Greetings. For the next few weeks I will be poking around a modern astronomy/astrophysics research laboratory, specifically the Harvard-Smithsonian Center for Astrophysics in Cambridge MA. Anybody curious about how such places work is more than welcome to join me. Feel free to ask questions, comment on anything I write, and suggest areas you would like to see investigated. I'll start by telling you a little about what CFA does and then go on to present a short space/time trip around the place. In the days that follow we will visit cosmologists, SETIologists, planetary astronomers, and others who don magic glasses to see the universe. -- Fred Hapgood

---

Astronomy and the Internet

Yet there are a few corners where the degree of change has been as radical as any futurist could could hope for; where a profession has been torn up and remade practically overnight. Astronomy is one such case. Over this decade the digitization of astronomical data, the continuously falling prices of bandwidth, processing, and data storage, and a community-wide effort to hammer out data standards and write sophisticated analysis and data handling software, have all combined to create huge increases in connectivity among astronomers, their instruments, and their libraries. This new power has changed almost everything about the field.

For one, it has ruined astronomy's logo. Historically when directors of TV programs or journalists writing a story have wanted a scene that says `astronomer' they have gone to observatories: large, echoing, cold, red-dark, silent spaces (because observing has to be done at night, with only dim red lights on, in structures open to the sky, often at the top of mountains). Here the intrepid scientist could be found, wedged uncomfortably into the observing cage of a great telescope, sitting hour after hour while the world slept, in heroic pursuit of images from the edge of the universe.

In the last five or so years this canonical image has vanished from practice, though no doubt it will linger on in TV science series for another decade. Today astronomers keep the same hours, work in the same environment, and go through the same motions as everyone else: they come to their office in the morning, sit down at a workstation, and surf the net. When observations need to be made the researchers define the coordinates of the region in question and then email them to an observing facility. The request goes into a stack; eventually, depending on details like the popularity of that particular instrument and the scale of the request, the observations will be made and the results returned, also by email. "The astronomer used to go to the data; now the data goes to the astronomer" is how CFA scientist Stephen Murray sums up the change.

This new connectivity also allows astronomers to find and retrieve historical observations from research libraries all over the world in minutes, without travelling to those institutes or waiting for film to arrive by mail. With a bit of searching, a scientist can retrieve and inspect almost all the observations ever made of an object. This increase in access means that more and more useful research can be conducted from archives instead of new observations, which are expensive and take time to complete. (Murray says now half the publications in his field are based on archival research as opposed to new observations.)

Pulling observations out of the archives not only saves time and money; archives have the further advantage that they are indifferent to frequencies. Type in "Sirius" and you can get all the observations made of that object, across 15 magnitudes of wavelength, from the longest radio waves to the brightest gamma-rays. By contrast, a given physical observing instrument never sees beyond a small slice of the spectrum. Over the last 50 years this specificity balkanized the profession by spectral region, into x-ray astronomers, radio astronomers, and so on. A database is blind to these distinctions: once the right observations have been made, a researcher can pull the entire profile of an object up on the display. He or she can can see it complete and entire. This new perspective has begun to bring the profession back together, to make it whole as well. "We're all just astronomers now," Murray says.

Professional facilities like the Center of Astrophysics have changed as well, from being exclusively concerned with the building and operation of telescopes to organizing and running the equivalent of a WAN for astronomers, clearing (in the case of the CFA) 25,000 email messages a day from researchers looking for data or requiring assistance of some sort. The Center runs a half dozen data services, each organized around separate missions or instruments (such as organizing the data sent from different satellites), encyclopedic data archives, online bibliographic databases, libraries of programs used to manipulate data, and banks of support personal for astronomers using those programs or needing access to the data. The website of one the larger of these data services, the Astrophysics Data System (adswww.harvard.edu) got 1.7 million hits in October.

This new connectivity has obvious implications for amateur astronomy and astronomy education. As mentioned above, professional astronomers can order observations from any facility in the world (in theory). No one would think of requiring a professional astronomer to build his own facility before conducting his research. Amateurs have not had this freedom: an amateur astronomer has had to build or buy his own instrument or do without. Since good instruments are expensive and since most people live in areas where the viewing conditions are poor, most of us who were interested in the stars as children have had to let that interest die.

Steve Leiker of the CFA is working on an NSF-funded project that will bring the flexibility of a professional viewing to amateurs. He and his colleages at the CFA have built five small but serious unmanned optical telescopes (5.5" reflectors), all competent to be placed on a rooftop somewhere and then operated through the internet. They will work the same way contemporary professional telescopes do, automatically accepting observing requests, carrying them out, and then sending the results back over the net.

While the NSF project contemplates purely educational functions for these instruments, Leiker is well aware of another market: amateurs willing to pay a few dollars an hour for a few hours a week of observing time. Assuming the instrument is sited in a region permitting 1000 hours of viewing time a year (out of a total of 8746 hrs/yr), a $10/hour fee would return the purchase price of a $20,000 instrument in two years. One can imagine a range of instruments available at differing sensitivities and prices: time on weaker telescopes might be a dollar an hour; stronger machines, $25/hr, and so on. If these economics work out, the range of observing opportunities open to enthusiasts would increase spectacularly.

