Scientists have long speculated as to why animal species didn’t flourish sooner, once sufficient oxygen covered the Earth’s surface. Animals began to prosper at the end of the Proterozoic period, about 800 million years ago. But what about the billion-year stretch before that, when most researchers think there also was plenty of oxygen? Well, it seems the air wasn’t so great then, after all.
It’s not as bizarre as it sounds. Earth’s magnetic field has flipped many times throughout the planet’s history. Its dipole magnetic field, like that of a bar magnet, remains about the same intensity for thousands to millions of years, but for incompletely known reasons it occasionally weakens and, presumably over a few thousand years, reverses direction.
Methane-breathing microbes that inhabit rocky mounds on the seafloor could be preventing large volumes of the potent greenhouse gas from entering the oceans and reaching the atmosphere, according to a new study. The rock-dwelling microbes represent a previously unrecognized biological sink for methane and as a result could reshape scientists' understanding of where this greenhouse gas is being consumed in subseafloor habitats.
Washington State University undergraduate Kellie Wall, 21, recently looked for evidence that water influenced crystal formation in basalt, the dark volcanic rock that covers most of eastern Washington and Oregon. She then compared this with volcanic rock observations made by the rover Curiosity on Mars’ Gale Crater, inventing a new method for detecting water on Mars.
For decades, planetary geologists have speculated that glaciers might once have crept through Valles Marineris, the 2000-mile-long chasm that constitutes the Grand Canyon of Mars. A research team has now identified what could be the first mineralogical evidence of past glaciers within the Valles Marineris: a layer of mixed sulfate minerals halfway up three-mile-high cliffs in the canyon system.
Up to half of the water on Earth is likely older than the solar system itself, Univ. of Michigan astronomers theorize. The researchers' work helps to settle a debate about just how far back in galactic history our planet and our solar system's water formed. Were the molecules in comet ices and terrestrial oceans born with the system itself—in the planet-forming disk of dust and gas that circled the young sun 4.6 billion years ago?
Conditions on Earth for the first 500 million years after it formed may have been surprisingly similar to the present day, complete with oceans, continents and active crustal plates. This alternate view of Earth’s first geologic eon, called the Hadean, has gained substantial new support from the first detailed comparison of zircon crystals that formed more than 4 billion years ago with those formed contemporaneously in Iceland.
Scientists at NIST have determined that polonium-209, the longest-lived isotope of this radioactive heavy element, has a half-life about 25% longer than the previously determined value, which had been in use for decades. The new NIST measurements could affect geophysical studies such as the dating of sediment samples from ocean and lake floors.
Picture the fearsome creatures of "Jurassic Park" crossed with the shark from "Jaws." Then super-size to the biggest predator ever to roam Earth. Now add a crocodile snout as big as a person and feet like a duck's. The result gives you some idea of a bizarre dinosaur scientists unveiled Thursday. This patchwork of critters, a 50-foot predator, is the only known dinosaur to live much of its life in the water.
A new study published in The Journal of Geology provides support for the theory that a cosmic impact event over North America some 13,000 years ago caused a major period of climate change known as the Younger Dryas stadial, or “Big Freeze.” The key to the mystery of the Big Freeze lies in nanodiamonds scattered across Europe, North America, and portions of South America.
When a segment of a major fault line goes quiet, it can mean one of two things: The “seismic gap” may simply be inactive, or the segment may be a source of potential earthquakes, quietly building tension over decades until an inevitable seismic release. Researchers from Massachusetts Institute of Technology and Turkey have found evidence for both types of behavior on different segments of the North Anatolian Fault.
A high-tech survey reveals that there is more to Stonehenge than meets the eye, finding previously unknown monuments. Researchers have produced digital maps of what's beneath the World Heritage Site, using ground-penetrating radar, high-resolution magnetometers and other techniques to peer deep into the soil. And they have found some surprises.
