Le spettacolari immagini dell'eclissi lunare...
Filmato di Arecibo
Scientist probes outer space for aliens
Unlocking Language in Space and on Earth
Mars and the Teachable Moment
Jill Tarter Named to TIME Magazine’s Top
(CNN) -- For more than a quarter century, researcher Jill Tarter has sought to solve a mystery that has long intrigued scientists and science-fiction buffs: Are we alone in the universe? "This is the oldest unanswered question, which is why I love working on it," Tarter said. "It's a fundamental question that humanity would like to answer, and we live in the first age where we can try and do an experiment and get that answer." In the movie "Contact," in which she serves as the inspiration for Jodie Foster's character, Tarter is portrayed as a stubborn crusader with a lifelong passion for space. The characterization is apt, Tarter said. "It might have been the Saturday morning 'Flash Gordon' cartoon shows or something that I watched," Tarter said, explaining her early interest in the universe. "I spent a lot of time walking ... with my dad, looking at the sky at night. It just seemed quite reasonable that those stars could be someone else's suns." Born in upstate New York, Jill Tarter grew up as a self-described tomboy. After studying engineering physics at Cornell University, she focused on astrophysics while pursuing her doctorate at the University of California at Berkeley. There, she found the inspiration for her life's work -- an engineering study called the Cyclops report. The report, which advanced the idea of using radio telescopes to detect extraterrestrials, proposed that if there are intelligent civilizations somewhere in space, they might be transmitting a radio beacon to the cosmos. If people on Earth tune in, the report noted, they might find evidence of alien broadcasting. Despite colleagues' warnings that she would fall into scientific obscurity, Tarter set out to build a career tuning in to potential extraterrestrial signals. Over time, Tarter found a lot of company on Earth, if not from space. In 1984, she co-founded the Search for Extraterrestrial Intelligence Institute in California, known as SETI. As the lead researcher at the privately funded institute, she's seen the field move from the fringes of science toward the mainstream. In 1989, the professional group Women in Aerospace awarded Tarter the Lifetime Achievement Award for her contribution to the branch of biology concerned with the search for life outside the Earth. NASA has also recognized Tarter's achievements, awarding the astrophysicist two public service medals. In 2002, the American Association for the Advancement of Science -- the world's largest scientific society -- elected Tarter a fellow, one of only a handful from the astronomy field picked that year. While they have gained acceptance from her peers and the public, Tarter and her team know they still face a long, difficult challenge. There are about 400 billion stars in the Milky Way galaxy alone, Tarter said, and so far, all searchers for extraterrestrial intelligence have examined only about 10,000 stars. For now, Tarter says there is no other question she would rather spend her career trying to answer than whether life exists beyond the Earth. "For me, the important thing about detecting another intelligent species somewhere else in the universe is that it holds up a mirror to the Earth," she said. "And it says, 'OK, humans. You're all humans.' And the differences between us and ... that life form are vast, and they should trivialize the differences among humans that we find so hard to live with these days."
