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Search for ETs Focuses on 166 "Promising" Signals By John Roach

Last Updated 16/01/05 17:44

The following article was published in National Geographic News March 27^th, 2003

Astronomers searching for signs of intelligent extraterrestrial life wrapped up their mission in Puerto Rico Wednesday to home in on some of the more exciting radio transmission to reach Earth. They collected data on 166 sources, exceeding their original goal of 150.

The astronomers' quick, real-time analysis of the data revealed no evidence of an extraterrestrial civilization, but they will take a more thorough look at it over the next several weeks.

The trip was the culmination of four years of research conducted by SETI@home, a hugely popular distributed-computing project in which more than 4 million people in 226 countries have volunteered their computer's free time to the search for extraterrestrial intelligence (SETI).

"Millions of people around the world have helped get us to the point where we could identify potential targets and take a second look," Bruce Betts, Director of Projects at the The Planetary Society in Pasadena, California, said in a statement. The society is principal sponsor of the project.

"Now the new data will go back to the SETI@home volunteers for more help with this early but critical step in our continuing search for extraterrestrial intelligence," he said. The volunteers download a screensaver program from the University of California at Berkeley (UC Berkeley) that kicks in when their computer sits idle. The program sorts through chunks of data received from the university via the Internet for unusual radio signals that might be from alien civilizations.The chunks of data are bits of digitized noise collected by SETI@home researchers who have a special receiver on the National Science Foundation's Arecibo Radio Telescope in Puerto Rico that allows them to "piggyback" on other researchers' use of the telescope.

"We send our data out in what we call work units to the millions of people who use our screensaver program," said David Anderson, a computer scientist and director of the SETI@home project. "It does signal analysis, looking for signals that are not known to occur naturally."

The screensaver then sends back, via the Internet, the most interesting candidates for further analysis by researchers at UC Berkeley. Since the program was started in 1999, the screensavers have sent the university about 5 billion signals worthy of further analysis.

"We've been weeding through all this stuff," said Dan Werthimer, a physicist and chief scientist for the SETI@home project. "We go through and find what is really interesting."

Through a careful analysis of all this information, the SETI@home researchers narrowed the field of candidates to about 150. They scheduled 15 hours of dedicated telescope time beginning March 18 at Arecibo to re-examine these most interesting parts of the sky in the hopes that one of the signals is truly from alien life. The dedicated observing time was interrupted by a need to re-observe a giant solar flare, but resumed March 24.

Roelof Engelbrecht, a SETI@home volunteer in College Station, Texas who freely distributes an add-on feature to the screensaver program called SETI Spy that enables computers to data crunch more efficiently, said he is pleased that the researchers secured dedicated time on the Arecibo telescope.

"So far all observations have been made while piggybacking on someone else's telescope positions, but now it is SETI@home's turn, even if just for a [day]," he said.

In addition to the 166 candidates identified by SETI@home, the researchers also observed 5 extrasolar planetary systems, 35 nearby sun-like stars, 15 nearby galaxies, and 6 candidates from a second SETI Program at UC Berkeley called Serendip (Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations.)

As well as conducting a thorough analysis of the data collected over the past two weeks, the SETI@home volunteers will continue to sort through the data collected by the special receiver on the telescope and send the most interesting candidates to Berkeley for further analysis. The hope is that one day they really will find an interesting signal.

Against the Odds

Werthimer, who headed for Puerto Rico with two other colleagues while Anderson stayed in California to run the computers, is not optimistic that any of the signals are from an extraterrestrial life-form and cautions against people getting too excited. He puts the chance of success at less than 1 percent.

Since becoming involved with SETI 24 years ago, 11 of them using Arecibo's 1,000-foot (305-meter)-diameter telescope, Werthimer has re-examined several promising signals only to find out they were from a passing satellite, random noise, or some other glitch.

"I don't expect to find ET next week," he said in an interview prior to the trip. "But I am optimistic that Earthlings will find ET in the next 100 years." Technological advances, he added, are making SETI searches much more powerful.

Out of the 150 signals that were selected as the most promising candidates, Anderson said that all of them exhibit characteristics that are consistent with random noise. Given that, he too is not optimistic that ET will be encountered.

"It is really hard to put a number to it, but most people feel the odds are quite low," he said.

Nevertheless, the scientists carefully narrowed down the most likely candidates, ranking them based on criteria such as strength, whether or not the signal was detected more than once, and whether or not it is coming from a star known to have planets.

Looking for a Match

As the team re-examined the spots in the sky where the candidate signals came from, they conducted a limited amount of analysis of the data. If something very strong or interesting appeared they would have stopped the search and repeated it to make sure it was not radio pollution or some other kind of noise. On this most current mission, nothing interesting appeared. If the scientists do eventually find something that looks exciting, they will ask for independent confirmation of the signal by another group of astronomers using a different telescope and processing software.

"If they see something too, we can measure distance to it, train on it, then make an announcement that we found an interesting signal," said Werthimer.

Richard Factor, president of an organization dedicated to the search for evidence of extraterrestrial life called the SETI League, in Little Ferry, New Jersey is pleased that SETI@home has the opportunity to look at these 150 areas, but agreed that the chances of finding ET on this outing were slim.

"Since they stated that these candidates are about what one would expect from a statistical analysis of receiver noise, I am not unduly optimistic," he said.

Factor is optimistic that chances of finding ET in the future are good, but he is not at all impressed by the 4,287,000-plus people who have downloaded the SETI@home screensaver.

"That's less than one tenth of one per cent of the Earth's population," he said. "I should like to think that SETI is far more important than this indicates."

Alien Life? Astronomers Predict Contact by 2025 Hillary Mayell

The Following article was published by National Geographic News November 14^th, 2003

Earthlings could make contact with extraterrestrial beings by the year 2025, two astronomers predict in a new book. The authors say it's unlikely space aliens look like Hollywood's ET—little, green, and hairless—and that while aliens are highly unlikely to pay Earth a visit, they may be sending radio signals across space to let us know they exist.

