In work published in Science Advances, a team of researchers have determined a new pressure scale, which is critical for understanding the Earth's composition.
that they thought was 42 kilometers, but finding they had only really run 34 kilometers. While 20% might seem like a modest correction, it has big implications. An accurate pressure scale is critical for understanding the composition of the Earth.
In particular, the coreis hotly debated as it is important both for understanding our planet at present, and for understanding the evolution of the solar system in the distant past. While it is generally accepted that the core is mostly iron, evidence from tracking the propagation of seismic waves from earthquakes suggests the core also contains lighter material. When the new scale was used to interpret the seismological model, the team found that the amount of light material in theis about double what was previously expected, and indeed the total mass of light material in the entire core is probably five times, or more, that of the Earth's crust—the layer that we live on. In the new work, the team, led by Alfred Q.R. Baron of the RIKEN SPring-8 Center, and Daijo Ikuta and Eiji Ohtani of Tohoku University, used Inelastic X-ray Scattering to measure the sound velocity of a rhenium sample under pressure. A tiny rhenium sample shifts in the energy of the X-rays scattered from the rhenium were carefully measured, allowing the researchers to determine the sound velocity of the rhenium. They determined both compressional/longitudinal and shear/transverse sound velocities, and the density of the rhenium. That allowed the researchers to determine the pressure that the rhenium was subjected to. The new study provides a direct relationship between rhenium density and pressure. Baron says,"The density of rhenium at high pressure is straightforward and fast to measure, and there are many facilities worldwide where such measurements can be made. However, measuring the sound velocity is much more difficult, and, at these pressures, is probably only practically possible using RIKEN's spectrometer at BL43LXU of SPring-8." The team has done the heavy lifting so that other scientists can now use a much easier-to-measure density to determine pressure. As Ikuta, Ohtani, and Baron say,"When we used our new scale to interpret the behavior of metallic iron under high pressure and compared it with the seismic model of the Earth, we found that the light material hidden in the inner core is probably about double what was previously expected. Similar changes, perhaps even larger in magnitude, may be expected in considering the structure of other . Our work also suggests reassessment of the pressure dependence of nearly all material properties that have been measured at pressures similar or larger than that of the Earth's core."Daijo Ikuta et al, Density deficit of Earth's core revealed by a multimegabar primary pressure scale,
United States Latest News, United States Headlines
Similar News:You can also read news stories similar to this one that we have collected from other news sources.
Ukraine makes ‘further advances’ to take back more land amid worry over fighting near nuke plantGeolocated footage shows that Kyiv’s forces made “further advances” northwest of Verbove, a village in the western part of the Zaporizhzhia region, according to the U.S.-based thi…
Read more »
Operation to extract American researcher from one of the world's deepest caves advances to 700mRescue teams on Sunday in Turkey successfully carried an American researcher up from the depth of a cave at 1040 meters (3412.07 feet) to the 700-meter (2296.59 feet) mark where he will rest before they continue the taxing journey to the surface.
Read more »
Earnings Estimates Are Rising, a Welcome Sign for 2023 Market RallyStock advances have surprised many investors, partly because expectations for company earnings hadn’t kept up.
Read more »
Redefining Earth’s Core: Synchrotron Reveals Hidden Light MaterialResearchers unveil a more accurate pressure scale using advanced x-rays, revealing Earth's inner core has twice the light material previously estimated. Their methodology provides an easier path for future pressure measurements. In research published on September 8 in the journal Science Advances
Read more »