Of course the same revolution in connectivity makes it simpler for amateurs to build up their own star atlases, to extract and coordinate material drawn from multiple archives, and publish those atlases on the net. Over time perhaps the most important effect of the new connectivity -- in astronomy and elsewhere -- will be to blur the line between the professional and lay science communities.--Fred Hapgood

Sent By:Fred Hapgood on Monday, November 11, 1996 at 16:56:39.

QuasarFuzz: Smooth & Well-Formed

One morning last January Kim McLoud, juggler, mandolin player, and post-graduate student at the CFA, came down to breakfast, poured her cereal, opened her local city paper and read that the subject of her Ph.D. thesis had just gone away; that data from the Hubble has shown it to be as fictious as Percival Lowell's Martian Canals. Thankfully the Boston Globe didn't mention her specifically ("Nature leaves local astronomer looking like a fool") but she says it was a shock nonetheless. Politicians might expect to find such personally relevant material laid out before the general public, but astronomers are not generally so favored.

Months passed and today McLoud is telling her story before a packed auditorium at the CFA. She is standing down off the stage, on the floor, like Oprah or Donahue. She pauses. The room is silent. There is an impish expression on her face. In front of her is a group of amateurs, enthusiasts, and neighbors drawn in from the ambient community. They had come not to hear McLoud exactly, but to take part in a venerable CFA event called Viewing Nights. Still, she has them in her hand.

The researcher had written her thesis on a class of enormously energetic objects called quasars that live out on the far edges of the universe. More specifically she had written about "fuzz": clouds of matter that previous observations had discovered associated with quasars. The presence of this fuzz seemed logical enough. Quasars had to come from somewhere. Theories had been proposed detailing how quasars might have assembled themselves out of this material. In her thesis McLoud had explored these theories and the observations on which they were based.

Shortly after her thesis had been finished the defects in the Hubble Space Telescope were repaired and the instrument started to make observations. One item on its to-do list was to take a closer look at these clouds of quasar-associated fuzz. When it did, to the astonishment of the observers directing the scope, the fuzz had disappeared. The quasars appeared stripped clean, naked as newborns.

These observations threw quasar astronomy into an uproar. On the one hand, the Hubble was a very classy and expensive piece of equipment, and its results had to be taken seriously. But if the ground-based observatories hadn't been seeing real material all this time, what had they been seeing? Worse -- and far more important -- how could quasars have developed if there was nothing for them to develop from? Had they leaked in from some other universe? The waves generated from this discovery were so considerable even McLoud's local paper had taken note, and it was this story she had read that January morning.

At this point McLoud began passing mailing tubes out to the audience. Each tube had a bit of film at one end that was scored with hundreds of tiny lines -- these are called diffraction gratings -- and a cover at the other with a narrow slit cut through it. When you pointed the tube at a light source and looked through the end covered by the grating, small rainbow fringes appeared inside the tube on the edges of your field of view. Inside the green and purple bands of color making up these fringes were bright lines, where the hues became exceptionally rich. These lines, as several precocious youth scattered through the audience explained, were the signatures of specific elements that happened to radiate more intensely in those points in the spectrum. (The lines we were looking at belonged to mercury and phosphorus, which were associated with the artificial light sources in the auditorium.) The devices are called spectrometers, and astronomers use them to find out what distant objects are made of.

When astronomers first pointed their spectrometers at quasars, years ago, they were startled to see a completely unknown signature, as if some element or molecule new to the known universe was out there, signalling them. Then an astronomer named Maartin Schmidt realized that they were seeing the normal energy emissions of hydrogen -- only radically distorted. The size of this distortion could only be explained by assuming quasars were moving very rapidly, which meant they had to be immensely far away (the more distant an object is from us, the faster it moves relative to our viewpoint). Since they were so distant, any light they generated would take a very long time to reach us, which meant astronomers looking at quasars were looking at a landscape of the very early universe. In McCloud's terms, they were looking at a baby universe, a universe just beginning to organize itself.

The Hubble observations seemed to suggest billions of years ago the universe was able to make large energy-producing objects out of nothing. This certainly does not happen today. In our universe, objects emerge from clearly defined predecessor states: stars condense out of nebulae, black holes aggregate from collisions in the center of galaxies, and so on. As the ancients said, nothing comes out of nothing. It was as if the first chapters of the universe had run on one set of physics and the later chapters, another.

McCloud remembers getting up from her breakfast table and turning to the internet, where the astronomical community was starting to hammer away at the Hubble results. Over the next few weeks a countertheory took shape, which was that the fuzz surrounding quasars happened to be of a form and nature that made it very hard to see using Hubble technology. Ground telescopes had looked for objects and structures radiating in the infrared, whereas the Hubble was an optical instrument; ground telescopes had integrated many observations taken over long periods of time, while the Hubble, pressed by demands from astronomers all around the globe, had made quick observations.

Quick optical observations would have worked if these young, distant galaxies had had the same structure as the galaxies we see around us, but that seems not to be the case. The fuzz seems to be smooth and well-formed, without the trailing arms and complicated geometry that make our neighboring nebulae so conspicuous. In short, the early universe was different, but not bizarre.

After McLoud had finished the audience was invited up to the roof of the Center to look through the Center's oldest telescopes, built when American astronomy was in its infancy. (This was the part of the evening that gave the "Viewing Nights" series its name.) A long line formed over the roof, and one by one we got a few minutes of a close view of Saturn, the highlight of that particular Viewing Night.