When Dr. Laurance Doyle lectures to undergraduates, he tells them "math is not in the chalk," it is a tool they can use to understand the universe. Doyle finds math everywhere; in the signatures of radio waves that might reveal communication technology on other worlds; the distribution and orbits of planets circling distant stars; and in the calls of marine mammals. At first glance, studying an endangered species may seem off target for the SETI Institute astronomer, whose special expertise is planet detection. Doyle, however, has exceptionally varied research interests. He has written extensively on circumstellar habitable zones (cosmic real estate that is bio-friendly), is a scientific collaborator on the NASA Kepler mission, and teaches a course on Native American history. He also works with biologists Brenda McCowan and Sean Hauser, of the University of California, Davis, studying non-human communication systems to better understand the nature of language and intelligence, which in turn has direct relevance to the search for extraterrestrial intelligence (SETI). Quantitative tools for intelligence studies are and few and far between, making the Drake Equation term Fi (fraction of planets on which intelligence develops) one of the most elusive facets of SETI research. Doyle’s team uses statistical tools from a field known as "information theory" to measure the complexity of different species’ communication systems and thus learn how much information individual animals can transfer between each other. This allows the scientists to draw inferences about the intelligence of the communicating species, which in turn gives Fi researchers a better understanding of intelligence as an evolutionary adaptation. Information theory may also teach us how to approach the analysis of a signal from distant worlds should SETI astronomers make a confirmed detection. And -- as a surprising "SETI spin-off" -- information theory may also help protect one of the planet’s best-loved marine mammals. Doyle explains the connection. "I was watching a television show about whales." It was the late 70s, and he was working at JPL, processing image data from Voyager. "The researchers were having trouble picking out individual signals from the animals. I wanted to help." Doyle knew his signal processing experience with Voyager could be useful. "We were using a Hough transform to pick out signals from the noise." Realizing that this signal processing technique could be applied to the marine mammal calls, he contacted the Hubbs Research Center at Marine World and was connected with researcher Sheldon Fischer. The pair began to identify individual signals using the JPL technique. Unfortunately, the analysis required intensive computational power which, unlike today, was not practical for all but the largest research budgets. The project was ultimately dropped, but the experience sparked Doyle’s interest. He "sat on it for seven years" before joining the SETI Institute in 1987, where he first encountered the small network of researchers interested in dolphin intelligence and SETI. "We all intuited that the study of dolphins may have something to do with SETI," Doyle explains, "but we didn’t know how to tie it all in." Eventually, the right combination of research expertise would coalesce into a collaboration between Doyle, McCowan, and Hauser. In the late 1990s a paper appeared in the journal Science, describing a novel use of information theory to analyze the "language" of DNA. An Institute colleague made "an off-hand comment" on the paper over lunch with Doyle, and the germ of an idea took root. "I went home that night with preprints of Brenda’s dolphin signal paper, and did a Zipf plot." The Zipf plot is a tool within information theory that shows the relationship between repetitive and novel units of communication within a system. Language, Doyle explains, has a characteristic Zipf slope of 45 degrees. So did the dolphin. The results astounded the astronomer, who remembers, "First I had to have a cup of tea to make sure I got the figures right, then I called Brenda!" Over the next year, the group pursued this line of research. In 2000, Doyle’s group, which also included Institute colleagues Dr. Christopher Chyba and Taylor Bucci, launched an expedition to Glacier Bay, Alaska. The researchers lowered hydrophones from their kayaks and gathered signals from the feeding whales. In the course of the studies, says Doyle, "we heard a lot of shipping noise, and decided to look for it in the data." Before returning home, the team gave a talk in the Glacier Bay community, and caught the interest of local scientists who offered to share several years of recordings with the California researchers. This bonanza included data gathered during feeding sessions free of shipping noise, allowing the team to build a baseline against which they could compare the "noisy" recordings. The results showed quantitatively that the boat noise was impacting the communication. The humpbacks were having to "shout" above the noise, repeating and simplifying their calls to each other, much like humans trying to converse above the din of a noisy party. "We detected an information decrease of about 28 percent in the presence of boat noise," says Doyle. In the limited visibility environment of the ocean, humpbacks rely upon vocalization for their social behavior, which includes feeding. Shipping traffic was disrupting their communication, and by inference, their social activities. The researchers will soon be collaborating with the Alaskan Whale Foundation to gather more data, and coordinate the communication studies with other research on the humpbacks, such as studies of their physical health. The future offers compelling research opportunities -- and challenges. "There is plenty of work that needs to be done," says Doyle. Asked about next steps, he explains, "We’d like to set up an array of hydrophones so that we can triangulate individuals." Identifying individual whales by their signals is highly sought goal of many marine mammal researchers. Doyle smiles as he contemplates the road ahead. The research team would like to build upon their work with whales and dolphins to include many species in a survey of non-human communication systems. "We know how to do it," he says earnestly. "All we need is the funding." For now, Doyle’s colleague Hauser looks forward to another season in Alaska with the Whale Foundation. The more data the group has to analyze, the more they can learn about the communication system, the behavior, and the effects of the environmental context in which the humpbacks socialize. "It’s a start," says Doyle. And a wonderful way to think about the utility of math as we celebrate Earth Day.
