Harvard-Smithsonian Center for Astrophysics|
The CfA Almanac Vol. XIII No. 1, March 2000
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Professor Margaret Geller has been chosen to be the first speaker in a new Smithsonian Institution annual series of "Distinguished Research Lectures" to be given by a Smithsonian scholar "who has made stellar contributions to his or her field and whose career demonstrates sustained excellence."
A committee of the Smithsonian Congress of Scholars chose Geller from a list of candidates nominated by other Institution investigators as well as by the directors of the Smithsonian museums and research centers. The candidates were evaluated on the basis of their sustained scholarly achievements, the impact their contributions have made on their field, and their excellence as public speakers.
Geller will deliver her lecture, "The Smithsonian Universe," at 4 pm, Tuesday, April 18, in the Carmichael Auditorium of the National Museum of American History in Washington. The lecture, which is open to the public, will be followed by a reception in her honor.
(Geller also has been elected to the Council of the National Academy of Sciences, one of this country's most prestigious science positions.)
Matt Holman of the CfA's Planetary Sciences Division and Norman Murray of the Canadian Institute for Theoretical Astrophysics, University of Toronto, have won the coveted Newcomb Cleveland Prize for " the most outstanding paper published in Science in 1999."
Their report, "The Origin of Chaos in the Outer Solar System," appeared in the 19 March 1999 issue, pp. 1877-1881. The prize was presented at the annual meeting of the American Association for the Advancement of Science, publisher of Science, in Washington, DC, in February.
Professor Owen Gingerich, Astronomer and Historian of Science, received the LeRoy Doggett Prize of the Historical Astronomy Division of the American Astronomical Society (AAS). The award was presented at the January meeting of the AAS in Atlanta, GA. He topped off the award with his presentation of the 2000 Doggett Prize Lecture. In April, Gingerich will describe his personal and scholarly "Great Copernicus Chase" when he presents the O.B. Hardison Lecture at the UMass Amherst Center for Renaissance Studies. (A recent spate of thefts of rare copies of Copernicus' de Revolutionibus from Eastern European libraries brought Gingerich some not necessarily desired press attention, as international investigators sought out his expertise on the missing volumes.)
The first in a series of biennial CfA conferences on theoretical astrophysics sponsored by Raymond and Beverly Sackler will be held this spring in Cambridge. Organized by the Theoretical Astrophysics Division, "The First Generation of Cosmic Structures," will bring a host of distinguished scientists to Harvard's Cronkhite Center for three days (May 15-18) of talks, poster sessions, and discussions about the still-mysterious beginnings of almost everything in the Universe. Attendance is limited to paid registrations, but a delayed-broadcast video recording of all talks will be presented in the Phillips Auditorium during the conference for the benefit of CfA staff (and others) who cannot afford either the registration fee or the time commitment.
The MMT telescope, now converted from a six-element optical array to a 6.5-meter-diameter single-mirror instrument, will be formally rededicated at ceremonies in Amado, Arizona, on Saturday, May 20. Smithsonian Institution Undersecretary for Science Dennis O'Connor and University of Arizona President Peter Likins, representing the two organizations that jointly built, refurbished, and continue to operate the telescope, will be among the distinguished guests at the event, which will take place at the Whipple Observatory Visitors Center. All CfA, MMTO, and FLWO staff are cordially invited to attend the ceremonies and reception that will follow.
Cambridge-based staff who may find it difficult to travel westward on that weekend will have a second chance to celebrate on June 3, also at Amado, when the MMTO and FLWO staffs will host a special "Community Day" for residents of the Santa Cruz Valley. More informal and definitely more family-friendly, the all-day (and early evening) program will include demonstrations, lectures, and exhibits on astronomy, nature, and local culture, with star-gazing from the Visitors Center patio and parking lot into the night. The day will be supported by the Smithsonian's Latino Initiatives Fund, the UofA, Citizens Utilities, and other local interests.
And, in answer to the inevitable question, MMTO Director Craig Foltz assures astrophiles and others that, despite its new configuration and new persona, the telescope will keep its old name, and still be known simply as "the MMT."
This year's Lowell Lectures on Astronomy, entitled "CRITICAL MASS: The Bay State's Vital Contributions to Space Exploration," will highlight the very special contributions made by Massachusetts-based astronomers and engineers to the exploration of space and the understanding of cosmic phenomena. Lectures will feature the most recent space science experiments and their results, as well as preview some of the advanced orbiting observatories planned for the future. Speakers will be local scientists who participated in the conception, development, and operation of these home-experiments and instruments.
