Driving along the old Athens-Corinth highway, a mysterious structure can be seen a few meters above the Elefsin shipyards. Triangular and gigantic, it stands in the water next to the shipyard’s tanks, a reminder of a secret defense project. It’s about the Delta Berenice, a pioneering research vessel that was once meant to unravel the mysteries of the universe and has taken on the role of protagonist in the country’s most ambitious science project. Decommissioned today, it is a double symbol of our great potential and our missed opportunities.

But what story does he want to tell us? To find the answer, we will have to go back to the late 80s and the EKPA Physics Laboratory. There we meet the director, professor of physics Leonidas Resvanis, who had something grand: the installation in Greece of a neutrino telescope, which will be the first scientific one in Europe.

“Neutrinos are the strangest elementary particles we know. At high energies, they are born in great cosmic explosions, and when they reach the Earth, they penetrate into it. Matter is as transparent to neutrinos as glass is to light. So we follow Aristotle, who, in his On the Origin of Animals, speaks of these “madmen” descending into deep wells to see the stars. That is why we go with our telescopes as deep as we can, where cosmic radiation is minimized, and in this way we detect neutrinos from the other side of the Earth,” physicist Sophocles Sotiriou, once a graduate student Leonidas Resvanis, tells us. This is a hunt for bits of matter that came from the depths of the universe and the beginning of time, and thanks to this, they can perhaps reveal valuable secrets to us. In search of this, our weapons are special “telescopes” of gigantic volume, which we must install in places where cosmic radiation is minimal, for example, at the bottom of the deepest seas.

Leonidas Resvanis and his collaborators also wanted to capture flying neutrinos there when, in 1989, they began working closely with the Institutes of Nuclear Physics and Oceanography of the USSR Academy of Sciences. After three years of research, he confirmed that the ideal location for the telescope was five kilometers below the surface of the Ionian Sea, near Pylos, at the deepest point in the entire Mediterranean Sea, the so-called “Frere Oinousa”. In an attempt to strengthen the project through cooperation (at the very moment when the Soviet Union collapsed, unable to service the oceanographic ships absolutely necessary for the experiment), he organized a series of international conferences, two at Pylos Castle (1992 and 1993) and one in Sounio, at the Egeon Hotel (1994). In 1998, with the support of the Greek state, the Institute of Deep Sea Technology and Research and Physics of Neutrino Astroparticles was founded in Pylos. Its name is an acronym for the area’s history: NESTOR (Neutrino Extended Underwater Telescope with Oceanographic Research). NESTOR found a place, but he also had to find a way.

After careful research, the NESTOR team came up with an original, reasonable and practical proposal, which is summarized in the text he wrote at the time: “Imagine at the bottom of the sea not one, but ten at least twelve-story “towers”. , each of which is taller than the Eiffel Tower. The floor of each floor is shaped like a hexagon, with sensitive photomultipliers at each corner that detect the bright glow emitted when neutrinos interact with water atoms. In the center of the hexagon, a titanium sphere contains the complex electronics of the experiment, which receives signals from the detectors. A high-tech fiber optic cable transmits signals from a depth of 5 kilometers to land.”

Like…a robot from a movie

In photographs from that time, we see these “metal starfish”, 17-meter “tentacles” made of titanium, plunging into the sea, and there is something from science fiction in the image. The spherical photomultipliers at the ends of the metal starfish’s “tentacles” are reminiscent of Star Wars robots. In the center of the starfish is a no less futuristic titanium sphere, which houses the electronic “floor” installation. Twelve of these “floors” make up a “tower” that firmly holds a metal pyramid below with an anchor made of railway wheels. There is something cosmic about everything in this building. They are like the efforts of astronaut scientists to find ways to live on new planets.

