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Greenland Ice Stores Liquid Water Year-Round

By Guest PostDecember 30, 2013Environmentairborne radar imagery, catastrophic, clement miege, climate change, effects, equation, global ocean, greenland ice, greenland ice sheet, liquid water, little data, meltwater runoff, nasa operation icebridge, perennial firn aquifer, rick forster, rising sea levels, sea level changes, store, subglacial streams, university of utah, west virginia

Potential for Storing Meltwater Important for Calculating Sea-Level Rise

Researchers at the University of Utah have discovered a new aquifer in the Greenland Ice Sheet that holds liquid water all year long in the otherwise perpetually frozen winter landscape. The aquifer is extensive, covering 27,000 square miles.

The reservoir is known as a “perennial firn aquifer” because water persists within the firn – layers of snow and ice that don’t melt for at least one season. Researchers believe it figures significantly in understanding the contribution of snowmelt and ice melt to rising sea levels. (more…)

How Computers Push on the Molecules They Simulate

By Guest PostJanuary 9, 2013Scienceacceleration, albert einstein, algorithm, analytical results, artifacts, atoms and molecules, behavior, Berkeley, berkeley lab, calculation, california, california institute, chemical fuel, collide, computer method, conserve energy, david sivak, digital representation, digitize time, dna repair, driving force, effective friction, energy dense, equation, error, finite time steps, fluid, french physicist, gavin crooks, john chodera, langevin dynamics, model brownian motion, modeling molecular system, modern computer, molecular machines, molecular scale motion, molecule, momentum, natural system, nonequilibrium driving force, nonequilibrium statistical mechanics, particle, passage of time, paul langevin, photosynthesis, pollen grain, qb3, quantitative biosciences, quantum mechanics, real world, simulation, source, tenacious errors, theoretical method, thermal energy, toy models, university, velocity, water, water molecules

Berkeley Lab bioscientists and their colleagues decipher a far-reaching problem in computer simulations

Because modern computers have to depict the real world with digital representations of numbers instead of physical analogues, to simulate the continuous passage of time they have to digitize time into small slices. This kind of simulation is essential in disciplines from medical and biological research, to new materials, to fundamental considerations of quantum mechanics, and the fact that it inevitably introduces errors is an ongoing problem for scientists.

Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have now identified and characterized the source of tenacious errors and come up with a way to separate the realistic aspects of a simulation from the artifacts of the computer method. The research was done by David Sivak and his advisor Gavin Crooks in Berkeley Lab’s Physical Biosciences Division and John Chodera, a colleague at the California Institute of Quantitative Biosciences (QB3) at the University of California at Berkeley. The three report their results in Physical Review X. (more…)

Fast Times in Physics

By Guest PostNovember 29, 2011Scienceatomic clocks, beams of neutrinos, c, Chicago, einstein, equation, Europe, faster than light, fermilab, Japan, marvin marshak, minos, neutrinos, northern minnesota, opera, physicists, scientific world, soudan underground laboratory, speed of light, subatomic particles, time, university of minnesota, vacuum, vibrations of cesium atoms

A U physicist will help determine if neutrinos can outrace light

Back in 2007, a physics experiment clocked elusive subatomic particles called neutrinos going faster than light.

That wasn’t supposed to happen. If the speed of light in a vacuum—denoted “c” by physicists—isn’t the universal speed limit, it would mean that Einstein put the wrong number in his famous E=mc² equation.

University of Minnesota physicist Marvin Marshak was part of the experiment, called MINOS. It clocked beams of neutrinos shot from Fermilab, a national physics lab near Chicago, to a detector 457 miles away in the Soudan Underground Laboratory in northern Minnesota. (more…)

Tag Archives: equation

Greenland Ice Stores Liquid Water Year-Round

How Computers Push on the Molecules They Simulate

Fast Times in Physics