frontiers

Yukon Territory aurora / © Paul Nicklen

Everyday work at the frontiers of modern physics usually involves complex concepts and extreme conditions. We speak of quantum fields, entanglement, or supersymmetry, and analyse the ridiculously small or conceptualize the incomprehensibly large. Just as Willie Sutton famously explained that he robbed banks because "that's where the money is", so we do these things because "that's where the Unknown is".

from Fantastic Realities, Frank Wilczek (Nobel Prize in Physics, 2004)

Analysis and synthesis - creativity and limitations

... analysis has brought us to foundational models that come close to achieving perfection. The history of physics emphasizes that synthesis is a challenging and deeply creative activity in its own right. It is more open-ended, however, and less easy to summarise, so I'll only be able to mention a few illustrative high points. We shall also see that, in the course of its triumphal advance, ironically the method of analysis and synthesis has itself discovered profound, sharply defined limits to its explanatory power. 

Frank Anthony Wilczek [American theoretical physicist, Nobel Prize in Physics 2004] 
in Analysis and Synthesis: What Matters for Matter

Contingency

Hieronymus Bosch - The Garden of Earthly Delights

The progress of scientific Analysis has revealed several perfectly objective profound effects that limit the power of scientific Analysis. I identify three such phenomena: projection (i.e., the fact that we don’t get to see everything), the probabilistic logic of quantum mechanics, and chaos (i.e., extreme sensitivity to initial conditions). These effects will make it impossible, in practice, to go from the solution (if we had it) of the basic equations (if we had them) to a complete description of the experience. The technical word for this is contingency – you can’t analyze everything, some things are just accidents … Thus reason discovers its own limitations. 

Frank Anthony Wilczek [American theoretical physicist, Nobel Prize in Physics 2004]

Stars die

NGC 6210 - the last gasp of a star slightly less massive than our Sun at the final stage of its life cycle

Hubble Space Telescope

Tree cracked and mountain cried

Bridges broke and window sighed

Cells grew up and rivers burst

Sound obscured and sense reversed

Stars die

Blinding skies

Steve Wilson [Stars die, 1995]

Porcupine Tree - Stars die

in the beginning was the plasma

Aurora / © Tom Eklund

... And if the night sky on which we observe the planets is at a high latitude, outside this lecture hall - perhaps over a small island in the archipelago of Stockholm - we may also see in the sky an aurora, which is a cosmic plasma, reminding us of the time when our world was born out of plasma. Because in the beginning was the plasma.

Hannes Alfvén (30 May 1908 - 2 April 1995), Nobel Prize in Physics 1970

from his Nobel Lecture "Plasma Physics, Space Research and the Origin of the Solar System"

Lightbulb Sun

The solar radiation energy absorbed in some form by the Earth's atmosphere, oceans, continents and living organisms in or on them has an average value of 250 watts per square meter. 250 watts correspond to the power of four humble standard lightbulbs. 

Despite its rather modest magnitude this energy, combined with the equally modest greenhouse effect of the terrestrial atmosphere, keeps the average temperature of our planet at 15 degrees centigrade, making life - as we know it - possible on Earth.

Astronomy Domine

Saturn by Cassini / © Cassini Imaging Team, SSI, JPL, ESA, NASA

Lime and limpid green, a second scene
A fight between the blue you once knew.
Floating down, the sound surrounds
Around the icy waters underground.
Jupiter and Saturn, Oberon, Miranda and Titania.
Neptune, Titan, Stars can frighten.

Syd Barett - Astronomy Domine (1967)

Pink Floyd - Astronomy Domine

Paradox

© Babis Pylarinos

How wonderful that we have met this paradox. Now we have some hope of making progress.

Niels Henrik David Bohr [Danish physicist, Nobel prize 1922, commenting to observers when an experiment took an unexpected turn]

Stars die

The Cat's Eye Nebula: Dying Star Creates Fantasy-like Sculpture of Gas and Dust

© NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA)

The moon shook and curled up like gentle fire
The ocean glazed and melted wire
Voices buzzed in spiral eyes
Stars dived in blinding skies

Stars die. Blinding skies.

