In a recent post (April 2012) I have discussed about Roman Dodecahedra.
After preparing a model of a Roman Dodecahedron, I was able to investigate it as an optical instrument.
In the paper "A Roman Dodecahedron for measuring distance", published in arXiv, http://arxiv.org/abs/1204.6497 you can find how a Roman soldier could had used it to determine the distance of a target.The dodecahedron is quite simple to use and portable. Someone could tell (or is telling) that it is more complicated compared to a simple cross-staff. Well, a cross-staff is rather long. In the case it were of bronze, the instrument turned out to be too heavy. Moreover, it seems that the cross-staff had been developed during the 14th century, therefore it was an instrument of the Middle Age in Europe.
(http://en.wikipedia.org/wiki/Jacob's_staff)
that is, ideas and information on Science and Technology, Archaeology, Arts and Literatures. Physics at http://physics-sparavigna.blogspot.com/
Welcome!
Benvenuti in queste pagine dedicate a scienza, storia ed arte. Amelia Carolina Sparavigna, Torino
Wednesday, May 2, 2012
Thursday, April 26, 2012
Roman Dodecahedra
Recently I have read a very interesting paper entitled "The magic dodecahedron of Gauls, that saved Roman legions: Mirror of Universe and gauge of seasons." by Cinzia di Cianni, published on La Stampa, in Italian (Il dodecaedro magico dei Galli che salvò le legioni romane: Specchio dell’Universo e misura delle stagioni:, July 28, 2010). Here I shortly discuss this article.
It starts with the following questions. Was is it, "a sacred symbol for Druids or the tip of a scepter? A gauge or a candlestick? Nobody knows what it is really, in spite of the fact that in museums and private collections, we find over than a hundred of them. It is a small hollow object of metal, dating from the fourth century and having a Gallo-Roman origin." The object exists in a variety of designs and sizes, always consists of 12 regular pentagons and this is known as "Roman dodecahedron". All the found "Roman dodecahedra" have a diameter between 4 and 11 cm. and have at the center of the 12 faces holes of different sizes. Each of the 20 vertices is surmounted by one or three knobs, may be to fit them on some surfaces.
"The Roman dodecahedron is a simple object, actually a "time capsule", containing an incredible density of history and myth. By itself it does not reveal anything relevant because it has no inscriptions on patterned surfaces. No document speaks about it." The article continues telling that, in fact, there are 27 theories about its use, ranging from a game for divination to surveying or military purposes. Scholars gave up probably until some new finds: however, some amateur archaeologists, among them Sjra Wagemans, continue to study this mystery, that is "what was it used for?"
Cinzia di Cianni tells that the first description of the geometrical volume of this object is in the "Timaeus" by Plato. It is a solid as the tetrahedron, octahedron, cube and icosahedron, that is, one of the five Platonic solids. Before Plato, it was also described in the fifth century BC by the Pythagorean Hippasus of Metaponto. "Harmony of proportions and mathematical properties, has continued to captivate artists and scientists, from Euclid to Poincare, from Leonardo to Luca Pacioli, to Escher. So, during several centuries, the dodecahedron had accumulated magic and symbolic features, from Greeks to Celts, from Renaissance to modern times." Di Cianni continues reporting the interest on dodecahedra by Francesco Maurolico, a Greek mathematician and astronomer of Sicily, who lived in the XVI century, and the contemporary astronomer Jean-Pierre Luminet, who works with data provided by the scientific probe "WMAP" (Wilkinson Microwave Anisotropy Probe), used to observe the cosmic background radiation in the microwave range.
For what concerns the Roman dodecahedra the article tells that all of them, collected in several European museums, always came from Gaul and the lands of the Celts: Great Britain, Belgium, Holland, Germany, Switzerland, Austria and Eastern Europe. A defined scholar theory about their use is still lacking. Recently Sjra Wagemans, of the Dutch multinational DSM Research and amateur archeology, proposed a theory which assigns an astronomical feature to these objects. Sjra used a bronze copy of a dodecahedron to see that it is possbile to determine the equinoxes of spring and autumn. "The dodecahedron is therefore linked to the agricultural cycle, both sophisticated and simple at the same time, to determine without a calendar, the most suitable period of time during the autumn for sowing wheat." And crops were of vital importance for the Roman legions. At the site www.romandodecahedron.com, Wagemans introduced the research and waiting for comments.
