The SW embankment of the castelliere in Galleriano (photo by F. Patat).

As I discovered in the initial phases of the study, the issue about the orientation of these sites had been already raised by other researchers. The first written reports (in the ’40s of last century) were mentioning that they all had the vertexes aligned along the cardinal axes. The same conclusion was reported also in several archaeological studies. But, most important of all, a more astronomically-oriented analysis had been published in 1986 by Aveni and Romano on the Journal for the History of Astronomy. Anthony Aveni is one of the most famous researchers in Archaeoastronomy and he has written many papers and books on this subject. This was more than sufficient to stimulate my curiosity, besides being a clear challenge. The first step was to establish a contact with archaeologist Dr Susi Corazza, who is working at the Laboratory of Protohistory at the University of Udine. She gave me several reports of archaeological digs carried out in these sites in the last ten years and she also invited me to visit an open excavation in Galleriano, one of the three well preserved sites.

Archaeological dig in Galleriano. Well visible is the cross section of the embankment.

There I was exposed to a completely new way of doing research. I could walk over the embankment, watch the stratigraphic sections, have samples of earth in my hands, smell the freshly excavated soil… a contact to objects which is forbidden to astrophysicists. And, most important of all, having to do with human artifacts. The excavation campaign, supervised by Susi, was conducted by undergraduates, PhD students and post-docs, under the hot sun of August. I must say I felt several times overwhelmed by emotions.

Two of the sites had been surveyed from the ground by the University using a classical ground-based total station, while for the third (Savalons) nothing was available. For this one I had a different idea. In fact, there is now the possibility of getting a 3D mapping of a site using an airborne laser device. This is typically used for civil purposes, like topography and the like, bit it has been used also for archaeology.

3D rendering of LIDAR elevation data for Savalons (Credit F. Patat).

The concept is very simple. A laser beam is sent down, reflected by the soil and received back by the device, which is capable of measuring the time it takes the signal to come back, with extremely high accuracy. If you then know precisely where your device is, you can then reconstruct the elevation profile of any 3D structure, with centimeter accuracy. Easy, uh? Well, yes, but it requires some expensive equipment and an helicopter. This is why I contacted HELICA, a local company, which is specialized in this kind of work. “We have never done this before” - said to me Diego Plos, Helica’s Director - “so we’ll give it a try and see what comes out of it”. And, yes, they did it. In a matter of a few seconds the LIDAR (that is the name of the device) has collected about a million points, spaced by about 30 cm. Amazing! A ground based survey of these structures takes many days, to collect a thousand points at most. Not only, but based on the properties of the reflected light, during the post-processing phase one can distinguish between ground and false-ground data (produced for instance by foliage). The data are so good that you can see the signs of cultivations in the fields.

Aerial view of Savalons (orthophoto - credit Helica).

But most interesting of all, the geometry of the site (approximately 180m on a side) appears very clearly. Clearly, the orientation analysis with digital, geo-referenced data is just a matter of computer skills and the smell of the archaeological digs is already far away.To complete the analysis (terrain slope, horizon) I also made use of the Shuttle Radar Topography Mission, which is essentially based on the same principle and it uses a radar instead of a laser. With this, for instance, I can check whether a site has been aligned along the direction of maximum slope, something which was typical in the Roman centuriation to favor the draining of rain water. Or I can try to see whether the orientation was done along the direction to some remarkable structure on the natural horizon, like a far, high mountain peak.

In fact, in archaeoastronomy is rather easy to be carried away and see alignments everywhere. This is actually a bit of a plague in this field, and the enthusiasm brought about by the findings in Stonehenge and the like has created a generation of improvised researchers, who have not exactly followed scientific criteria in their studies. Therefore, more than a grain of salt is necessary. And this actually makes the whole thing attractive for a scientist. The analysis is almost over and I am now convinced that there is no alignment to astronomically significant directions in these proto-historical sites. Even the orientation to cardinal points, suggested by early investigations (and reported more by tradition than by measurement), does not hold. At this point you might wonder whether the disproval of previously reported “facts” is really useful. Well, yes, it is. Here in archaeo-astronomy as well as in astrophysics or in any other science, for that matter.

The human skeleton found below the mound close to Savalons (credit University of Udine).

Meanwhile the archaeological digs have continued. Most remarkably, Susi and her collaborators have opened the mound close to Savalons, finding a human body deeply buried under it, which has now been dated around 1800 b.C. You can watch a movie about this finding here on YouTube.