The book, Cosmic Company, "is an explication of why we think they're out there, how we're looking for them, what they must be like, and a little bit of what it might mean" to find life on other planets, said co-author Seth Shostak, a senior astronomer at the Search for Extraterrestrial Intelligence Institute (SETI) in Mountain View, California.

The institute conducts research in astronomy, the planetary sciences, and evolution. Past research projects have been funded by NASA, the National Science Foundation, and numerous universities and foundations.

Beyond Our Galaxy

Shostak and co-author Alexandra Barnett, an astronomer and executive director of the Chabot Space and Science Center in Oakland, California, base their predictions on a number of factors.

They include the billions of years in which extraterrestrial life could have evolved and the abundance of planets and stars elsewhere in the universe that are likely to mimic environmental conditions found on Earth.

"It's a matter of statistics, really," said Barnett. "Depending on who you talk to, the universe is 12 to 15 billion years old. Humans have only been around for 40,000 years. We really are the new kids on the block. It would just be too tough a pill to swallow to believe that nothing else has evolved in all that time and space."

The universe is indeed vast. In 1924 astronomer Edwin Hubble showed that there are galaxies beyond our own. "More than a half century later, the Hubble telescope has shown that there are at least 100 billion such galaxies," said Shostak. Our galaxy, the Milky Way, is home to at least 100 billion stars.

Planets are also plentiful. Since 1995, when the first Jupiter-sized planet outside of our solar system was found, astronomers have been able to identify about 100 more planets, all of them around 300 times more massive than Earth.

"Planets really are as common as phone poles," said Shostak. "Right now, we know that there are planets out there [orbiting] ten or twenty percent of the stars we look at. So far, only huge planets have been found, but it would be a big surprise if there were only big ones. I don't think anyone expects that to be the case."

Until now, the search for intelligent life has been somewhat hampered by inadequate technology—too few stars surveyed at too low a sensitivity by Earth and space-based telescopes.

But in 2007, NASA will launch the Kepler Mission, a satellite probe able to detect smaller planets the size of Mercury, Mars, or the Earth. The mission is specifically designed to look for planets in what scientists consider the habitable zone: the distance from a star where liquid water can exist on the planet's surface.

Projects like the Kepler Mission and the new Allen Telescope Array, located near Mount Lassen, California, which will enable astronomers to survey 100,000 stars by 2015, should increase the odds of finding a radio signal broadcast by alien life, say the astronomers.

"The bottom line is that there is an enormous amount of real estate, and there doesn't seem to be anything particularly special about our neighborhood. The star that's our sun is nothing special. The Earth is just a rock," said Shostak. "To think anything else is to once again put ourselves at the center of the universe, and scientists are very [wary] of doing that. We've done it before and been proven wrong."

Searching for Intelligent Life

The building blocks of life on Earth—complex organic compounds and amino acids—are abundant in the universe and can be found in meteorites, comets, and interstellar gas and dust.

"There's a growing realization that there may be some other biology in our solar system," said Shostak. "There are deep oceans on the moons of Jupiter, and some evidence that Mars in its early days really should have had some life. So if there are two or maybe even three instances in this solar system alone, where life could have emerged, it's not unreasonable to consider that similar situations arose in other solar systems."

Of course, there is a difference between life and intelligent life, and scientists disagree about the likelihood of intelligence evolving on another planet.

Some believe that it takes very special conditions for intelligence to evolve. The late Stephen Jay Gould, the preeminent Harvard University evolutionary biologist and paleontologist, wrote that the creation of intelligence was a freak occurrence, requiring a number of specific events to occur that could never be replicated again.

Shostak and Barnett believe differently. They argue that there are evolutionary mechanisms that encourage intelligence, particularly among social beings.

"For instance, if you can intuit the actions of the males next to you—they're about to steal your food or your mate, say—then you're going to have increased breeding success, so the next generation is going to have more ability to live in a social environment," said Shostak. "This is very general behavior—it's not miraculous—you see it in the great apes, of course, but you also see it in dolphins, whales."

"JO Alien"

As to what an intelligent alien life-form might look like should such a thing exist, it's anyone's guess. Shostak and Barnett created "JO Alien," an animated character for a planetarium show at the National Space Centre in Leicester, England, to explore the question.

"It's the poster child of aliens," said Shostak. "A very conventional kind of alien—grey and smooth and humanoid—very anthropomorphic. Not what we really expect."

However, the genderless JO does demonstrate some of the basic principles of physics and engineering that might dictate what another life-form might look like.

"An alien would probably have to be bigger than a rat because rats have quite small brains, and an intelligent life-form would need a bigger brain," said Barnett. "So bigger than a cat, but not bigger than an elephant because there are limitations on how much weight a body can support."

JO Alien has two eyes, based on the assumption that an alien life-form would be found on a planet circling a star. Everything on Earth that lives in light has developed eyes. Why two instead of one? Two gives you the evolutionary advantage of being better able to catch your next meal, said Barnett. Why not ten eyes? It would take an enormous amount of brain-power to process all the signals, she said, with little or no extra benefit.

As far as limbs are concerned, the pair speculate that an extraterrestrial would have more than one, particularly if it's building radio telescopes, but a score would be a stretch. Again, it would require a great deal of brain-power to coordinate all 20, Barnett said.

Given the enormous distances between the stars, measured in terms of trillions of miles, Shostak doesn't expect a visit.

"There's a tremendous amount of interest in alien life, mostly from the point of view that we've been visited," he said. "I don't believe that, and I don't think most scientists do. What we'd most like to convey is that there's a possibility they exist even if they haven't visited, and we're searching for them."

While We're Watching Mars, Could Someone be Watching Us?