Tree cracked and mountain cried
Bridges broke, window sighed
Cells grew up and rivers burst
Sound obscured and sense reversed

Idle mind and severed soul
Silent nerves and begging bowl
Shallow haze to blast a way
Hyper sleep to end the day

Steven Wilson - Stars die (1995)

Porcupine Tree - Stars die

Living With a Star - a vast range of scales

Life on Earth would be extremely difficult, if not impossible, if our planet were not positioned very precisely in the habitable zone in our solar system, colloquially known as the “Goldilocks zone”. However, even positioned at this optimum distance from the Sun, the behaviour of our star has profound consequences for our lives. ‘Living with a Star’ is a challenge for a civilisation that has deployed technologies such as satellites and power grid systems that are vulnerable to particle energy emitted by our Sun. In recent decades, solar-terrestrial physics, the study of the interaction of the Sun with Earth, has been addressing the need to provide Space Weather forecasting to protect such technologies. This endeavour occupies a vast range of scales. The solar system is the largest complex system that mankind can study with in-situ observation. It involves dimensions ranging from the astronomical unit (1 AU = 150,000,000 km, the distance from the Earth to the Sun) to the radius of charged particle motions spiralling around magnetic fields which can be only a few centimetres. On the temporal scale, activity on the Sun varies on the “sunspot cycle” of 11 and 22 years whilst phenomena such as explosive energy events on the Sun and in near-Earth space require study on time scales of seconds.

The complete text is available here:

Living with a star

Ioannis A. Daglis, Christoph Jacobi and Mike Pinnock

in "A Voyage Through Scales - The Earth System in Space and Time", European Geosciences Union, pp. 26-31, 2015 (click here for the full article)

Ο ύπνος του Ήλιου

Ύπνος (αριστερά) και μαγνητικό ξύπνημα (δεξιά) του Ήλιου / © NASA/SDO

Ο ύπνος του μυρίζει πυρκαγιά ...

Είναι βολική σύμπτωση ότι ο στίχος εμφανίζεται στον Ήλιο τον Πρώτο του Οδυσσέα Ελύτη - αλλά σε άλλους ύπνους αναφέρεται, όχι στον μαγνητικό ύπνο του Ήλιου που χαρακτηρίζει το ελάχιστο του ενδεκαετούς κύκλου της περιοδικής έξαρσης και μείωσης της μαγνητικής δραστηριότητας του εγγύτατου στη Γη άστρου. 

NETSPACE

18-19 February 2014, The NETSPACE Workshop in Athens

NETworking technologies for efficient 
SPACE data dissemination and exploitation

The full proceedings are available here: ResearchGate.

MAARBLE

MAARBLE logo by George Karachristos

Brussels, 30 January 2015.
Successful Final Review of the MAARBLE project.

The end of a MAARBLE-ous project with outstanding achievements in the field of radiation belt research thanks to the efforts and devotion of an excellent Team:

Sebastien Bourdarie, Didier Lazaro, Vincent Maget, Angelica Sicard-Piet (ONERA, Toulouse)
Yuri Khotyaintsev, Meghan Mella, Ulrich Taubenschuss (IRF, Uppsala)
Ondrej Santolik, Benjamin Grison, Zuzana Hrbackova, Ivana Kolmasova, Eva Macusova, Jan Soucek (IAP, Prague)
Richard Horne, Sarah Glauert, Tobias Kersten, Nigel Meredith (BAS, Cambridge)
Ian Mann, Louis Ozeke, Maria Usanova (UAlberta, Edmonton)
Drew Turner, Vassilis Angelopoulos, Christine Gabrielse (UCLA, Los Angeles)
Anastasios Anastasiadis, George Balasis, Eleni Chatzichristou, Marina Georgiou, Sigiava Giamini, Omiros Giannakis, Christos Katsavrias, Ioannis Panagopoulos, Costas Papadimitriou, George Ropokis, Ingmar Sandberg (NOA, Athens)

We express our gratitude to our External Advisory Committee members
Iannis Dandouras, David Sibeck and Eftyhia Zesta,
for their valuable feedback and their encouragement!

An executive summary of MAARBLE will be posted soon.

