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Benvenuti in queste pagine dedicate a scienza, storia ed arte. Amelia Carolina Sparavigna, Torino

Friday, April 29, 2011

Four sons of Horus


Statuette dei quattro figli di Horus: Duamutef, a testa di sciacallo, Hapi, a testa di babbuino, Qebehsebuf, a testa di falco, Amset, a testa umana erano i protettori delle viscere del defunto, XXV-XXXI dinastia. Statuettes of the four sons of Horus:  Duamutef, jackal headed, Hapi, baboon headed,  Qebehsebuf, falcon headed, and human headed Amset, protectors of the deceased's viscera,  Dinasty XXV-XXXI
(712-332 BC)

Alcohol haze at galactic heart

BBC NEWS, Tuesday, 9 October, 2001, 14:34 GMT 15:34 UK
Alcohol haze at galactic heart
Online science editor Dr David Whitehouse
"The detection of yet more alcohol in a giant molecular cloud near the centre of our galaxy could give clues to the origin of complex organic molecules in space.Astronomers have long been seeking evidence of this particular alcohol to help explain how these life-promoting substances got started. ... Vinyl alcohol, actually a non-inebriating complex organic molecule, is an important part of many chemical reactions on Earth, and the last of the three stable members of the C2H4O group of molecules to be discovered in interstellar space. It was detected in a massive molecular cloud called Sagittarius B2, located 26,000 light-years from Earth, near the centre of our galaxy....The specific radio signature of vinyl alcohol was first detected using a 12-metre radio telescope during May and June of 2001. Results from the observations will soon be published in Astrophysical Journal Letters. Of the approximately 125 molecules so far detected in interstellar space, scientists believe that most are formed by a simple process in which smaller molecules (and occasionally atoms) stick together after they collide. Since the 1970s, scientists have speculated that molecules could form on the microscopic dust grains that drift in interstellar clouds. These dust grains are thought to trap the fast-moving molecules. The surface of these grains could act as a catalyst enabling the chemical reactions that form vinyl alcohol and other complex molecules. "Scientists speculate that since the dust lies near an area where young stars are forming, the energy from these stars could evaporate the icy surface layers of the grains, liberating the molecules from their chilly nurseries, depositing them into interstellar space where they can be detected by sensitive radio antennae on Earth.

Dark matter and galactic haze

"Annihilating dark matter at the heart of the Milky Way could account for signals detected by two space telescopes, according to a pair of US physicists. If true, the theory provides a new indirect measurement of one of astronomy's most elusive entities. However, some physicists believe that we don't know enough about the galactic core – or dark matter – to come to this conclusion."
Does dark matter link gamma rays to galactic haze? - physicsworld.com

Transparent materials for solar energy


"Researchers in the US have developed a new kind of organic solar cell that converts a small but significant fraction of the sunlight that falls onto it into electricity, while still allowing most of the visible part of that light to pass through. Thanks to this transparency, the team says that the cell could be mounted onto windows in buildings or cars in order to tap a currently under-exploited source of energy."
Transparent material opens a new window on solar energy - physicsworld.com

Spherical symmetry

Everything is the same in all directions (as if on the surface of a sphere).


Da un libro sulle simmetrie

Noether's (first) theorem

"Noether's (first) theorem states that any differentiable symmetry of the action of a physical system has a corresponding conservation law. The theorem was proved by German mathematician Emmy Noether in 1915 and published in 1918.[1] The action of a physical system is the integral over time of a Lagrangian function (which may or may not be an integral over space of a Lagrangian density function), from which the system's behavior can be determined by the principle of least action.
Noether's theorem has become a fundamental tool of modern theoretical physics and the calculus of variations. A generalization of the seminal formulations on constants of motion in Lagrangian and Hamiltonian mechanics (1788 and 1833, respectively), it does not apply to systems that cannot be modeled with a Lagrangian; for example,dissipative systems with continuous symmetries need not have a corresponding conservation law." Wikipedia, l'enciclopedia libera.

Emmy Noether

Professor Einstein Writes in Appreciation of a Fellow-Mathematician.

To the Editor of The New York Times:
The efforts of most human-beings are consumed in the struggle for their daily bread, but most of those who are, either through fortune or some special gift, relieved of this struggle are largely absorbed in further improving their worldly lot. Beneath the effort directed toward the accumulation of worldly goods lies all too frequently the illusion that this is the most substantial and desirable end to be achieved; but there is, fortunately, a minority composed of those who recognize early in their lives that the most beautiful and satisfying experiences open to humankind are not derived from the outside, but are bound up with the development of the individual's own feeling, thinking and acting. The genuine artists, investigators and thinkers have always been persons of this kind. However inconspicuously the life of these individuals runs its course, none the less the fruits of their endeavors are the most valuable contributions which one generation can make to its successors.
Within the past few days a distinguished mathematician, Professor Emmy Noether, formerly connected with the University of Göttingen and for the past two years at Bryn Mawr College, died in her fifty-third year. In the judgment of the most competent living mathematicians, Fräulein Noether was the most significant creative mathematical genius thus far produced since the higher education of women began. In the realm of algebra, in which the most gifted mathematicians have been busy for centuries, she discovered methods which have proved of enormous importance in the development of the present-day younger generation of mathematicians. Pure mathematics is, in its way, the poetry of logical ideas. One seeks the most general ideas of operation which will bring together in simple, logical and unified form the largest possible circle of formal relationships. In this effort toward logical beauty spiritual formulas are discovered necessary for the deeper penetration into the laws of nature.
Born in a Jewish family distinguished for the love of learning, Emmy Noether, who, in spite of the efforts of the great Göttingen mathematician, Hilbert, never reached the academic standing due her in her own country, none the less surrounded herself with a group of students and investigators at Göttingen, who have already become distinguished as teachers and investigators. Her unselfish, significant work over a period of many years was rewarded by the new rulers of Germany with a dismissal, which cost her the means of maintaining her simple life and the opportunity to carry on her mathematical studies. Farsighted friends of science in this country were fortunately able to make such arrangements at Bryn Mawr College and at Princeton that she found in America up to the day of her death not only colleagues who esteemed her friendship but grateful pupils whose enthusiasm made her last years the happiest and perhaps the most fruitful of her entire career.

Albert  Einstein.
Princeton University, May 1, 1935.
[The New York Times May 5, 1935]

Thursday, April 28, 2011

Hokusai manga - fox



Hokusai manga
Museo Arte Orientale, Torino




Four actors



A group of four actors
Tang Dinasty, first half of the 8th century AD
Museo Arte Orientale, Torino

Padmapani


Padmapani
Gandhara, II-III secolo d.C.

Il Bodhisattva Padmapani siede su un alto trono con il piede sinistro posato a terra e la gamba destra piegata a appoggiata sul ginocchio opposto. L’alto seggio su cui Padmapani è seduto ha una spessa base su cui si appoggiano i sandali (infradito!). Il Bodhisattva indossa paridhana e uttariya. Porta un turbante a fascia, grandi orecchini a testa di leone, collane e un cordone con piccoli involucri porta-preghiere, portato di traverso dalla spalla sinistra al fianco destro. Padmapani tiene nella mano sinistra un grosso bocciolo di fiore di loto, mentre l’altra, mancante, era rivolta verso la testa.

Museo Arte Orientale, Torino