If they’ll keep finding tombs like this (this is the 3rd one), we will be in the condition of starting an analysis about the orientation of proto-historical graves in the High Friulian Plain. This is another interesting topic connecting human life (well, actually human death) with astronomy. An example study can be found here.

In a subsequent post I will report a bit more in detail about the kind of analysis I have performed on the three sites.

This entry was posted on Friday, January 22nd, 2010 at 2:47 pm and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site. Edit this entry.

Map of St. Martin (Artegna-Italy).

I like astronomy very much at the level that I can say mine is not a profession, is rather a passion. But there are gray areas here and there. One of them, maybe the most important, is the level of abstraction it brings about. Having to deal with very far things, far in space and time, with no possibility to touch them, adds to the generic frustration that any scientist, if you look deeply enough, has to deal with. In astronomy, the closest you can get to your “object” is working on Solar System bodies. In some cases, you can even hope to get some extra-terrestrial piece of matter in your hands, dissection it, run chemical and physical analysis. But this is rather the [extraordinary] exception than the rule. For extra-galactic guys, like me, no way. Well, yes, maybe when a close-by Galactic Supernova will go off then we will have the chance of receiving even particles. But that might be the last thing we do

More seriously, at some point in my life, just before leaving for Chile, I started feeling a strong need for reconnecting to reality, to the day-to-day world, to humanities. How a supernova guy would do that without abandoning his profession was not clear for quite a while.

Sunset at St. Martin (Artegna-Italy) ten days after Vernal Equinox.

But the quest brought me somewhere. I have quite strong roots deeply planted in my homeland. And in the months preceding my departure to Chile (at that time I had no clue about how long I would stay there), I started reading all the books about the history of my small village. The eldest thing we have there is an ancient church, dedicated to St. Martin. When the Longobards  entered the Italic soil, they established in that area their first Earldom and, having a long knight tradition, they devoted many a church to St. Martin, S. George and St. Michael, all coming from a military tradition or having something to do with horses and knights. In one of the books there was a mention about the fact that St. Martin, rising on top of a prominent hill, like many ancient buildings, was oriented along the east-west axis. That was the start of it, because my attitude to measure things immediately generated the question about the accuracy of such an alignment.

Measuring the natural horizon at St. Agnes - Gemona del Friuli.

So, using rather simple methods, I measured the azimuth of the church’s axis, finding that it deviated  only 0.7 degrees from the geodetic E-W line. At that time I had not so much money, I was just out of my PhD and we had a 3 months baby. Chile was appearing close to the horizon and so I postponed any further study in that direction. But for the two following years I nursed this idea and I started a self-training in this discipline, which was indeed bringing me back to man through astronomy. I had finally found a way to reconnect to reality without giving up or betraying my “credo”. When, two years after, I got a position here at ESO-Garching (Germany), those places were much closer. I had some more money and I could afford buying a second hand Zeiss theodolite and a GPS receiver (at that time not so diffused as they are today). Equipped with this, a background in spherical astronomy, some home made software and lots of good will I started getting acquainted with the required techniques. I first started with ancient churches in Friuli, some of which were originally built around the V-VI century a.C., all erected on high hill tops. And something interesting indeed came out of it, bringing about a new kind of emotions, which my main research field could not have given me, by construction.

Castelliere (artist's impression).

Encouraged by the results I then moved one step further, and I started an orientation study on three proto-historical sites (about 1800-1500 b.C.) in the High Friulian Plain, in collaboration with the Laboratory of Proto-History of the University of Udine. These are large (150-200 m on a side) earthworks, usually called castellieri, with embankments that can reach 5 meters in elevation above the surrounding plane, and base widths reaching 20 meters. Imposing manufacts, indeed. If you know where they are you can easily see them in GoogleEarth (see the pictures below). Their purpose is not really clear, but the archaeologists think they were used as fortified villages. Although in the High Friulian Plain there are remnants of many such sites, only three are rather well preserved. The others have been leveled mostly  during the intensive agricultural activities that took place last century. These three sites have a roughly quadrangular form, in contrast to other similar structure seen for instance in Istria, which had a circular shape. This of course offers the possibility of running an orientation analysis. I will tell more about this in the next post.

The castelliere of Savalons (GoogleEarth).

The castelliere of Galleriano (GoogleEarth).

This has nothing to do with Astronomy (or maybe it does, but this it is not so important). I am just back from the Prinzregenten Theater in Munich, where David Fray gave a very impressive concert, playing Schubert and Bach. What amazes me is how actual and vivid Bach can sound in the hands of Fray. All that geometry transfigured into passion… Have a look to this and you’ll tell me. Certainly the guy is eccentric (and a beautiful man, ladies tell me), but when he plays Bach he brings about something I had never heard before. Bach and Astronomy are so strictly related in my own experience that I could not resist to share this with others.