I like very much the discussion by Cinzia di Cianni about this mistery of archaeology.
For what concerns the measurement of time, we know that Romans used gnomons (the Vitruvian equinoxial gnomons) to determine the latitude and that they had very good meridians. In fact, Vitruvius deeply describes in his De Archtectura, how to prepare the analemma. See my Measuring times to determine positions, http://arxiv.org/abs/1202.2746
It is possible that the dodecahedron was used to determine more precisely the time during the equinoctial period. According to Cinzia, there are many proposal for their use.
In my opinion it is necessary to study how they can move, since they are biased structures, in order to understand whether they could have been used as dice for divination or bowls for simply playing with them. In a static use of them, the hypothesis for measuring time is quite interesting.
However there is the possibility to use it to measure distances as in the following approach:
It starts with the following questions. Was is it, "a sacred symbol for Druids or the tip of a scepter? A gauge or a candlestick? Nobody knows what it is really, in spite of the fact that in museums and private collections, we find over than a hundred of them. It is a small hollow object of metal, dating from the fourth century and having a Gallo-Roman origin." The object exists in a variety of designs and sizes, always consists of 12 regular pentagons and this is known as "Roman dodecahedron". All the found "Roman dodecahedra" have a diameter between 4 and 11 cm. and have at the center of the 12 faces holes of different sizes. Each of the 20 vertices is surmounted by one or three knobs, may be to fit them on some surfaces.
"The Roman dodecahedron is a simple object, actually a "time capsule", containing an incredible density of history and myth. By itself it does not reveal anything relevant because it has no inscriptions on patterned surfaces. No document speaks about it." The article continues telling that, in fact, there are 27 theories about its use, ranging from a game for divination to surveying or military purposes. Scholars gave up probably until some new finds: however, some amateur archaeologists, among them Sjra Wagemans, continue to study this mystery, that is "what was it used for?"
Cinzia di Cianni tells that the first description of the geometrical volume of this object is in the "Timaeus" by Plato. It is a solid as the tetrahedron, octahedron, cube and icosahedron, that is, one of the five Platonic solids. Before Plato, it was also described in the fifth century BC by the Pythagorean Hippasus of Metaponto. "Harmony of proportions and mathematical properties, has continued to captivate artists and scientists, from Euclid to Poincare, from Leonardo to Luca Pacioli, to Escher. So, during several centuries, the dodecahedron had accumulated magic and symbolic features, from Greeks to Celts, from Renaissance to modern times." Di Cianni continues reporting the interest on dodecahedra by Francesco Maurolico, a Greek mathematician and astronomer of Sicily, who lived in the XVI century, and the contemporary astronomer Jean-Pierre Luminet, who works with data provided by the scientific probe "WMAP" (Wilkinson Microwave Anisotropy Probe), used to observe the cosmic background radiation in the microwave range.
For what concerns the Roman dodecahedra the article tells that all of them, collected in several European museums, always came from Gaul and the lands of the Celts: Great Britain, Belgium, Holland, Germany, Switzerland, Austria and Eastern Europe. A defined scholar theory about their use is still lacking. Recently Sjra Wagemans, of the Dutch multinational DSM Research and amateur archeology, proposed a theory which assigns an astronomical feature to these objects. Sjra used a bronze copy of a dodecahedron to see that it is possbile to determine the equinoxes of spring and autumn. "The dodecahedron is therefore linked to the agricultural cycle, both sophisticated and simple at the same time, to determine without a calendar, the most suitable period of time during the autumn for sowing wheat." And crops were of vital importance for the Roman legions. At the site www.romandodecahedron.com, Wagemans introduced the research and waiting for comments.
Courtesy: DieBuche, Wikipedia
I like very much the discussion by Cinzia di Cianni about this mistery of archaeology.
For what concerns the measurement of time, we know that Romans used gnomons (the Vitruvian equinoxial gnomons) to determine the latitude and that they had very good meridians. In fact, Vitruvius deeply describes in his De Archtectura, how to prepare the analemma. See my Measuring times to determine positions, http://arxiv.org/abs/1202.2746
It is possible that the dodecahedron was used to determine more precisely the time during the equinoctial period. According to Cinzia, there are many proposal for their use.