By Seth Shostak Senior Astronomer 22 January 2004 Have aliens sent mechanical emissaries to our solar system -- robotic probes on a snoopy mission to reconnoitre Earth? It’s certainly an intriguing idea: sophisticated spy satellites from light-years away monitoring our planet, watching the slow evolution of life, and reporting back to their alien masters. Such a scenario has frequently appeared in the SETI literature, and Allen Tough, at the University of Toronto, has urged that we take the idea seriously enough to make a search for these alien "bugs." You might question whether interstellar spying makes sense. After all, there are several hundred billion star systems in the Galaxy, spread across a disk 100,000 light-years in diameter. Sending billions of probes over such daunting distances sounds like a project that no alien congress would ever approve. But the idea can’t be dismissed that easily. Advanced societies -- even those that are only modestly beyond our own -- will have catalogs of planets known to support life. This inventory can be assembled by using large telescopes to collect and analyze the light reflected from the atmospheres of other worlds; looking for "biomarkers" such as oxygen and methane. Finding these gases on someone else’s planet would be a clue that biology is present. Surprising as it may seem, microbes can be detected at light-years’ distance using this technique. If worlds with life are plentiful, then some of them will be relatively close to the aliens’ home planet, encouraging a close-up look via a probe. If bio-worlds are rare, then these would be so singular as to make the greater travel times required to reach them worth the wait. Either way, there could be some stimulus to post a probe. And the total number of probes need not be extraordinarily large. How big do the probes have to be? Allen Tough has written that these alien bugs "could be smarter and more knowledgeable than any human being, yet… be smaller than a basketball or baseball." Smaller is better for two reasons: less energy is required to hurl them to other worlds, and they would be harder to find and confiscate by any intelligent beings on the spied-upon planet. On the other hand, the probes are pretty useless if they don’t have the oomph required to send back data, either via a radio signal or a tightly focused infrared laser (the latter seems more sensible to me). So the aliens might opt for a "master-slave" setup somewhat akin to the scheme used to retrieve data from the Mars rovers. A relatively small probe could orbit near to Earth, making high-resolution photos and collecting information, while a larger, more distant "mother ship" could be hanging out in, say, the asteroid belt, where it would process the data from the smaller probe and relay it back home. Another approach would be to have only one probe, but on a highly elliptical orbit (like a short-period comet). This scheme would keep the probe largely out of sight, but bring it close to our planet for detailed looks every few dozen years. What about the costs? For a truly advanced society, the bill for the hardware might be negligible. But to send a probe to the stars at even a leisurely one-tenth light speed requires a substantial dollop of energy. If the probe weighs 10 pounds, the minimum energy necessary to rocket it to target and then slow it down on arrival is roughly 5,000 trillion joules. If you buy that much energy from your local electric company, it will cost you $120 million. Frankly, although a bill that size would probably stupefy your spouse, it’s not an unthinkable amount (a Mars Exploration Rover costs three times as much). Still, there are some probe-o-phobes who ask, "why would the aliens bother? After all, the probes can only telemeter their data at the speed of light. Why wouldn’t the snoopy extraterrestrials simply await our television signals? These would reach them at the same time any report from a probe would." Indeed. And one could argue that the content of our broadcasts would tell alien viewers all they might want to know about our society (I won’t lapse into the obvious…) But there’s another angle. Life on Earth has been detectable (via atmospheric biomarkers) for two billion years. Intelligent life is only a recent, and so far, brief, phenomenon. Very few (if any) of the biologically active worlds investigated by probes are likely to have brainy life. The aliens will surely know this. They will send probes, not to find us – after all, our signals, in the end, will find them – but to investigate, up close and personal, life that isn’t ever going to broadcast. For 500 million years, there’s been a rich pantheon of plants and creatures on this planet, making it a natural history exhibit of enough interest to warrant a close-up look. So probes are a possibility. And maybe one was launched our way, sometime in the last two billion years. We might still be able to find it, if we knew where to look. Should we make a careful investigation of the asteroid belt? The Earth-Moon Lagrange points? Perhaps parked in a nearby orbit, or on the Earth itself? We just don’t know, and that makes the search space dreadfully large. Probes are not crazy, but how to find one is hazy.

Seth Shostak is the Public Programs Scientist at the SETI Institute and he has devoted much of his career to conducting radio astronomy research on galaxies. He has published approximately fifty papers in professional journals and authored several hundred popular articles on various topics in astronomy. He has also been involved in film and television - producing his own films. His book, “Sharing the Universe” was first published in 1998.

31^st January, 2004 From: Brenda Denzler Subject: Of Hubble SETI & UFOs FWIW

The following is a posting on UFO Updates

In the course of my work, I have the opportunity to travel from time to time. Recently, I chanced to meet a person who had a bunch of memorabilia from the Hubble space telescope project.

The nature of the things he had on display indicated that he had worked on that project for awhile, so I asked him about it. He told me what his role had been, and then discussed the impending closure of the project and whether the announcement was more a political strategy to get more funding from Congress rather than a reflection of any reality.

I then told him that I'd written my dissertation on UFOs and the UFO community (one of his eyebrows went up at this point), and said that those folks kept their fingers on the pulse of programs like the Hubble, because they were very interested in our (overt, anyway) space exploration programs.

He _then_ told me that before he'd worked on the Hubble, he had been at another well-known place of employment (which I shan't mention here so as to make it difficult for people to track him down by looking for his work history, should there be moles among us).

While there, he came in contact with people working on different "top, top, top secret" projects, the nature of which he could only surmise given the kind of contact he had with them. One day he was talking to one of those people and this person said, "I'll just tell you this: There's something out there." And this person pointed upward as he said it.

At this point I emphasized that when it comes to UFOs, we have too many high-quality sightings, with multiple independent witnesses and simultaneous instrumented data, to believe that nothing is going on. And I said that one has to admit that there's a lot of foolishness that attaches itself to the subject of UFOs, and a lot of religious or quasi-religious, perhaps wishful, thinking that gets wrapped up with it, but there is, nevertheless, that hard core of evidence to consider. He said yes, reliable evidence.

But, I pointed out, in relation to his contact's statement, the question is, "It's one thing to say there's something out there. It's another, entirely, to suggest that what is out there, has come here." He agreed. He said that based on his knowledge of this person's project (the basis for which he described in one or two words), he thought it was probably something like the SETI project. Then he made a joke about losing his job because of telling me this. My immediate thought, which I kept to myself, was that SETI is about listening, and what he had described could also be used for broadcasting/transmitting, or for tracking something, or.....

