If a time machine could take us back 4.6 billion years to the Earths birth, wed see our sun shining 20 to 25 percent less brightly than today. Without an earthly greenhouse to trap the suns energy and warm the atmosphere, our world would be a spinning ball of ice. Life may never have evolved.
But life did evolve, so greenhouse gases must have been around to warm the Earth. Evidence from the geologic record indicates an abundance of the greenhouse gas carbon dioxide. Methane probably was present as well, but that greenhouse gas doesnt leave enough of a geologic footprint to detect with certainty. Molecular oxygen wasnt around, indicate rocks from the era, which contain iron carbonate instead of iron oxide. Stone fingerprints of flowing streams, liquid oceans and minerals formed from evaporation confirm that 3 billion years ago, Earth was warm enough for liquid water.
Now, the geologic record revealed in some of Earths oldestrocks is telling a surprising tale of collapse of that greenhouse -- and its subsequent regeneration. But even more surprising, say the Stanford scientists who report these findings in the May 25 issue of the journal Geology, is the critical role that rocks played in the evolution of the early atmosphere.
Dawn Levy | Stanford University
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16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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12.07.2018 | Event News
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