In my opinion it is necessary to study how they can move, since they are biased structures, in order to understand whether they could have been used as dice for divination or bowls for simply playing with them. In a static use of them, the hypothesis for measuring time is quite interesting.
However there is the possibility to use it to measure distances as in the following approach:
Etichette:
ancient Rome,
archaeology,
Dodecahedron
Monday, April 23, 2012
Phonons and Auxetics
About me.
One of my researches is on dispersions of phonons.
Quite interesting are the new auxetic materials, providind phononic band-gaps
2011 SPARAVIGNA A.C., Vibrations of a One-Dimensional Host-Guest System, MATERIALS SCIENCES AND APPLICATIONS, Scientific Research, pp. 5, 2011, Vol. 2, pagine da 314 a 318, ISSN: 2153-117X, DOI:10.4236/msa.2011.25041
2007 SPARAVIGNA A., Phonons in conventional and auxetic honeycomb lattices, PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, APS, pp. 6, 2007, Vol. 76, ISSN: 1098-0121, DOI: 10.1103/PhysRevB.76.134302
2007 SPARAVIGNA A., Phonons dispersions in auxetic lattices, JOURNAL OF PHYSICS. CONFERENCE SERIES, 2007, Vol. 92, pagine da 012100-1 a 012100-4, ISSN: 1742-6596, DOI: 10.1088/1742-6596/92/1/012100
2007 SPARAVIGNA A.C., Phonons in lattices with rod-like particlesarXiv:0706.4076, 2007
2007 SPARAVIGNA A.C., Phonons in honeycomb and auxetic two-dimensional lattices arXiv:cond-mat/0703257, 2007
One of my researches is on dispersions of phonons.
Quite interesting are the new auxetic materials, providind phononic band-gaps
2011 SPARAVIGNA A.C., Vibrations of a One-Dimensional Host-Guest System, MATERIALS SCIENCES AND APPLICATIONS, Scientific Research, pp. 5, 2011, Vol. 2, pagine da 314 a 318, ISSN: 2153-117X, DOI:10.4236/msa.2011.25041
2007 SPARAVIGNA A., Phonons in conventional and auxetic honeycomb lattices, PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, APS, pp. 6, 2007, Vol. 76, ISSN: 1098-0121, DOI: 10.1103/PhysRevB.76.134302
2007 SPARAVIGNA A., Phonons dispersions in auxetic lattices, JOURNAL OF PHYSICS. CONFERENCE SERIES, 2007, Vol. 92, pagine da 012100-1 a 012100-4, ISSN: 1742-6596, DOI: 10.1088/1742-6596/92/1/012100
2007 SPARAVIGNA A.C., Phonons in lattices with rod-like particlesarXiv:0706.4076, 2007
2007 SPARAVIGNA A.C., Phonons in honeycomb and auxetic two-dimensional lattices arXiv:cond-mat/0703257, 2007
Sunday, April 22, 2012
Ale's stone boat
Ale's Stones (or Ales stenar) is a megalithic monument in Kaseberga, southern Sweden. It is a boat of stones, 67 meters long formed. There are 59 boulders of sandstone, up to 1.8 tonnes each. According to the local lores, King Ale lies buried there.
http://en.wikipedia.org/wiki/Ale's_Stones
http://en.wikipedia.org/wiki/Ale's_Stones
Friday, March 30, 2012
Calendar Puzzles Deciphered in Ancient Statue
Calendar Puzzles Deciphered in Ancient Statue, by Rossella Lorenzi
on the Trundholm Sun Cariot and my proposal of a calendar
http://news.discovery.com/history/bronze-age-calendar-120330.html
on the Trundholm Sun Cariot and my proposal of a calendar
http://news.discovery.com/history/bronze-age-calendar-120330.html
Friday, March 16, 2012
A calendar of the Bronze Age
Ancient bronze disks, decorations and calendars, http://arxiv.org/abs/1203.2512,
by Amelia Carolina Sparavigna, Department of Applied Science and Technology, Politecnico di Torino , Italy,
Among the burial objects of the Early Bronze Age, the Trundholm Sun Chariot (Fig.1, [4]) is beautiful and amazing for the contrast between the fine decoration of the disk and the stylized shapes of chariot and horse. This artifact is also known as Solvognen. The sculpture was discovered in 1902 in a peat bog on the Trundholm moor and is now in the collection of the National Museum of Denmark in Copenhagen. It was cast by the lost wax method [1,5,6]: it means that this technique was known during the Bronze Age. The disk has a diameter of approximately 25 cm. In fact, it consists of two bronze disks, flanged by an outer bronze ring. One of the disks had been gilded on one of his side. The models of the disks had been probably decorated with some standard punches, because concentric circles and spirals seem to be identical in the decoration.