We’re back on Mars with Spirit and Opportunity roving the surface and engaging the public in the search for evidence of water. Overhead, orbiters image the surface in exquisite detail. People worldwide are attentive to Mars -- it can even be easily seen in the evening sky with the naked eye. All of this makes Mars the logical focus for teaching science as a part of current events, and for dealing with pseudoscientific claims about Mars. It’s a good time for critical thinking in classrooms. With the observations being made from Mars orbiters, students and teachers can critically consider the "face on Mars". In a reprise of an earlier column, I offered my thoughts on this "face". Today, as NASA considers Mars as the past and future home for life, the critical consideration of the "face" continues to be relevant. In late March of 2002, the SETI Institute education team was at the National Science Teachers Association meeting in San Diego, CA along with about 14,000 other science teachers. It's a good thing that these NSTA meetings coincide with spring break, or no science would be taught in US schools during that week every spring. I had a long conversation with a high school science teacher about teaching science in a world where his students are continually exposed to pseudo-science or even phony science--the stuff they learn from watching television and reading the tabloids. What do they believe is real? The face on Mars, alien autopsies, Area 51 in the Nevada desert as an alien storage area, the "non-landings" on the Moon, UFO’s, alien kidnappings--these are all the grist of great story telling and speculation in the media. It is easy for uncritical kids (and adults) to "believe" the "evidence" of alien beings and encounters when it is all carefully gift-wrapped by the creative television producers who crank out dramatic programs depicting these events with well-trained actors and elaborate sets. Of course, these are the same folks who bring us fantastic science fiction films which we ALL know are entertainment, not science education--or at least I function under that illusion. The pseudo-science accounts are carefully filmed and professionally narrated for television as "documentaries" about mysteries, or unexplained events. All aim to convince the public that aliens have been here or nearby on the Moon or Mars, and that all of the "evidence" is being covered up by a grand conspiracy of seriously un-fun people in the government, universities, and research organizations. Folks like me. Denying, providing alternative explanations, or criticizing the "evidence" simply proves there is a cover-up. About 50% of the American public believes that UFO's are real, and what they mean by "real" is that UFO's are piloted by aliens from some distant world, not Earthlings from the local Air Force Base or actors in Hollywood costumes. Think about that, and then consider teaching space science and astronomy in this social context. Take the face on Mars. The first photograph of this bumpy mesa was snapped by the Viking Orbiter, and released by NASA to the public on July 31, 1976. <>What did NASA say about the photograph? "Caption of JPL Viking Press Release P-17384 National Aeronautics and Space Administration Viking New Center Viking 1-61 Pasadena, CAP-17384 (35A72) July 31, 1976 This picture is one of many taken in the northern latitudes of Mars by the Viking 1 Orbiter in search of a landing site for Viking 2. The picture shows eroded mesa-like landforms. The huge rock formation in the center, which resembles a human head, is formed by shadows giving the illusion of eyes, nose and mouth. The feature is 1.5 kilometers one mile across, with the sun angle at approximately 20 degrees. The speckled appearance of the image is due to bit errors, emphasized by enlargement of the photo. The picture was taken on July 25 from a range of 1873 kilometers (1162) miles). Viking 2 will arrive in Mars orbit next Saturday (August 7) with a landing scheduled for early September. " It is an intriguing image, and certainly does look like a face. In fact, since then, this "face" on Mars has inspired a whole library of books and groups of true believers that now find "evidence" of a "Pyramid" and an "Inca City" as well --all, of course, photographed by Viking but covered up by NASA officials. Note that all of the publications help to put bread on the table and pay the rent for the creative folks churning out books, articles, and tabloid stories about "the face." Now, image being a science teacher with a classroom full of 15-year old students who believe the television accounts of the face on Mars, cities on the Moon, alien autopsies, etc. etc., and you are teaching your unit on space and astronomy. A careful excursion through the characteristics of the planets and their moons interests your students--the red spot on Jupiter would hold at least 3 Earths, a cool factoid--but it doesn't grab them. The face on Mars does. And this was what I discussed with the science teacher at NSTA. The face on Mars is a teachable moment. Turn your students into scientists. Present the evidence for the students to consider. There is the Viking photograph, taken in 1976 and the Mars Global Surveyor (MGS) photographs taken about 25 years later. Ask the