Several years ago, when a friend found out that I was working on a UFO-related dissertation, she said that her friend's husband had been working for several years as part of a team under a government contract to figure out how we would communicate with an alien race.

Makes you wonder if SETI is a front organization, and real contact has already been made. When the Powers That Be decide to let the cat officially out of the bag, will SETI be the "front man" for doing so?

It also makes you wonder how much of the cat we actually have _in_ the bag, and whether there may not be different parts of the cat contained in different bags - the holders of any one bag-with-parts being unknown to those who hold still other parts and all thinking (mistakenly) that they themselves have the only, the full, and the complete cat.

If it should appear to be fiscally or politically necessary for one bag-holder to let their part of the cat out (which they may erroneously believe is the whole cat), could it precipitate, in self-defense as public opinion creates a groundswell of support for massive funding for that bag-opening group, a chain reaction of bag openings?

Or, perhaps some of the bag-holders have a sketchy awareness that other folks elsewhere in the political/military/research complex seem to have bags with something in them. In the battle for financial and other resources to continue their work, they want to know who their competitors are for the resources, so they snoop. One good way to snoop is to keep your ear tuned to the UFO community, where tidbits of info from insiders (or former insiders) periodically surfaces. Like the conversation I've just related to you all.

I realize that this all falls under the category of "yet another unofficial tidbit about alien life" that cannot be verified... all the more so because I am withholding details about this person that might enable him to be identified by someone who really wanted to track him down. But I guess I see it as kind of like throwing another bean into the pot. By itself, not very nourishing. But when we put _all_ the beans into the pot together, an interesting stew seems to present itself for our consideration.

So, for what it's worth, there it is. My bean for the day. (Ha! In this case, it's a human bean! - Pah-dump-DUMP!)

Brenda

Tarter discusses search for aliens

The following article was published in “The Daily Mississippian”, 27^th February, 2004

Renowned scientist Jill Tarter [ left ]spoke Tuesday at the Ford Center for the Performing Arts, detailing her role in the search for extraterrestrial life. Tarter, director of the once-defunct Search for Extraterrestrial Intelligence program, described the process in combing through the expanding universe, exploring the possibility of intelligent life.

"When we ask ourselves are we the only one in the universe, we're asking, 'Are there any other intelligent...life in the universe that wonder if they are alone.'"

The SETI program, which was featured in the 1997 movie "Contact," written by famed astronomer Carl Sagan, utilizes what Tarter called "primitive technology" to search for life.

"We are the youngest technology out there," Tarter said, explaining that if she and her team of scientist make contact, the signal sent by the extraterrestrial life would be far more superior.

However, to begin her search for the life, Tarter said, she and her scientists use radio telescopes to find signals emitted by light, starts and planetary objects.

"The signal from the stars are very, very faint," Tarter said. "If you take a single cell phone (transmitter) and put the transmitter on the moon, it is the second strongest signal in the sky."

With the SETI program, Tarter began searching for the faint signals in 1975 after she received her doctorate from the University of California at Berkeley, and when NASA terminated the program in 1993, Tarter had to find another resource to continue her love.

"We are rising from the ashes of congressional termination," Tarter said.

Tarter and her colleagues created the privately funded Project Phoenix, a project that uses the largest radio telescope in the world in Arecibo, Puerto Rico, with another in England to search for signals simultaneously.

"We haven't yet detected a signal, but we really haven't done a lot of searching."

With Project Phoenix, the telescopes can only comb through about one million stars, around 0.001 percent of the Milky Way Galaxy, Tarter said.

In 2007, Tarter said scientists are planning to build the Allen Telespan Array, a group of more than 300 radio telescopes in California, to expand in their search for signals.

"It will be 300 times faster than today in 2007."

After Tarter and her team of scientists find a signal, she said they will try to deduce from the information the composition of the planet's atmosphere. If water, ozone and methane are present in the atmosphere, like Earth, scientist believe life also may be existent, Tarter said.

The lecture was sponsored by the UM National Remote Sensing and Space Law Center, the Sarah Isom Center for Women and the Mississippi Space Grant Program.

Although Tarter has yet to find any life, she still remains an eternal optimist.

"I've worked hard in this project, and that's no reason at all to be (discouraged), because it's a huge universe out there."

Jill Tartar, Ph.D

Jill Tartar is at the cutting edge of the scientific effort to discover intelligent life in the universe beyond our planet. She is a director of the SETI (Search for Extraterrestrial Intelligence) Institute and leads a scientific team developing and utilizing observational and analytical methods in order to search the universe for signals which may indicate evidence of intelligent life.

After receiving her Ph.D. in Astronomy from the University of California at Berkeley, she began SETI research with UUCP’s project SERENDIP as a graduate student. After a post-doctoral appointment with NASA Ames' Space Sciences Office, Dr. Tarter continued research in SETI and was named Project Scientist for NASA's High Resolution Microwave Survey. After the loss of NASA funding for SETI, Dr. Tarter was named Director of the Institute's Project Phoenix, a position which she continues to hold.

She was named 1997 "Person of the Year" by Chabot Science Centre and is the recipient of two Public Service Medals from the National Aeronautics and Space Administration.

Europa: Frozen Alive Or Wasteland?

An Interview with Christopher Chyba by Henry Bortman for Astrobiology Magazine

Moffett Field – April 5^th, 2004

Christopher Chyba is the principal investigator for the SETI Institute lead team of the NASA Astrobiology Institute (NAI). Chyba formerly headed the SETI Institute's Center for the Study of Life in the Universe. His NAI team is pursuing a wide range of research activities, looking at both life's beginnings on Earth and the possibility of life on other worlds. Several of his team's research projects will examine the potential for life - and how one might go about detecting it - on Jupiter's moon Europa. Astrobiology Magazine's managing editor Henry Bortman recently spoke with Chyba about this work.