Good night.

Like everyday, this morning I brought my little son to the kinder-garden. On the way I met Tim de Zeeuw, the Director General of ESO. From the window of my office I can see his and I had noticed he had been away for quite some time. I took advantage of this for briefly chatting with him about how jet-lag is annoying and so on. “Yes” - he said - “but sometimes interesting things happen”. I was kind of guessing that something exceptional was coming and the conversation was going to turn into something much less trivial than jet-lag…

Michelle Bachelet, President of Chile

And, in fact… “While visiting our sites in Chile, I was sitting in my office in Santiago and, at some point, I got a phone call”, he started off. “The President of Chile was on the other side of the line”. From this point I can only imagine how things went and what follows is a fiction like dialog (but I guess things were not very much different from this).

-”You are planning to build a very large telescope, right?

-”Yes, Madame President, that is true”.

-”Have you already decided where you will put it?”

-”We are in the process, Madame President”.

-”Would you consider placing it in our Country?”

-”Yes, Madame President, we are certainly considering that”.

-”I am glad to hear that, prof. de Zeeuw. What can we do to help you?”

Of course this is only my guess on how things went, Tim did not reveal the real nature of the meeting. But in sight of the big enterprise ESO is going to start soon (that is the building of the largest optical/near-IR telescope on the planet, the E-ELT), I would not be surprised the topic of the discussion was quite an interesting one.

Although I am not in the least involved in these political things and the future of the E-ELT does not depend on my skills and wills, it is quite exciting to be very close to where things happen.

You can find some more details in this ESO press release.

I am now sitting in the meeting room in an hotel, together with other people from my Division. The topic of this 3 days retreat is the revision of the current end-to-end data flow system of the VLT, in sight of the E-ELT era. Yes, because contrary to what I had naively thought when I started my career in astronomy, operating a [big]  telescope is not only matter of screws, optics, electronics. It also means scheduling, data archival and distribution, astronomers training, operational plans and so on. And all of this makes into the success of this kind of facilities.

Tomorrow I will jump back to science. The plan is to finish up a paper for the Journal of Archaeastronomy, edited by the University of Texas. In my next post I will talk about this.

While reading Rare Earths by Peter Ward, I found the following quotation:

“Much of the work we do as scientists involves filling in the details about matters that are basically understood already, applying standard techniques to new specific cases. But occasionally there is a question that offers an opportunity for a really major discovery.”

W. Alvarez, “T. Rex and the crater of Doom“, 1997, Princeton, NJ, Princeton University Press

If you are a scientist you will certainly recognize yourself in there. All your professional life is about this quest. And what (but only sometimes) makes you sad is that you are aware this major discovery will never come. Times have changed and those mythical ages when isolated scientists were making exceptional discoveries are now probably over. But still, in the back of your head, there is a small flame, always burning. It is the hope, against all facts, that someday something great will come. If it won’t, well, I tell you it is worth the effort anyway

The relics of the Roman Forum in Zuglio (Julium Carnicum)

It is almost time to leave for Xmas vacations. Finishing up a few things  and getting ready to leave to Italy. There are many aspects that make these holidays appealing. Among those, is an archaeological exploration foreseen for the first sunny day between X-mas and new year’s eve. This story begins a couple of years ago, when I studied the orientation of the ancient church of St. Peter above Zuglio (the Roman town Julium Carnicum). While reading the related literature I realized that, at the times of Romans, this and other similar sites (all on mountain tops), were used as sight stations, to visually communicate the arrival of possible invaders (by means of smoke in daytime and fire during the night) to the large town of Aquileia. This town had been founded in 181 b.C. to prevent the invasions by barbaric tribes from the NE of the Italic peninsula (ad Illyricos objecta montes), which has a rather easy to cross border. One of the possible ways to trespass the Roman limes was a narrow pass, today known as Plockenpass. But from there all the way to Aquileia (about 80 km to the south, on the Adriatic sea) the landscape is full of mountains and it requires a number of intermediate stations before one finally reaches the Friulian plain.