A staff member lectured the waiting citizenry about the major features of the sky visible at that moment, using a powerful spotlight as a pointer. The rings of Saturn were edge-on that night, so that the planet looked as it had been sliced in half by a sharp knife. A tiny hairline of light slanted through this slice, as though the knife had cut into the firmament, leaving a rent from which light was spilling into space from a source lying just behind the universe.--Fred Hapgood

Sent By: Fred Hapgood on Saturday, November 9, 1996 at 21:38:46.

Direct Hit? The Collision Lottery

The risk of being struck down from outer space is greater than that of being killed in a storm, flood, or earthquake. This is so even though no American has been killed by a meteor yet: risk depends on both probability and the scale of mortality, and nothing kills in wholesale lots like a rock hundreds of yards wide hitting the ground at thousands of miles an hour.

Three times in this century meteors have hit the earth with enough force to have killed tens of thousands, had they struck areas with no more than average population density. (Fortunately, they did not; two hit in Siberia and one in a remote region of Brazil.) According to a recent analysis* the odds that we will receive an impact next year that will kill 1% of the total worldwide population of H. sapiens is one in fifty thousand, or about half the risk a random American has of being murdered. The odds of a hit that will kill 25% of the global population is 3 in a million. Millions of lottery tickets are sold every day that offer worse odds. The risk of the species being wiped out entirely, by an object like the one that killed the dinosaurs, is 1 in a hundred million; low, but then the stakes are considerable. When you add all these risks up the average lifetime risk of being killed by a meteor is 1 in 20,000.

We expose ourselves to geological and meteorological risks no better than these, but we do something about those. We monitor hurricanes and support an extensive research program into earthquakes. For some reason the civilization does almost nothing to find and track the objects out there capable of taking out a city. According to Brian Marsden, director of the offices that monitor these killers--The Minor Planets Center and the Central Bureau for Astronomical Telegrams at the Center for Astrophysics--the little we are doing is deteriorating. "In fact, we're worse off now from the point of view of observing facilities than we have been at any time in the last twenty years," he says.

"One problem is funding cuts," he says. "But another is that astronomy is changing imaging technologies, and the detection of potentially hazardous asteroids (PHAs) has been fumbled during the transition." The shift Marsden is referring to is from film to CCDs, or charge-coupled devices. CCDs work a bit the way rods and cones do in the retina: they are electronic materials that release a signal once a certain number of photons have hit a target. You make an observing instrument out of them by weaving together a mosaic of large numbers of CCDs, each one counting the photons arriving from a tiny region of the sky, and then using computers to collect the outputs of all these devices, filter out noise, assemble them into a single picture, and then print the graphic on a computer terminal or store the data on a hard disc.

One motive driving this transition is that CCDs are highly compatible with digital technology; another is that magnetic storage costs less than film. (A single good astronomical photograph costs $100.) According to Marsden, observatory directors have been anticipating handsome savings by slicing film budgets, but before enough wide-view CCD-based observatories have been built and put in place.

Right now the search is dependent largely, though not entirely, on amateurs. In 1994 Marsden received 72,000 observations of objects either orbiting the sun or passing through the solar system, of which several hundred were worth closer inspection. These observations come from 126 sites around the world; 2/3rds of which are run by amateurs.

"The natural point to pick up one of these minor planets is when they're at their brightest, when they are closest to the sun," says Marsden. "That means that every subsequent observation gets dimmer and dimmer." The consequence is that even when an object is found the observations might not be good enough to predict its orbit for any length of time. There are thought to be about 3000 objects out there large enough to kill 1% of the population (objects with diameters of 1 km or .6 mile) and whose orbits overlap that of earth. Good orbits are known for about 3% - 5% of these. The numbers of fainter objects, smaller but still large enough to cause catastrophic damage, is much larger, and the fraction of their known orbits even fewer.

Surprisingly, there is no protocol for announcing the identification of a possible impact. The Center would of course ask other observatories to confirm the observation, but beyond that the responsibilities for communicating the news to the public would fall on the public relations officers of the various institutions. I asked the Public Relations Officer of the Center, Jim Cornell, how he thought he would cope with consequences of a reported impact. "I suspect that the focus of interest would shift pretty rapidly to the US Military," he said.

Reading: Hazards Due to Comets and Asteroids; Tom Gehrels, ed. University of Arizona Press. 1994 -- Fred Hapgood

Sent By: Fred Hapgood on Wednesday, November 6, 1996 at 20:43:09.

Robot Telescopes & Sim Galaxies

For all its history astronomy has been a handicraft science, with one person making one observation at a time. The SETI observatory at Oak Ridge is part of an advance into a new era, an age of "industrial astronomy," when the activities that once defined the profession are turned over to machines and performed automatically.

While this trend is still in its early years, the SETI telescope is far from the only case. Sally Baliunas, research scientist at the Center, is using what she calls APTs -- Automatic Photoelectric Telescopes -- to accumulate a database of variations in the energy output of normal stars. Among other applications, the base will be used to test hypotheses about the relations between changes in the behavior of our sun and Earth's climate.

Ten years ago, when Baliunas first decided to study the link between solar output and climate, very little information was available on the historic behavior of our sun. She would have liked to supplement the record with observations of other stars like our own, but that data was even thinner. Changes in normal stars like ours are small and undramatic, and few astronomers have seen any point in spending time and money making records of these tiny changes, year after year. (There is a well-studied class of objects called variable stars, but these are old stars near the end of their life cycle. Their changes are probably irrelevent to those that appear on young stars like our sun.)

