Deep below the Earth's surface lies a thick, rocky layer called the mantle, which makes up the majority of our planet's volume. For decades, scientists have known that most of the lower mantle is a silicate mineral with a perovskite structure that is stable under the high-pressure and high-temperature conditions found in this region.
It’s likely that most of the large impact craters on Earth have already been discovered and that others have been erased, according to a new calculation by a pair of Purdue Univ. graduate students. Although it's known that natural processes erase craters fairly quickly from the Earth's surface, this model was the first to quantify how many craters have likely been erased.
A moderate earthquake shook northwest Alaska on Monday, the fifth temblor of the same magnitude since April in an area with otherwise little activity, seismologists said. The swarm of magnitude-5.7 quakes is connected to more than 300 smaller aftershocks, some with magnitudes in the high 3s, Ruppert said. The series of earthquakes has scientists puzzled about activity that is considered very unusual in the region of Noatak.
Beneath the barren whiteness of Greenland, a mysterious world has popped into view. Using ice-penetrating radar, researchers have discovered ragged blocks of ice as tall as city skyscrapers and as wide as the island of Manhattan at the bottom of the ice sheet, apparently formed as water beneath the ice refreezes and warps the surrounding ice upwards. The newly revealed forms may help scientists understand more about how ice sheets behave.
Researchers report evidence for an oceans worth of water deep beneath the U.S. Though not in the familiar liquid form—the ingredients for water are bound up in rock deep in the Earth’s mantle—the discovery may represent the planet’s largest water reservoir. The presence of liquid water on the surface is what makes our “blue planet” habitable, and scientists have tried to figure out just how much water may be cycling between Earth’s surface.
The slopes of a giant Martian volcano, once covered in glacial ice, may have been home to one of the most recent habitable environments yet found on the Red Planet, according to new research led by Brown Univ. geologists. Nearly twice as tall as Mount Everest, Arsia Mons is the third tallest volcano on Mars and one of the largest mountains in the solar system.
Researchers at the Univ. of Washington have concluded that Antarctica's fast-moving Thwaites Glacier will likely disappear in a matter of centuries, potentially raising sea level by more than a half a meter. Data gathered by airborne radar, detailed topography maps and computer modeling were used to make the determination. The fastest scenario based on the data, the researchers said, is 200 years, and the longest is more than 1,000 years.
Studies of Antarctica have shown the earth is “rebounding” due to the overlying ice sheet shrinking in response to climate change. This movement of the land was understood to be an elastic response and a very slow uplift over thousands of years. But new research has revealed that the land in this region is actually rising at a phenomenal rate of 15 mm a year, much greater than can be accounted for by the present-day elastic response alone.
Volcanologists in the U.K. have discovered that a process called frictional melting plays a role in determining how a volcano will erupt by dictating how fast magma can ascend to the surface, and how much resistance it faces en-route. The process occurs in lava dome volcanoes when magma and rocks melt as they rub against each other, creating a stop start movement in the magma as it makes its way towards the earth’s surface.
Alaska's seismic network records thousands of quakes produced by glaciers, capturing valuable data that scientists could use to better understand their behavior, but instead their seismic signals are set aside as oddities. The current earthquake monitoring system could be "tweaked" to target the dynamic movement of the state's glaciers, suggests State Seismologist Michael West.
The southern hemisphere of Mars is home to a crater that contains very well-preserved gullies and debris flow deposits. According to a recent study by geology experts in Sweden, the geomorphological attributes of these landforms provide evidence that they were formed by the action of liquid water in geologically recent time.
Glaciers and ice sheets are commonly thought to work like a belt sander. As they move over the land they scrape off everything, including vegetation, soil and even the top layer of bedrock. So a team of university scientists and a NASA colleague were greatly surprised to discover an ancient tundra landscape preserved under the Greenland Ice Sheet, below two miles of ice.
Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists exploring large fields of impact glass in Argentina suggest that what happened on Earth might well have happened on Mars millions of years ago. Martian impact glass could hold traces of organic compounds.
