Amazing Science

A team of researchers has discovered a flaw in the way past ocean temperatures have been estimated up to now. Their findings could mean that the current period of climate change is unparalleled over the last 100 million years.

A low level of atmospheric oxygen in Earth's middle ages held back evolution for 2 billion years, raising fresh questions about the origins of life on this planet. New research by the University of Exeter explains how oxygen was trapped at such low levels.

Professor Tim Lenton and Dr Stuart Daines of the University of Exeter Geography department, created a computer model to explain how oxygen stabilised at low levels and failed to rise any further, despite oxygen already being produced by early photosynthesis. Their research helps explain why the 'great oxidation event', which introduced oxygen into the atmosphere around 2.4 billion years ago, did not generate modern levels of oxygen.

In their paper, published in Nature Communications, Atmospheric oxygen regulation at low Proterozoic levels by incomplete oxidative weathering of sedimentary organic carbon, the University of Exeter scientists explain how organic material -- the dead bodies of simple lifeforms -- accumulated in the earth's sedimentary rocks. After the Great Oxidation, and once plate tectonics pushed these sediments to the surface, they reacted with oxygen in the atmosphere for the first time.

The more oxygen in the atmosphere, the faster it reacted with this organic material, creating a regulatory mechanism whereby the oxygen was consumed by the sediments at the same rate at which it was produced. This mechanism broke down with the rise of land plants and a resultant doubling of global photosynthesis. The increasing concentration of oxygen in the atmosphere eventually overwhelmed the control on oxygen and meant it could finally rise to the levels we are used to today. This helped animals colonize the land, leading eventually to the evolution of humankind.

The model suggests atmospheric oxygen was likely at around 10% of present day levels during the two billion years following the Great Oxidation Event, and no lower than 1% of the oxygen levels we know today.

A team of researchers from Princeton University, the Scripps Institution of Oceanography, the University of Maine and Oregon State University has drilled and retrieved a 2.7-million-year-old ice core from a spot in Antarctica.

Until recently, scientists believed that ice core samples taken from either pole had an age limit of approximately 800,000 years—this was because ice at the bottom melted due to heat from inside the Earth. But a team at Princeton discovered a few year ago that another type of ice could hold much older ice known as blue ice. It forms on glaciers due to snowfall which, over time, becomes compressed, squeezing out air bubbles, making the ice look blue. But it also has another characteristic—over time, the ice at the bottom is pushed upwards, protecting it from melting. In this new effort, the team drilled at a site called the Allan Hills, near McMurdo Station.

Ice cores taken from glaciers present problems because they are more difficult to date—cores from other places are dated by counting their layers. The older ice, it was found, could be dated by studying trace amounts of potassium and argon—though not as precise as layer counting, the researchers believe it is accurate to within 100,000 years. One of the first teams to take a core sample from the older ice drilled to a depth of 128 meters. In this latest effort, the team drilled to 205 meters and found ice that was nearly twice as old.

Ice cores are important because they contain very small air bubbles that are samples of atmospheric conditions. Air bubbles from 2.7 million years ago offer evidence of climactic conditions during the time before the ice ages began, perhaps offering clues as to why they occurred. Already, the team has found that atmospheric carbon dioxide levels were at approximately 300 ppm, which is considerably lower than today's 400 ppm. But the team notes that the core sample represents something perhaps even more exciting—the possibility of finding core samples that are much older, perhaps as old as 5 million years.

What's happening behind those houses? Pictured here are not auroras but nearby light pillars, a nearby phenomenon that can appear as a distant one. In most places on Earth, a lucky viewer can see a Sun-pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere. Usually these ice crystals evaporate before reaching the ground. During freezing temperatures, however, flat fluttering ice crystals may form near the ground in a form of light snow, sometimes known as a crystal fog. These ice crystals may then reflect ground lights in columns not unlike a Sun-pillar. The featured image was taken in FortWainwright near Fairbanks in central Alaska.

Google has partnered with the European Commission’s Joint Research Centre to produce the greatest views of water on the surface of Earth ever. The images show changing water levels, and reveal some of the stories behind the changes from the past three decades to see how they "have shaped the world over time, in unprecedented detail." The project took more than three years and involved thousands of computers downloading 1.8 petabytes of data from the USGS/NASA Landsat satellite program. Each pixel in 3 million satellite images, going back to 1984, was analyzed by an algorithm developed by the Joint Research Centre running on the Google Earth Engine platform.

