A rough, whitish block recovered from an Elizabethan shipwreck may be a sunstone, the fabled crystal believed by some to have helped Vikings and other medieval seafarers navigate the high seas, researchers say. That's because of a property known as birefringence, which splits light beams in a way that can reveal the direction of their source with a high degree of accuracy.
Salmon are beginning to swim up the Elwha River for the first time in more than a century. But University of Washington marine geologists are watching what’s beginning to flow downstream—sediments from the largest dam-removal project ever undertaken. It turns out there is even more sediment than originally thought—about 34 million cubic yards.
Unlike conventional electrical insulators, which do not conduct electricity, topological insulators have the unique property of conducting electricity on their surface, while acting as an insulator inside. In a step toward understanding and exploiting an exotic form of matter that has been sparking excitement for potential applications in a new genre of supercomputers, scientists are reporting the first identification of a naturally occurring topological insulator that was retrieved from an abandoned gold mine in the Czech Republic.
New research led by the University of Washington challenges the 140-year-old assumption that finding fossilized remains of prehistoric animals with such teeth meant the animals were living in grasslands and savannas. Instead it appears certain South American mammals evolved the teeth in response to the gritty dust and volcanic ash they encountered while feeding in an ancient tropical forest.
Millions of people in Bangladesh and neighboring countries are chronically exposed to arsenic-contaminated groundwater, which causes skin lesions and increases the risk of certain cancers. According to an international team of scientists, human activities are not the primary cause of arsenic found in groundwater in Bangladesh. They found instead that the arsenic is part of a natural process that predates any recent human activity, such as intensive pumping.
New research on a mineral called molybdenite by a team led by Robert Hazen at Carnegie's Geophysical Laboratory provides important new insights about the changing chemistry of our planet as a result of geological and biological processes. Analysis of the mineral showed that concentrations of rhenium, a trace element that is sensitive to oxidation reactions, increased significantly—by a factor of eight—over the past three billion years.
National Science Foundation-funded researchers at Amherst College in Massachusetts and the University of Texas at Austin have described a new technique based in particle physics that might one day reveal, in more detail than ever before, the composition and characteristics of the deep Earth. There's just one catch: the technique relies on a fifth force of nature that has not yet been detected, but some particle physicists think it might exist.
By analyzing Mercury's rocky surface, scientists have been able to partially reconstruct the planet's history over billions of years. Now, drawing upon the chemical composition of rock features on the planet's surface, scientists have proposed that Mercury may have harbored a large, roiling ocean of magma very early in its history, shortly after its formation about 4.5 billion years ago.
Fresh off drilling into a rock for the first time, the Mars rover Curiosity is prepping for the next step—dissecting the pulverized rock to determine what it's made of. NASA said Wednesday it received confirmation that Curiosity successfully collected a tablespoon of powder from the drilling two weeks ago and was poised to transfer a pinch to its onboard laboratories. It's the first time a spacecraft has bored into a rock on Mars to retrieve a sample from the interior.
Traces of water have been detected within the crystalline structure of mineral samples from the lunar highland upper crust obtained during the Apollo missions, according to a University of Michigan researcher and his colleagues. The lunar highlands are thought to represent the original crust, crystallized from a magma ocean on a mostly molten early moon. The new findings indicate that the early moon was wet and that water there was not substantially lost during the moon's formation.
Scientists have found more than 50 tiny fragments of a meteor that exploded over Russia's Ural Mountains with the power of dozens of atomic bombs. Most are less than a centimeter in diameter, but locals saw a big meteorite fall into the lake on Friday, leaving a 6-m-wide hole in the ice. A meteor up to 50-60 cm could eventually be found in the lake.
Scientists at the University of Wisconsin-Madison are helping search for evidence of alien life not by looking into outer space, but by studying some rocks right here on Earth. Some of the rocks are up to 3.5 billion years old. The scientists are looking for crucial information to understand how life might have arisen elsewhere in the universe and guide the search for life on Mars one day.