In 1985 Baliunas was approached after a public lecture by representatives of a group that had built something they called The Fairborn Observatory in Ohio. The members of this group were amateur astronomers but professional engineers, and by combining these interests they had realized an ancient dream of astronomers: to spend the night sleeping in their own bed. As they told the fascinated astronomer, they had built a device that did the observing for them.

The machine as they described it seemed exceptionally clever. First it waited for the sun to go down and then it checked for rain. If no rain was found the device opened its housing, looked at the sky, and assessed viewing conditions. If less starlight was received than expected, it concluded the skies were overcast, shut down for an hour and then tried again. If conditions were favorable, the machine scanned the sky for the brightest stars and used the locations of those stars to calculate how the sky was oriented on that particular night. Once that was understood, it started working its way down the worklist of stars that had been entered by the members of the group, making observations until the sun came up or the weather interfered. All of these observations were made on CCDs and either stored electronically, on hard disks, or emailed to the members of the group.

Baliunas realized she had the solution to her solar variability problem. She organized a design and construction project at Tennessee State University (a historically black engineering school in Nashville) where she is also an adjunct professor. Today, though the telescope itself sits on Mt. Wilson in California, it is run from TSU, giving the students access to a state of the art facility. Every night for the last five years, viewing conditions permitting, the instrument has cycled through a list of the same 100 stars, systematically taking measurements of each in several different frequencies. Over time these observations will grow into an authoritative encyclopedia of the behavior of normal stars, showing us what our sun has in common with other stars and how it is different.

Baliunas sees applications for the machines wherever the signal of interest is so faint, or so diffused over time, it can only be found by processing very large numbers of preliminary observations. For instance, one way of searching for extraterrestial planets is to look for very slight alternating shifts in the spectra of the system. This behavior reflects the Doppler effect of orbiting planets -- planets moving away from the observer will shift the spectra of the star slightly into the red, whereas after they have swung around the star and are coming back towards the observer the specta will shift slightly into the blue. Finding this small rhythmic effect requires processing, and therefore making, a great many observations of a given system. Robot telescopes are perfect for this kind of scut work.

Robot telescopes lower the cost of making astronomical observations, both because they dispense with the need for onsite personnel and because they use electronics (CCDs) instead of film. Over time, as the cost of the electronics continues to decline, the price of making these observations will fall further and further. Levels of observing quality that can now only be attained by large telescopes or from orbit will be achievable with small telescopes on the ground, since advanced signal processing software can convert large numbers of poor observations into a few good ones. As the software gets more sophisticated it will be able to examine the data directly, beeping the researcher only when it sees anomalous or interesting behavior. This will allow astromers to ask more and more ambitious questions, involving the examination of tens or hundreds of thousands of data points.

Finally, the flood of observations following the mechanization of astronomy will make it possible to build massive simulations of our universe, dynamic sky atlases that will show the universe from any perspective and at any range of frequencies. They would let us embark on virtual voyages through the universe without worrying about the speed of light: we could travel to Andromeda, orbit around Centurii, penetrate the bright lights of the galactic core. And this casade of consequences all began, at least historically, for the most domestic of motives: because some amateur astronomers in Ohio wanted to sleep at night. --Fred Hapgood

Sent By: Fred Hapgood on Wednesday, October 30, 1996 at 16:30:23

FAQs About SETI

What's new about the SETI upgrade? Here are some of the frequently asked questions, where I get to both ask and answer. -- Fred Hapgood

Q: How does the SETI device work?

A: Known as BETA (Billion-channel Extraterrestrial Assay), it should be imagined as 250 million radios. Each one of these radios can be tuned to eight different stations or wavelengths. When the device is on, each radio scans down its list of eight stations, stopping to listen at each one for two seconds. In 16 seconds BETA listens to a total of two billion stations (250 million x 8). At the end of those 16 seconds each radio cycles back to the start of its list of eight and begins again. In that time the earth will have rotated, moving the instrument under a different part of the sky. Since these radios (unlike ordinary radios) are highly directional, that means they will be receiving a new set of two billion channels, and then another two billion 16 seconds after that. This comes to about 10 trillion sampling operations a day. In one year BETA will examine 75 percent of the sky--the other 25 percent being too far South.

What number of star systems this translates into depends on how powerful a beacon is being transmitted from the other direction. BETA would be able to pick up a transmitter about as good as we could build with our own current technology from a distance of about 1000 light-years. Under those assumptions it could cover the nearest million systems.

A great deal of design effort has gone into processing the data generated by the project (a torrential 250 Mbytes/second) quickly and intelligently. Intelligently, to discard terrestrial signals and other false positives; quickly, so that the device can return immediately to any part of the sky showing a signal of interest. The 250 megs are processed with 20 Pentiums running 40,000 million instructions per second through 3.1 gigabytes of RAM. All in all, BETA is one of the largest supercomputers in the world.

Q: Who pays for this?

A: The Planetary Society (http://planetary.org/tps) is the major funder. The Bosack/Kruger Foundation, the Micron Electronics Corporation, and other companies and donors have provided funds and equipment. NASA and the Center for Astrophysics have provided technical input and administrative manpower. SETI gets no government money. It is a proof-by- existence that basic scientific research can be funded entirely by enthusiasts and volunteers. Many people feel this demonstration alone assures SETI's importance to the culture, even if no signals are received.

Q: What are the risks?