Of the pointing missions of that time, physicist Sophocles Sotiriou, who worked on the experiment from 1992 to 1998, recalls: “In May 1997, we conducted a test pointing of two “floors” of the telescope, made by the OTE cable ship.” Thales. It is worth saying that OTE supported the project, as it was the only company that had the necessary experience with submarine cables. It was a mission straight out of the movie. In addition to physicists, oceanographers, engineers, cable-layers and electronics specialists from Greece, Italy, Russia and Germany worked like a well-oiled machine for a common goal. This image “taken from the film” was supplemented a few years later by the Berenice Delta mentioned at the beginning – a special self-propelled platform from which the “floors” of the underwater telescope tower were lowered. Ingenious, innovative and unique in the world, the structure, inspired by oil platforms in the North Atlantic, is an isosceles triangle with a “deck” of 1000 sq.m. and sides 44 meters long, which were held in the air by three cylinders at the corners of the triangle. Inside each of these cylinders were 322-horsepower engines, which, in combination with azimuth water cannons and an advanced wave absorption system, allowed the platform to bombard the towers at a depth of up to five kilometers with an accuracy of better than one meter, even in surface conditions. 6 Beaufort. Its construction was carried out at the Elefsina Shipyards, who generously assisted in the entire project. However, the onset of the crisis slowed down everything.

In the bay of Elefsina, the “Delta of Bereniki” remained, a triangular floating platform, reminiscent of the vision of Professor Leonidas Resvanis.

First missions

Returning to the first laying expeditions, it is worth mentioning a landmark moment for the experiment – the laying of a 36-kilometer submarine cable in 2001 with the help of OTE. However, due to the failure of the guidance ship, the cable was “damaged”, preventing it from communicating with the telescope. In 2003, the research team fished out the broken cable and repaired it, so the first two floors of the telescope were connected by a bridge. For several months in 2003, while the cable was running, it was convincingly demonstrated that the whole experiment worked, and for the first time in the world, this is the correct methodology for detecting neutrinos. But a few months later, the already damaged cable was cut again, stopping data collection.

Since 2006, research work has been merged with the new European project “KM3NeT”, and now the telescope has two new possible installation sites. Greek, Italian and French science stations were attacked, and eventually Italian and French science stations were set up with significant government funding.

The Institute was affiliated in 2003 to the National Observatory of Athens and in 2010 to Democritus, to which it still belongs today. In the same year, Rezvanis retired, and the economic crisis knocked out the Institute of Scientific and Technical Workers. Today on the official website of KM3NeT we read a characteristic phrase: “The NESTOR expansion is subject to future funding. Onshore facilities are available but need new equipment.” At the same time, the Delta Berenice is decommissioned, but always imposing, in the bay of Elefsina.

Finally, while the vision of Leonidas Resvanis is taking shape today, it is not being driven by the Greek research community, as it might be, but by European and other global partners. “Such research efforts do not survive with occasional support. They should be part of the country’s strategy, and in the case of NESTOR this did not happen,” Sophocles Sotiriou will tell us today, who remembers the professor as an inspiring “captain” of efforts. “It was his vision and passion that guided us.” However, as Leonidas Resvanis himself says, “passion, foresight or scientific ability is not enough to complete such an effort. It also needs multifaceted, stable and long-term support from the relevant government.”

In a conversation with Associate Professor of Physics at the Hellenic Academy of Sciences Efstratios Anasontzis, a key partner of Leonidas Resvanis in the experiment, we hear something more pragmatic: “This is how research and science develop with constant and repetitive efforts”, while Leonidas concludes with Resvanis adding : “This journey was worth it because, given the internal conditions, we achieved much more than we really expected. And it’s a trip that I would do again because it was great and I met amazing people doing it.”

Another Greece

Another major collaborator of the experiment, professor at the University of Crete and former rector Giorgos Grammatikakis, said of these people: “NESTOR was a human and scientific epic, which, as the poet says, had “incalculable significance for the present and for the future.” That he had a bitter and the infamous end does not detract from its importance.Inspirer and creator Leonidas Resvanis, a man of high scientific constitution, inexhaustible energy and devotion to an innovative idea, at some point also met Ionas Siotis, a versatile and creative personality, whose recent loss plunged the scientific world into a difficult sorrow. Men like them, working on such an ambitious experiment, brought Greece out of scientific obscurity. However, the scope and requirements of the experiment were in constant conflict with the Greek “reality. So it was not difficult to imagine who would win in the end.”

Giorgos Grammatikakis sums up: “Greece of empty words and devaluation of values ​​is opposed by another Greece, one that is made up of people who, despite the surrounding atmosphere, still do the right thing and the hard way and go with responsibility and passion. In essence, Nestor’s experience was the expression and vision of this Greece.”