Astrobiology Magazine: One of the areas of focus of your personal research has been the possibility of life on Jupiter's moon Europa. Several of the projects funded by your NAI grant deal with this ice-covered world.

Christopher Chyba: Right. We're interested in interactions of life and planetary evolution. There are three worlds that are most interesting from that point of view: Earth, Mars and Europa. And we have a handful of projects going that are relevant to Europa.

Cynthia Phillips is the leader of one of those projects; my grad student here at Stanford, Kevin Hand, heads up another one; and Max Bernstein, who's a SETI Institute P.I., is a leader on the third.There are two components to Cynthia's projects. One that I think is really exciting is what she calls "change comparison." That goes back to her days of being a graduate associate on the Galileo imaging team, where she did comparisons to look for surface changes on another of Jupiter's moons, Io, and was able to extend her comparisons to include older Voyager images of Io.

We have Galileo images of Io, taken in the late 1990s, and we have Voyager images of Io, taken in 1979. So there are two decades between the two. If you can do a faithful comparison of the images, then you can learn about what's changed in the interim, get some sense of how geologically active the world is. Cynthia did this comparison for Io, then did it for the much more subtle features of Europa.

That may sound like a trivial task. And for really gross features I suppose it is. You just look at the images and see if something's changed. But since the Voyager camera was so different, since its images were taken at different lighting angles than Galileo images, since the spectral filters were different, there are all sorts of things that, once you get beyond the biggest scale of examination, make that much more difficult than it sounds. Cynthia takes the old Voyager images and, if you will, transforms them as closely as one can into Galileo-type images. Then she overlays the images, so to speak, and does a computer check for geological changes.

When she did this with Europa as part of her Ph.D. thesis, she found that there were no observable changes in 20 years on those parts of Europa that we have images for from both spacecraft. At least not at the resolution of the Voyager spacecraft - you're stuck with the lowest resolution, say about two kilometers per pixel.

Over the duration of the Galileo mission, you've got at best five and a half years. Cynthia's idea is that you're more likely to detect change in smaller features, in a Galileo-to-Galileo comparison, at the much higher resolution that Galileo gives you, than you were working with images that were taken 20 years apart but that require you to work at two kilometers per pixel. So she's going to do the Galileo-to-Galileo comparison.

The reason this is interesting from an astrobiological perspective is that any sign of geological activity on Europa might give us some clues about how the ocean and the surface interact. The other component of Cynthia's project is to better understand the suite of processes involved in those interactions and what their astrobiological implications might be.

AM: You and Kevin Hand are working together to study some of the chemical interactions believed to be taking place on Europa. What specifically will you be looking at?

There are a number of components of the work I'm doing with Kevin. One component stems from a paper that Kevin and I had in Science in 2001, which has to do with the simultaneous production of electron donors and electron acceptors. Life as we know it, if it doesn't use sunlight, makes its living by combining electron donors and acceptors and harvesting the liberated energy.

For example, we humans, like other animals, combine our electron donor, which is reduced carbon, with oxygen, which is our electron acceptor. Microbes, depending on the microbe, may use one, or several, of many possible different pairings of electron donors and electron acceptors. Kevin and I were finding abiotic ways that these pairings could be produced on Europa, using what we understand about Europa now. Many of these are produced through the action of radiation. We're going to continue that work in much more detailed simulations.

We're also going to look at the survival potential of biomarkers at Europa's surface. That is to say, if you're trying to look for biomarkers from an orbiter, without getting down to the surface and digging, what sort of molecules would you look for and what are your prospects for actually seeing them, given that there's an intense radiation environment at the surface that should slowly degrade them?

Maybe it won't even be that slow. That's part of what we want to understand. How long can you expect certain biomarkers that would be revelatory about biology to survive on the surface? Is it so short that looking from orbit doesn't make any sense at all, or is it long enough that it might be useful?

That has to be folded into an understanding of turnover, or so-called "impact gardening" on the surface, which is another component of my work with Cynthia Phillips', by the way. Kevin will be getting at that by looking at terrestrial analogs.

AM: How do you determine which biomarkers to study?

CC: There are certain chemical compounds that are commonly used as biomarkers in rocks that go back billions of years in the terrestrial past. Hopanes, for example, are viewed as biomarkers in the case of cyanobacteria. These biomarkers withstood whatever background radiation was present in those rocks from the decay of incorporated uranium, potassium, and so on, for over two billion years.

That gives us a kind of empirical baseline for survivability of certain kinds of biomarkers. We want to understand how that compares to the radiation and oxidation environment on the surface of Europa, which is going to be much harsher.

Both Kevin and Max Bernstein are going to get after that question by doing laboratory simulations. Max is going to be irradiating nitrogen-containing biomarkers at very low temperatures in his laboratory apparatus, trying to understand the survivability of the biomarkers and how radiation changes them.

AM: Because even if the biomarkers don't survive in their original form they might get transformed into another form that a spacecraft could detect?

CC: That's potentially the case. Or they might get converted into something that is indistinguishable from meteoritic background. The point is to do the experiment and find out. And to get a good sense of the time scale.

That's going to be important for another reason as well. The kind of terrestrial comparison I just mentioned, while I think it's something we should know, potentially has limits because any organic molecule on the surface of Europa is in a highly oxidizing environment, where the oxygen's getting produced by the radiation reacting with the ice. Europa's surface is probably more oxidizing than the environment organic molecules would experience trapped in a rock on the Earth. Since Max will be doing these radiation experiments in ice, he will be able to give us a good simulation of the surface environment on Europa.

Is strange space signal a sign that ET's mother has called back?

The following article was published in “The Scotsman”, 2^{nd
September, 2004}

Is strange space signal a sign that ET's mother has called back?

JAMES REYNOLDS

SCIENCE CORRESPONDENT

AMATEUR radio hams are usually excited by the faint buzz of a distant shortwave station, but a group of scientists believe they have received a message from extra-terrestrials. Astronomers think that a signal picked up by a radio telescope last year shows the highest probability yet that ET's family may have returned his call.