Horizon azimuthal map for Cesclans (credit F. Patat)

My curiosity was captured by the fact that while it was clear how the visual signals would get along the valley from Plockenpass down to what today is called Cesclans (known archaeological site on a high, easily defensible top), much less clear was how those signals could get to the plain. In fact, a chain of mountains prevents the sight of the Friulian plain from Cesclans. Clearly, a further station was required. I took a note and let the thing rest for quite some time. But at some point, I realized that I could use the SRTM survey data for my archaeoastronomical studies. While doing this I also thought that they might be of some help to solving the problem of the missing station remotely, even before thinking about an on site expedition (it is about 500 km from here, just across the Austrian/Italian Alps). The idea is simple. You write a program that, using the digital elevation data provided by the Shuttle Mission (and free for download), determines the distance of the horizon in all directions seen from a given site (taking into account Earth’s curvature and atmospheric refraction). I had originally done this to produce synthetic horizon profiles for the analysis of some proto-historical sites in the Friulian Plane. But the application to the case of Cesclans was straightforward. You can see the result in the graph here to to right. The red dot marks the position of Cesclans. As you can see, there are several windows that open the sighting to NE and NW (the rightmost is the one which connects to the Plockenpass valley), while to the south the horizon is closed. With one, narrow exception (marked with the red circle).

Mount Faet at dawn (Venus is rising to the left).

If you go to a map, you will see that this coincides with a 750m mountain in the pre-Alps. This is Mount Faet, by coincidence (!) just above my small town of Artegna. Immediately after finding this result I wrote to a friend of mine that lives in the area, asking him to verify whether this window was real and not just an artifact of my calculations. The day after I received a digital picture taken with a tele-lens from Cesclans in the appropriate direction. And, indeed, a tiny portion of mount Faet was visible (if you knew it was there).

The next step was to go on site, with the aid of a GPS, to see whether in the relevant area (my calculations were giving a spot with a diameter of roughly a km, at an altitude between 550 and 600m above sea level) there was any trace of human artifacts that could indicate the possible presence of statio. Nice plan for summer vacations.

The stone paved path that leads to the top of Faet.

So, at the end of August, with my young assistant Riccardo, I left my place and started hiking along an ancient path that leaves from the base of the mountain. Interestingly, there is a network of stone paved paths that lead to the mountain top, which have been attributed by archaeologists to post-roman epochs. According to them, the mountain was used a refuge during the barbaric invasions that followed the fall of the Roman Empire. We started off very early, in the fresh air of dawn break. The GPS was telling me that it would take about one hour to reach the site, although the straight line distance from the starting point (placed at about 300m above sea level) was less than two km. I knew that path, since I had been there many time during my childhood to collect chestnuts. But I had never paid so much attention to the way the path was paved. Indeed, it is kilometers of stones. At times, in between the threes, we could see flat embankments surrounded by stone walls, probable relics of those ancient refuges identified by the archaeologists. From time to time, we get a glance of the Friulian plane that extends to the south. At some point, a message appears on the GPS, telling us that we are within 50 meters from the targeted position.

Cesclans seen from mt. Faet.

By coincidence, there is a clearing in the wood produced by a track recently built to facilitate the access to the mountain (to prevent fires and so on). From there, we can finally look into the direction of Cesclans. And indeed, there it is. We can see the mighty tower of Cesclans’ church with naked eye in the light of the rising sun, just above the low mountain. You can easily see it if you click on the photo here to the right.

This is the definite proof that there is a sight-line between the two sites. Notably, from mt. Faet you can see down the whole Friulian Plain and, in clear days, you can even see the sea. Obviously, Aquileia is still far, but the Plain has several hills that could be easily used as intermediate stations. So, this is not much of a problem. However, having a viable sight-line is one thing. Being certain it was used by Romans as part of their defensive signaling system is a different issue, which can only be demonstrated by archaeological findings.

Relics of stone walls on mt. Faet (about 580m a.s.l.).

For the time being this remains an interesting possibility, supported by visible, ancient human manufacts. That day, Riccardo and I adventured a bit in the bushes and found several traces of stone walls close to the sighting site. At home, then, I had a look into a book describing an archaeological surfaces survey carried out in the early eighties in this part of mt. Faet. Indeed, these manufacts were classified as defensive structures dating back to the Longobard period, possibly built on Roman relics. All of this makes the thing even more appealing. In the same publication I also found the description of a number of proto-historical mounds, not far from the site Riccardo and I visited last August. That is the target of the visit planned for the X-mas holidays. This has now brought me rather far from astronomy (from which I started), but it is extremely stimulating and helps me getting back from void spaces into humanities. Although far into the past…

Bob Kirshner (right) and Brian Schmidt (left)

When I was close to the end of my Master in Astronomy at the University of Padua, I do not exactly remember why I decided to do my thesis work on Supernovae, under the supervision of prof. Roberto Barbon. So, sometime in early 1991 I got a date with him and his collaborators to discuss a possible project. At the end of the meeting, one of his two assistants (the inseparable duo Turatto&Cappellaro/Cappellaro&Turatto) gave me four reviews and told me: “Here is all what you need to know about Supernovae“. On the train that brought me back home, I started having a look. It was in fact papers by Robert Kirshner, David Branch, Alex Filippenko and Craig Wheeler, whom I immediately considered as the bosses in the supernova field (and I still do). As seen in retrospective they clearly doomed my fate. Many years have passed, but time does not seem to have had any effect on them. However, they (as we all do) are getting of age.