Video visualization of storm-time dynamics of the radiation belts 

by Sebastien Bourdarie (ONERA)

Physics and equations

Paul Dirac: Professor of Mathematics at the University of Cambridge 

and discoverer of antimatter

What it means really to understand an equation — that is, in more than a strictly mathematical sense — was described by Dirac. He said: “I understand what an equation means if I have a way of figuring out the characteristics of its solution without actually solving it”. So if we have a way of knowing what should happen in given circumstances without actually solving the equations, then we “understand” the equations, as applied to these circumstances. A physical understanding is a completely unmathematical, imprecise, and inexact thing, but absolutely necessary for a physicist.

Richard Feynman [1918-1988, 1965 Nobel Prize in Physics]

Μαγνητόσφαιρα

Ήλιος και μαγνητόσφαιρα της Γης

Ανακάλυψη είναι όταν βλέποντας αυτό που έχουν δει οι πάντες, να σκέφτεσαι κάτι που δεν έχει σκεφτεί κανείς.
Thomas Gold

Πριν από 55 χρόνια ένας προικισμένος φυσικός του αιώνα μας βάφτισε το μαγνητικό κουκούλι που προστατεύει τη Γη μας από τον απειλητικό άνεμο καυτής ιονισμένης μάζας που εκπέμπει αδιάκοπα ο Ήλιος. Ήταν ο Τόμας Γκολντ (Thomas Gold) που το 1959 έγραφε σε ένα άρθρο του στο έγκριτο επιστημονικό περιοδικό Journal of Geophysical Research: «Γνωρίζουμε ότι η περιοχή πάνω από την ιονόσφαιρα, όπου το μαγνητικό πεδίο της Γης ελέγχει την κίνηση των αερίων και των φορτισμένων σωματιδίων, εκτείνεται σε αποστάσεις της τάξης των 10 ακτίνων Γης. Η κατάλληλη ονομασία αυτής της περιοχής είναι μαγνητόσφαιρα.» 

Η μαγνητόσφαιρα της Γης είναι μια περιοχή του διαστημικού περιβάλλοντος του πλανήτη μας στην οποία κυριαρχεί, όπως σωστά ανέφερε στον ορισμό του ο Γκολντ, το μαγνητικό πεδίο της Γης. Το σχήμα της μαγνητόσφαιρας, που είναι περισσότερο ελλειψοειδές παρά σφαιρικό, καθορίζεται από το γεωμαγνητικό πεδίο, το πλάσμα (δηλαδή την πλήρως ιονισμένη ύλη) του ηλιακού ανέμου και το διαπλανητικό μαγνητικό πεδίο, δηλαδή το μαγνητικό πεδίο του Ήλιου που εκτείνεται σε ολόκληρο το ηλιακό σύστημα, με ένταση που πέφτει όσο απομακρυνόμαστε από τον Ήλιο.

Το πλήρες άρθρο βρίσκεται εδώ: Ο νονός της μαγνητόσφαιρας

Μικρά Πράσινα Ανθρωπάκια (ΜΠΑ)

Από το βιβλίο "Άρτεμις Φευγάτη" / © Γιάννης Δαγκλής & Γιώργος Καραχρήστος 

Αφιερωμένο στην Τζόσελιν Μπελ που ΔΕΝ πήρε το Νόμπελ Φυσικής

Axford

Στη μνήμη του Δασκάλου μου
In memory of my PhD Supervisor


One of the giants of space physics and 20th century astrophysics, Sir
 William Ian Axford, died on Saturday, March 13, 2010 at his Napier home 
in New Zealand after a long illness. Born in Dannevirke, N.Z., on 
January 2, 1933, he was 77 years old and widely regarded as one of New 
Zealand's greatest scientists. Despite his enduring passion for the 
New Zealand cricket and rugby teams, he lived most of his adult life 
outside New Zealand, starting in 1957 when he began his graduate 
studies in the Mathematics Department of Manchester University in the 
U.K. This occurred just prior to the launch of Sputnik I, an event that 
eventually greatly influenced his career. His thesis supervisor was the 
renowned aerodynamicist Sir James Lighthill, but Ian also learned a 
great deal from astrophysicists such as Franz Kahn and Allin 
Goldsworthy who were also at Manchester. Ian spent time at Cambridge's 
Department of Applied Mathematics and Theoretical Physics, encountering 
numerous interesting people who later distinguished themselves in 
plasma physics and astrophysics. Among them was Fred Hoyle whose ideas 
about cosmic rays very much later motivated one of Ian's most 
outstanding discoveries - the mechanism of diffusive shock acceleration 
- and with it the almost universally accepted explanation for the 
observed cosmic ray spectrum (at least up to about 10^14 eV/nucleon), 
solar energetic particle events, anomalous cosmic rays, and so forth. 
Ian's time in the U.K. cemented his style of scientific presentation, 
which, for some of us, occasionally presented a challenge - an 
interesting marriage of acute physical insight, an uncanny ability for 
order of magnitude estimates, and a desire that everything appear as 
effortless as possible! This conciseness of exposition made his 
publications both very readable on the surface, but very frustrating 
for students and others needing to work out the details.