In February 2003, scientists involved in the search for extra-terrestrial intelligence (SETI) pointed the huge radio telescope in Arecibo, Puerto Rico, at about 200 sections of the sky. Unexplained radio signals had been detected twice by the same telescope in these areas and scientists were trying to confirm the findings.

It may sound fanciful, but a report in the journal NewScientist reveals how the team has now finished analysing the data, and all the signals seem to have disappeared - except for one which has got stronger. Detected on three separate occasions, the signal is "an enigma", say researchers.

So far, explanations have included conjecture that it could be generated by a previously unknown astronomical phenomenon, or may even be something far more pedestrian, such as an artefact on the telescope itself interfering with measurements.

But the astronomy team says that it also happens to be the best candidate yet for a contact by intelligent aliens in the six-year history of the SETI@home project, which uses programmes running as screen-savers on millions of personal computers worldwide to sift through signals picked up by the Arecibo telescope.

Dr Dan Wertheimer, a radio astronomer at the University of California (Berkeley) and the chief scientist for the project, said: "It is the most interesting signal from SETI@home. We are not jumping up and down, but we are continuing to observe it."

Named SHGb02+14a, the possible alien communication has a frequency of about 1420 megahertz - one of the main frequencies at which hydrogen, the most common element in the universe, readily absorbs and emits energy.

Some astronomers have suggested that aliens trying to announce their presence would be likely to transmit at this frequency, and SETI researchers regularly scan this part of the radio spectrum.

The unexplained signal appears to be emanating from a point between the constellations of Pisces and Aries, where there is no obvious star or planetary system within 1,000 light years, and the transmission is also very faint.

Dr Eric Korpela, of the research team, said: "We are looking for something that screams out 'artificial'. This just doesn't do that, but it could be because it is distant."

So far, the telescope has managed to pick up the signal for only about a minute in total, which is not sufficient for astronomers to analyse it fully. Dr Korpela believes that it is unlikely the "message" is the result of any obvious radio interference or noise, and it does not resemble any known astronomical object.

Others, however, are more sceptical, saying the current lack of explanation does not mean that it could only have been produced by aliens.

Dr Jocelyn Bell Burnell, of the University of Bath, said: "It may be a natural phenomenon of a previously undreamed-of kind - like I stumbled over."

It was Dr Bell Burnell who, in 1967, observed a pulsed radio signal which the research team at the time believed was from extra-terrestrials, but which later was confirmed as the first sighting ever of a spinning collapsed star.

Other questions arise over the signal's frequency, which oscillates by between eight and 37 hertz a second.

Paul Horowitz, a Harvard University astronomer who looks for alien signals using optical telescopes, believes that the drift in the signal makes it "fishy".

David Anderson, the director of the SETI@home project, is also sceptical but curious about the signal. He told NewScientist: "It is unlikely to be real, but we will definitely continue to observe it."

Meanwhile, a new analysis of interstellar communications claims that, rather than sending radio signals, aliens would find it far more efficient to send a "message in a bottle".

Scientists at Rutgers University in New Jersey claim that beaming a radio signal that can be detected 10,000 light years away would demand a million billion times as much energy as just shooting out matter on which the data is inscribed.

Seth Talks To BBC

Seth Shostak – interviewed by the BBC

The following interview was broadcast on the BBC Science and Nature Programme, on 12th November 2004

Ben: Do you believe in extra-terrestrials?

Seth Shostak: "Well, Ben, if I didn't, I wouldn't continue to do this work. It would be very frustrating to think that we're looking for something that doesn't exist."

Duncan: How do you use radios to listen for aliens?

Seth Shostak: "The scheme that we use is to point very large antennas in the directions of sun-like stars, and look for signals that are clearly produced by a transmitter, and not natural cosmic static."

Sara: What type of signals do you expect aliens to make?

Seth Shostak: "Well, Sara, I expect aliens to make all kinds of signals, but the kind that we look for are so-called narrow-band signals. These are at one particular spot on the radio dial. These are the types of signals that would be most easy to detect from great distances."

Vicki: Is there any possible chance we could encounter alien life in our lifetime?

Seth Shostak: "I don't think we're going to encounter it face-to-proboscis. I don't expect them to come here, and we're not going there, but we might find a signal from them in the next several decades."

Martin: Does the SETI dish transmit as well as receive?

Seth Shostak: "The Arecibo antenna does have a powerful transmitter, but we don't use it. We're just trying to eavesdrop."

Mike: Do you think any contact will be understandable to us, will we recognise it?

Seth Shostak: "If they are being altruistic, and trying to educate us, they may make their message simple for us. But personally, I don't expect this. I suspect we'll not understand their message."

Rob Sharp: If we're not alone, why all the sightings and no contact?

Seth Shostak: "Most of the sightings can be explained as natural phenomena or aircraft or balloons or other mundane stuff. I still haven't seen any evidence that any of these sightings involve alien spacecraft. I think the aliens exist - I just don't think they're visiting."

Marcos Scriven: There is a screen saver which uses your PC while you're not using it, to analyse SETI signals. Do you know if anyone has turned up anything interesting using this method?

Seth Shostak: "There has been a lot of processed data, but it will be a few years before they will know if SETI@home has turned up ET's faint whine."

Simon Zerafa: What are the chances that ET might be a machine intelligence rather that biological?

Seth Shostak: "Personally, I think it's quite likely that the bulk of the intelligence in the galaxy is not soft and squishy, but rather, artificial."

Michael Somers: Do you think places like Stonehenge where created by aliens?

Seth Shostak: "That would be a disservice to druid engineers! I'm sure Stonehenge, the pyramids, and the lines in Peru, were all made by clever humans."

Loz Herbert: If aliens were found, would it not be kept quiet due to the potential mass hysteria?

Seth Shostak: "No I don't. The majority of folk believe that the aliens are already here, and I don't see them rioting in the street about that. Any discovery would be made public immediately."

Neil Mackie: Has it been confirmed yet that life did exist on Mars?

Seth Shostak: "Alas, Neil, not yet. There is some very suggestive evidence, but a lot of controversy. We may not know for sure for many years."

