Xenophon Moussas

National and Kapodistrian University of Athens, Physics, Faculty Member

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(retired) Professor of Space Physics,
one of the protagonists of the study of the oldest known computer, the Antikythera Mechanism.
He has served as Head of Space Physics group, as Director of the Astrophysics Laboratory, as Director of the Observatory of the National and Kapodistrian University of Athens, as Deputy Chairman of the Faculty of Physics, as Senator of the National and Kapodistrian University of Athens, as President of the Association of Professors of Science.
Awards include: NASA group achievement award, Ulysses Mission, 2009, Geophysical Research Letters editor’s citation for excellence in refereeing in Space Physics, American Geophysical Union, Boston, 2001,
Hipparchus award, Arcadia, Athens, 2010,
Award of the Association of Attica Private Tutorial Teachers and the Federation of Private Tutorial Teachers of Greece, 2017
Honorary Doctor of the International Academy of Education and Science, Ukrainian Institute of Scientific and Cultural History (Pontic Institute), Kiev, Ukraine, 2017.

Research interests include Space physics: Ulysses mission (ESA) team member, WIND/WAVES and STEREO space mission (NASA) as co-investigator, cosmic rays, solar physics, and planetary physics.
He has supervised 26 PhDs, many MSc these, and 200 BSc theses.
Numerous exhibitions worldwide about the Antikythera Mechanism, Astronomy etc.
Honorary Doctor of the International Academy of Education and Science, Ukrainian Institute of Scientific and Cultural History (Pontic Institute), Kiev, Ukraine, 2017.
Supervisors: He has supervised 26 PhDs, many MSc these, and 200 BSc theses.
Phone: +306978792891
Address:
Department of Astrophysics, Astronomy and Mechanics
Faculty of Physics
School of Science
National and Kapodistrian University of Athens
Panepistimiopolis, GR 15783 Zographos, Athens, Greece
e-mail: xmoussas@phys.uoa.gr
e-mail: xmoussas@gmail.com
http://artemis-iv.phys.uoa.gr/
http://www.antikythera-mechanism.gr
cv:
http://www.antikythera-mechanism.gr/project/team/academic/xenophon-moussas
https://scholar.google.gr/citations?hl=el&user=b8aDvyIAAAAJ

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Papers by Xenophon Moussas

Exact Solution of the Three-Body Santilli-Shillady Model of the Hydrogen Molecule

The conventional representation of the H 2 molecule characterizes a 4-body system due to the inde... more The conventional representation of the H 2 molecule characterizes a 4-body system due to the independence of the orbitals of the two valence electrons as requested by quantum chemistry, under which conditions no exact solution is possible. To overcome this problem, Santilli and Shillady introduced in 1999 a new model of the H 2 -molecule in which the two valence electrons are deeply bounded-correlated into a single quasi-particle they called isoelectronium that is permitted by the covering hadronic chemistry. They pointed out that their new H 2 -model is a restricted 3-body system that, as such, is expected to admit an exact solution and suggested independent studies for its identification due to its relevance, e.g., for other molecules. In 2000, Aringazin and Kucherenko did study the Santilli-Shillady restricted 3-body model of the H 2 molecules, but they presented a variational solution that, as such, is not exact. In any case, the latter approach produced significant deviations f...

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Statistics on the Occurrence of Solar Radio Bursts (Type IV and IV) and their Relation with CMEs and Flares Covering the Time Interval 1996-2001 (Rising and Maximum Phase of Solar Cycle 23)

Plato's Triangle and Gnomonic Factor: An Application to Herodotus' Oracles

A modification to the gnomonic factor (fg) (Perez-Enriquez 2000) using the concept of Plato’s tri... more A modification to the gnomonic factor (fg) (Perez-Enriquez 2000) using the concept of Plato’s triangle is presented. With the aid of the platonic gnomonic factor (fgp) as we called it, we found that the oracles mentioned by Herodotus in his History (Dodona in Greece and Ammon in Oasis Siwa, Egypt) could have been placed there because the noon shadow of the sun of a vertical gnomon formed Plato’s triangle the former, and the Egyptian “sacred triangle” (sides 3:4:5) the latter; sites where the value of fgp is equal to 1/1 and 1/3, respectively. This could mean that both concepts were known by Egyptians in Thebes long before, they were formalized by the Greeks. The priestesses, about whom Herodotus talks, knew the right angle triangle concept as an idealization of the sun’s observation as it was proposed by Magdolen (2001), i.e., the triangle is the shadow casted by a gnomon. We consider that the idea of the use of a gnomon for site location could be found in other regions along the Va...