Cosponsored by the Charles Hayden Planetarium of the Museum of Science, Boston, and the Harvard-Smithsonian Center for Astrophysics, with support from the Lowell Institute, the free lectures will be presented on five consecutive Wednesday nights, beginning April 26, when Jay Bookbinder of CfA will discuss "Watching the Sun: Space Experiments Across the Spectrum." Other speakers and topics are: May 3, Andrea Dupree of CfA, "The Ultraviolet Sky: From Celescope to FUSE;" May 10, Claude Canizares of MIT, "The Violent Universe: Chandra and X-ray Astronomy;" May 17, Gary Melnick of CfA, "From Molecules to Stars: Tracing Stellar Formation in the Submillimeter with SWAS;" and, May 24, Giovanni Fazio of CfA, "A Window on the Future: SIRTF and the Infrared Cosmos."
The Lowell Lectures are intended for general audiences and will be given in the Hayden Planetarium, beginning at 7:30 pm. A question-and-answer period with the speaker will follow each of the illustrated lectures. Although free to the public, seating for the lectures is limited and reservations are necessary. To obtain tickets for an individual lecture, one may make a reservation by phone (617-589-0270).
Wired with body readouts and telemetry that will monitor and transmit her heart rate, pace, and calorie consumption, Dayna Muller's run for glory will be broadcast live on WBZ-TV 4 and the WBZ website during this year's Boston Marathon. "Testing the Limits," an unusual collaboration between WBZ and the Science Media Group of CfA's Science Education Department, will focus on runner and Harvard Graduate School of Education student Muller, as she trains for and competes in the marathon. The marathon project is a part of "SportSmarts," a national education campaign initiated by Matt Schneps and his SMG staff to help improve the public's understanding of the role of science in sports--and to increase the science content of regularly scheduled sports coverage on television.
Yet another successful "New Astronomies" was held at the Whipple Observatory December 8-12, 1999. This program is the longest running study tour of the Smithsonian Associates--a subsidiary of the Institution that conducts scores of educational tours and seminars around the world on a wide variety of topics. Organized and conducted by Public Affairs Specialist Dan Brocious, this week-long series of lectures and trips to Whipple Observatory, Kitt Peak, and other notable astronomy sites in southern Arizona has been running for almost twenty years. And, rather than interest waning (most Associate tours are discontinued for lack of interest after a couple of years), the "New Astronomies" program just seems to become more popular. In fact, the Associates have asked that the program be given biannually - once in December and again in May. The next "New Astronomies" trip to Arizona will be held May 22-28.
Supernova 1987A Blazes Back to Life
A team of CfA scientists using NASA's Hubble Space Telescope (HST) Wide Field and Planetary Camera to image the glowing gas ring around Supernova 1987A have found that the gas, initially excited by light from the stellar explosion but steadily fading for the past decade, is now being lit up again by the long-awaited arrival of an invisible shockwave expanding outward from the original stellar cataclysm. Observed by other astronomers using ground-based instruments, the distinct, bright knots seen in the ring are the first signs that a dramatic and violent collision between gas and shock wave may continue over the next few years, rejuvenating SN1987A as a powerful source of X-ray and radio emissions.
Stellar Heavy Breathing
In apparent contradiction of current stellar birth theories, a team of radio astronomers led by SAO scientists has found that a massive protostar in the constellation Orion seems to be exhaling--when it should be inhaling. Detailed images of the dense gas surrounding the aborning star provide graphic evidence for there being two oppositely directed cones of gas flowing away from the star's polar regions. More remarkable, the team also found an apparently separate outflow of gas from a doughnut-like ring around the protostar's equator. The images were obtained with two National Science Foundation radio telescope facilities, the continent-spanning Very Long Baseline Array (VLBA) and the Very Large Array (VLA) in New Mexico.
Solar Weather Goal of SAO Experiment
SAO has been selected as one of the experimenters aboard the planned Solar-B spacecraft, an international collaboration involving Japan, Germany, the United Kingdom, and the United States. The mission's coordinated set of optical, ultraviolet, and x-ray instruments, including one contributed by SAO, will study interactions between the Sun's magnetic field and its hot, ionized atmosphere in an attempt to better understand what forces produce the "solar weather."