A: Our own experience with contacts between industrial and Neolithic societies is pretty sobering, but those were physical contacts. If the lightspeed barrier is really as high as it seems any contact we make is going to be both one-way and data-only for a long time. We'd have to wait 2000 years for a reply to our response to a signal sent from 1000 light years distant.

Maybe a contact would release all manner of freakish, millenial, quasi-religious impulses, sending the culture spinning off into a period of extended craziness. Some SETIologists think that any civilization sending a beacon would couple it with a data channel in a nearby part of the spectrum. Unlike the beacon, whose only job is to get attention, the data channel would carry real information, useful science. Maybe having access to such advanced knowledge will destroy the incentive to do our own science, making the culture intellectually debilitated and dependent. Or perhaps the event will have no importance one way or another. After all (people might say) the National Enquirer had this story years ago, and with pictures.

The worse risk, or at least the gravest consequences, is that the speed of light might not turn out to be absolute after all. Then if we get a signal, and send out a reply, we might be entertaining (and who knows in what sense of the word) extraterrestrial visitors a few days thereafter.

The one thing we will know for sure on getting a signal is there is at least one civilization out there that is not worried about any of these possibilities, which means it is either incredibly self- confident or really dumb. The latter possibility reminds us of another risk, one seldom mentioned: that we might find the extraterrestials terrible company: dreary, self-involved, and boring. In this business no possibilities can be ruled out entirely.--Fred Hapgood

Sent By: Fred Hapgood on Monday, October 28, 1996 at 18:46:13.

#4 Good Morning, Sentient Universe!

Each region of the spectrum reveals elements and objects radiating energies at that frequency; each opens a window onto a different universe, a distinct cosmic landscape. If we were to tune our magic glasses across the radio region of the spectrum, we would find much to divert us -- glowing skies, radiant neighborhoods, blazing points.* At the lower portion of this region, where energy arrives in waves measuring tens or even hundreds of meters, the sky is particularly brilliant: here we would see the galactic center hanging in the sky like a second sun.

But as we travel up the radio region, moving to shorter and shorter wavelengths, the sky will grow steadily dimmer, as though someone was turning down a rheostat. In the region of 1 to 20 centimeters, the lights of the universe are particularly faint. Some few molecular species -- H2O, HO+, a few others -- radiate in this wavelength (the region is called "the water hole" because this is where water broadcasts), but there are not many of these and their bands are very narrow. A person dialing through the water hole would pick up the signal being put out by these molecules as just a few bright, transient, flashes. Otherwise the sky would be very dark, very quiet. It would lose its interest as a landscape and start being interesting as a communications medium.

The guiding assumption of the researchers looking for extraterrestrial intelligence is that at least two populations of beings exist in the universe that are eager to establish contact with other civilizations on other systems. Humans are one; determining the identity of the other(s) is the focus of current research. The SETIologists (SETI = Search for Extraterrestrial Intelligence) reason that if there were such a population, and if it were sophisticated enough to set up a beacon in the first place, it would know about the water hole. It would therefore choose this frequency as the right spot on which to broadcast its welcoming signal, both for reasons of efficiency and because it would figure that any population competent to receive its signal would look first in this region. So it is that the world's SETI projects are all camped out around the water hole, gazing into the dark, watching for a light.

Perhaps the key instrument in the effort to detect extraterrestials -- to establish a contact of the first kind -- lies at Oak Ridge Observatory, an 84' radio telescope located in Harvard, Mass. and administered by the CFA. (http://oir-www.harvard.edu/oakridge/oak.ridge.html)

This extraordinary device is probably the most powerful spectrum analyzer in astronomy. Every eight seconds the instrument points two highly directional antennae at two circles of sky, side by side, and each about the diameter of the moon. The energies coming out of those small windows are measured at a billion frequencies or channels.

After listening for eight seconds the antennae move; the leading antenna listens to a new spot in the sky, while the trailing antenna gives the previous spot a relisten. All this data is channeled through a massive computer that looks for signals that a) stayed constant over both listening periods and b) were not detected by a third antenna focussed exclusively on terrestial sources. Signals that pass these tests get kicked out for closer examination. About 250 megabytes a second flow through the circuitry. All this is completely automated. (One of the most common reasons for researchers to be at the site is to manage visits from schoolchildren, which function no one is interested in automating.)

This remarkable instrument was built entirely with voluntary contributions. SETIology is the first scientific profession to grow up outside the influence of public money, which some analysts suspect has pushed the sciences into trading a close, enthusiastic, dynamic relation with the lay culture for the austere rewards of "professionalization"; into an emphasis of method at the expense of content. P>If the SETI program is a fair test of how sciences organized around volunteer enthusiasts will work this bargain was a poor one. A year ago, last October 30, Carl Sagan's Planetary Society, the primary funding source for the work at Oak Ridge, installed an upgrade to the facility. Publicly-funded sciences have no reason to pay attention to such small events, but privately- funded sciences can't afford to let any chance for outreach slip by.

When I arrived, just before the dedication, a heterogeneous crowd of two or three hundred people were wandering around the base of the dish. There seemed to be almost as many children as adults. Youngsters from a local elementary school were interviewing visitors for school projects. There were also a fair number of senior citizens, some of whom serious donors, and of course lots of techies and trekkers wearing that slept-in style that is their satorial ID. A couple of women wore clothes with astronomical motifs, as if they were alchemists. It was a gorgeous day. People strolled about, smiling and nodding.

