Tech & Science
Technology and Science news from Boulder, Colorado
STRONGEST EVIDENCE YET INDICATES ICY SATURN MOON HIDING SALTWATER OCEAN
Jun 22nd
The new discovery was made during the Cassini-Huygens mission to Saturn, a collaboration of NASA, the European Space Agency and the Italian Space Agency. Launched in 1997, the mission spacecraft arrived at the Saturn system in 2004 and has been touring the giant ringed planet and its vast moon system ever since.
The plumes shooting water vapor and tiny grains of ice into space were originally discovered emanating from Enceladus — one of 19 known moons of Saturn — by the Cassini spacecraft in 2005. The plumes were originating from the so-called “tiger stripe” surface fractures at the moon’s south pole and apparently have created the material for the faint E Ring that traces the orbit of Enceladus around Saturn.
During three of Cassini’s passes through the plume in 2008 and 2009, the Cosmic Dust Analyser, or CDA, on board measured the composition of freshly ejected plume grains. The icy particles hit the detector’s target at speeds of up to 11 miles per second, instantly vaporizing them. The CDA separated the constituents of the resulting vapor clouds, allowing scientists to analyze them.
The study shows the ice grains found further out from Enceladus are relatively small and mostly ice-poor, closely matching the composition of the E Ring. Closer to the moon, however, the Cassini observations indicate that relatively large, salt-rich grains dominate.
“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than the salt water under Enceladus’ icy surface,” said Frank Postberg of the University of Germany, lead author of a study being published in Nature on June 23. Other co-authors include Jürgen Schmidt from the University of Potsdam, Jonathan Hillier from Open University headquartered in Milton Keynes, England, and Ralf Srama from the University of Stuttgart.
“The study indicates that ‘salt-poor’ particles are being ejected from the underground ocean through cracks in the moon at a much higher speed than the larger, salt-rich particles,” said CU-Boulder faculty member and study co-author Sascha Kempf of the Laboratory for Atmospheric and Space Physics.
“The E Ring is made up predominately of such salt-poor grains, although we discovered that 99 percent of the mass of the particles ejected by the plumes was made up of salt-rich grains, which was an unexpected finding,” said Kempf. “Since the salt-rich particles were ejected at a lower speed than the salt-poor particles, they fell back onto the moon’s icy surface rather than making it to the E Ring.”
According to the researchers, the salt-rich particles have an “ocean-like” composition that indicates most, if not all, of the expelled ice comes from the evaporation of liquid salt water rather than from the icy surface of the moon. When salt water freezes slowly the salt is “squeezed out,” leaving pure water ice behind. If the plumes were coming from the surface ice, there should be very little salt in them, which was not the case, according to the research team.
The researchers believe that perhaps 50 miles beneath the surface crust of Enceladus a layer of water exists between the rocky core and the icy mantle that is kept in a liquid state by gravitationally driven tidal forces created by Saturn and several neighboring moons, as well as by heat generated by radioactive decay.
According to the scientists, roughly 440 pounds of water vapor is lost every second from the plumes, along with smaller amounts of ice grains. Calculations show the liquid ocean must have a sizable evaporating surface or it would easily freeze over, halting the formation of the plumes. “This study implies that nearly all of the matter in the Enceladus plumes originates from a saltwater ocean that has a very large evaporating surface,” said Kempf.
Salt in the rock dissolves into the water, which accumulates in a liquid ocean beneath the icy crust, according to the Nature authors. When the outermost layer of the Enceladus crust cracks open, the reservoir is exposed to space. The drop in pressure causes the liquid to evaporate into a vapor, with some of it “flash-freezing” into salty ice grains, which subsequently creates the plumes, the science team believes.
“Enceladus is a tiny, icy moon located in a region of the outer Solar System where no liquid water was expected to exist because of its large distance from the sun,” said Nicolas Altobelli, ESA’s project scientist for the Cassini-Huygens mission. “This finding is therefore a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life may be sustainable on icy bodies orbiting gas giant planets.”
