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In this issue:
Seeking Dark Matter on a Desktop
Fermi Telescope Spotted over Hawaii
Are Enchantment and Science Compatible?
Colloquium Today: Saturn and its Rings: Results from Cassini

SLAC Today

Monday - March 15, 2010

Seeking Dark Matter on a Desktop

(Photo - Shoucheng Zhang)
Shoucheng Zhang of the Stanford Institute for Materials and Energy Science. (Photo courtesy Brad Plummer.)

Desktop experiments could point the way to dark matter discovery, complementing grand astronomical searches and deep underground observations. According to recent theoretical results, small blocks of matter on a tabletop could reveal elusive properties of the as-yet-unidentified dark matter particles that make up a quarter of the universe, potentially making future large-scale searches easier. This finding was announced today by theorists from the Stanford Institute for Materials and Energy Science, a joint institute of the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University, at the American Physical Society meeting in Portland, Oregon.

"Tabletop experiments can be extremely illuminating," said condensed matter theorist Shoucheng Zhang, who published the results with SIMES colleagues Rundong Li, Jing Wang and Xiao-Liang Qi. "We can make observations in tabletop experiments that help us figure the deeper mysteries of the universe."

In a paper published in the March 7 online edition of Nature Physics, Zhang and his colleagues describe an experimental set-up that could detect for the first time the axion, a theoretical tiny, lightweight particle conjectured to permeate the universe. With its very small mass and lack of electric charge, the axion is a candidate for the mysterious dark matter particle. Yet, despite much effort, the axion has never been observed experimentally.  Read more...

Fermi Telescope Spotted over Hawaii

(Photo - Richard Dubois in Hawaii)
Richard Dubois presents his poster and shows off his Hawiian shirt—the conference handed them out to all participants—at the 2010 HEAD meeting in Hawaii. (Image courtesy Richard Dubois.)

I had just stopped on the very dark sidewalk on the two-mile trek from a local eatery to my hotel at the 2010 High Energy Astrophysics Division meeting inin Waikoloa, Hawaii, when my colleague on the Fermi Gamma-ray Space Telescope, Luis Reyes from the Kavli Institute in Chicago, almost literally ran into me. And asked if I was looking for Fermi. I had sent mail to the Fermi attendees asking whether any would be searching the skies for it.

Our colleague Tom Glanzman, left behind at SLAC, had been asking if we'd seen it down here, and sure enough, we found it after just a few minutes. It was on what's called the 19:40 pass , with 37 degrees maximum elevation above the horizon, a faint dot moving from west to east. I have to give Luis credit for the discovery—His experience with the VERITAS observatory helped him guess where 37 degrees elevation is, and his eye caught the faint movement. But I did confirm immediately!

I think the telescope might have soon gone into eclipse, as we lost it when a car went by and did not pick it up again. (Admittedly we did not try hard, since we'd already had success!) We think we might be the only Fermi folks yet to see it in orbit.

(Photo - Roger Blandford)
Roger Blandford.
(Photo by Christine Aguilar.)

Are Enchantment and Science Compatible?

Is there meaning in our increasingly rational and secular world? Is science motivated by wonder or by cold logic?  Joshua Landy, Stanford associate professor of French, and Roger Blandford, professor of physics and director of the Kavli Institute for Particle Astrophysics and Cosmology, offer their perspectives In the latest installment of the Thinking Twice Forum.

Colloquium Today:
Saturn and its Rings: Results from Cassini

(Image - SLAC Colloquium banner)

NASA's Cassini spacecraft has been touring the Saturn system since 2004, sending back a continuing stream of images and other scientific measurements of the planet Saturn and its rings and moons. The data reveal such exotic features as lakes of liquid methane on the moon Titan and plumes of ice crystals emerging from cracks in the surface of Enceladus. The ring system reveals features that seem to defy our most basic understanding about the laws of Keplerian dynamics.

Today at 4:15 p.m. in Panofsky Auditorium, Mark Showalter, a Principal Investigator at the SETI Institute and co-I on the Cassini Project, will present an overview of the latest results from the mission. He will give particular emphasis on some of his favorite puzzles posed by Saturn's intricate ring system, and what they might mean for broader questions about the formation and evolution of planetary systems.

Mark Showalter is a planetary astronomer at the SETI Institute in Mountain View, specializing in planetary ring-moon systems and orbital dynamics. He is a co-investigator for the thermal infrared instrument on the Cassini Mission to Saturn, and served on the New Horizons team for its 2007 flyby of Jupiter. He has also been the principal investigator on numerous observing programs with the Hubble Space Telescope, encompassing all four giant planets. Earlier in his career, he worked extensively with Voyager data and is credited with the discoveries of Saturn's innermost moon, Pan, and a faint outer ring of Jupiter. More recently, he discovered two small moons and two faint rings of Uranus in Hubble images.


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