A few minutes before the upgrade was to be switched online the Executive Director of The Planetary Society, Louis Freedman, started warming up the crowd by evoking The Moment, the first Encounter of the First Kind, when humanity learns it is not alone, that its long spell in solitary is over. "Today we bring up the first link in the galactic internet!" Freedman cried. A big knife switch had been jury-rigged in front of the radio telescope. One name from the members of The Planetary Society in attendance w as picked out of a hat.

The winner of that lottery, the Director, and an important donor from Micron Technologies, put their three hands on the switch and, while a wall of videocams ground on, pushed. The theme from Close Encounters came out of speakers scattered around the event and the great ear began to shift, slowly scanning the skies.

We all broke for lunch. The people involved with designing and building the upgrade made themselves available for anyone who wanted to talk about any aspect of the project. Later in the day someone pointed the radio telescope straight up, so it became like a pair of cupped hands. Visitors were invited up into the bowl, where we walked around like ants in a saucer. A person scrambling up to the rim could see the delicate tones of a dry New England autumn sketching the landscape, stroke by stroke, straight to the towers of Boston fifty miles to the East.

That night festivities continued at Harvard University, where a number of speakers described the philosophy and technology of the project. Freeman Dyson pointed out when we colonized the universe we would be as likely to live on artificial structures as planets, and speculated that this might be true for developed civilizations in general. He urged the project to think about focusing on the most exotic parts of the universe, places like galactic cores or black holes or regions of condensed matter. Such "tourist attractions," he suggested, would make natural gathering points for interstellar civilizations.

A year after that celebration the huge spectrum analyzer is chugging away, sweeping the skies. Most of the time it works unaided; occasionally humans show up to do maintenance. One recent night found Darren Leigh, a graduate student in physics at Harvard (who identifies himself as "chief cook and bottle washer" on the project), tinkering with the boards. "Suppose you get a signal here?" he was asked. "What will be different a month afterwards?"

"Nothing much," he said. "People already think there is life out there. They've seen a flying saucer; they have a cousin who was abducted by aliens. I don't think it would add up to much, except that a finding would recruit a lot more interest on the volunteer level."

A finding would certainly raise the issue of risk-assessment. So far humans looking for extraterrestial life have (with one exception -- a physical plaque sent out of the system on a rocket) listened instead of speaking. We have made no announcement, set up no beacon. Partly this is from resource limitations (transmitting is more expensive than receiving), and partly from some nervousness over whether attracting attention to ourselves would be a thoroughly good idea, given our total ignorance of who might be out there. So far we have peered quietly into the dark, waiting for signs of something "unnatural" to fall out of our instruments.

The paradox of this search is that we cannot look for casual, inadvertent, transmissions, like alien sitcoms, since at any reasonable distance these would be indistinguishable from noise. All we can listen for are beacons: immensely powerful bursts of energy that could have no other purpose than heralding the fact of a civilization that is not just technologically advanced, but could care less who knows it. (And might in fact be communicating not "here I am", but "come and get me". There is no way of distinguishing between the two.)

That means the only possible candidates we have for contact are civilizations confident they can face down any threat likely to appear from any quarter of the universe. Do we want to know such creatures in the first place? Leigh thought so, though obviously we would want to listen for some time while we tried to decide whether the universe was benign or malign. "If the culture doesn't care, if we're not going to see any difference even if we get a finding, what's the point?" Leigh was asked.

"The point is joining the network of intelligent civilizations," he said. "That's not going to happen a month after the first finding. It might not happen for centuries. The payoff for this project might be 1000 or 2000 years off." Leigh leaned back in his chair and grinned. A thousand years sounds like forever, but somehow, surrounded with the stacks of boards and rows of computer cases standing around us, with the analyzer spitting out interesting findings every minute or so, it seemed like a manageable unit of time. 996 A.D. wasn't *that* long ago. --Fred Hapgood

*For examples of radio regions of the sky, check out: Skyview http://skview.gsfc.nasa.gov/skyview.html The Radio Sky at 4850 MHz; http://wwwpks.atnf.csiro.au/databases/surveys/aitoff/aitoff.html

--FH

Sent By:Fred Hapgood on Thursday, October 24, 1996 at 14:00:38.

#3 AXAF & the X-Ray Sky

The CFA is the model of a modern observatory, operating across all the issues of modern astrophysics: designing telescopes, conducting experiments, maintaining data archives, providing professional services, and running networks. Scientifically, members of the Center make observations everywhere on the spectrum, working on unsolved problems ranging from the minor planets of this system to the structure of gravitational objects embracing thousands of galaxies and stretching over regions of the sky larger than the sun. Ranking these projects in terms of intellectual importance is a subjective business, but measured in terms of money and manpower one stands out: the $2 billion orbiting X-ray observatory called AXAF (Advanced X-ray Astrophysical Facility). Scheduled to orbit at the end of 1998, AXAF occupies the energies of a quarter of the Center's staff.

AXAF is comparable to the Hubble Telescope in its basic dimensions: 40 feet long, 60 feet wide (counting solar panels), weighing five tons, and looking rather like a whale with wings. (More details, including pictures, can be found at http://hea-www.harvard.edu/asc/axaf- welcome.html.) Scientifically it is even more important, since the Hubble is an optical instrument, sensitive to visible photons, and optical astronomy can be done from the ground. The science is not totally reliant on high-performance orbiting instruments, though of course they are nice to have. X-rays, on the other hand, as famous as their powers of penetration might be, can pass almost no distance at all through the Earth's atmosphere without being absorbed. An X-ray astronomer confined to the surface of the planet might as well be sitting on the bottom of the ocean.