Bruno Leibundgut and Nikolaj Chugai

There is a tradition in the astronomical community: whenever one of the VIPs turns sixty an international conference is organized in her/his honor. Last August it was the turn of Robert (Bob) Kirshner, who was celebrated at the Stellar Death Conference at the Kavli Institute for Theoretical Physics in Santa Barbara (CA). Conferences are ideal to exchange ideas, to see what others are doing, to say things that you would not write in a paper, to brain-storm an so on. But are also great occasions to touch the more human aspect of science, to better know our collaborators (and competitors), to meet brilliant people on grounds which are all but scientific. And this conference was particularly good under all aspects. Basically all people working in the SN field (both theoreticians and observers) were there. More than 150 researchers from all over the world. The conference, which was very well organized, was very fruitful and has clearly shown how active the supernova field is.

Sunset in Santa Barbara (CA).

As the title of the conference tells you, the topic was the [explosive] endings of stars. And the zoo is getting indeed full of weird beasts. The new searches looking for transient phenomena have already started finding new kinds of explosive events. And more will come in the next years, as the projects get up to speed. These surveys are run with robotic telescopes equipped with wide field of view cameras, able to scan the whole sky in a week or less. They start exploring a time domain that so far was not accessible, and produce huge amounts of digital data at an astounding rate. And, of course, whenever new objects are discovered, new problems and questions come up. This is why astronomy, and science in general, will always have something to work on. Amazing. When Fritz Zwicky started working on Supernovae (actually, he and Walter Baade named them), he had troubles in convincing people that this was worth doing.

Adam Riess is perplexed about "lambda" (left) but he feels much more comfortable with "w" (right). Ask a cosmologist if you wish to appreciate the humor;-)

It was actually Roberto Barbon (who spent some time at Caltech under the supervision of Fritz Zwicky) to tell me that story. Zwicky had started his own supernova search, but it was very hard for him to get funded, essentially because who was distributing the grants did not see the purpose of such an effort. And today we discover about one new SN per day. This number is doomed to grow to thousands per year as soon as the large automatic surveys will be deployed.

The study of supernova explosion is important for a number of reasons. The first, most intuitive one, is that this is really the only way to see the interiors of a star. Normal stars (like our sun), spend their lives in a quiet way, and the only thing we can observe is the radiation they emit (in the case of the sun we also get some particles, the solar wind). And from this we have to deduce how things work in its inner parts. But in the case of a supernova explosion, the star is taken apart. In this process the “normal nuclear burning is altered and so we do not exactly see how the star looked like during its previous life, but still we see how it looks inside.

Alex Filippenko, Kenichi Nomoto and his wife

That is one thing. But then, you can imagine that the ejected material, which travels at speeds exceeding 10,000 km/hour, must have some impact on the surrounding regions. And that is indeed true. It is believed that supernovae are the major contributors to the kinetic energy of the interstellar medium. And so what? Well, the fact is that this energy input is fundamental, for instance, to trigger episodes of star formation. So, dying stars provoke the birth of new stars.

Finally, normal stars synthesize heavy elements (iron, calcium, oxygen, …) in their interiors through the nuclear fusion. However, these elements are doomed to remain buried there forever. Some stars actually lose material from their surface (for instance, planetary nebulae), but a supernova ejects into space large amounts of matter in very short amounts of time. And this has a major effect on the chemical evolution of galaxies. That gas, which is initially dispersed into the interstellar medium, one day would form a cloud, which will collapse and give birth to new stars with a modified chemical composition (or more metal rich, as astrophysicists would tell you).

There are many more reasons why studying supernovae is very important in a general astrophysical context, and all of them had a part in the Stellar Death conference. If you are interested have a look here, were you can also find the online talks. In particular, if you wish to see my presentation, here it is.