From Cambridge, Axford joined the Defense Research Telecommunications 
Establishment (DRTE) In Ottawa, Canada where with Colin Hines, he did 
some of his most renowned work in developing our understanding of the 
Earth's magnetosphere and ionosphere (although Ian heartily disliked 
the distinction between the two preferring Gold's definition that 
incorporated both). Illustrating Ian's insight, one of his most 
renowned papers (with Colin Hines addressing magnetospheric convection) 
contains only one equation, E+VxB=0, despite being a theory paper! It 
was during this period too in Canada that Ian began to develop his 
lifelong appreciation for the science done in the then Soviet Union, 
often providing an important if informal role in communicating 
important observations and theoretical ideas to the west. This did not 
always endear Ian to some but he could be quite cutting in return. 
After a year spent in New Zealand, Ian moved to Cornell University in 
1963. The `60's and the Apollo era was a time of considerable 
excitement for space physics - the golden age - with an abundance of 
funding, exciting open problems wherever one turned, and a community 
that was young and vigorous. Ian was at the forefront of many of the 
new ideas being developed, including ideas about cosmic ray transport, 
the effects of modulation (ranging from the cosmic ray transport 
equation, particle diffusion, the telegrapher equation, amongst others), 
solar flares, substorms, collisionless shocks, the always contentious 
issue of reconnection, and even the coronal heating problem. Indeed, 
the idea that the Earth possessed a bow shock was for a time extremely 
controversial given the absence of particle collisions but Ian was, 
with others, instrumental in developing and pushing forward the 
collisionless shock concept. While at Cornell and then later at the 
University of California, San Diego, Ian supervised a number of 
students through their PhD degrees, including Len Fisk and Tom Holzer 
(later to be NASA Associate Administrator and Director of the High 
Altitude Observatory in Boulder respectively).

Not surprisingly, Sir Ian became editor of the Journal of Geophysical 
Research in 1969, introducing a number of innovations that persist to 
this day, including the use of at least two referees and their 
identification. Under his leadership, the JGR was propelled to its 
current preeminence. During this period, Ian was prominent in helping 
lay the groundwork for future space missions, many of which came to 
fruition a decade or more later. This included what later came to be 
the Voyager missions, originally conceived of as the Mariner-Jupiter-
Saturn missions. It was at this time too that the first out-of-ecliptic 
mission was conceived as part of a coordinated plan to explore the 
outer solar system. This became of course the equally successful 
Ulysses mission.
With the new missions, Ian's interests gravitated a little towards the 
magnetospheres of the outer planets, especially their interactions with 
the active moons. The Voyager missions were rightly regarded by Ian as 
one the greatest scientific-cultural achievements of the 20th century 
and he was a strong advocate and supporter of the program. The breadth 
of Ian's scientific interests is reflected in virtually every aspect of 
the Voyager mission, from the various planetary magnetospheres, their 
moons and interactions, particle acceleration, all the way to the 
nature of the solar wind interaction with the interstellar medium. His 
1972 review of the solar wind - LISM interaction was the standard in 
the field for decades and the prescience of his views on the importance 
of interstellar neutral hydrogen in shaping the physics and structure 
of the large-scale heliosphere only came to be fully appreciated in the 
mid-1990's.