For decades astronomers were among the few who understood the limitations of confining an observational science to visible photons. (The visible part of the spectrum is about a billionth of the total, counting by wavelengths.) X-rays were especially attractive since X-rays are made when atoms are brought under severe stress, perhaps squeezed by very powerful magnetic fields or struck by an intense pulse of energy. Looking on these spectra filters out the quiet, low- and medium-energy parts of the universe, leaving just the dramatic parts: huge intergalactic gas clouds glowing at millions of degrees, brilliant quasars blinking like lighthouses from the edges of the universe, magnetic fields trillions of times stronger than the strongest terrestrial magnets, spectacular thermonuclear explosions, novae, supernovae, and a bestiary of exotic creatures, like binary star systems connected by a great umbilicus of flowing material, or black holes eating up the hearts of galaxies. The x-ray window opens up to a direct view on the factories of the universe: where and when cosmic objects are collapsing together or blowing apart.

In the 50's and 60's balloons and rockets gave a few quick glimpses behind this curtain, but the results were no more than tantalizing. Perhaps precisely because x-rays are so energetic the universe does not make many of them (one x-ray might reach the earth for every trillion visible photons) and this faint patter of data requires long observing times to make a good record. In the 70's and 80's a few x-ray satellites were launched, but their instruments were not very powerful. Past any serious distance, the universe was just a blur.

Over the 70's and 80's astronomy began to focus on the very questions for which x-rays supply the best information: the lifecycles and evolution of stars, galaxies, clusters of galaxies, and how these levels of the cosmic hierarchy interact. For instance, over their lifetimes stars convert their reserves of hydrogen and helium atoms (the raw materials of the universe) into heavier elements, like carbon or nitrogen. When stars die they explode; those explosions heat these elements to very high energies and spray them into the interstellar medium like a cosmic pinata. The ejected elements then drift about, radiating x-rays. An astronomer who can measure the distribution of these heavier elements in a galaxy can meausure its history through the number of stars that have died so far, but to do so he or she needs an instrument sensitive to x- rays.

As the importance of these questions grew so did the need for a massive increase in the observing power dedicated to the x-ray part of the spectrum. Calculations showed that looking far enough to see whole populations of sources instead of isolated individuals, or to track diffuse x-ray radiation smearing the sky to its origins, or to measure the number of novae in a distant galaxy's past, would require an instrument whose mirrors had been machined to a billionth of a meter: standards of precision that at the time were unprecedented.

According to Steve Murray of the CFA, it was not clear that such an instrument was feasible. The first phase of AXAF was occupied with proving that an instrument capable of seeing ten to a hundred times further than previous satellites was more than just science fiction. Eventually satisfaction was achieved on the point, appropriations were passed (AXAF is being funded out of the NASA budget) and planning began. Teams were organized in the CFA to plan and oversee the fabrication and testing of the mirrors, the design of its cameras, the experiment schedule, and the information systems that will process and handle access to the data returned over the operating lifetime of the instrument.

When AXAF flies in 1998, it will show us that the sky we see is an artifact of how we see. Visible photons are middle-energy creatures, produced by middle-energy processes. It is no great surprise that the landscape they reveal is relatively cool, static, and stable, constant from night to night, year after year. The high-energy sky is a different kind of country: it winks and pulses and buzzes. Some objects flash hundreds of times a minute; others, once or twice a month. Some blink randomly; some in a precise, orderly, pattern. The X-ray universe has a beat; it jumps. Early observers of the x-ray universe wondered if they were receiving communications from intelligent civilizations. AXAF will show us a new night sky: the cosmos as Times Square.-- Fred Hapgood .

Sent By: Fred Hapgood on Monday, October 21, 1996 at 20:33:55.

#2 Evolution of an Observatory

Observatories are sited in high remote regions. Tomorrow that will mean going to the far side of the Moon and the orbit of Jupiter, where the dust of the inner system begins to thin and instruments will have a clear view out for billions of light years. Today high and remote means orbiting a few hundred miles over the Earth. But in 1839, when Harvard College decided to build an observatory, high and remote meant going a mile northwest of Harvard Square, to a hill that crested at sixty feet.

It was a simpler time, and the universe that wrapped the night sky was a simpler universe. Not much in astronomy had changed since Newton had announced his laws more than 150 years before and the founders of the observatory had no special reason to expect the next 150 years to be that different.

Twenty years later a daguerretypist from Massachusetts General named Fred Whipple, who had broken into the profession as a specialist in photographing corpses, began riding up to the observatory to take pictures of the night sky (which didn't move either). His plates made up the first detailed, high-quality, atlas of the heavens. As these records accumulated and were studied and restudied, here and in other institutions, the universe began to roll open.

In the 1920's an astronomer at the Observatory named Harlow Shapley discovered that the solar system was on the distant edge of an undistinguished galaxy in a universe made up of tens of billions of galaxies, with each containing a hundred billion stars (on average). In the 1930's Henrietta Levitt found the Cepheid variables, a class of star that beats like a heart and could be used a clock. The Cepheids allowed Edwin Hubble (who was in Palomar in California) to discover that the universe was billions of light-years large, and had apparently discovered or invented itself billions of years ago.