The Huygens probe was released from the main spacecraft and parachuted through the atmosphere to the surface of Saturn’s largest moon, Titan, in 2005.
The Cassini spacecraft is carrying 12 science instruments, including a $12.5 million CU-Boulder ultraviolet imaging spectrograph designed and built by a LASP team led by Professor Larry Esposito.
CU-BOULDER PART OF INTERNATIONAL TEAM TO DISCOVER NEUTRINOS CAN CHANGE ‘FLAVORS’
Jun 15th
An international research team led by Japan and including the University of Colorado Boulder may have taken a significant step in discovering why matter trumped antimatter at the time of the Big Bang, helping to create virtually all of the galaxies and stars in the universe.
The experiment, known as the Tokai to Kamioka experiment, or T2K, included shooting a beam of neutrinos underground from the Japan Proton Accelerator Research Complex, or J-PARC, on the country’s east coast to a detector near Japan’s west coast, a distance of about 185 miles. Elementary particles that are fundamental building blocks of nature, neutrinos generally travel at the speed of light and can pass through ordinary matter, like Earth’s crust, with ease. Neutrinos come in three types: muon, electron and tau.
The T2K team discovered that muon neutrinos can spontaneously change their “flavor” to electron neutrinos, a finding that may help explain why the universe is made up mostly of matter rather than antimatter, said CU-Boulder Assistant Professor Alysia Marino of the physics department, who is part of a university contingent that participated in the experiment. Scientists had previously measured the change of muon neutrinos to tau neutrinos and electron neutrinos to muon neutrinos or tau neutrinos, she said.
The shift of muon neutrinos to electron neutrinos detected in the new experiment is a new type of neutron oscillation that opens the way for new studies of a matter-antimatter symmetry called charge-parity, or CP violation, said Marino. “This CP violation phenomenon has not yet been observed in a neutrino, but may be the reason that our universe today is made up mostly of matter and not antimatter,” she said.
Scientists believe matter and antimatter were present in nearly equal proportions at the onset of the Big Bang. Since matter and antimatter particles cancel each other out, it has been proposed that there must have been CP violation in the early universe that produced slightly more matter than antimatter, which accounts for all the stars, galaxies, planets and life present today.
The T2K project is a collaboration of roughly 500 scientists from 12 nations. Other participating U.S. institutions include Boston University, Brookhaven National Laboratory, the University of California-Irvine, Colorado State University, Duke University, Louisiana State University, Stony Brook University, the University of Pittsburgh, the University of Rochester and the University of Washington. The United States contingent is funded by the U.S. Department of Energy.
The CU-Boulder group includes Marino, physics Associate Professor Eric D. Zimmerman, postdoctoral researchers Stephen Coleman and Robert Johnson, graduate students Andrew Missert and Tianlu Yuan, and former undergraduates Christopher Vanek, Bryan Kaufman, Eric Hansen, Zhon Butcher and Joshua Spitz.
The CU-Boulder team designed and built one of three magnetic horns used to generate neutrino beams. The horns are large aluminum conductors that use very high electrical currents to produce a magnetic field. The magnetic field focuses on short-lived neutrino-producing particles called pions and kaons, enhancing the intensity of the neutrino beam, said Zimmerman.
The CU-Boulder researchers also developed a device to monitor the position of the proton beam that creates the neutrinos. In addition, they contributed to the installation and operation of a T2K detector at the J-PARC site 60 miles northeast of Tokyo that measures the neutrinos right after they are produced, Marino said.
Zimmerman said more data will be required to confirm the new results. The J-PARC accelerator is being repaired following damage from the earthquake that hit Japan on March 11. The accelerator and experiment are expected to be operational again by the end of the year, said Zimmerman.
John Metzger, Metzger & Associates, on Boulder Startup Weekend
May 28th
John Metzger, Metzger and associates, talks about Startup Boulder Weekend and provides us a little history on Metzger Associates and how they’ve evloved into new media online.