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Gizmorama - August 2, 2017

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The search for water inside the Earth's mantle has been made much easier thanks to electrical conductivity.

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,

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*-- Conductivity measurements to help scientists map water in Earth's mantle --*

Scientists at Lawrence Livermore National Laboratory believe their improved understanding of electrical conductivity inside Earth's mantle will help them map the distribution of water inside Earth.

Earth is the only planet in the solar system to develop plate tectonics and large liquid water oceans on its surface. Planetary scientists believe the distribution of significant amounts of water inside Earth's mantle is linked with the two phenomena.

Understanding the diffusion of hydrogen in the mantle is key to measuring the distribution of water inside Earth. Hydrogen plays an important role in encouraging electric conductivity, but researchers haven't been able to accurately quantify the relationship between hydrogen and conductivity.

To do so, scientists looked to olivine, the most abundant mineral in the upper mantle.

"We approached the problem from a different perspective, using new hydrogen diffusion measurements to infer what the contribution of hydrogen would be to electrical conductivity," lead researcher Wyatt Du Frane, a scientists at LLNL, said in a news release. "Our experiments on olivine indicated a larger temperature dependence than previously thought to occur for this phenomenon. The contribution of hydrogen to electrical conductivity, while modest at lower temperatures, becomes quite large at the temperatures expected to occur in the mantle."

Not only does the diffusion of hydrogen help explain the high conductivity measured in the upper mantle, it also confirms the significant concentration of dissolved water in Earth's interior.

"The amount of hydrogen required to match geophysical measurements of electrical conductivity inside Earth are in line with the concentrations that are observed in oceanic basalts," Du Frane said. "This demonstrates that geophysical measurements of electrical conductivity are a promising tool for mapping out water distributions deep inside the Earth."

Scientists detailed their analysis of hydrogen diffusion and conductivity in olivine in the journal Scientific Reports.

*-- Dark Energy Camera helps astronomers study the cosmic 'dark ages' --*

New observations of faraway, early galaxies are helping astronomers pinpoint the birth of the earliest stars and galaxies, as well as the reionization of the cosmos. The observation were captured by the Dark Energy Camera, an instrument on the Victor M. Blanco Telescope in Chile.

The reionization of the universe occurred between 300 million years and one billion years after the Big Bang, but astronomers haven't been able to determine exactly when and how quickly it happened.

The phenomenon describes the ionization of hydrogen gas as the first stars, quasars, galaxies and black holes came into existence. Prior to the reionization, the universe was without distinct light sources. Diffuse light dominated, and most radiation was absorbed by neutral hydrogen gas.

But as stars, galaxies and other cosmic objects ionized the gas, a full range of wavelengths were able to penetrate the intergalactic voids.

"Before re-ionization, these galaxies were very hard to see, because their light is scattered by gas between galaxies, like a car's headlights in fog," Sangeeta Malhotra, an astronomer at Arizona State University, said in a news release. "As enough galaxies turn on and 'burn off the fog' they become easier to see. By doing so, they help provide a diagnostic to see how much of the 'fog' remains at any time in the early universe."

The Dark Energy Camera, or DECam, allows astronomers to survey the red end of the visible spectrum, as well near-infrared light, from the early universe. Researchers used a filter to make the DECam even more sensitive to the earliest galaxies in the cosmos.

"The combination of large survey size and sensitivity of this survey enables us to study galaxies that are common but faint, as well as those that are bright but rare, at this early stage in the universe," said Malhotra.

Early results from the DECam survey -- part of the "Lyman Alpha Galaxies in the Epoch of Reionization" project -- suggest the majority of the reionization process was triggered by galaxies born when the universe was just 800 million years old.

As scientists find and analyze more early galaxies, they will be able to build a more accurate timeline of the epoch of reionization.


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