It's a Wet, Wet Universe
Launched from a Pegasus XL vehicle in December 1998, the SAO-designed Submillimeter Wave Astronomy Satellite (SWAS) is the first spaceborne observatory to operate at submillimeter wavelengths and is giving astronomers hope that they may solve many cosmic mysteries, including how stars--and their accompanying planets--are born. Indeed, SWAS has discovered that large amounts of water seem to pervade the interstellar medium, with especially copious amounts found in the huge molecular clouds thought to be the incubators of newborn stars. By contrast, SWAS has so far failed to detect molecular oxygen in those same interstellar clouds. However, in this case, no news may be perceived as good news, since the apparent absence of molecular oxygen, a byproduct of a slow chemical "aging processes" in these clouds, may actually help astronomers to determine their ages.
A Multiple-Planet System Seen Around Another Star
A star orbited by three satellites has been mapped by two separate teams of astronomers, one at the Lick Observatory in California and the other at the Smithsonian's Whipple Observatory in Arizona. The innermost planet circling the star Upsilon Andromedae (44 light-years from Earth) had been known previously but the discovery of its two siblings is new. The presence of the three planets was inferred from irregularities in the star's light emission. The masses for the three planets (working outwards, 0.75, 2, and 4 Jupiter masses) and their orbit sizes (0.06, 0.83, and 2.5 times the Earth-Sun distance) are puzzling, since some theories suggest no Jupiter-sized planet (much less three of them) should have formed so close to a star. (See related story in this issue on the first "direct" observation of an extrasolar planet.)
Our Sun's Long Day's Journey Into Night
Using the VLBA radio telescope system, SAO astronomers have measured precisely for the first time the motion of the Solar System around the Milky Way. The Sun and its family of planets are orbiting about the galaxy at a speed of about 216 kilometers per second. This means it takes us about 226 million years to make one circuit.
Little Red Clumps Lead to Big Cosmic Jumps
SAO scientists have found an alternative method for determining the distance to the Large Magellanic Cloud (LMC)--arguably one of the most critical numbers in modern cosmology. By measuring the brightness of so-called red clump stars in this Southern Hemisphere companion to the Milky Way galaxy, the astronomers hope to determine its precise distance from Earth, which, in turn, could then be used to calibrate distances to objects even deeper in the universe. Red clump stars are ancient giants, 2 to 10 billion years old, which shine with unusual constancy, thus making them excellent potential "standard candles" for marking other cosmic milestones.
For nearly four decades, solar scientists have been puzzled by the fact that the high-speed portion of the solar wind travels twice as fast as predicted by theory, with some particles reaching velocities of 2 million miles per hour as they stream out of the Sun and wash over the entire Solar System. Now, observations made with instruments built by SAO and flown aboard NASA's Spartan 201 spacecraft (deployed from the Space Shuttle during John Glenn's historic return to space) and the international Solar and Heliospheric Observatory (SOHO) have revealed a surprising explanation for this mystery: Magnetic waves propel the particles through the corona like surfboarders riding the crests of a cosmic sea.
The Sun's outermost atmosphere, or corona, is an extremely tenuous, electrically charged gas that is seen from Earth only during a total eclipse of the Sun by the Moon, when it appears as a shimmering white veil surrounding the black lunar disk. Using ultraviolet coronagraph spectrometers on Spartan and SOHO to create artificial eclipses, SAO scientists detected rapidly vibrating magnetic fields within the corona that form magnetic waves that, in turn, appear to accelerate the solar wind.
"These vibrating magnetic waves give solar wind particles a push, just like an ocean wave gives a surfer a ride," according to John Kohl, a senior astrophysicist at SAO and principal investigator for both instruments.
The electrical charges of the solar wind particles, or ions, force them to spiral around invisible magnetic lines in the corona as they rush into space. When the lines vibrate, as they do in a magnetic wave, the spiraling ions are accelerated out and away from the Sun. Indeed, SAO scientists believe there are magnetic waves in the corona with many different "wiggling periods," or frequencies. Thus, these waves can accelerate various solar wind particles at different rates. In one surprising discovery, for example, SAO researchers found that the heavier oxygen ions actually move faster than the lighter hydrogen ions.
These observations may help scientists better understand not only solar-wind dynamics but also the nature of "coronal holes," those apparent gaps in the Sun's outer atmosphere from which the solar wind gushes forth to energize electrons in the Earth's Van Allen radiation belts, produce spectacular auroras, and, sometimes, affect electrical systems on Earth or aboard orbiting satellites.
(An occasional feature offering astro-verse related--or not--to the work of CfA's astro-toilers. Contributions from staff, friends, and associates are welcome.)
Up above our world so far,
Wobble red and wobble blue
Does a planet circle you?
Does its shadow dim your light
--Margaret Lewis 1999
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