Bob Kirshner during the party in his honor (artist's impression)

Of course, in this kind of conferences there is always lots of young people, PhD students and post-docs, who make the whole thing very lively. And it is actually they who bring a very cheerful atmosphere, which makes evenings very relaxing and entertaining (especially after hours of listening to complex presentations on neutron fingers ;-). I probably do not belong to the young generation anymore, but I kind of pretended it and mixed with them, together with my wife Adele, who always enjoys very much the atmosphere one breaths in these occasions. I think that the night immersions in that beautiful, steaming jacuzzi at the hotel (in hours when it was officially closed) will remain in the memories of many of us

The conference was the best one I have ever attended, for all aspects (the fact that Adele and I were alone, with no kids, like in second a honey moon, is not to be underestimated ;-). I have seen old friends that I had not met for a long time. Like Nikolaj Chugai, head of the Dept. of Astronomy in Moscow, to whom I owe so much. Or Craig Wheeler, whose fascinating personality never stops to surprise me. I will visit him in Texas next year and I already feel excited about it, because he has the power of arising my enthusiasm.

We are all thankful to Bob Kirshner and we wish him to turn sixty again… next year!

Happy birthday, Bob!

Wouldn’t it be nice for a scientist to be able to proof everybody else is wrong? And if you are in astrophysics, why shouldn’t you dream about showing that the cosmological castle is built on sand and you have found *the* thing that would make it fall apart? Don’t be shy, if you admit it, I would fully understand you The history of science is full of such examples, which have usually brought about far reaching revolutions, with effects that have gone well beyond the strict academic circles and, in the end, have influenced philosophy and the way we perceive the world. Just think about Copernicus… Many of us (including myself) spend their scientific careers working on subjects which are usually dubbed “small science”. Interesting and hard work, which though adds only small pebbles to the enormous wall of science. While there are others (among which cosmologists) who work on the “big science”, whose purpose is to investigate the grand picture of the universe. Certainly ambitious and not lacking fascination. In astrophysics it is quite common to have to deal with problems which involve most of known physics and (most intriguing) a good fraction of unknown physics. An example? Dark matter. We need it, but we do not have a clue about its nature. Another example? Inflation. Another, more recent example? Dark energy. And so on.

Jayant Narlikar in my office.

One of the reasons that pushed me into the arms of Science was the search for truth. This might sound more rhetoric than actually is.  In school you are told that things are so and so. But at some point some of us develop an intimate need to verify this with their own eyes, hands and thoughts. And, in the most brilliant cases, one ends up giving her own view on things, finding a new law of nature, proving another one was wrong, inventing a new technique. Clearly, one can’t go out and try to verify each single bit of information she has been given. That would be mad. But it is the right (and the must) of any scientist to question certain things. Or, to put it in a more general way, to keep the doors open to other possibilities, although at the edge of the common understanding and the main stream.

As you may know, in the sixties the two models of the universe (Big Bang and Steady State) were equally valued and the debate was completely open.  The Steady State Cosmology (SSC), the only serious alternative to Big Bang, had been proposed by Fred Hoyle, Thomas Gold and Herman Bondi, back in 1948. I will not enter here in the debate (which reached quite strong tones at some point) and I just mention that the SSC lost credit mostly with the discovery of the cosmic microwave background radiation in 1965. In the following decades the SSC almost disappeared from the scenes. However, in 1993, a modified version (the Quasi Steady State Cosmology, QSSC)  was proposed by Fred Hoyle, Geoffrey Burbidge, and Jayant V. Narlikar. After this, Narlikar and his collaborators have worked quite a bit on it, especially after the new WMAP and Supernova data become available. The theory is still strongly adversed (and probably ignored) by the vast majority of cosmologists, who argue QSSC fails to reproduce the observed data (for instance, have a look at this note by E.L. Wright).

Jayant and me

Although I have been interested in these issues, I certainly cannot claim I fully understand the arguments (on both sides). My field of research is rather far from theoretical cosmology and my expertise is more in observational astronomy. On top of that, I must admit I do not really care too much about cosmology in itself ;-).  After all I am a stellar guy. However, a few years ago Jayant Narlikar visited ESO for six months. He gave a very interesting series of lectures (Cosmology from the Sidelines) and this has raised my curiosity. So, I proposed him to collaborate. The first thing that struck me was Jayant’s personality. He is a very reflective and calm person, armed with a disarming culture. Despite the fact that he grew up scientifically under the supervision of sir Fred Hoyle (one of the most brilliant astronomers of the 20th century), he his not an intimidating person. He has more than 200 publications in refereed journals, he has written several books (see for instance this one or this), and even science fiction. He is now the director of the Inter-University Centre for Astronomy and Astrophysics in Pune (India). I actually have a nice anecdote about him. While preparing the Shadow of the Earth, I was looking for an ancient poem somehow related to cosmology. And I really wanted to avoid the Genesis, because it has been used so many times in all possible ways. So, I wrote to Jayant asking for an advice. And he came up with a very interesting idea. “What you are looking for is the Hymn of Creation in the Rg’Veda” - he said. “You should find somebody that read Sanskrit on top of which another person would proclaim the translation“.  This was happening only a week before the premiere. No time to organize such a thing (Sanskrit readers are not that common in this part of the world). So I wrote him back: “Jayant, why don’t you read it, record an mp3 and send it to me?“. A few days after I received the recording. Here you can listen to the original initial part (mp3), and here is the final version (synth: Glauco Venier; Voice: Massimo Somaglino). The result had a great effect.