In the typical textbook picture, volcanoes, such as those that are forming the Hawaiian islands, erupt when magma gushes out as narrow jets from deep inside Earth. But that picture is wrong, according to a new study from researchers at Caltech and the Univ. of Miami. New seismology data are now confirming that such narrow jets don't actually exist.
For years scientists have theorized about how large rocks, some weighing hundreds of pounds, zigzag across Racetrack Playa in Death Valley National Park, leaving long trails etched in the earth. Now two researchers at the Scripps Institution of Oceanography at the Univ. of California, San Diego, have photographed these "sailing rocks" being blown by light winds across the former lake bed.
An international group of scientists posit that a comet collision with Earth played a major role in the extinction of most of North America’s megafauna close to 13,000 years ago. In a new study, they have focused on the character and distribution of nanodiamonds, which are produced during such an extraterrestrial collision. The researchers found an abundance of these tiny diamonds distributed over 50 million km2 in the Northern Hemisphere.
According to a new study, in the unlikely event of a volcanic super-eruption at Yellowstone National Park, the northern Rocky Mountains would be blanketed in meters of ash, and millimeters would be deposited as far away as New York City, Los Angeles and Miami. An improved computer model finds that the hypothetical, large eruption would create a distinctive kind of ash cloud known as an umbrella, which expands evenly in all directions.
Astronomers using the Green Bank Telescope have discovered that filaments of star-forming gas near the Orion Nebula may be brimming with pebble-size particles: planetary building blocks 100 to 1,000 times larger than the dust grains typically found around protostars. If confirmed, these dense ribbons of rocky material may well represent a new, mid-size class of interstellar particles that could help jump-start planet formation.
Research published last week in Science suggested that the makeup of the Earth's lower mantle, which makes up the largest part of the Earth by volume, is significantly different than previously thought. According to scientists, the work performed at Argonne National Laboratory’s Advanced Photon Source will have a significant impact on our understanding of the lower mantle.
The tectonic plate that dominates the Pacific “Ring of Fire” is not as rigid as many scientists assume, according to researchers at Rice Univ. and the Univ. of Nevada. The researchers have determined that cooling of the lithosphere makes some sections of the Pacific plate contract horizontally at faster rates than others and cause the plate to deform.
The moon appears to be a tranquil place, but modeling done by Univ. of New Hampshire and NASA scientists suggests that, over the eons, periodic storms of solar energetic particles may have significantly altered the properties of the soil in the moon’s coldest craters through the process of sparking—a finding that could change our understanding of the evolution of planetary surfaces in the solar system.
As climate change alters habitats for birds and bees and everything in between, so too does the way humans decide to use land. Researchers have, for the first time, found a way to determine the potential combined impacts of both climate and land-use change on plants, animals and ecosystems across the country.
Since 2006, when NASA’s Stardust spacecraft delivered its aerogel and aluminum foil dust collectors back to Earth, a team of scientists has combed through them. They now report finding seven dust motes that probably came from outside our solar system, perhaps created in a supernova explosion and altered by eons of exposure to the extremes of space. They would be the first confirmed samples of contemporary interstellar dust.
From research stations drifting on ice floes to high-tech aircraft radar, scientists have been tracking the depth of snow that accumulates on Arctic sea ice for almost a century. Now that people are more concerned than ever about what is happening at the poles, research led by the Univ. of Washington and NASA confirms that snow has thinned significantly in the Arctic, particularly on sea ice in western waters near Alaska.
The Jurassic and Cretaceous periods were the golden age of dinosaurs, during which the prehistoric giants roamed the Earth for nearly 135 million years. Paleontologists have unearthed numerous fossils from these periods, suggesting that dinosaurs were abundant throughout the world. But where and when dinosaurs first came into existence has been difficult to ascertain.
Turning what seemed like a science fiction tale into reality, an unmanned probe swung alongside a comet on Wednesday after a 4-billion mile chase through outer space over the course of a decade. Europe's Rosetta probe will orbit and study the giant lump of dust and ice as it hurtles toward the sun and, if all goes according to plan, drop a lander onto the comet in the coming months.