*Collaboration reveals results from 100-day experiment*
Today, scientists from the XENON collaboration announced the result from their search for the elusive component of our universe known as dark matter. After analyzing one hundred days of data taken with the XENON100 experiment, they see no evidence for the existence of Weakly Interacting Massive Particles (WIMPs), the leading candidates for the mysterious dark matter. The XENON100 experiment is operated deep underground at the Gran Sasso National Laboratory of the Italian National Institute for Physics (INFN). (more…)
In a paradox typical of the quantum world, JILA scientists have eliminated collisions between atoms in an atomic clock by packing the atoms closer together. The surprising discovery, described in the Feb. 3 issue of Science Express, can boost the performance of experimental atomic clocks made of thousands or tens of thousands of neutral atoms trapped by intersecting laser beams
JILA is jointly operated by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder. (more…)
Nearly 14 billion years ago, the universe began with a bang — a big one.
Scientists believe that the universe and everything within it began as an extremely hot, dense “soup” that eventually gave rise to galaxies, stars, planets and life and that continues to expand to this day.
Now scientists around the world are pushing back the frontiers of our understanding about the moment the universe was born using the Large Hadron Collider (LHC), a giant particle accelerator at CERN (the European Organization for Nuclear Research) near Geneva, Switzerland. (more…)
ANN ARBOR, Mich.— Under just the right conditions — which involve an ultra-high-intensity laser beam and a two-mile-long particle accelerator — it could be possible to create something out of nothing, according to University of Michigan researchers.
The scientists and engineers have developed new equations that show how a high-energy electron beam combined with an intense laser pulse could rip apart a vacuum into its fundamental matter and antimatter components, and set off a cascade of events that generates additional pairs of particles and antiparticles. (more…)
Fireworks. Downtown Miami on July 4, 2007. Image credit: Marc Averette. Source: Wikipedia
Fireworks can be spectacular. However, the gas and smoke produced by the colorful explosions carry extremely high levels of toxic particles, according to a study by Audrey Smargiassi, a professor at the Université de Montreal Department of Environmental and Occupational Health.
Smargiassi conducted one of the first studies examining the composition of the emitted gases and the concentration of the particles. In addition, her study is unique as she collected her data below the fireworks display where spectators usually stand. Previous studies usually collected data from nearby rooftops.
The study was conducted in 2007 during nine separate shows presented at La Ronde amusement park where 5.7 million spectators attend an international fireworks competition every summer. (more…)
*Initial science results on comet released from University of Maryland, much more to come UMD scientists say.*
Jets Galore. This enhanced image, one of the closest taken of comet Hartley 2. Image credit: University of Maryland
COLLEGE PARK, Md. – One of the biggest comet findings coming out of the amazing images and data taken by the University of Maryland-ledEPOXI mission as it zipped past comet Hartley 2 last week is that dry ice is the ‘jet’ fuel for this comet and perhaps many others.
Images from the flyby show spectacular jets of gas and particles bursting from many distinct spots on the surface of the comet. This is the first time images of a comet have been sharp enough to allow scientists to link jets of dust and gas with specific surface features. Analysis of the spectral signatures of the materials coming from the jets shows primarily CO2 gas (carbon dioxide) and particles of dust and ice.
“Previously it was thought that water vapor from water ice was the propulsive force behind jets of material coming off of the body, or nucleus, of the comet,” said University of Maryland Astronomy Professor Jessica Sunshine, who is deputy principal investigator for the EPOXI mission. “We now have unambiguous evidence that solar heating of subsurface frozen carbon dioxide (dry ice), directly to a gas, a process known as sublimation, is powering the many jets of material coming from the comet. This is a finding that only could have been made by traveling to a comet, because ground based telescopes can’t detect CO2 and current space telescopes aren’t tuned to look for this gas,” Sunshine said.(more…)
Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air.
Some suspect that extended “volcanic winters” from gigantic eruptions helped kill off dinosaurs and Neanderthals.
In the summer following Indonesia’s 1815 Tambora eruption, frost wrecked crops as far away as New England, and the 1991 blowout of the Philippines’ Mount Pinatubo lowered average global temperatures by 0.7 degrees F — enough to mask the effects of greenhouse gases for a year or so. (more…)