Steve: Is there any means for sending messages so that they reach other planets more quickly than they do with radio waves?

Seth Shostak: "As far as we know, nothing can beat radio or light for speed - Albert Einstein told us that, and so far there's no reason to disbelieve him."

Kevin Mckay: Would aliens have to be water or carbon based?

Seth Shostak: "Not necessarily, but carbon is exceptional in its ability to hook up with other atoms and make complex molecules, and life, as you are undoubtedly aware, is mostly about complex molecules."

Tania Jones: What would aliens look like?

Seth Shostak: "I haven't the slightest idea!"

Tony Stone: If the aliens are at a state to receive would they not have been broadcasting themselves?

Seth Shostak: "The problem is, we've only been broadcasting for half a century. So our signals haven't reached many star systems yet."

Will: Do you think aliens are listening for us?

Seth Shostak: "That doesn't sound unreasonable to me, to use a cautionary double negative!"

Vill: Seth, do you think that there is life as we know it?

Seth Shostak: "Yes, in the sense that I think that a lot of extra-terrestrial life will be based on carbon chemistry the way ours is, so in that sense, we know it."

Anthony Crolla: How did you get into this field of astronomy?

Seth Shostak: "I was a radio astronomer, and the techniques I was using to study galaxies are exactly those required to listen for ET."

Unlixes Neilstropp: Why is it so many scientists believe alien life would be carbon based?

Seth Shostak: "Again, carbon is good at making complex chemistry. There is also a lot of carbon around, and in any liquid environment, you can expect it to start doing interesting things."

James Carter: If you were listening to our radio/TV channels, and watching for instance the events of World War 2, would you contact Earth?

Seth Shostak: "I don't think that the aliens will be put off by our petty problems any more than Columbus refused to discover America because the American Indians were occasionally at war with one another."

Bob Davies: Do we have a plan in the case of a 'Contact' scenario?

Seth Shostak: "We do, but it's very simple. It merely states that we should tell all the astronomers, tell the public, and tell the government."

Michael Vigor: What are the future plans of the SETI project?

Seth Shostak: "The SETI Institute, where I work, is building a new radio telescope called the Allen Telescope Array, and this telescope will be 100 times faster than what we're doing today. We're also starting experiments to look for flashing laser pulses from other worlds."

Jill Newcombe: Can you give me some info on clubs and organisations I can join?

Seth Shostak: "There are two possibilities that come to mind. One is the SETI Institute's Team SETI, and the other is the free screensaver - SETI@home. Check the SETI Institute's website: http://www.seti.org for more information."

Jason Timmins: What about the 1976(?) signal?

Seth Shostak: "I think Jason is referring to the so-called 'Wow' signal, (which by the way was 1977), however, every attempt to find that signal again has failed, so we can't assume it was ET."

Phil Elias: How can you be sure that aliens know about radio waves and are able to detect them?

Seth Shostak: "The aliens will have the same physics we do, and they'll surely discover this very efficient way of sending information from one star to another."

Alex Locke: About radio waves - how could aliens hear our radio signals amidst all the noise from the Sun?

Seth Shostak: "Surprisingly, Alex, the Sun actually makes weaker radio signals than the BBC. So they could indeed sort out our transmitters from the Sun's background noise."

Paul Pitchford: Seth, I am very sceptical and struggle to believe that there is intelligent life forms out there. What makes you think there is?

Seth Shostak: "If we are alone then that's extraordinarily remarkable in such a vast universe.Personally, I don't think we're that special."

A Muppet: Have we found *any* planets within the correct distances from their suns to support life?

Seth Shostak: "There are a few, but they are giant planets, not the kind of world ET would like to call 'home'. But we expect that there are also many small planets that we cannot yet find. The limitations of the techniques that we use can only find very large planets."

Stuart Travers: In a "Star Trek" world, all the alien races walk on two legs or something similar, what do you think the chances of real ET's being like us are?

Seth Shostak: "Well, when I go to the local zoo, I find that most of the critters walk on four legs, and most of the critters in my house walk on six legs. So, it's not clear to me that ET will only have two."

Chris Carter: Are you ever worried that programs such as SETI might attract the attention of malevolent aliens?

Seth Shostak: "Well, keep in mind that we don't broadcast - we only listen. So the aliens won't know that we're even doing SETI.I think the likelihood of malevolent aliens existing is as likely as me going into the backyard, rooting out the ants and exterminating them! I don't think we're that interesting."

Marianne Oates: If you discovered life, Seth, what would be the first thing you would do?

Seth Shostak: "Probably lose a lot of sleep! But for the next week we would be busy verifying the signal and collecting as much data as we could."

Anne Marigold: On the basis of 'nothing unites like a common enemy' do you think proof of ETI would unite the people of the world?

Seth Shostak: "It's a nice thought, but I'm somewhat sceptical! I think there would be a lot of contention about who should have access to the big radio telescopes in order to get this new information."

Steve Norton: If a radio signal took fifty years to find a hit, how long would it take us to travel to the destination?

Seth Shostak: "Radio signals travel at the speed of light, which is at least ten thousand times faster than our best rockets.In the future, we might be able to build rockets that could go at ten percent of the speed of light, so it would take five hundred years to get there."

ab3456: Will SETI ever stop?

Seth Shostak: "I certainly hope not. Remember, we're looking for a needle in a haystack, and we've checked out a handful of hay, so it's very early days to think about stopping."

Affro Em: Would mobile phone signals be heard by aliens?

Seth Shostak: "No. They're entirely too weak - in fact, we often don't hear them properly here on Earth!"

Nastar: How far has the original Voyager probe reached and are we still in contact with it?

Seth Shostak: "It's now ten thousand million kilometres from earth, and we still receive signals from these craft."

Paul Smith1: Do you view "first contact" as an essential part of this planet's future survival?

Seth Shostak: "I'm not so sure it's essential for our survival, but I do think it will happen."

Farris Willson: Even if we had a contact how can we confirm it was from ET and not a Pulsar or other different waves?