More than 10 million hours of computing time was needed for this, roughly equivalent to a modern 2-core computer running day and night for 600 years. From this, the researchers were able to establish that, over the past 32 years, 90,000 square kilometers of water - the equivalent of half of the lakes in Europe - have vanished, while 200,000 square kilometers of new, mostly man-made water bodies appeared.

The continuing drying up of the Aral Sea in Uzbekistan and Kazakhstan accounts for the biggest loss in the world. Iran and Afghanistan lost over a half, Iraq over a third of its water area.

The mantle - the mostly solid, rocky part of Earth's interior - is about 60 degrees Celsius hotter than previously thought, a new study has found.

The findings led by Woods Hole Oceanographic Institution (WHOI) in the US could change how scientists think about many issues in Earth science including how ocean basins form.

Sarafian modified her starting sample by adding spheres of a mineral called olivine, which occurs naturally in the mantle. The spheres were large enough for Sarafian to analyse their water content using secondary ion mass spectrometry (SIMS). From there, she was able to calculate the water content of her entire starting sample. To her surprise, she found it contained approximately the same amount of water known to be in the mantle. Based on her results, Sarafian concluded that mantle melting had to be starting at a shallower depth under the seafloor than previously expected.

To verify her results, Sarafian turned magnetotellurics - a technique that analyses the electrical conductivity of the crust and mantle under the seafloor. Reconciling the temperatures and pressures Sarafian measured in her experiments with the melting depth from an earlier study led her to a startling conclusion: The oceanic upper mantle must be 60 degrees Celsius hotter than current estimates.

The Earth's geomagnetic field increased in intensity around the Levant during the late eighth century B.C. before rapidly weakening.

The Earth is surrounded by a magnetic field that arises from the motion of iron in the liquid outer core. Direct observation of the field has been possible for only about 180 years, Ben-Yosef told Live Science. In that time, the field has weakened by about 10 percent, he said. Some researchers think the fieldmight be in the process of flipping, so that magnetic north becomes magnetic south and vice versa.

The new study reveals much faster changes in intensity. There was a spike in intensity during the late eighth century B.C., culminating in a rapid decline after about 732 B.C., Ben-Yosef and his colleagues reported today (Feb. 13) in the journal Proceedings of the National Academy of the Sciences. In a mere 31 years beginning in the year 732 B.C., there was a 27 percent decrease in the strength of the magnetic field, the researchers found. From the sixth century B.C. to the second century B.C., the field was generally stable, with a slight gradual decline.

"Our research shows that the field is very fluctuating," Ben-Yosef said. "It fluctuates quite rapidly, so there is nothing to worry about," as far as the current decline, he said. This doesn't mean that the magnetic field isn't going to flip in the near future; the new study looked at only strength of the field, not directionality. The findings do suggest that there's no reason to worry that a 10 percent decline in the field strength over more than a century is abnormal, Ben-Yosef said.

At least in the Levant, that is. All of the pottery in the study came from this region, which encompasses what is now Syria, Jordan, Israel, Palestine, Lebanon and nearby areas. That means researchers can't be sure whether the same fluctuations were happening elsewhere. Because the scientists also don't know for sure the precise locations within the Levant where the pottery was fired, they can't say anything about the direction of the geomagnetic field at the time, only its strength.

Kids are frequently taught that seven continents exist: Africa, Asia, Antarctica, Australia, Europe, North America, and South America. Geologists, who look at the rocks (and tend to ignore the humans), group Europe and Asia into its own supercontinent - Eurasia - making for a total of six geologic continents.

But according to a new study of Earth's crust, there's a seventh geologic continent called 'Zealandia', and it has been hiding under our figurative noses for millennia. The 11 researchers behind the study argue that New Zealand and New Caledonia aren't merely an island chain.

Instead, they're both part of a single, 4.9-million-square kilometer (1.89 million-square-mile) slab of continental crust that's distinct from Australia. "This is not a sudden discovery but a gradual realization; as recently as 10 years ago we would not have had the accumulated data or confidence in interpretation to write this paper," they wrote in GSA Today, a Geological Society of America journal.

Ten of the researchers work for organizations or companies within the new continent; one works for a university in Australia.