Ian's stay at UCSD ended in 1974 when he was appointed, at the age of 
41, to the position of Director of the Max-Planck-Institute of Aeronomy 
(MPAe) in Kattlenburg-Lindau, Germany. There is little doubt that Ian 
had a transformational effect on the MPAe, drawing an international 
cast of visiting scientists and propelling the institute into multiple 
spacecraft missions. For many, the MPAe became for a time very much 
one of the world-leading centers for space physics and planetary 
physics, and many of us came of age scientifically in Katlenburg-Lindau, 
spending time working with or drawing inspiration from Ian. We well 
recall the afternoon tea times spent on a somewhat overused and shabby 
couch in front of a blackboard in the refectory, trying to formulate 
mathematically some problem or other. This was a wonderful time and 
wonderful way of doing science, which sadly appears to be disappearing 
from our scientific culture.
The spacecraft missions that Ian was especially involved with during 
his time at the MPAe included Ulysses, the cometary mission Giotto, and 
SOHO. These missions were outstandingly successful scientifically, but 
their genesis and shepherding to successful launches demanded skills at 
an international political level that were very demanding. Ian's 
stature and his dual US-European perspective proved invaluable in 
ensuring that these missions became the success that they were. One of 
the great legacies from these missions, especially Giotto, was the 
drawing of smaller countries without a strong space physics tradition, 
such as Ireland, into major spacecraft missions. This had a 
tremendously stimulating effect across Europe. These administrative and 
political activities of course drew heavily on his time, but he still 
found time to pursue some of his scientific interests. Among his most 
important contributions in his later career was, as mentioned above, 
his elucidation of the diffusive shock acceleration mechanism that is 
now thought to operate at collisionless shock waves. This work in many 
ways epitomizes Ian - in discovering the idea of diffusive shock 
acceleration, Ian drew from his extraordinary knowledge of cosmic ray 
transport, and his deep understanding of shock waves and MHD. It is 
probably no exaggeration to suggest that perhaps nearly 80% of 
published papers in space- and astrophysics discussing particle 
energization rely on the diffusive shock acceleration mechanism, 
illustrating the remarkable fruitfulness of Ian's many ideas. Ian also 
contributed in 1999 to a mechanism, now highly favored, of explaining 
non-thermal X-rays from clusters of galaxies. Sir Ian retired from the 
MPAe as Director in 2001. During his time as Director of MPAe, Ian also 
served as Vice-Chancellor at Victoria University in Wellington from 
1982. Here he led the creation of the research school of earth sciences 
and encouraged the development of the Institute of Policy Studies and 
the Stout Research Centre. Ian continued to be active for some years 
after retirement, accepting the Pei-Ling Chan Chair of Physics at the 
University of Alabama in Huntsville (2002-04), as well as spending a 
number of months each year at the University of California, Riverside 
and the MPAe. In addition to science, Ian took a considerable interest 
in history, co-authoring an interesting book ("In Soso's Web") with Tamara 
Breus about life in the USSR.

Given Ian's extraordinary career track, he was the recipient of 
numerous honors and prizes. At the remarkably young age of 39 (1972), 
he was awarded the John Adams Fleming medal by the AGU. Other notable 
international awards include the Space Science Award by the American 
Institute of Aeronautics and Astronautics (1970), the Tsiolkovsky Medal 
by the Kosmonautical Federation of the USSR (1987) the Chapman Medal by 
the Royal Astronomical Society (1994), and the New Zealand Science and 
Technology Gold Medal (1994). Ian was greatly honored in New Zealand, 
receiving awards and honors not typical of an ordinary scientist. Ian 
was awarded New Zealand's top science honor, the Rutherford Medal, in 
1995, "for his excellent contribution to fundamental research which has 
led to a deeper understanding of the nature of planetary magnetospheres, 
comets, interplanetary space, the behaviour of interstellar gas and the 
origin of cosmic rays." At the end of 1995, he was made a Knight 
Bachelor - one of the last under the imperial system before the 
introduction of New Zealand honors - one year after being named New 
Zealander of the Year ... Ian also led a number of international 
organizations, serving as president of COSPAR, the Space Research 
Committee of the International Council of Scientific Unions, and the 
European Geophysical Society, and was vice-president of the Asia-
Oceania Geophysical Society. Finally, Ian was a foreign associate of 
the National Academy of Sciences in the United States, a fellow of the 
Academia Europaea, a fellow of the Royal Society, and a fellow of the 
American Geophysical Union.

