In Focus...
Arecibo Radar Gets 11th-Hour Reprieve
From Sky and Telescope Magazine
by J. Kelly Beatty
The 305-meter (1,000-foot) radio telescope near Arecibo, Puerto Rico, has been used for radar probing of solar-system objects since the early 1960s. The facility underwent a $27 million upgrade in the mid-1990s.
Click the image for a larger view.
Photograph by David Parker (Science Photo Library); courtesy NAIC/Arecibo Observatory.
Facing tight budgets for its space-science activities, last week NASA abruptly decided to end its funding of radar research at Arecibo Observatory (about $550,000 annually), effective January 1, 2002. Thomas H. Morgan of NASA Headquarters sent a formal notice of the termination to Donald B. Campbell (Cornell University), who heads Arecibo's planetary-radar group.
Today the space agency did an equally abrupt about face, opting to provide $400,000 through the end of fiscal 2002. "We made a mistake," said Edward J. Weiler, who directs NASA's space-science efforts, "and we've fixed it."
The central issue revolves around the fact that the Arecibo program has become part of NASA's effort to find and catalog potentially hazardous near-Earth objects, or NEOs. (Congress has mandated that NASA track down 90 percent of all 1-km-wide asteroids in Earth-crossing orbits by 2008.) But the Arecibo facility doesn't find asteroids --- astronomers use it to make follow-up observations of the ones spotted first by telescopic surveys. Morgan, who manages NASA's NEO program, wants to maximize the discovery rate, and to do so more of his $3.55 million budget must go to the four observing teams that are actively searching for NEOs.
The cancellation decision created a shock wave of disbelief among asteroid researchers and triggered several calls for reconsideration from astronomical organizations. Arecibo has been at the forefront of radar studies since 1960, and astronomers routinely direct its powerful megawatt transmitter toward the Moon, Venus, Mercury, and Jupiter's Galilean satellites. NASA also conducts some radar work using its 70-meter-wide tracking antenna near Goldstone, California. But Arecibo's dish boasts a more powerful transmitter and is at least 10 time better at picking up faint radar echoes.
Researchers were thus fearful of losing their single best ground-based tool for studying asteroidal surfaces and for refining their orbits. These characteristics are of more than purely scientific interest: should astronomers discover an asteroid on a collision course with Earth, knowing its makeup and exact trajectory would be crucial to mounting a defense strategy. Arecibo is the "premier astronomical research facility in the world" for this work, notes theorist Eric Asphaug (University of California, Santa Cruz), because it targets a wide spectrum of asteroids and comets, whereas spacecraft have visited few of these bodies.
Although the Arecibo program has secure (if diminished) fiscal footing for 2002, it still faces funding challenges in the years ahead. For one thing, Weiler has demanded that future research proposals utilizing the Arecibo radar system undergo peer review. Ultimately, he would like to see responsibility for Campbell's group transferred to the National Science Foundation, which already provides $9.5 million each year for Arecibo's general operation.
On-Site Insights
Posted by Joy/CO
on the High School Chatboard
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Block Scheduling
I've been teaching 22 years and I would never return to a traditional schedule after teaching a modified block for seven years (approximately). Our school has 1700 students. We teach four periods one day and a different four periods the next (8 class periods, still called 1-8.) All of our classes are taught in the 90 minute format. We have been able to preserve a typical semester/year long curriculum but, each class meets just every other day. All subject matter has adapted to the format, including music and foreign language.
We were initially worried about "skills' kids" attention spans. But what we found was that making them change gears less often actually allowed them to get focused. Imagine half as many passing periods, clean up and set up minutes, etc. Poor teachers have been forced to improve their teaching strategies. Changing gears within a class period is essential but, then meets more learning styles.
Our math teachers are including more and more simulations (even in advanced level classes), which would have really helped me as a student. Lab teachers would have it no other way. Computer graphic art students still get mad at the bell because they're so engrossed in their projects. Speech students actually learn important audience skills. Language arts students can actually read and write in the same class period.
By the way, I CAN keep a class entertained for a 90 minute period with lecture. Some teachers really need to work on their presentation skills.
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