Seth Shostak: "The characteristics of the signal would betray it as being sent by a transmitter and not by some noisy natural source. For example, pulsars spread their radio energy all over the dial, which is very inefficient. ET wouldn't do that."

Colin Finch: If contact is established, who agrees what we send back?

Seth Shostak: "Good question, Colin. At the moment, there is a proposal to require international agreement on any reply, but frankly, we've been sending television signals into space for 50 years. So our reply is already out there."

Simon Stephens: Seth, do you believe that the American government has covered up alien aircraft discoveries?

Seth Shostak: "No, I don't. No matter what you may think of the American government, they're not that efficient!"

Ayasami Fukuno: Do you think Aliens have any special powers like teleporting and stuff?

Seth Shostak: "Well, I'm sure they're more advanced than we are - the ones we will hear. But they're stuck with the same physics that we are. Teleporting might not be allowed by physics - even for aliens!"

Matt: What do you think the chances are of a real 'Planet of the Apes'?

Seth Shostak: "All I know is that our ancestors managed to wipe out the Neanderthals and the apes are a lot further behind us, in an evolutionary sense, than the Neanderthals were. So I personally am not worried. But I am stocking up on bananas!"

Tricia: Why expend even more dollars on detecting intelligent life in space when the fact of its existence can be of no material benefit to us? Is it that scientists such as yourself are really philosophers at heart?

Seth Shostak: "I'll take that as a compliment! I think it's mostly curiosity, in the same sense that Galileo did his work on the basis of curiosity. We always want to know what's over the next hill."

James2: Can you give a quick synopsis of what you have discovered so far?

Seth Shostak: "Yes, we can - we have yet to find ET's signal, period! But that may change tomorrow. In terms of the area that we have covered, essentially, all of the sky has been looked at with low sensitivity, but only 500 star systems have been carefully scrutinised."

Vicky Webb: Seth, if a normal person would be scanning through the radio channels could we hear signals from ETs?

Seth Shostak: "Unfortunately, Vicky, unless they've bought the local AM radio station, they won't. You need a much larger antenna than you're likely to have at home."

Paul Calderbank: If it takes 15 billion years to make a sentient life form able to view the universe (i.e. us), how do you expect any one else to be ahead of the game?

Seth Shostak: "Keep in mind that the earth has only been here for four and a half billion years, so there are plenty of older star systems, and consequently, I suspect,plenty of more advanced societies."

BBC Host: That is all we have time for. Here is Bob with a final word....

Seth Shostak: "I appreciate everyone's interest, and the very good questions, and I hope you'll stay tuned, because we will!"

Listening for ET: Two Decades by David Pescovitz

The following article was published in Astrobiology Magazine, 7th January, 2005

The Allen Telescope Array of more than three-hundred dishes is
under construction at Hat Creek five hours north of San Francisco.

The SETI Institute predicts that we'll detect an extraterrestrial transmission within twenty years.

If that turns out to be true, it'll probably be the folks at UC Berkeley's Hat Creek radio observatory who will have heard the call. Right now, the Allen Telescope Array of more than three-hundred dishes is under construction at Hat Creek five hours north of San Francisco. Within a year, the first thirty dishes will be operational, forming the basis of a giant ear that listens for intelligent beings in space while simultaneously gathering data for groundbreaking astronomy research.

William "Jack" Welch, UC Berkeley professor of electrical engineering and astronomy, has been a driving force in the design and construction of the Allen Telescope Array (ATA) since the project first got off the ground five years ago as a joint effort between UC Berkeley and the SETI Institute. Named for major donor Paul Allen, co-founder of Microsoft, the array will eventually consist of 350 6.1-meter radio dishes electronically networked together into a radio telescope with unprecedented sensitivity. Precisely distributed across 2.6-acres on the Hat Creek grounds, the combined dishes will have far greater sensitivity than much more expensive 100-meter telescopes.

The SETI project scours millions of radio channels for narrow-band signals, indicative of intelligent origin. It's like listening for a station as you twist your car radio's tuning knob past all the static. Until now, SETI has used limited time from myriad radio telescopes around the world, limiting the number of stars that can be observed. However, the ATA will be dedicated to the project, speeding up the SETI search by a factor of 100.
Meanwhile, the unique design of the system enables astronomers to monitor a huge range of wavelengths to observe other cosmic phenomena simultaneously with the SETI search. "SETI is admittedly a long-shot," says Welch, holder of UC Berkeley's first Chair in the Search for Extraterrestrial Intelligence. "I don't have the patience to do only that, so it appeals to me to have a steady flow of other data for us to study as well."

For example, Welch and his colleagues will use the array to make a cosmological map of atomic hydrogen, the most abundant element we know of. Indeed, the visible universe may be composed of up to ninety-percent hydrogen. Determining its spatial distribution in nearby galaxies could provide insight into the evolution of the cosmos and the mysteries of dark matter.
"We'll be able to look halfway back to the beginning of the universe," Welch says. "The ability to observe that far back into time is limited right now."

To crank up the telescope's sensitivity, Welch and his colleagues devised a bit of ingenious antenna technology. In traditional pyramid-shaped antennas like those used in the ATA, the signal is picked up at the tip of the structure, called the feed, and runs down wires to the receiver.

The problem, Welch explains, is that much of the signal gets lost along the way. To keep the signal as pure as possible, the Berkeley researchers shoehorned the receiver components inside the feed itself.

"It's just one new wrinkle for technology that was originally developed in the 1950s, but it enables our feed to essentially have no limitation on bandwidth," Welch says. Right now, just three prototype dishes are being put through their paces at Hat Creek.

In the next few months though, the researchers will install more than two-dozen others, nearly one dish a day.

By Summer, Welch hopes this first small array will be scanning stars many light-years away. Whether ET is intelligent enough to call remains to be seen, or rather heard, but Welch is convinced that there's something out there.

"The recent discovery of planets around many nearby stars is a strong argument that our solar system isn't really unique at all," he says. "That in itself makes it almost certain that there are nearby planets with some kind of life on it."