students what they see in the 1976 photograph--like everyone else, they will see a face. I see a face in that photograph too. Humans interact with the natural world by organizing perception into recognizable form. Who has not watched clouds on a summer day, and "seen" horses, dragons, beautiful men/women, ships, and such? In the early part of the century, astronomer, Lowell, was convinced he saw canals on Mars through his telescope in Arizona. Subsequently, other observers and photography of Mars proved that his mind was "connecting" broken features into lines, the canals, but that it was all in his mind not on Mars. We humans are pattern seekers, and seeing familiar forms in strange places helps us to organize our perceptions of the natural world. There was a rock formation near my childhood home in the Sierra Nevada mountains that looked like a bear, but I never assumed that it was carved by some unknown being to make me ponder bears or believe in unknown beings. I understood that it was jagged granite, and the fact that it looked like a bear was a coincidence. I also had to stand in the right place to see the bear; otherwise, it just looked like a mountain peak. Like the bear, to see the face on Mars, you have to "stand" in the right place, and at the right time of day. Move forward a couple of decades. We've returned to Mars. We have new, higher resolution photographs of the same mesa taken by MGS and posted to the web by Malin Space Science Systems, the designers and builders of the camera onboard MGS. These are detailed, new views, including views from different places at different times of the day. The raw data from MGS is image processed to bring out the details on the mesa, and a clear explanation for how scientists accomplish this work helps students to understand that there is not cover up. It's more like an uncovering to reduce raw data to images. There are movies that allow you to fly around the "face" and check out the terrain for yourself. Send your students there for the evidence. What does the mesa look like see more clearly, more closely? You decide: The shadows cast by the low Sun angle in 1976 created a lovely illusion--a giant face-like mesa on Mars. The new images, taken by MGS reveal the "face" as a rocky mesa, one of many in the Cydonia region of Mars. It looks a lot like mesas in the western region of the United States. In fact, it looks a lot like other mesas in that same region on Mars--similar in size, dimension, and height. It's an ordinary feature on Mars, not a gargantuan piece of artwork left to make us ponder whether alien artists who sculpted on a grand scale had visited Mars. But, don't ask students to "believe" in science, provide the evidence, and allow them to critically consider what we now know about the "face" on Mars. Give them the same opportunity granted the space scientists who took the images with Viking and with MGS. Finally, ask yourself and your students how much money people made and continue to make from selling pseudoscientific accounts and films to the gullible public. That discussion might reveal why the "face on Mars" is so persistent.
The TIME 100 recognizes the world's elite in business, art, politics, science and other fields, men and women who have succeeded thanks to a combination of intelligence, hard work and good fortune. “Jill is that remarkable person you’ll tell your children and grand-children about when you’ve had the honor to work with her.” ~ David R. DeBoer All who know her would agree that SETI Institute scientist Jill Tarter has that rare quality often described as “presence.” She has been a driving force behind many facets of the SETI Institute -- its SETI and education projects, its growth, its direction -- and has often been a highly visible representative of the organization at home and abroad. Her influence is widespread, and she is building a legacy that will include a world-class radio telescope that will change the way these instruments are built, and a generation of women scientists for whom she’s been a role model. Small wonder then, that TIME magazine selected Jill Tarter as one of their top 100 people of power and influence for the year 2004. Dr. Tarter has touched the lives of many people in different ways. She has gathered much of the scientific talent that currently distinguishes the SETI Institute, and several scientists credit the well-known SETI Institute scientist for their academic and professional career paths. Those who work closely with Jill are always impressed by her energy, determination, and humanity. “I've had the good fortune to work as Jill Tarter's assistant for almost 15 years,” notes Chris Neller, Tarter’s executive administrative assistant. “During that time I've grown to know and appreciate Jill for the truly extraordinary person she is. Jill is a brilliant scientist, public speaker, and author. She is also wise, funny, and kind. Jill has tremendous energy and focus; these qualities enable her to succeed in many areas. It has been, and will continue to be challenging, entertaining, and most of all, never dull to work with Jill.” We asked four of her other colleagues to share their impressions of Jill Tarter with our Voices readers. You can hear what they have to say by clicking on their pictures