APS News

Speakers Reflect on Telescopes Old and New

By Calla Cofield

Richard Ellis rang in the 2009 APS April Meeting with his keynote address “The Quest for Giant Telescopes: Four Centuries of Challenge & Scientific Discovery.” Ellis, a professor at Caltech, took more than 300 audience members down a winding historical path, from the continuing challenge to mold larger and larger mirrors, through the development of CCDs and the push to stretch telescopes beyond the optical range. Other speakers at the meeting filled out Ellis’s talk with their own reports on current and future telescopic endeavors.

Peter Michelson of Stanford University announced new results from the Fermi Gamma Ray Telescope, which hit online news sources shortly after his plenary talk on Saturday. Fermi has successfully collected counts of electrons and positrons with energies above 100 GeV, similar to data collected by the PAMELA satellite observatory. The particles could be emanating from nearby pulsars, or they might be signatures of dark matter. The telescope awaits data to analyze photons in this energy range, information they hope will clarify the source of the particles.

April Meeting attendees were invited to comment on and ask questions about the upcoming Joint Dark Energy Mission, JDEM, at a town hall meeting Sunday night. The JDEM satellite mission planned by NASA and the U.S Department of Energy hopes to study the nature of the accelerating universe.  

“Dark energy is the mystery of our time,” said Neil Gehrels of NASA Goddard who spoke on the current state of JDEM. “I think the time is right for JDEM for a number of reasons…New technology, large format detectors are now available. There really should be a mission to fly these and do a wide-field spectroscopic survey of the sky.”
Mike Salamon of NASA and Kathy Turner of DOE spoke about their agencies’ dedication to a cooperative, cost-effective mission, with Salamon noting that cost constraints are “a very serious issue,” for JDEM.

Alexandre Refregier from the French institute CEA Saclay spoke about EUCLID, an equivalent dark energy mission that the European Space Agency is planning. When asked if the US and European projects had any intention of joining forces, representatives said they certainly intended to have the projects work cooperatively, and they couldn’t rule out the possibility of a combined mission.

The future of JDEM may partially depend on Astro2010, the decadal survey by the National Research Council (NRC) of the National Academy of Sciences. With input from members of the scientific community, Astro2010 will survey the fields of space- and ground-based astronomy and astrophysics, and prioritize the most important scientific and technical activities for 2010-2020. The survey’s target audiences are funding agencies and policy makers.

Ellis concluded the keynote talk by noting a curious pattern in telescope history: “[Astronomers] always do better than they say they’re going to do,” he said, stirring up laughter from the audience. He noted, for example, that few of the largest discoveries made by the Keck telescope were projected in the planning stages in 1985. He added, “Research changes so rapidly, it’s inevitable that we do things differently than we predict.”

With that in mind, it may be impossible to imagine what new results will appear at next year’s meeting!.

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Editor: Alan Chodos