The two sides of the disk are considered as representations of the sun, on a chariot pulled by a horse across the heavens from East to West during the day, showing its bright side, the gilded one. During the night, it returns from West to East [1], showing his “dark side” to the Earth. The sculpture is dated to about 1400 BC [1]. However, the same reference is telling, “a model of a horse-drawn vehicle spoked wheels in Northern Europe at such an early time is surprising”. They were common in the Late Bronze Age, which ranges from 1100 BC to 550 BC. Ref.1 is suggesting a possible Danubian origin or influence, although the Museum supposes it of Nordic origin.
Let us consider the gilded side of the disk: it has the outer zone, which may represent the solar rays (Fig.2, [7]). There is an annulus (the region lying between two large concentric circles) decorated with small multiple concentric circles, linked by a looping band, which creates a “yin and yang” ornamental motif (see Fig.3 on the left) [8]. The image on the right of the same figure is reproducing the dark side of the sun. In Ref.2 the author is proposing that this side is a calendar. The author, Klaus Randsborg is considering the following calculation. Starting from the centre of the disk, we add the number of spirals in each annulus of the disk, multiplied by the order of the annulus where they are, that is (1x1 + 2x8 + 3x20 + 4x25). This results in a total of 177, a number very close to the number of days in six synodic months. In the Reference 2, the author is also proposing a calendar for the Egtved disk and other objects, supposing that the “spiral” symbol, that is, the figure formed by multiple concentric circles or by a true spiral, is representing the day. The annulus where the symbol is places provides the multiplication factor.
Here I propose another interpretation for the decoration in Fig.3, right panel, that is, of the side corresponding to the night. In the inner part of the disk (see the Figure 4), there are the days of a “week”, having therefore 8 days. For the moment, let us not consider the central large circle with many concentric circumferences. It could be a symbol for the cosmos as an ordered and harmonic system, as the cosmos was for the ancient Greeks. In the outer two annuli, there are the weeks of the year, which are 45. Then if we multiply the days in a week by the number of weeks, we obtain 360 days. That is: (8 days) x (45 weeks) = 360 days of the year. As in the ancient Egypt, the year has 360 days: the Egypt divided the year into 12 months of 30 days each, plus five extra days. Let us note that the weeks (see Fig.4) are grouped in two annuli: if we consider the winter solstice as the beginning of the year, the two groups of weeks could have the meaning that during the year there are two seasons, that of a “young sun” followed by the season of a “mature and then old” sun.
Let us note that weeks having eight days existed. The ancient Etruscans developed a week known as the nundinal cycle, around the 8th or 7th century BC. This system passed to Rome, no later than the 6th century BC. It seems that Rome had for a certain period of time a calendar based on two cycles, one having weeks of seven days and the other having eight-day weeks [9]. In any case, using two markers, a marker for the day in the central part and another marker for the week in the outer part, we can use the disk in Fig. 4 as a calendar for a nundinal system. Of course, we need a reference axis, as the black one in the figure. For the five extra days at the end of the year, we can use the circle at the centre of the disk. This is the centre of rotations: everything is turning about it. This figure contains both the end and the beginning of the year, able to “adjust” the circle of time, restoring the cosmic order.
For what concerns the other side of the Trundholm disk, the gilded day-side, I can only tell that, if we consider the total number of spirals (52), central included, and assume that each spiral is representing a week having seven days, we can obtain 364. The central “week” is larger because it contains one or two extra days, depending on years. Is it possible that the Trundholm disk is a calendar having two cycles? The answer is beyond the author’s knowledge. I consider more reliable the 360 days calendar, as in Fig.4, using the night-side of the disk.