Ken Freeman.

At that time we were already working on a project, whose name was to search for stars older than the Universe. The sentence sounds awkward. And it is awkward, indeed. According to the so called concordance model (which tries to put everything together) our universe is about 13.7 billion years old. Therefore, all objects in this universe must be younger than this figure. Quoting Jayant: “The daughter cannot be older than her mother”. From this comes the basic idea: if you find objects with an age larger than, say, 15 billion years, then the standard model is in trouble. Of course things are not as easy as they seem. At the beginning Jayant thought about dating white dwarfs. These old objects set on a cooling track and, using theory and observed data one can in principle date them. But at the age of, say, 20 billion years, they are damn faint. At some point Jayant brought up the issue with Ken Freeman, a well known astronomer now professor at the Research School of Astronomy & Astrophysics, Mount Stromlo Observatory (Australia). And finally Ken came up with an interesting proposal. I will not go into the details here, but the concept is that if stars older than 15 billion years do exist, they should show up when one looks sufficiently deep in a particular region of the Hertzsprung-Russel diagram of a stellar population. This practically means taking very deep, multi color images of stellar fields at a known distance (so that at least one unknown is… well… known). After long discussions we have decided to go for the Large Magellanic Cloud, the well studied galaxy, satellite to our Milky Way. A major role in this project has been played by Vijay Mohan, post-doc at the Inter-University Centre for Astronomy and Astrophysics under the supervision of Jayant. He is the one who has done the real work, reducing and analyzing the data (taken both with the Very Large Telescope and the Hubble Space Telescope).

Do not think this is an easy task. It is difficult for two reasons: 1) you are going against the main stream, so that prejudice plays an important part in the game; 2) you are questioning the very fundaments of a well established theory. Therefore you have to provide solid arguments for your conclusions. Extraordinary claims require extraordinary evidence, used to say Carl Sagan. Even within the collaboration long discussions took and still are taking place. But almost after two years, last week, I received a draft of the paper, whose title is ” Observational evidence for old stars“.  The claim is rather strong, although in the paper a number of possible alternative explanatiosn to what we have found are duly discussed. The manuscript will have now to go through the refereeing process, which I can anticipate will be quite painful.

I do not really known which cosmological model is the right one. I would not stick my [small] reputation to the claim that we have found 20 billion years old stars. But certainly, this has been a very interesting and stimulating experience, and has exposed me to two very brilliant and open minds, those of Ken and Jayant. Thankyou lads for sharing this with me!

The sundial

Today I was all day long in a Time Management training course, organized by ESO. You might wonder why on earth an astronomer should take a course in time management… but actually, more and more (especially in big organizations as ESO is) astronomers (as they come of age) get also some managerial responsibilities. This is very much the case when they act as project scientists and have to interact with engineers, who are used to proceed in a very structured way (as opposed to scientists, who [often] know where they are but not where they are heading to). One of the most important aspects is how you manage time. And thinking about this it occurred to me that last August, during my summer vacations in Northern Italy, I had done something about time management. Not the way the trainer has told us today, though.

My father at work.

In fact, starting in the early ‘90, I have designed and constructed a number of sundials (actually, as an exercise of spherical trigonometry, I had also derived the equations that govern the drawings of a solar clock). My father Giovanni happens to be a professional sculptor, and has spent all of his life mainly working on stone. So, occasionally, we have manufactured some sundial cast in stone (if you wish this is another way of mixing astronomy and art). Sundials are usually painted on walls, but having them deeply engraved in stone makes them practically everlasting and adds to the concept that their mechanism (in contrast to any mechanical/electronic clock) will never stop working (well, actually it will, as soon as the sun will become a red giant. But Earth will have disappeared by that time…). Some years ago, for the birth of their last child, a family of friends had commissioned us a solar clock, and they wanted something special. And by chance in the atelier of my father there was a slab of stone that had been found along a creek. It had the peculiarity that ice had broken it into two almost identical pieces, a few centimeters think, with almost parallel surfaces.

