In the first study to directly measure when and how quickly rivers outside of growing mountain ranges cut through rock, geologists at the University of Vermont have determined that it was about 35,000 years ago that the Susquehanna and Potomac rivers, respectively, began carving out the Great Falls of the Potomac and Holtwood Gorge. Great Falls, located about 15 miles outside of Washington, D.C., hosts hundreds of thousands of visitors each year; Holtwood Gorge lies along the Susquehanna River, near Harrisburg, Penn.
As reported in the July 23 issue of the journal Science, the geologists analyzed rock samples collected from the gorges for 10-beryllium, a very rare isotope that is produced when cosmic rays collide with rocks and sediments at the earth’s surface. These analyses helped them gauge when the rivers abandoned their ancient beds and, consequently, exposed bare rock surfaces, known as terraces, where people climb and hike today. Knowing the age of each river terrace and its height above its current river bed, they were able to calculate how quickly the rivers cut through bedrock. Their conclusions: Incision of the 10- to 20-meter-deep gorges happened at a rate far more rapid than previously thought, and was prompted more by regional climate changes tied to the last ice age than by water pouring from melting glacial ice.
“The period of incision we measured correlates with a period of cold and stormy climate during the last glacial period that is also recorded in ice cores drilled into the Greenland ice sheet,” said Luke Reusser, a graduate student of geology at the University of Vermont and lead author of “Rapid Late Pleistocene Incision of Atlantic Passive-Margin River Gorges.”
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The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
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15.11.2017 | Event News
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