Of course, the decorations in the disk could be simply a beautiful decoration. In any case, if we try to repeat it, we need to arrange in some manner the number of circles/spirals at specific relative distances. The two diagrams of Fig.5 are showing how the artist could have assembled the decoration, subdividing in some angular sectors the disk. It is probable that the artist possessed some specific knowledge of geometric rules. In my opinion, further studies of the decorations of ancient bronze artifacts can be useful to understand the progression of human knowledge of mathematics and geometry.
References
1. Trundholm sun chariot http://en.wikipedia.org/wiki/Trundholm_sun_chariot
2. Klavs Randsborg, SPIRALS! Calendars in the Bronze Age in Denmark, 2010, Adoranten. Vol.2009, http://www.ssfpa.se/pdf/2009/Randsborg.pdf
3. Egtved Girl, http://en.wikipedia.org/wiki/Egtved_Girl
4. The image of the Trundholm sun chariot was created by Malene Thyssen, downloadable from Wikipedia, http://commons.wikimedia.org/wiki/User:Malene
5. Lost-wax casting http://en.wikipedia.org/wiki/Lost-wax_casting
6. Molding (process),. http://en.wikipedia.org/wiki/Molding_(process)
7. Note the “rays” at the rim of the golden disk in the image adapted from a picture taken at the National Museum, Copenhagen Denmark, by Kim Bach.
8. The sketches in the Figures 3, 4 and 5 have been created according to the drawings reported in Reference 2. Please see this reference to see the details, which are amazing.
9. Week, http://en.wikipedia.org/wiki/Week, Nundinal cyle,
http://en.wikipedia.org/wiki/Roman_calendar#Nundinal_cycle
Fig.3 Decorations of the front/day (left) and back/night (right) sides of the disk of the Trundholm sun chariot. Note on the left image, the circles linked by a “yin and yang” pattern.
Fig.4. In the inner part of the disk, there are the “days” of a week having 8 days. In the outer two annuli, the weeks of the year, that is 45, subdivided in two “seasons”. We have (8 days) x (45 weeks) = 360 days of the year. We can use the decoration as a calendar, using two markers: one (red) for the day and the other (blue) for the week. In the lower part of the image we can see two examples. We count clockwise from the vertical axis. This calendar is working as a clock with two hands for days and weeks. For the days, the red marker turns on the first ring. The second marker, the blue, turns on the second ring for the first season, and on the third ring for the second.
Fig.5. Two diagrams are showing how, probably, the artist had assembled the decoration, subdividing the disk in a few sectors. It seems that the artist knew some geometric rules.
Tuesday, March 6, 2012
Every breath you take, Every move you make
"Engineers have designed a device that harvests energy from the reverberation of heartbeats through the chest and converts it to electricity to run a pacemaker or an implanted defibrillator.
According to a statement, these medical machines — developed at Michigan University — send electrical signals to the heart to keep it beating in a healthy rhythm.
By taking the place of the batteries that power them today, the new energy harvester could save patients from repeated surgeries."
Read more:
Energy caught from heartbeats could power implanted devices | News | The Engineer
According to a statement, these medical machines — developed at Michigan University — send electrical signals to the heart to keep it beating in a healthy rhythm.
By taking the place of the batteries that power them today, the new energy harvester could save patients from repeated surgeries."
Read more:
Thursday, March 1, 2012
Why the Ocean is Blue?
"Why is the ocean blue? Speculation about the blue color of the ocean, as seen from above, goes way back. Lord Rayleigh claimed it was simply reflection of the blue sky. The correct explanation required combining the 19th-century ideas of Robert Bunsen, who felt that the color depended on light absorption by water, and Jacques-Louis Soret, who felt that the color was entirely due to scattering. C. V. Raman pointed out the importance of molecular scattering, and in 1923 Vasily Shuleikin combined those ideas to develop a complete explanation of the color of the sea."
In Physics Today, Shedding new light on light in the ocean
Tommy D. Dickey, George W. Kattawar, and Kenneth J. Voss
April 2011, http://dx.doi.org/10.1063/1.3580492
Recent advances are making it possible for optical oceanographers to solve a host of pressing environmental problems.
