Tag Archives: cosmic rays

Groundwater dating

Sturchio co-authors Nature Geoscience paper on technique to date groundwater

Neil Sturchio, chair of the Department of Geological Sciences at University of Delaware, is co-author of a Nature Geoscience paper detailing a pioneering new technique to date groundwater

Knowing the age of the groundwater provides important clues about the sustainability of water resources, information that is particularly important in dry or arid climates.  (more…)

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It’s go time for LUX-Zeplin experiment in dark matter

From the physics labs at Yale University to the bottom of a played-out gold mine in South Dakota, a new generation of dark matter experiments is ready to commence.

The U.S. Department of Energy’s Office of Science and the National Science Foundation recently gave the go-ahead to LUX-Zeplin (LZ), a key experiment in the hunt for dark matter, the invisible substance that may make up much of the universe. Daniel McKinsey, a professor of physics, leads a contingent of Yale scientists working on the project. (more…)

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Do We Live in a Computer Simulation? UW Researchers Say Idea Can be Tested

A decade ago, a British philosopher put forth the notion that the universe we live in might in fact be a computer simulation run by our descendants. While that seems far-fetched, perhaps even incomprehensible, a team of physicists at the University of Washington has come up with a potential test to see if the idea holds water.

The concept that current humanity could possibly be living in a computer simulation comes from a 2003 paper published in Philosophical Quarterly by Nick Bostrom, a philosophy professor at the University of Oxford. In the paper, he argued that at least one of three possibilities is true:

  • The human species is likely to go extinct before reaching a “posthuman” stage.
  • Any posthuman civilization is very unlikely to run a significant number of simulations of its evolutionary history.
  • We are almost certainly living in a computer simulation. (more…)

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The Search for Dark Matter Goes Deeper Underground

With LUX ZEPLIN Berkeley Lab researchers seek to increase the sensitivity of LUX, the most sensitive search for dark matter yet, by orders of magnitude

Although it’s invisible, dark matter accounts for at least 80 percent of the matter in the universe. No one knows what it is, but most scientists would bet on weakly interacting massive particles, or WIMPs.

LUX, the Large Underground Xenon detector at the Sanford Underground Research Facility in the Black Hills of South Dakota, is calling that bet with a titanium bottle holding 350 kilograms of liquid xenon, placed in a cavern 4,850 feet down in the former Homestake gold mine. LUX is a trap set for dark-matter WIMPs. (more…)

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Titanium Paternity Test Fingers Earth as Moon’s Sole Parent

A new chemical analysis of lunar material collected by Apollo astronauts in the 1970s conflicts with the widely held theory that a giant collision between Earth and a Mars-sized object gave birth to the moon 4.5 billion years ago.

In the giant-collision scenario, computer simulations suggest that the moon had two parents: Earth and a hypothetical planetary body that scientists call “Theia.” But a comparative analysis of titanium from the moon, Earth and meteorites, published by Junjun Zhang, graduate student in geophysical sciences at the University of Chicago, and four co-authors indicates the moon’s material came from Earth alone. (more…)

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The First Spectroscopic Measurement of an Anti-Atom

*Berkeley Lab scientists helped build and operate the ALPHA antimatter trap at CERN, which has now probed the internal structure of the antihydrogen atom for the first time, taking the first step toward possible new insights into the difference between matter and antimatter*

The ALPHA collaboration at CERN in Geneva has scored another coup on the antimatter front by performing the first-ever spectroscopic measurements of the internal state of the antihydrogen atom. Their results are reported in a forthcoming issue of Nature and are now online.

Ordinary hydrogen atoms are the most plentiful in the universe, and also the simplest – so simple, in fact, that some of the most fundamental physical constants have been discovered by measuring the tiny energy shifts resulting from the magnetic and electric interactions of hydrogen’s proton nucleus with its single orbiting electron. (more…)

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First Data from Daya Bay: Closing in on a Neutrino Mystery

*Berkeley Lab researchers are leaders in an international effort to close in on neutrino mass*

Some of the most intriguing questions in basic physics focus on neutrinos. How much do the different kinds weigh and which is the heaviest? The answers lie in how the three “flavors” of neutrinos – electron, muon, and tau neutrinos – oscillate or mix, changing from one to another as they race virtually without interruption through unbounded reaches of matter and space.

Three mathematical terms known as “mixing angles” described the process, and the Daya Bay Reactor Neutrino Experiment has just begun taking data to establish the last, least-known mixing angle to unprecedented precision. China and the United States lead the international Daya Bay Collaboration, including participants from Russia, the Czech Republic, Hong Kong, and Taiwan. U.S. participation is led by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). (more…)

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Dawn Reaches Milestone Approaching Asteroid Vesta

PASADENA, Calif. — NASA’s Dawn spacecraft has reached its official approach phase to the asteroid Vesta and will begin using cameras for the first time to aid navigation for an expected July 16 orbital encounter. The large asteroid is known as a protoplanet — a celestial body that almost formed into a planet.

At the start of this three-month final approach to this massive body in the asteroid belt, Dawn is 1.21 million kilometers (752,000 miles) from Vesta, or about three times the distance between Earth and the moon. During the approach phase, the spacecraft’s main activity will be thrusting with a special, hyper-efficient ion engine that uses electricity to ionize and accelerate xenon. The 12-inch-wide ion thrusters provide less thrust than conventional engines, but will provide propulsion for years during the mission and provide far greater capability to change velocity. (more…)

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