A detail.

In the sundials we had done before, besides the dial drawing, my father had sculpted figures like bats (to indicate the night), a field of wheat (for the summer) or his view of the Hyakutake comet (in a sundial made in 1997, when the comet had passed close to the sun). But this time he said Nature had done a better job and his hand should not dare to alter its wonderful shape and textures. In his view, the slab was a sculpture in itself (lately, while sculpting, he has been trying to preserve the imprint of nature, following her guidelines and without altering them too much). Our friends did not have yet a proper wall where to place it, so the stone remained dormant in my father’s atelier, waiting to see the light. The time was mature last summer, when their new house was in a stage where we could start working on it. And so, in one hot day in August, armed with my old device to estimate the inclination of the wall with respect to the east-west line, I did a few measurements. The wall turned out to be declinant by only 7.8 degrees, so that the equinoctial line would be only slightly inclined with respect to the horizon.

The twin, horizontal sundial at winter solstice.

After measuring the latitude of the site, I entered the data in a simple computer program I wrote many years ago and I produced the numbers which I then traced directly on the slab, in the fresh shade of my father’s lab (note that the same calculations can be done “by hand. Speaking of time management, it just takes longer…). The sundials we had done so far were drawn on rectangular, machine-cut slabs, and there the task was easy. In this case the shape of the stone was all but rectangular, although it certainly had an elegant geometry, whose curves would well harmonize with the human-made analemn. After a few attempts, we finally found what seemed to be a good scaling and positioning of the dial. After tracing the lines (both straight and curved) with a hard pencil, my father used a few hundred gram hammer and a chisel to give a first pass, engraving the lines to a depth of roughly a millimeter. Then, with a very fast rotating diamondwork disk cooled with water he has deepened the straight lines (hours and equinoctial line). For the curved ones he has done the same, but with a hand tool. Finally, he has engraved our names and the date (GPN MMIX).

The sundial goes is in place, but silent...

All this took less than an afternoon and the day after, just before sunset, the slab was mounted on the wall. But the sundial was left “silent”, that is without the gnomon (the small stick that casts the shadow). For this I had asked my good old and ingenious friend Armando (you might remember he has done also the big Pendulum for the Shadow of the Earth). I usually build the gnomon myself, but for this particular one we wanted to have something very special. And special it was. In fact, he managed to have it in stainless steel, with a laser-cut star at the top, giving a very high-tech look to the whole thing. Contrarily to what one would expect there is no contrast between the shapes carved by nature and this metallic artifact. The gnomon is now ready and just waits to be put in place. This is going to happen around the winter solstice, when we will properly celebrate the event. From then on the sundial will start marking the time for the years to come.

Gee, it’s past midnight!! Talking about time, it is now time to go to bed. Tomorrow morning I’m back in the time management course. I’d better go to get some sleep. Good night.

This is a somewhat unusual post when compared to my usual ones. In fact, today my Grand Mother Vittoria turns 100! She was born in Buia (Italy) on December 3rd, 1909. One hundred years ago, almost exactly 300 years after the Galilean Nights. She has seen two world wars, experienced invasion, bombing, forced emigration, destitution and earthquakes. Hundred years are a lot and almost nothing in the same time.  In 1909 the construction of Titanic was started, Herman Minkowski died, Guglielmo Marconi got the Nobel Prize, Rita Levi Montalcini (Nobel Prize in 1986) was born, Louis Bleriot was the first man to fly across the English Channel…

I am not sure what happened in 1909 in connection to the 300th anniversary of the Galilean astronomical discoveries. What I found on the Internet is a reference to two publications: Muller, Der Galilei Process (Fribourg, 1909), and Muller, Galileo Galilei, und das Kopernikanische Weltsystem (Fribourg, 1909), but it is not clear to me whether these works were published to celebrate that recurrence.  By that time the largest telescope in the world was the 60 inch Hale Telescope at Mount Wilson Observatory, which saw the first light on December 8th, 1908. Many telescopes, larger and larger, have been built in these hundred years, and our vision of the physical world has changed quite a bit. At that time the nature of the spiral nebulae was not yet clarified, quasars were not known and the Sun was supposed to be sustained by radioactive decay… And this was “only” hundred years ago. A short step for mankind, but still a very long one for a human being

Happy Birthday Grandma!.