G. Zank, J.F. McKenzie, and R. Lieu [AGU SPA Section Newsletter, 16 March 2010]

 

Three papers that we co-authored with Ian: 

Daglis and Axford (1996): Fast ionospheric response to enhanced activity in geospace: Ion feeding of the inner magnetotail

Daglis, Axford, et al (1996): Auroral Ionospheric Ion Feeding of the Inner Plasma Sheet during Substorms

Wilken, Axford, Daglis, et al (1997): RAPID – The Imaging Energetic Particle Spectrometer on Cluster

Φως

Με τα μάτια μας βλέπουμε μόνο ένα απειροελάχιστο μέρος της φυσικής πραγματικότητας. Το οπτικό μας νεύρο είναι ευαίσθητο μόνο σε μια πολύ στενή περιοχή του ηλεκτρομαγνητικού φάσματος - το "ορατό". Χάρη στις τεχνολογίες που αναπτύχθηκαν τους δύο τελευταίους αιώνες, ο άνθρωπος μπόρεσε να "δει" ή να χρησιμοποιήσει με διάφορους τρόπους σχεδόν όλο το εύρος της ηλεκτρομαγνητικής ακτινοβολίας. Έτσι έχουμε γίνει μέτοχοι της εκτυφλωτικής ομορφιάς του σύμπαντος.

Ο γαλαξίας NGC 1512 όπως τον βλέπουμε με τα μάτια μας ...

... και όπως τον βλέπουμε με τα "μάτια" του διαστημικού τηλεσκοπίου Χαμπλ (σε διάφορες περιοχές του ηλεκτρομαγνητικού φάσματος, από το υπέρυθρο ως το υπεριώδες, και σε μια συνθετική εικόνα)

Από την εκδήλωση "Τα Τραγούδια της Γης: Ήχοι από το Εγγύς Διάστημα" στο Μουσείο Ιστορίας του Πανεπιστημίου Αθηνών τον Φεβρουάριο 2013

AC/DC

70 years from his death

Nikola Tesla (Serbian: Никола Тесла; born 10 July 1856, died 7 January 1943) was an inventor, mechanical engineer, and electrical engineer. He was an important contributor to the birth of commercial electricity, and is best known for his many revolutionary developments in the field of electromagnetism in the late 19th and early 20th centuries. Tesla's patents and theoretical work formed the basis of modern alternating current (AC) electric power systems, including the polyphase system of electrical distribution and the AC motor. This work helped usher in the Second Industrial Revolution.
Born an ethnic Serb in the village of Smiljan (now part of Gospić), in the Croatian Military Frontier of the Austrian Empire (modern-day Croatia), Tesla was a subject of the Austrian Empire by birth and later became an American citizen. Because of his 1894 demonstration of wireless communication through radio and as the eventual victor in the "War of Currents", he was widely respected as one of the greatest electrical engineers who worked in America. He pioneered modern electrical engineering and many of his discoveries were of groundbreaking importance. In the United States during this time, Tesla's fame rivaled that of any other inventor or scientist in history or popular culture. Tesla demonstrated wireless energy transfer to power electronic devices as early as 1893, and aspired to intercontinental wireless transmission of industrial power in his unfinished Wardenclyffe Tower project.

Interplanetary magnetic field and Dst index (intensity profile proxy of a geospace magnetic storm), 

both measured in nanoTeslas 

(from a paper by Daglis et al., Planetary and Space Science, 2007)

The SI unit measuring magnetic field B (also referred to as the magnetic flux density and magnetic induction), the tesla (T), was named in his honor (at the CGPM, Paris, 1960).

Nikola Tesla on the 100 Serbian dinar banknote, 2006 issue, front

Horizon 2020 Space

Round table on the Horizon 2020 space programme at the 2nd FP7 Space Conference in Larnaca, Cyprus.

 

My expectations from the Horizon 2020 space programme overall:
- Continue support for coordinated space-data exploitation, which did not exist at European level before FP7 and before the establishment of the European Space Policy in 2007.
- Continue support for international collaboration.
- Raise space awareness among citizens.

My suggestions for the support of specific space related topics:
- Development of critical technologies for space exploration and for European non-dependence in space.
- Comprehensive understanding of the consequences of solar variability on planetary magnetospheres / ionospheres / atmospheres and in particular on Geospace and specific space weather products corresponding to needs of our space infrastructure and related services.
- Search for habitable planets outside our solar system.
- Development of hyperspectral imaging technology.