But other geologists are almost certain to accept the research team's continent-size conclusions, says Bruce Luyendyk, a geophysicist at the University of California, Santa Barbara (he wasn't involved in the study). "These people here are A-list earth scientists," Luyendyk explains. "I think they have put together a solid collection of evidence that's really thorough. I don't see that the

These transient features are so named because they last about 20 milliseconds.

Scientists don't know much about the mysterious, powerful electric discharges that sometimes occur in the upper levels of the atmosphere in conjunction with thunderstorms. The first photograph of the phenomenon—which can occur as high as about 90km above the surface of the Earth and are known variously as sprites, pixies, elves, or jets—was only taken from Earth in 1989.

Fortunately for scientists interested in these storms, the International Space Station offers an excellent vantage point at an altitude of about 400km. So Danish researchers devised a "Thor experiment"—named after the hammer-wielding Norse god—to study the phenomenon. As part of the experiment, an astronaut on board the station would image thunderstorms under certain conditions, and these observations would be correlated with data collected by satellites and ground-based radar and lightning detection systems.

Tremendous amounts of soot, lofted into the air from global wildfires following a massive asteroid strike 66 million years ago, would have plunged Earth into darkness for nearly two years, new research finds. This would have shut down photosynthesis, drastically cooled the planet, and contributed to the mass extinction that marked the end of the age of dinosaurs.

 These new details about how the climate could have dramatically changed following the impact of a 10-kilometer-wide asteroid will be published Aug. 21 in the Proceedings of the National Academy of Sciences. The study, led by the National Center for Atmospheric Research (NCAR) with support from NASA and the University of Colorado Boulder, used a world-class computer model to paint a rich picture of how Earth's conditions might have looked at the end of the Cretaceous Period, information that paleobiologists may be able to use to better understand why some species died, especially in the oceans, while others survived.

Scientists estimate that more than three-quarters of all species on Earth, including all non-avian dinosaurs, disappeared at the boundary of the Cretaceous-Paleogene periods, an event known as the K-Pg extinction. Evidence shows that the extinction occurred at the same time that a large asteroid hit Earth in what is now the Yucatán Peninsula. The collision would have triggered earthquakes, tsunamis, and even volcanic eruptions.

Scientists also calculate that the force of the impact would have launched vaporized rock high above Earth's surface, where it would have condensed into small particles known as spherules. As the spherules fell back to Earth, they would have been heated by friction to temperatures high enough to spark global fires and broil Earth's surface. A thin layer of spherules can be found worldwide in the geologic record.

"The extinction of many of the large animals on land could have been caused by the immediate aftermath of the impact, but animals that lived in the oceans or those that could burrow underground or slip underwater temporarily could have survived," said NCAR scientist Charles Bardeen, who led the study. "Our study picks up the story after the initial effects—after the earthquakes and the tsunamis and the broiling. We wanted to look at the long-term consequences of the amount of soot we think was created and what those consequences might have meant for the animals that were left."

Researchers collaborated with citizen scientists and astrophotographers to pinpoint a mysterious new aurora feature, nicknamed "Steve."

Photographer Dave Markel caught this view of a strange aurora-like feature that appears in the skies of northern Canada. Based on data from European Space Agency's Swarm satellites, it appears to be a 16-mile-wide (25 km) ribbon of flowing gas in an area whose temperature is 5,500 degrees Fahrenheit (3,000 degrees Celsius) higher than the surroundings; the gas flows at 3.5 miles per second (6 km/s) compared to a speed of 33 feet/second (10 m/s) on either side of the ribbon. They're calling the feature "Steve."

What caused the largest glaciation event in Earth's history, known as 'snowball Earth'? Geologists and climate scientists have been searching for the answer for years but the root cause of the phenomenon remains elusive.

Now, Harvard University researchers have a new hypothesis about what caused the runaway glaciation that covered Earth pole-to-pole in ice. The research is published in Geophysical Research Letters.

Researchers have pinpointed the start of what's known as the Sturtian snowball Earth event to about 717 million years ago -- give or take a few 100,000 years. At around that time, a huge volcanic event devastated an area from present-day Alaska to Greenland. Coincidence?

Harvard professors Francis Macdonald and Robin Wordsworth thought not. "We know that volcanic activity can have a major effect on the environment, so the big question was, how are these two events related," said Macdonald, the John L. Loeb Associate Professor of the Natural Sciences.