In a Mars first, the Curiosity rover drilled into a rock and prepared to dump an aspirin-sized pinch of powder into its onboard laboratories for closer inspection. Using the drill at the end of its 7-foot-long robotic arm, Curiosity on Friday chipped away at a flat, veined rock bearing numerous signs of past water flow. The exercise was so complex that engineers spent several days commanding Curiosity to tap the rock outcrop, drill test holes and perform a "mini-drill" in anticipation of the real show.
A new Rice University-led study finds the real estate mantra “location, location, location” may also explain one of Earth’s enduring climate mysteries. The study suggests that Earth’s repeated flip-flopping between greenhouse and icehouse states over the past 500 million years may have been driven by the episodic flare up of volcanoes at key locations where enormous amounts of carbon dioxide are poised for release into the atmosphere.
Researchers searching the galaxy for planets that could pass the litmus test of sustaining water-based life must find whether those planets fall in what’s known as a habitable zone. New work, led by a team of Penn State University researchers, will help scientists in that search.
Ridges in impact craters on Mars appear to be fossils of cracks in the Martian surface, formed by minerals deposited by flowing water. Water flowing beneath the surface suggests life may once have been possible on Mars.
New information coming from researchers analyzing spectrometer data from NASA's Mars Reconnaissance Orbiter (MRO), which looked down on the floor of McLaughlin Crater on the Red Planet’s surface, suggests the formation of the carbonates and clay in a groundwater-fed lake within the closed basin of the crater. The depth of the crater may have helped allow the lake to form.
Warmer temperatures due to climate change could cause soils to release additional carbon into the atmosphere, thereby enhancing climate change—but that effect diminishes over the long term. The new study sheds new light on how soil microorganisms respond to temperature and could improve predictions of how climate warming will affect the carbon dioxide flux from soils.
It looked like a fireball in the sky. It created a sonic boom. It vaporized upon entering the atmosphere. It's all of the above: The Sutter's Mill Meteorite had the force of 4 kilotons of TNT upon descent and spilled samples of itself over the towns of Columa and Lotus in northern California when it hit Earth last spring. And now a consortium of scientists has determined that the Sutter's Mill Meteorite is the most pristine sample yet collected of the rare Carbonaceous-Mighei chondrite class of meteorites.
In December 2011, Caltech mineral-physics expert Jennifer Jackson reported that she and a team of researchers had used diamond-anvil cells to compress tiny samples of iron—the main element of the Earth's core. By squeezing the samples to reproduce the extreme pressures felt at the core, the team was able to get a closer estimate of the melting point of iron. At the time, the measurements that the researchers made were unprecedented in detail. Now, they have taken that research one step further by adding infrared laser beams to the mix.
Scientists at the Universities of York and Leeds have made a significant discovery about the cause of the destruction of ozone over oceans. They have established that the majority of ozone-depleting iodine oxide observed over the remote ocean comes from a previously unknown marine source.
An international collaboration has discovered that the Earth's core formed under more oxidizing condition's than previously proposed. Through a series of laser-heated diamond anvil cell experiments at high pressure (350,000 to 700,000 atmospheres of pressure) and temperatures (5,120 to 7,460 F), the team demonstrated that the depletion of siderophile elements can be produced by core formation under more oxidizing conditions than earlier predictions.
Magma forms far deeper than geologists previously thought, according to new research at Rice University. The research group put very small samples of peridotite under very large pressures in a Rice laboratory to determine that rock can and does liquify, at least in small amounts, as deep as 250 kilometers in the mantle beneath the ocean floor. This explains several puzzles that have bothered scientists.
Images taken by the framing camera onboard NASA's space probe Dawn show two enormous craters in the southern hemisphere of the asteroid Vesta, a remarkable protoplanet that is a time capsule of early planet formation in the solar system. Scientists have recently found that the asteroids that created these impact features also delivered dark, carbonaceous material to the protoplanet.
A series of rapid environmental changes in East Africa roughly 2 million years ago may be responsible for driving human evolution, according to researchers at Penn State University and Rutgers University.