A team of computer scientists, mathematicians and geophysicists in Germany have optimized the SeisSol earthquake simulation software at Leibniz Supercomputing Center to push its performance beyond the one petaflop/sec mark, which equates to one quadrillion floating point operations per second. SeisSol is used to investigate rupture processes and seismic waves.
In 2005, NASA's Cassini spacecraft sent pictures back to Earth depicting an icy Saturnian moon spewing water vapor and ice from fractures, known as "tiger stripes," in its frozen surface. It was big news that tiny Enceladus was such an active place. Since then, scientists have hypothesized that a large reservoir of water lies beneath that icy surface, possibly fueling the plumes.
New Yale Univ.-led research suggests how and when Earth came to develop one of its most distinct features—rigid tectonic plates—and why Venus, Earth’s twin-like neighbor, never has. Earth has a unique network of shifting plates embedded in its cold and rocky outermost layer, the lithosphere. The motion of these plates drives many Earth processes, while also stabilizing the planet’s climate and enabling life.
Fossil remains show that sometime around 252 million years ago, about 90% of all species on Earth were suddenly wiped out in what was the largest of this planet’s five known mass extinctions. But pinpointing the culprit has been difficult, and controversial. Now, a team of Massachusetts Institute of Technology researchers may have found enough evidence to convict the guilty parties, but you’ll need a microscope to see the killers.
Experts say a bigger earthquake along the lesser-known fault that gave Southern California a moderate shake on Friday could do more damage to the region than the long-dreaded "Big One" from the more famous San Andreas Fault. The Puente Hills thrust fault stretches from northern Orange County under downtown Los Angeles into Hollywood, a heavily populated swath of the Los Angeles area.
Seeking to better understand the composition of the lowermost part of Earth’s mantle, located nearly 2,900 km (1,800 miles) below the surface, a team of Arizona State Univ. researchers has developed new simulations that depict the dynamics of deep Earth. A paper published in Nature Geoscience reports the team’s findings, which could be used to explain the complex geochemistry of lava from hotspots such as Hawaii.
An international research team has documented evidence suggesting that part of the reason that the Earth has become neither sweltering like Venus nor frigid like Mars lies with a built-in atmospheric carbon dioxide regulator. Basically, ”fresh” rock exposed by uplift also emits carbon through a chemical weathering process, which replenishes the atmospheric carbon dioxide.
The frustrated attempts of a Univ. of California, Los Angeles graduate student to quantify the amount of water draining from Greenland's melting ice sheet led him to devise a new way to measure river flows from outer space, he and his professor report in a new study. The new approach relies exclusively on the measurements of a river's width over time, which can be obtained from freely available satellite imagery.
Will one-atom-thick layers of molybdenum disulfide, a compound that occurs naturally in rocks, prove to be better than graphene for electronic applications? Recent research into phenomena occurring in the crystal network of this material show signs that might prove to be the case. But physicists in Poland have shown that the nature of the phenomena occurring in layered materials are still ill-understood.
The Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. For the most part, the magnetosphere acts as a shield to protect the Earth from this high-energy solar activity. But when this field comes into contact with the sun’s magnetic field, powerful electrical currents from the sun can stream into Earth’s atmosphere.
Researchers from ETH Zurich and the Univ. of Tubingen in Europehave recently described a process that suppresses the formation of methane in soils that are rich in humic substances. The soils act as a battery, releasing to and accepting electrons from soil bacteria depending on the presence of oxygen. The study shows that electron transfer to and from humic substances is an important process with global implications for methane release.
Volcanic eruptions in the early part of the 21st century have cooled the planet, according to a study led by Lawrence Livermore National Laboratory. This cooling partly offset the warming produced by greenhouse gases. Despite continuing increases in atmospheric levels of greenhouse gases, and in the total heat content of the ocean, global-mean temperatures at the surface of the planet have shown relatively little warming since 1998.