These great discoveries were made only 60 and 70 years ago. People are still alive today who remember yesterday's universe: small, young, and comfy as a Victorian parlor. Today the Observatory, now the Harvard-Smithsonian Center for Astrophysics, looks out at a domain that stretches though magnitudes of time and space humans cannot begin to grasp. Everything can be found there, possibly even wormholes to other universes. Certainly there is life, almost certainly intelligence, and probably other Centers of Astrophysics, craning their attention in our direction as eagerly as we are in theirs.

If other civilizations do exist they probably resemble each other most closely in their observatories. It is the same universe, after all; every civilization out there is watching the same great drama cycle across the sky. However different we may be we are all members of this audience, sharing the same sense of rapt wonder.

A Tour Of The Grounds

The projects and offices of the CFA are spread over the globe, from Taiwan and Chile to cyberspace, but its root is scattered over time. The CFA headquarters lies in a single complex of buildings stacked flat on a hill with a scattering of trees around its borders. Beyond these trees a parking lot circles much of the building like a vestigial moat. Within these two circles, at the crest, lies a jumble of extensions and incorporations. Some rooms open into the 19th century, when interior design was defined by the facts that wood was cheap, concrete unimagined, and artificial light and heat expensive. As these facts changed design changed with them, but for whatever reason Harvard has never renovated the old designs entirely, merely building around and over them.

Every month the local starhounds walk up the hill, though the trees and over the parking lot, into a meeting hall that is edged with fine old wood and looks like it belongs in a museum. (This might have been the very hall from which Emerson fled to compose his famous poem attacking academic astronomy.) Here researchers come to talk about black holes and the big bang and quasars, to add to the picture we have of a universe that is violent and turbulent and rich in structure on every scale.

After these talks, the Center always makes the 19th century telescopes on the roof available and the audience files up. Looking through these antiques, you can see the sky as it was a hundred years ago: cool, remote, scattered, and utterly calm. It seems a paradox the universe should change so radically in only 100 years, or that one institution should have done so much to convert one into the other, but the facts are here, side by side. --Fred Hapgood

Sent By: Fred Hapgood on Friday, October 18, 1996 at 16:50:38.

In the Beginning: The Electromagnetic Landscape

We all have two bonds holding us to the universe: gravity operates through our physical bodies and the electromagnetic spectrum through our more subtle senses (and minds). The Center for Astrophysics looks at the second.

Unlike the astronomers of old, who confined themselves just to the visible part of the spectrum, The Center looks across the whole landscape, from the long, slow, cool, weak energies of the radio, the bass end of the spectrum, through the infrared and visible, up to the bright fireworks of the X- and Gamma rays.

The spectrum is not just a way of thinking about the properties of radiation (wavelength, energy, etc.) though that is how it usually presented. It also controls the optical properties of matter: the conditions under which a substance is opaque, transparent, reflective, luminescent, or one color or another. No material or object "is" any of these things. How it looks depends on the wavelengths falling on it. Water is transparent to visible light but opaque in the radio (because H2O absorbs radio). The earth is opaque to visible light but perfectly transparent at much longer wavelengths. If you had a pair of magic glasses that could be tuned to very low frequencies, the earth under your feet would open up into a vast transparent sphere, a huge crys tal bubble, allowing you to look straight through to the opposite side of the planet.

The same is true of everything in the sky. Suppose we had a pair of glasses that could be tuned across the spectrum. If we looked up and started to turn the dial we would see one universe transform into another, as if multiple or parallel universes were distributed up and down the spectrum. For instance, at the low end, in the radio, we would see not one but two suns hanging in the sky. The first would be Sol; the second, the center of the galaxy. The reason is that while the galactic center puts out huge amounts of energy in both the visible and the radio regions, the visible light is absorbed by huge clouds of interstellar dust that lie between the solar system and center of the galaxy. These clouds are transparent to radio, allowing the heart of the Milky Way to shine like a lamp in our sky.

As we tune our glasses up into the microwave region, we would see the sky take on a uniform lambent glow. This is the so-called Black Body radiation, the fading embers of the burst of energy that created the universe. Jumping higher, into the ultraviolet and X-ray regions, would open up a hotter and younger universe. We would start to see stars being born, a sight usually masked by curtains of dust. In the X-ray our sky would be dominated by enormously bright point sources, objects producing vast amounts of energy: the so-called X-ray bursters. In the gamma region we would see even brighter sources, the mysterious gamma-ray bursters, and, scattered over the sky, the signatures of the processes responsible for nucleosynthesis, the fa brication of elements.

The idea of these glasses is partly a futuristic conceit and partly a perfectly realistic analogy to a modern astrophysical observatory. The Center for Astrophysics is our magic glasses: it looks at all the starscapes distributed up and down the spectrum. Lacking magic glasses, the Center uses optical telescopes, huge radio antennae, orbiting satellites, deep-space probes, weather balloons, vast amounts of computing power, and all the resources of the internet for this purpose. Over the next few weeks I'll show you what I mean.

Sent By:Fred Hapgood on Thursday, October 17, 1996 at 13:49:49.

Home || Prime Time || Live Science || Machine Dreams || Project Open Book || SF-Fantasy-Horror
Continuum || Antimatter || Mind-Brain Lab || Interactive IQ || Gallery || Cartoons