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Sunspot photometry and area measurements from SOHO/MDI images during the 23rd solar cycle

We present area and photometry measurements of all sunspots (aprox. 12000) for the 23rd solar cyc... more We present area and photometry measurements of all sunspots (aprox. 12000) for the 23rd solar cycle. The images that have been used for our analysis have been taken by the MDI instrument on board So.H.O during the last solar cycle through the years 1997 to 2007. At the completion of our analysis, with a simple algorithm, more than 3.300 images in photometry stage have been used. Initially we determined the sunspot pixel-positions from MDI images and registered them to the data base consisting of a complete record of sunspots during the last cycle, derived from the Mt. Wilson data base. We used a novel algorithm serving the purposes of this analysis, which measures the lowest intensity and the area of every sunspot umbra. Finally, groups penumbral and umbral data will be presented for all sunspot groups.

On the smooth surface of the northern bow shock of Mars, based on Mars Global Surveyor's measurements

ABSTRACT

Numerical study of energetic particle parallel, perpendicular and energy diffusion and drift motion in interplanetary space

The procedure employed in the present study is based on techniques reported by Jones et al. (1973... more The procedure employed in the present study is based on techniques reported by Jones et al. (1973) and Mousas et al. (1975). The problems investigated are related to the spatial and energy dependence of the parallel diffusion mean free path (derived from the pitch angle scattering coefficient), the energy dependence of the diffusion coefficients in energy space due to the interplanetary acceleration process studied by Fisk (1976), and the modification of the guiding center drift motion by scattering. The considered modification may have implications for the conclusions of Jokipii et al. (1976) concerning off-ecliptic modulation effects. Attention is given to details regarding the employed data and the numerical method, questions concerning the validity of the employed flux equation, results on space diffusion, and results on acceleration coefficients.

Cryovolcanic candidate regions on Titan: Promising landing sites

Cryovolcanic activity and morphotectonic features on Titan and Enceladus: Connection to terrestrial geology

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Potentially active regions on Titan: New processing of Cassini/VIMS data

The Cassini Visual and Infrared Mapping Spectrometer (VIMS) obtained data of Titan's surface ... more The Cassini Visual and Infrared Mapping Spectrometer (VIMS) obtained data of Titan's surface from flybys performed during the last seven years. In the 0.8-5.2 µm range, these spectro-imaging data showed that the surface consists of a multivariable geological terrain hosting complex geological processes. The data from the seven narrow methane spectral "windows" centered at 0.93, 1.08, 1.27, 1.59, 2.03, 2.8 and 5 µm provide some information on the lower atmospheric context and the surface parameters that we want to determine. Atmospheric scattering and absorption need to be clearly evaluated before we can extract the surface properties. We apply here a statistical method [1, 2] and a radiative transfer method [3, 1] on three potentially "active" regions on Titan, i.e. regions possibly subject to change over time (in brightness and/or in color etc) [4]: Tui Regio (20°S, 130°W) [5], a 1,500-km long flow-like figure, Hotei Regio (26°S, 78°W) [6], a 700-km wide vol...

