomers think there are about 70,000 KBOs that are larger than 100 kilometers in diameter, the objects' relatively small size and location make it hard to study them in detail.

One method that has been has been proposed for studying KBOs is to observe one as it passes briefly in front of a bright star; such events, known as stellar occultations, have yielded useful information about other planets in the solar system.

By monitoring the changes in starlight that occur during an occultation, astronomers can determine the object's size and temperature, whether it has any companion objects and if it has an atmosphere.

The trick is to know enough about the orbit of a KBO to be able to predict its path and observe it as it passes in front of a star. This was done successfully for the first time last October when a team of 18 astronomy groups led by James Elliot, a professor of planetary astronomy in MIT's Department of Earth, Atmospheric and Planetary Sciences, observed an occultation by an object named "KBO 55636."

As Elliot and his colleagues report in a paper published to be published June 17 in Nature, the occultation provided enough data to determine the KBO's size and albedo, or how strongly it reflects light. The surface of 55636 turns out to be as reflective as snow and ice, which surprised the researchers because ancient objects in space usually have weathered, dull surfaces.

The high albedo suggests that the KBO's surface is made of reflective water-ice particles, and that would support a theory about how the KBO formed. Many researchers believe there was a collision that occurred one billion years ago between a dwarf planet in the Kuiper Belt known as Haumea and another object that caused Haumea's icy mantle to break into a dozen or so smaller bodies, including 55636.

More importantly, the research demonstrates that astronomers can predict occultations accurately enough to contribute to a new NASA mission known as the Stratospheric Observatory For Infrared Astronomy (SOFIA) that completed its first in-flight observations in May.

Researchers Chart Genomic Map Spanning Over 2 Dozen Cancers

An international team of researchers has created a genome-scale map of 26 different cancers, revealing more than 100 genomic sites where DNA from tumors is either missing or abnormally duplicated compared to normal tissues.

The study, the largest of its kind, finds that most of these genetic abnormalities are not unique to one form of cancer, but are shared across multiple cancers. The work appears in the February 18 issue of the journal Nature.

"Our findings show that many genome alterations are universal across different cancers. Although this has been known for some types of changes, the degree to which so many alterations are shared was pretty surprising to us," said senior author Matthew Meyerson, a professor of pathology at the Dana-Farber Cancer Institute and senior associate member of the Broad Institute of Harvard and MIT.

"It suggests that, in the future, a driving force behind cancer treatment will be common genomic alterations, rather than tumors' tissue of origin."

Today, cancers are characterized largely by their symptoms: the organ in the body in which they first arise and the appearance of tumour cells under a microscope.

Although this information is valuable, it fails to highlight cancers' molecular underpinnings, which could be used in the laboratory to discover new, more effective cancer therapies and in the clinic to improve diagnosis and treatment.

A goal of modern biomedical research is to fill this knowledge gap and describe all cancers based on what drives them - that is, the genetic aberrations that initiate and maintain tumor growth.