In 1998, Paul F. Hoffman and Daniel P. Schrag at Harvard University put forth a chilling description of earths climate some 650 million years ago. Their theory, dubbed snowball earth, held that between 750 million and 580 million years ago, ice repeatedly enveloped our planet, coating the seas from pole to pole and killing off early life almost completely. During the past few years, the idea has stirred up a great deal of debate. And new data published in the December issue of Geology only further throws snowball earth into question.
Lead author Martin Kennedy at the University of California, Riverside, and colleagues collected limestone and dolomite rocks from Precambrain glacial deposits in northern Namibia, central Australia and the North American Cordillera. When they analyzed these samples, they discovered that the ratio of the carbon isotope 13C to 12C was higher during the glaciation than after the ice had melted. This pattern, they say, suggests that the oceans supported a healthy ecosystem at the time — which would be hard to do were they frozen over.
"If there was no photosynthesis or life in the ocean, the carbon isotope values would be the same as the mantle," Kennedy says. "Only the presence of life causes a difference in those values. We did not find isotopic evidence that a global ice sheet impacted overall marine productivity. We would think that if an ice sheet covered the oceans it would have had an impact on marine production or photosynthesis and we find no carbon isotopic evidence for this. The oceans just look normal."
Kristin Leutwyler | Scientific American
Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America
Ice stream draining Greenland Ice Sheet sensitive to changes over past 45,000 years
14.05.2018 | Oregon State University
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology