Ultimo aggiornamento 26.01.08





La Terra e Marte in una danza di Asteroidi


Mentre risulta ormai confermato che il piccolo Asteroide 2007 WD5 non impatterà sul pianeta rosso Marte Giovedi 31 Gennaio 2008, ma passerà molto vicino ad esso ad una distanza di circa 4000Km, un nuovo Asteroide di più grosse dimensioni passerà invece molto vicino al nostro pianeta Terra.

L'oggetto chiamato 2007 TU24 passerà Martedi 29 Gennaio 2008  ad una distanza di circa  mezzo milione di KM  tra la Terra e  la Luna, nessun pericolo d'impatto con il nostro pianeta ma sicuramente offrirà  ottime possibilità di osservarlo  da vicino  anche con

modesti telescopi amatoriali.

  L'ASTEROIDE 2007 TU24                                                   Posizione  Martedi 29 Gennaio 2008








Foto By NASA



ESA News (Osservate Nuove Stelle Pulsar)    21/12/2007



                                                    Pulsar Rotating Radio Transient

XMM-Newton has detected periodic X-ray emission, or the pulsed heartbeat of a weird new type of star. Collecting the X-rays from the so-called rotating radio transient has confirmed the nature of the underlying celestial object and given astronomers a new insight into these exotic objects.
The observations were made using XMM-Newton’s European Photon Imaging Camera (EPIC), which targeted the celestial object RRAT J1819–1458. Astronomers observed the object for around 12 hours and detected pulsations in the X-ray data that show the source to be rotating once every 4.26 seconds.

Previously, astronomers had only seen radio outbursts from this object. It erupts every three minutes or so with a brief burst of radio emission lasting just 3 milliseconds. Such behaviour defines the object as a rotating radio transient (RRAT).

The RRATs were announced in February 2006. Eleven objects were found using the Parkes radio telescope. Astronomers suspected that RRATs were neutron stars, the compact remnants of dead stars made of neutrons and measuring just 10–12 km across yet containing more matter than the Sun. They are therefore extremely dense. Most observed neutron stars are radio pulsars; rotating quickly and sweeping lighthouse beams of radiation across space that make them appear to pulsate. The RRATs, however, were only detected through their radio bursts.

The new XMM-Newton observations show that periodic emission, linked to the object’s rotation, can be detected in X-rays. “It is now definite that RRATs are rotating neutron stars as we can see the 4.26-second rotation period of the RRAT in the X-ray data,” says Maura McLaughlin, West Virginia University, USA, who took the lead in the research.  

In addition to the identification of the underlying celestial object from the discovery of the X-ray pulsations, XMM-Newton also revealed another facet of the RRAT’s behaviour. Something appears to be absorbing certain frequencies of the X-rays after they are emitted from the surface of the neutron star.

The absorption could either be happening in an atmosphere of gases surrounding the neutron star or by particles trapped in the neutron star’s magnetic field. If the second reason is the cause of the absorption, it would indicate that the magnetic field of this RRAT is strong.

“We can’t say for sure where the absorption is coming from with these observations,” says Nanda Rea, University of Amsterdam, Netherlands. She estimates that an observation twice as long would collect enough data to determine where the absorption is taking place.

She also hopes to follow-up this observation by targeting other RRATs. Before that can happen, however, the team must refine the positions they have for these objects. To do this, they continue to observe the RRATs with radio telescopes across the world, timing the outbursts. From careful measurements of the arrival times of the bursts over the course of the year, their positions in the sky can be determined more accurately. Once these locations are known, X-ray telescopes can be pointed in their direction.

Since the original discovery of 11 RRATs, McLaughlin’s team has found an additional 10. This indicates that they may form a substantial population in the Milky Way, with over 100 000 of them dotted around our galaxy.


 Nasa(Potenti emissioni energetiche da un Buco Nero) 18.12.2007


 A powerful jet from a supermassive black hole is blasting a nearby galaxy, according to new data from NASA observatories. This never-before witnessed galactic violence may have a profound effect on planets in the jet's path and trigger a burst of star birth in its destructive wake.

This real-life scene, worthy of the most outlandish science fiction, is playing out in a faraway binary galaxy system known as 3C321. Two galaxies are in orbit around one another. A supermassive black hole at the core of the system's larger galaxy is spewing a jet in the direction of its smaller companion.

see caption

Above: A composite image of 3C321. Scroll down the page to see an artist's illustration labeling the galaxies and the jet. [more]

"We've seen many jets produced by black holes, but this is the first time we've seen one punch into another galaxy," says Dan Evans, a scientist at the Harvard-Smithsonian Center for Astrophysics and leader of the study. "This jet could be causing all sorts of problems for the smaller galaxy it is pummeling."

Jets from super massive black holes produce large amounts of radiation, especially high-energy X-rays and gamma-rays, which can be lethal in large quantities. The combined effects of this radiation and particles traveling at almost the speed of light could severely damage the atmospheres of planets lying in the path of the jet. For example, protective layers of ozone in the upper atmosphere of planets could be destroyed.

see caption

Above: An artist's illustration of 3C321 with galaxies and jets labeled. [more]

The effect of the jet on the companion galaxy is likely to be substantial, because the galaxies in 3C321 are extremely close at a distance of only about 20,000 light years apart. They lie approximately the same distance as Earth is from the center of the Milky Way galaxy.

The jet and galactic assault were discovered through the combined efforts of both space and ground-based telescopes. NASA's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope were part of the effort. Two sophisticated radio telescopes--the Very Large Array (VLA) in Socorro, New Mexico, and the Multi-Element Radio Linked Interferometer Network (MERLIN) in the United Kingdom--were also needed for the finding.

A bright spot in the VLA and MERLIN images shows where the jet has struck the side of the galaxy, dissipating some of the jet's energy. The collision disrupted and deflected the jet. 

A unique aspect of the discovery in 3C321 is how relatively short-lived this event is on a cosmic time scale. Features seen in the VLA and Chandra images indicate that the jet began impacting the galaxy about one million years ago, a small fraction of the system's lifetime.

It's possible that the event is not all bad news for the beleaguered galaxy. The massive influx of energy and radiation from the jet could spark the formation of large numbers of stars and planets after its initial wake of destruction is complete. In the distant future, say researchers, whole new star systems may have the lethal jet to thank for their very existance.


Captate onde radio di origine sconosciuta  dal Radio telescopio di Parkes(Australia)                                              

                                                                                  28 Settembre 2007


Due galassie in collisione (Reuters)
    Due galassie in collisione
Da un luogo remoto al di fuori della nostra galassia Via Lattea gli astronomi hanno ricevuto un flusso di onde radio molto potente che li imbarazza perché non sanno spiegarne l’origine. La scoperta è singolare e intrigante perché ciò che hanno davanti si presenta come un complicato puzzle da risolvere. Diciamo subito per evitare equivoci che hanno escluso subito si tratti di segnali radio lanciati da esseri intelligenti. La provenienza, anche se da decifrare, è di natura rigorosamente astrale.
LA SCOPERTA - La scoperta è avvenuta analizzando i dati raccolti negli ultimi sei anni con il radiotelescopio di Parkes in Australia. Guardandoli con più attenzione di quanto non abbiamo fatto i suoi colleghi in passato, David Narkevic della West Virginia University (USA) ha rilevato una sorgente di onde radio collocata a circa 1,6 miliardi di anni luce dalla Terra. «Ma da dove arriva questa?» si chiedeva David assieme al suo gruppetto di osservatori. E lo stupore era notevole perché in realtà loro erano impegnati nella caccia alle pulsar, cioè stelle a neutroni rotanti, all’interno della Via Lattea. E invece si imbattono in un densissimo fiume di radioonde che in soli cinque millisecondi rilasciava tanta energia quanto ne emette il Sole nell’arco di un intero mese. Il segnale era registrato per 90 ore e poi scompariva senza più farsi sentire. Questo ha complicato notevolmente le cose.
TANTE IPOTESI - Ora il gruppo di astronomi è impegnato a leggere, ma soprattutto a cercare una spiegazione plausibile. Intanto si ipotizza che tutto possa essere nato dallo scontro tra due stelle tradizionali oppure che si tratti di una sorgente associata ad un lampo di raggi gamma; ma di quest’ultimo, verificando, non s’è trovata traccia. Un’altra ipotesi avanzata è stata la fusione tra due stelle a neutroni dalla quale, secondo la teoria delle relatività generale – si ricorda – dovrebbero scaturire delle onde gravitazionali. E anzi qualcuno ipotizza che la caccia a questo tipo di segnali possa condurre anche alla cattura delle stesse fantomatiche onde gravitazionali finora mai avvistate. Insomma tante spiegazioni, nessuna certezza e molte speranze anche azzardate. Per il momento, per cercare di dissolvere il mistero, non resta che approfondire lo studio e la ricerca di sorgenti analoghe.
Giovanni Caprara
28 settembre 2007(Fonte Corriere della Sera)



3C 438 Radio Source

30Maggio 2007

 Astronomers using NASA's Chandra X-ray Observatory have found evidence for an "awesome upheaval" in a massive cluster of galaxies. A bright arc of ferociously hot gas extending more than two million light years requires one of the most energetic events ever detected.

"The huge feature we detected in the cluster combined with its high temperature (170 million oC) points to an exceptionally dramatic event in the nearby Universe," says Ralph Kraft of the Harvard-Smithsonian Center for Astrophysics, leader of a team of astronomers involved in this research. "While we're not sure what caused it, we have narrowed it down to a couple of exciting possibilities."

see caption

Above: In this side-by-side comparison, an apparently ordinary star field in optical light (left) is shown to be dramatically different when observed in X-rays (right). Chandra's image of 3C438, the central galaxy within a massive cluster, reveals evidence for one of the most energetic events in the local Universe.

The favored explanation is that two massive galaxy clusters are running into each other at about 4 million miles per hour. When hot clouds of gas in the two clusters meet, shock waves produce a sharp change in pressure along the boundary where the collision is taking place, giving rise to the observed arc, which resembles an titanic weather front.

"Although this would be an extreme collision, one of the most powerful ever seen, we think this may be what is going on," says team member Martin Hardcastle of the University of Hertfordshire in the United Kingdom.

One problem with the collision theory is that only a single peak in the X-ray emission is seen, whereas two would be expected. Longer observations with Chandra and the XMM-Newton X-ray observatories should help determine how serious this problem is for the collision hypothesis.

Another possible explanation is that the disturbance was caused by an outburst generated by matter falling into a supermassive black hole. In this scenario, the black hole would inhale most of the matter but expel some of it outward in a pair of high-speed jets, heating and pushing aside surrounding gas.

see captionSuch events are known to occur in this cluster. A galaxy named 3C438 near the center of the cluster is a powerful source of explosive activity--presumably due to a supermassive black hole. But the energy in these outbursts is not nearly large enough to explain the Chandra data.

Right: A radio map of 3C438 reveals jets spewing from the galaxy's core--a sign of explosive activity. [More]

"If this event was an outburst from a supermassive black hole, then it's by far the most powerful one ever seen," says team member Bill Forman, also from the Center for Astrophysics.

The phenomenal amount of energy involved implies a very large amount of mass swallowed by the black hole, about 30 billion times the Sun's mass consumed over a period of 200 million years. The authors consider this rate of black hole growth implausible.

"These values have never been seen before and, truthfully, are hard to believe," notes Kraft. Until these issues are sorted out, the awesome upheaval remains a mystery.

Andromeda Way Will Make For A Nice Retirement Home For Our Sol          


          By Space Dally Report



The Andromeda spiral galaxy.

 May 22, 2007
For decades, astronomers have known that the Milky Way galaxy is on a collision course with the neighboring Andromeda spiral galaxy. What was unknown until now: the fate of the Sun and our solar system in that melee. New calculations by theorists T.J. Cox and Avi Loeb(Harvard-Smithsonian Center for Astrophysics) show that the Sun and its planets will be exiled to the outer reaches of the merged galaxy.

Moreover, the collision will take place within the Sun's lifetime, before it becomes a burned-out white dwarf star. Although this collision is a long way off, the research provides insight into how cosmic events will shape the future of Earth and, ultimately, life on our planet.

"You could say that we're being sent to a retirement home in the country," said Cox. "We're living in the suburbs of the Milky Way right now, but we're likely to move much farther out after the coming cosmic smash-up."

Computer simulations by Cox and Loeb show that big changes are coming in only 2 billion years, when the Milky Way and Andromeda experience their first close pass. A viewer on Earth would see the night sky evolve from a strip of stars (the Milky Way seen edge-on) to a muddled mess as Andromeda's powerful pull flings stars from their stately orbits.

At that time, the Sun will still be a hydrogen-burning main-sequence star, although it will have brightened and heated enough to boil the oceans from the Earth.

The two galaxies will swing around each other a couple of times, intermingling their stars as gravitational forces stir them together.

About 5 billion years from now, Andromeda and the Milky Way will have completely combined to form a single, football-shaped elliptical galaxy. The Sun will be an aging star nearing the red giant phase and the end of its lifetime. It and the solar system likely will reside 100,000 light-years from the center of the new galaxy -- 4 times further than the current 25,000 light-year distance.

Any descendants of humans observing the future sky will experience a very different view. The strip of Milky Way will be gone, replaced by a huge bulge of billions of stars. Future scientists may look back on today's research as the first prediction of things to come.

"This is the first paper in my publication record that has a chance of being cited five billion years from now," joked Loeb.


European and worldwide Radio telescopes listen to SMART-1

21 July 2006
In Spring this year European radio astronomers started a test observation campaign to track from Earth the trajectory of the SMART-1 spacecraft around the Moon. While other worldwide radio telescopes are now joining the campaign, the experts have started analysing the first results, precious for tracking SMART-1 up to its lunar impact and future lunar missions as well.
The campaign started on 25 May 2006, when European radio astronomers led by Dr Leonid Gurvits, from the Joint Institute for VLBI (Very Long Baseline Interferometry) in Europe (JIVE) in the Netherlands, started the spacecraft observation campaign in coordination with the ESA SMART-1 team.

The 8-hour long observing session involved three European radio telescopes - the Medicina station close to Bologna, Italy, the Metsähovi station in Kylmälä, Finland, and the Westerbork Radio Observatory at Hooghalen in The Netherlands. In particular, the Medicina station detected SMART-1 in real time, as the telescope is equipped with a real-time spectrum analyser. Further tests were also performed at Westerbork on 17 July 2006.  
The test campaign proved to be very successful, and it confirmed that radio observations prior and during the SMART-1 impact are technically feasible and now fully tested with the VLBI setup.

In the meantime, a group of Chinese radio telescopes, under coordination of the Shangaii Astronomical Observatory and in collaboration with the ESA SMART-1 and the JIVE VLBI teams, have also detected and tracked the SMART-1 spacecraft. This will help the Chinese group to validate the ground stations to be used for the Chinese Chang'E1 lunar orbiter, due for launch in 2007.

Two radio telescopes in South America - TIGO station in Chile and the Fortaleza station in Brazil have also agreed to join the club of Smart-1 radio observers. Their participation is extremely valuable as they are located most favourably to conduct the observation just before and during the impact.

Under the coordination of JIVE , also the SMART-1 observing test using TIGO and Fortaleza on 15 and 16 June 2006 was successful, with the spacecraft radio signal clearly detected at both stations. The data arrived to JIVE for further analysis. "This test proves that the setup and scheduling procedure for telescopes never before involved in this kind of observations and based on our earlier test run with the European antennas is correct" says Leonid Gurvits, leader of the JIVE team.

Indeed for both TIGO and Fortaleza this was the first experience in tracking a spacecraft. In particular, the two stations will take advantage of their favourable location to observe the SMART-1 impact, due to take place on 3 September 2006 between 02:00 and 08:00 (CEST).

"It is exciting that worldwide radio telescopes can listen to SMART-1 until impact", says Bernard Foing, SMART-1 Project Scientist. The impact is due to take place on 3 September 2006 at 07:41 CEST (05:41 UT), with an uncertainty of plus or minus 7 hours. "This also proves that SMART-1 is helping to prepare ground stations, radio telescopes and VLBI experiments for future international lunar and planetary missions".
BY  ESA  Report


Nuovi segnali Radio  emessi dal Sole


Un gruppo europeo di ricercatori, tra cui astronomi dell’INAF-Osservatorio Astronomico di Trieste, ha scoperto che il Sole emette dei segnali radio di durata molto breve, alcuni millesimi di secondo, 10 volte più “corti” dei più brevi segnali radio solari finora noti.

La scoperta degli SSS, “Super Short Structure” come sono stati chiamati, è giudicata importante perché può fornire utili informazioni sui meccanismi fisici che governano l’attività della corona solare, la regione più esterna dell’atmosfera della nostra stella.

Sono i segnali radio più brevi emessi dal Sole finora noti e possono durare solo alcuni millesimi di secondo, cioè fino a 10 volte meno dei più brevi impulsi radio provenienti dalla nostra stella finora conosciuti. Gli SSS, Super Short Structure, sono stati individuati in modo definitivo da un team di ricercatori dell'INAF-Osservatorio Astronomico di Trieste, dell'Università di Zagabria e di quella di Atene, utilizzando l’antenna da 10 metri di diametro TSRS, Trieste Solar Radio System, posta sulle colline del Carso, in combinazione con il radiospettrometro Artemis IV di Atene. I risultati del lavoro che ha portato alla scoperta sono stati recentemente pubblicati in un articolo sulla rivista Astrophysical Journal Letters.

Il nostro Sole è un laboratorio cosmico di fisica unico, dato che è di gran lunga la stella più vicina a noi e l’unica che possiamo studiare nel dettaglio in tutte le bande di lunghezza d’onda. I ricercatori hanno studiato i segnali radio provenienti dal Sole, registrati contemporaneamente dal TSRS e dall’Artemis IV in 10 periodi tra il 2000 e il 2002, nella banda di frequenze compresa tra 200 e 450 MHz, all’incirca quella utilizzata nelle comunicazioni radiotelevisive. Dall’analisi dei dati raccolti sono stati rivelati i brevissimi impulsi SSS che durano, in alcuni casi, solo 4 millesimi di secondo, ossia circa 10 volte meno dei più brevi segnali radio di origine solare finora noti alle stesse frequenze.

Gli autori della scoperta ritengono quindi di aver individuato una nuova categoria di segnali radio solari che promette di essere molto importante nello studio della fisica del Sole, dato che è connessa con i “brillamenti”, immani esplosioni durante le quali vengono emessi, dalla superficie solare, getti di gas e radiazione, dai raggi gamma fino alle onde radio. I risultati delle osservazioni degli SSS permetteranno di fornire utili informazioni per comprendere in maggiore dettaglio i meccanismi fisici connessi ai brillamenti e le interazioni di questi ultimi con la corona solare, la regione più esterna dell’atmosfera della nostra stella, attualmente non ancora ben spiegati dalle teorie.

Un ruolo importante nella scoperta degli SSS lo ha giocato il TSRS, una attrezzatura, antenna e strumentazione per osservazioni nella banda radio dell’attività solare, unica in Italia installata presso la sede di Basovizza dell’Osservatorio Astronomico di Trieste-INAF, con cui si “ascoltano” costantemente le emissioni radio solari. Grazie ad esse è stato infatti possibile analizzare l’andamento nel tempo dei segnali con un dettaglio di solo un millesimo di secondo, una caratteristica che pochi altri strumenti simili nel mondo possono vantare.


Scientist probes outer space for aliens


 (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."



Filmato di Arecibo

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Unlocking Language in Space and

on Earth

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.



Mars and the Teachable Moment


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.


Jill Tarter Named to TIME Magazine’s Top


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