In Physics Today, Shedding new light on light in the ocean
Tommy D. Dickey, George W. Kattawar, and Kenneth J. Voss
April 2011, http://dx.doi.org/10.1063/1.3580492
Recent advances are making it possible for optical oceanographers to solve a host of pressing environmental problems.
More Planets than Stars
Microlensing suggests that our galaxy has more planets than stars, buBertram M. Schwarzschild
March 2012, http://dx.doi.org/10.1063/PT.3.1463, Physics Today
Gravitational bending of light reveals exoplanets with large orbital radii.
"Most of the more than 600 exoplanets discovered to date have been found through Doppler evidence of periodic host-star motion or photometric evidence of transits across a star’s face. Both methods are strongly biased in favor of planets with orbital radii much smaller than Earth’s, which defines 1 astronomical unit (AU). Gravitational microlensing is an alternative technique that’s most sensitive to planets a few AU from their stars. It favors very distant stars and it’s relatively unbiased as to stellar mass. Though microlensing’s discovery rate is still modest, it appeals to those who seek a representative galactic survey of planets with orbits like those of the solar system." http://www.physicstoday.org/resource/1/phtoad/v65/i3/p19_s1
March 2012, http://dx.doi.org/10.1063/PT.3.1463, Physics Today
Gravitational bending of light reveals exoplanets with large orbital radii.
"Most of the more than 600 exoplanets discovered to date have been found through Doppler evidence of periodic host-star motion or photometric evidence of transits across a star’s face. Both methods are strongly biased in favor of planets with orbital radii much smaller than Earth’s, which defines 1 astronomical unit (AU). Gravitational microlensing is an alternative technique that’s most sensitive to planets a few AU from their stars. It favors very distant stars and it’s relatively unbiased as to stellar mass. Though microlensing’s discovery rate is still modest, it appeals to those who seek a representative galactic survey of planets with orbits like those of the solar system." http://www.physicstoday.org/resource/1/phtoad/v65/i3/p19_s1
Isaac Newton and the Philosopher's Stone
From http://en.wikipedia.org/wiki/Isaac_Newton's_occult_studies
"Of the material sold during the 1936 Sotheby's auction, several documents indicate an interest by Newton in the procurement or development of The Philosopher's Stone. Most notably are documents entitled, "Artephius his secret Book", ... "The Epistle of Iohn Pontanus"..... , these are themselves a collection of excerpts from another work entitled, "Nicholas Flammel, His Exposition of the Hieroglyphicall Figures which he caused to be painted upon an Arch in St Innocents Church-yard in Paris. Together with The secret Booke of Artephius, And the Epistle of Iohn Pontanus: Containing both the Theoricke and the Practicke of the Philosophers Stone". ... Nicolas Flamel, (one subject of the aforementioned work) was a notable, though mysterious figure, often associated with the discovery of The Philosopher's Stone, Hieroglyphical Figures, early forms of tarot, and occultism. Artephius, and his "secret book", were also subjects of interest to 17th century alchemists."
As told in the previous post, Isaac Newton became the Master of the Mint. In the case that he had actually discovered the Philosopher's Stone.
"Of the material sold during the 1936 Sotheby's auction, several documents indicate an interest by Newton in the procurement or development of The Philosopher's Stone. Most notably are documents entitled, "Artephius his secret Book", ... "The Epistle of Iohn Pontanus"..... , these are themselves a collection of excerpts from another work entitled, "Nicholas Flammel, His Exposition of the Hieroglyphicall Figures which he caused to be painted upon an Arch in St Innocents Church-yard in Paris. Together with The secret Booke of Artephius, And the Epistle of Iohn Pontanus: Containing both the Theoricke and the Practicke of the Philosophers Stone". ... Nicolas Flamel, (one subject of the aforementioned work) was a notable, though mysterious figure, often associated with the discovery of The Philosopher's Stone, Hieroglyphical Figures, early forms of tarot, and occultism. Artephius, and his "secret book", were also subjects of interest to 17th century alchemists."
As told in the previous post, Isaac Newton became the Master of the Mint. In the case that he had actually discovered the Philosopher's Stone.