Evolution of possibly active regions on Titan using Cassini/VIMS data analysis

ABSTRACT We present a study of Titan&#39;s complex geology with a focus on the satellite&... more ABSTRACT We present a study of Titan&#39;s complex geology with a focus on the satellite&#39;s surface regions that are showing spectral variations with time possibly linked to geological activity. We apply a statistical method, the Principal Component Analysis (PCA) [1] and a radiative transfer method (RT) [1,2] on three potentially &#39;active&#39; regions on Titan, i.e. surface areas possibly subject to change over time (in brightness and/or in color etc.), namely Tui Regio (20°S, 130°W), a 1,500-km long flow-like figure, Hotei Regio (26°S, 78°W), a 700-km wide volcanic-like terrain, and Sotra Facula (15°S, 42°W), a 235-km in diameter area. With our PCA method we manage to isolate regions of distinct spectral response in all data available for our three study areas. Then, with our follow-up radiative transfer code we retrieve the surface albedo of the isolated regions with respect to the Huygens landing site albedo, which we use as a reference region and we compare them. Using this double procedure, we study the temporal surface variations of the three regions witnessing albedo changes with time for Tui Regio from 2005-2009 (darkening) and Sotra Facula from 2005-2006 (brightening) at all wavelengths. Hotei Regio has been suggested to present brightness variations over a two-year period (2004-2005) by Nelson et al. 2009 [3]. However, we find that the to-date available observations of that region present issues (geometry, resolution) that prevent an accurate application of our radiative transfer model to infer surface information with the desired accuracy. Therefore, we do not detect any significant surface albedo variations over time from 2004 and until 2009 given the uncertainties involved. The surface albedo variations, which we currently investigate in terms of chemical composition, and the volcanic-like features such as calderas, domes and lobate flows, which are present within the regions as shown by RADAR data analysis [e.g. 4], suggest that these features are compatible with internal phenomena such as cryovolcanism. Another study focusing on these areas suggests that Tui Regio and Hotei Regio could be paleolake clusters [5]. In the future, considering that the extracted surface albedos contain information on the chemical composition of the regions and their nature, we plan to better evaluate the temporal changes and to associate chemical composition inferences with morphological information to determine the nature of these regions. References: [1] Solomonidou, A., et al.: in prep. [2] Hirtzig, M., et al.: submitted to Icarus. [3] Nelson, R., et al.: Icarus 199, 429-441, 2009. [4] Lopes, R.M.C., et al.: JGR, in press. [5] Moore, J.M., and Howard, A.D.: GRL 37, L22205, 2010.

On the existence of characteristic microscale magnetohydrodynamic fluctuations inside a corotating interaction region at 2.5 AU

Astronomy and Astrophysics, 1996

A detailed analysis of small period (15-900s) Magnetohydrodynamic (MHD) turbulence of the interpl... more

Joint observations of solar radio bursts and cosmic ray events recorded by the ARTEMIS IV radio spectrograph and Athens Cosmic Ray Station (Super 6NM-64) of the University of Athens

Fine Structure in Type IV Solar Radio Bursts

Coronal Disturbances, 1974

Solar Phys.). The fine structure in solar type IV radio bursts was studied using the 169 MHz Nang... more Solar Phys.). The fine structure in solar type IV radio bursts was studied using the 169 MHz Nangay radioheliograph and the 60 channel radiospectrograph at Utrecht (160-320 MHz). The observed fine structure includes pulsating structure, zebra patterns (parallel drifting bands) and intermediate drift bursts. All are con sidered as modulation of high frequency radiation by low frequency oscillations or as the result of up conversion of low frequency oscillations to higher frequencies (Rosenberg, 1973). Definite proof is presented that the pulsating structure is produced by a source which is imbedded in the continuum source and which is considerably smaller than the continuum source (Caroubalos et a/., 1973). The zebra patterns can be understood as due to the coupling of electron Bernstein waves and upper hybrid waves. These waves become unstable if a hot electron cloud is trapped inside a magnetic flux tube filled with cooler coronal plasma (Chiuderi et al., 1974). A source size of 1000 km and an energy density in the plasma waves and Bern stein waves equal to 10" 3 of the thermal coronal energy density is compatible with the observations. It is concluded that stationary type IV radiation is not synchrotron radiation but magnetoplasma radiation strongly dependent upon the magnetic field (Chiuderi et al. 9 1973). References

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Energetic particle acceleration and propagation in the heliosphere

Results from computer experiments based on high resolution interplanetary magnetic field and plas... more Results from computer experiments based on high resolution interplanetary magnetic field and plasma data from spacecrafts Pioneer 10 and 11 are presented. Energetic particle acceleration and propagation play an important role in high energy astrophysics and especially to the origin of cosmic rays. Spacecraft measurements of cosmic rays and of the solar wind (plasma velocity and magnetic field) give a

Heliosphere revisited: POST ULYSSES 3-D turbulent Picture

Diffusive shock acceleration and the March 1991 solar events

Geophysical Research Letters, 1992

Spectral and anisotropy measurements are reported for protons between 0.5 and 1.4 MeV during the ... more Spectral and anisotropy measurements are reported for protons between 0.5 and 1.4 MeV during the particle increases associated with the passage of 3 interplanetary shocks past Ulysses between March 19 and March 31 1991. The data are interpreted in terms of diffusive shock acceleration in the travel!ing solar induced disturbances to the solar plasma. geles, CA 90009, U.

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The Breakdown of Diffusive Shock Acceleration Theory in the Relativistic Highly Oblique and Highly Turbulent Limits

Energy Balance at the Earth's Magnetosphere

The Effect of Helio-Geomagnetic Activity on the Proceedings in the Emergency Department of Two Greek Hospitals

Study of the solar and geomagnetic activity influence on the emergency proceedings in Greece, for... more Study of the solar and geomagnetic activity influence on the emergency proceedings in Greece, for selected months of solar cycle 23 and especially for the year 2005 is presented. We examined the time association between the magnetic storms (Dst geomagnetic index), daily numbers of solar flares and Coronal Mass Ejections (CMEs) with the emergency proceedings. The sample of about 30000

A study on the relationship of type III radio bursts CME and solar flares during the active period October-November 2003

Proceedings of the International Astronomical Union, 2008

Within a period of intense activity (20 October to 5 November 2003), the injection and propagatio... more Within a period of intense activity (20 October to 5 November 2003), the injection and propagation of near relativistic electrons, resulted in hundreds of type III bursts recorded by the ARTEMISIV radio spectrograph (20–650 MHz). For a number of these type III events association with GOES SXR/Hα flare and/or SOHO/LASCO CME was established. We study the variation of characteristic type III parameters and their relationship with features of the associated flares and/or CMEs.

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Exact Solution of the Three-Body Santilli-Shillady Model of the Hydrogen Molecule

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Statistics on the Occurrence of Solar Radio Bursts (Type IV and IV) and their Relation with CMEs and Flares Covering the Time Interval 1996-2001 (Rising and Maximum Phase of Solar Cycle 23)

Plato's Triangle and Gnomonic Factor: An Application to Herodotus' Oracles

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Sunspot photometry and area measurements from SOHO/MDI images during the 23rd solar cycle

On the smooth surface of the northern bow shock of Mars, based on Mars Global Surveyor's measurements

ABSTRACT

Numerical study of energetic particle parallel, perpendicular and energy diffusion and drift motion in interplanetary space

Cryovolcanic candidate regions on Titan: Promising landing sites

Cryovolcanic activity and morphotectonic features on Titan and Enceladus: Connection to terrestrial geology

Download

Potentially active regions on Titan: New processing of Cassini/VIMS data

Evolution of possibly active regions on Titan using Cassini/VIMS data analysis

On the existence of characteristic microscale magnetohydrodynamic fluctuations inside a corotating interaction region at 2.5 AU

Astronomy and Astrophysics, 1996

A detailed analysis of small period (15-900s) Magnetohydrodynamic (MHD) turbulence of the interpl... more

Joint observations of solar radio bursts and cosmic ray events recorded by the ARTEMIS IV radio spectrograph and Athens Cosmic Ray Station (Super 6NM-64) of the University of Athens

Fine Structure in Type IV Solar Radio Bursts

Coronal Disturbances, 1974

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Energetic particle acceleration and propagation in the heliosphere

Heliosphere revisited: POST ULYSSES 3-D turbulent Picture

Diffusive shock acceleration and the March 1991 solar events

Geophysical Research Letters, 1992

Download

The Breakdown of Diffusive Shock Acceleration Theory in the Relativistic Highly Oblique and Highly Turbulent Limits

Energy Balance at the Earth's Magnetosphere

The Effect of Helio-Geomagnetic Activity on the Proceedings in the Emergency Department of Two Greek Hospitals

A study on the relationship of type III radio bursts CME and solar flares during the active period October-November 2003

Proceedings of the International Astronomical Union, 2008

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Ο Μηχανισμός των Αντικυθήρων: από τα Κυκλαδικά τηγανόσχημα στο αρχαιότερο τάμπλετ Ναξιακά Χρονικά, 2017. O MHXANSIMOS ANTIKYTHERON NAXIAKA XRONIKA 2017 2

Ο Μηχανισμός των Αντικυθήρων, είναι ο πρόγονος όλου του τεχνολογικού πολιτισμού, τα μπιτ και τα ... more Ο Μηχανισμός των Αντικυθήρων, είναι ο πρόγονος όλου του τεχνολογικού πολιτισμού, τα μπιτ και τα μπάιτ των ηλεκτρονικών υπολογιστών έχουν ρίζες στα γρανάζια και τα δοντάκια του μηχανισμού. Ο μηχανισμός είναι αστρονομικό ρολόι. Προβλέπει όλα τα αστρονομικά φαινόμενα που ήταν γνωστά τότε. Τις θέσεις ηλίου και Σελήνης, τις φάσεις της σελήνης, την αρχή του σεληνιακού μήνα, του έτους κ.λπ.
Ο μηχανισμός των Αντικυθήρων είναι ένα πανάρχαιο πολύπλοκο μηχάνημα με γρανάζια βρέθηκε σε ένα τεράστιο ναυάγιο γεμάτο με Ελληνικούς θησαυρούς, ένα πραγματικό μουσείο, που βυθίστηκε πιθανότατα ανάμεσα στα 80 με 60 π.Χ. στο βόρειο άκρο των Αντικυθήρων με πολύτιμα αντικείμενα διαφόρων εποχών που με χιλιάδες παρόμοια φορτία οι Ρωμαίοι κατάκλεψαν την Ελλάδα. Από τότε ο Συμιακός δύτης ανέσυρε στην επιφάνεια τον Μηχανισμό έχει γίνει βαθμιαία αντιληπτό ότι είναι ο αρχαιότερος γνωστός υπολογιστής και μηχανικός σύμπαν και πιθανότατα ένα αστρονομικό ρολόι που λειτουργεί με γρανάζια και το οποίο για αιώνες ονομαζόταν πινακίδιον (μικρό πίνακα, δηλαδή tablet). Ο μηχανισμός προβλέπει όλα τα τότε γνωστά φυσικά φαινόμενα που βλέπουμε στον ουρανό, την θέση του Ήλιου και της Σελήνης, της οποίας δείχνει και την φάση, όπως και τις εκλείψεις και πιθανότατα και τις θέσεις των πλανητών.
Ο μηχανισμός είναι η επιτομή της Ελληνικής φιλοσοφίας και ειδικότερα στις αντιλήψεις των Πυθαγορείων. Θα επιχειρήσουμε να κατανοήσουμε πώς ο άνθρωπος συνέλαβε και κατασκεύασε ένα αυτόματο πολύπλοκο μηχάνημα που προβλέπει φυσικά φαινόμενα. Η ανθρωπότητα στο προϊστορικό Αιγαίο κάνει ίσως τα πρώτα σταθερά βήματα προς τον πολιτισμό, όπως τον αντιλαμβανόμαστε σήμερα με την ανάπτυξη των επιστημών και της τεχνολογίας, όπως φαίνεται στις αναγνώσεις που κάνουμε των αγγείων που ονομάζονται τηγανόσχημα και βρίσκονται κυρίως στις Κυκλάδες.
Ο άνθρωπος είναι το μόνο έμβιο ον που άλλαξε ριζικά την ζωή του αλλάζοντας τις συνθήκες στο περιβάλλον, αλλά και αυτό το ίδιο ώστε να ζει καλύτερα στον πλανήτη μας, με την γέννηση τις τεχνολογίας, των επιστημών και με κορωνίδα την φιλοσοφία, ξεκινώντας με την αστρονομία.

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"Ex Ionia Scientia - 'Knowledge' in Archaic Greece", International Conference, Athens, Dec 11-14, 2016 ## the booklet with program, all abstracts, and list of participants ##

by Alexander Herda, Robert Hahn, Sotiris Fournaros, G. Iliou, Rostyslav Oreshko, Ute Wartenberg, George N Vlahakis, and Xenophon Moussas

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Xenophon Moussas

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