At first, Macdonald's team thought basaltic rock -- which breaks down into magnesium and calcium -- interacted with CO2 in the atmosphere and caused cooling. However, if that were the case, cooling would have happened over millions of years and radio-isotopic dating from volcanic rocks in Arctic Canada suggest a far more precise coincidence with cooling.

Macdonald turned to Wordsworth, who models climates of non-Earth planets, and asked: could aerosols emitted from these volcanos have rapidly cooled Earth? The answer: yes, under the right conditions.

"It is not unique to have large volcanic provinces erupting," said Wordsworth, assistant professor of Environmental Science and Engineering at the Harvard John A. Paulson School of Engineering and Applied Science. "These types of eruptions have happened over and over again throughout geological time but they're not always associated with cooling events. So, the question is, what made this event different?"

Geological and chemical studies of this region, known as the Franklin large igneous province, showed that volcanic rocks erupted through sulfur-rich sediments, which would have been pushed into the atmosphere during eruption as sulfur dioxide. When sulfur dioxide gets into the upper layers of the atmosphere, it's very good at blocking solar radiation. The 1991 eruption of Mount Pinatubo in the Philippines, which shot about 10 million metric tons of sulfur into the air, reduced global temperatures about 1 degree Fahrenheit for a year.

Sulfur dioxide is most effective at blocking solar radiation if it gets past the tropopause, the boundary separating the troposphere and stratosphere. If it reaches this height, it's less likely to be brought back down to earth in precipitation or mixed with other particles, extending its presence in the atmosphere from about a week to about a year. The height of the tropopause barrier all depends on the background climate of the planet -- the cooler the planet, the lower the tropopause.

"In periods of Earth's history when it was very warm, volcanic cooling would not have been very important because Earth would have been shielded by this warm, high tropopause," said Wordsworth. "In cooler conditions, Earth becomes uniquely vulnerable to having these kinds of volcanic perturbations to climate."

University of Miami Rosenstiel School of Marine and Atmospheric Science scientist Mark Donelan and his Norwegian Meteorological Institute colleague captured new information about extreme waves, as one of the steepest ever recorded passed by the North Sea Ekofisk platforms in the early morning hours of Nov. 9 2007.

Within the first hour of the day, the Andrea wave passed by a four-point square array of ocean sensors designed by the researchers to measure the wavelength, direction, amplitude and frequency of waves at the ocean surface. Using the information from the wave set—a total of 13,535 individual waves—collected by the system installed on a bridge between two offshore platforms, the researchers took the wave apart to examine how the components came together to produce such a steep wave.

The data from the 100-meter wide “wall of water” moving at 40 miles per hour showed that Andrea may have reached heights greater than the recorded height of 49 feet above mean sea level. They also found that rogue waves are not rare as previously thought and occur roughly twice daily at any given location in a storm. The findings showed that the steeper the waves are, the less frequent their occurrence, which is about every three weeks at any location for the steepest rogues.

The Andrea crest height was 1.63 times the significant height (average height of the one third highest waves).

Optimal focusing of the Andrea wave showed that the crest could have been even higher and limited by breaking at 1.7 times the significant height. This establishes the greatest height rogues can reach for any given (or forecasted) significant height. “Rogue waves are known to have caused loss of life as well as damage to ships and offshore structures,” said Mark Donelan, professor emeritus of ocean sciences at the UM Rosenstiel School. “Our results, while representing the worst-case rogue wave forecast, are new knowledge important for the design and safe operations for ships and platforms at sea.”

The study, titled “The Making of the Andrea Wave and other Rogues,” was published in the March 8 issue of the journal Scientific Reports. The authors include: Donelan and Anne-Karin Magnusson from the Norwegian Meteorological Institute. The work was partly performed within the ExWaMar project (ID 256466/O80) funded by the Norwegian Research Council. ConocoPhillips provided the wave data.

It took billions of years for most of the Earth's minerals to form, but scientists say hundreds more have been created in the years since the industrial revolution.

Human-made minerals created in the years since the industrial revolution have been uncovered by scientists, who want them to be accepted as real minerals. Armed with the discovery, they are pushing to have the geological time scale recognise 'the Anthropocene' time period — or the epoch of human activity.

"We define different periods of Earth history by the distinctive things we find in them," said Robert Hazen, a mineralogist at Washington's Carnegie Institution for Science. "They [the minerals] would tell future geologists that something was different about this layer — I think there is no question about it."

The new minerals were created by chance, when substances that would otherwise have never encountered one another came into contact as a result of human activity.