pic via @astroperinaldo
By Gianluigi Filippelli on Wednesday, July 22, 2015
about @LHCbExperiment #pentaquark discovery
Once upon a time, there was a controversy in particle physics. There were some physicists who denied the existence of structures more elementary than hadrons, and searched for a self-consistent interpretation wherein all hadron states, stable or resonant, were equally elementary. Others, appalled by the teeming democracy of hadrons, insisted on the existence of a small number of fundamental constituents and a simple underlying force law. In terms of these more fundamental things, hadron spectroscopy should be qualitatively described and essentially understood just as are atomic and nuclear physics.(11)
The need of the partonsWhen we descrive the collisions between particles, we calculate the cross section, the area of the distribution of the collisions' products. The mathematical object used to calculate the cross section are the structure functions, that mathematically describes the inner structure of the particle. In 1969 studying the deep inelastic scattering J. D. Bjorken(4, 18), in order to explain the experimental results, proposed a particular property for the hadronic structure function in the cross section called scaling. In the same year Richard Feynman(5, 18) suggested the necessity to adopt a new description of hadrons: they had to be made by smaller components, more elementary than the hadrons themselves. These components are called partons.
The Feynman's thesys was immediatly verified by Bjorken and Paschos(6, 7, 18), in this way starting a great discussion about the parton models, described in the paper by De Rújula, Georgi and Glashow quoted at the beginning of the post(11) (an interesting review of the parton model and its story is in Greenberg(18)).
Probably the most strong motivation to adopt the parton model to describe hadrons is the great production of particles in the ring particles accelerators(5). So, theoretical physicists produced a lot of model, but the most succesfull is the quarks model, developed by Murray Gell-Mann(1) and Georg Zweig(2, 3), that introduced a new quantum number, the flavor. The first formulation involved three type of quarks (and so three flavors): up, down and strange. To this first set of elementary particles in 1970 the quark charm was added by Glashow, Iliopulos and Maiani(8) and finally in 1973 Kobayashi and Maskawa(9) completed the family with the two last quark, top and bottom, named by Harari(10) in 1975.
Three quarks for Muster Mark!
Sure he has not got much of a bark
And sure any he has it's all beside the mark.
from Finnegan's Wake by James Joyce
By Gianluigi Filippelli on Monday, July 20, 2015
John Philipps Emslie (1839–1913) was a British topographical artist and folklorist.He also realized a lot of scientific illustration, something like the modern infographics. For example the map of the Moon (via core77) at the beginning of the post. The caption of the map was a quotation by William Scoresby about his observation of the Moon at the Lord Rosse's telescope between 1847-48:
From 1854, Emslie studied at The Working Men's College, and was a student of Dante Gabriel Rossetti. He became a topographical artist, and illustrated The Illustrated topical record of London vol. 9. in 1900. He wrote and illustrated the New Canterbury Tales (Griffith, Farran, Okeden & Welsh) ca.1887.
Emslie was an original member of The Folklore Society and was a council member for that Society. He gathered local folklore from around England, making notes and topographical drawings.
It appeared like a Globe of Molten Silver, and every object of the extent of a hundred yards was quite visible. Edifices, therefore of the size of York Minster might be early perceived if they had existed. But there was no appearance of anything of that nature neither was there any in diction of the existence of water or of an atmosphere. There was a vast number of extinct volcanoes, several miles in the breadth through one of them there was a line in continuance of one about 160 miles in length, which ran in a straight direction on like a railway. The general appearance however was like one vast ruin of nature.
By Gianluigi Filippelli on Wednesday, July 15, 2015
The story of the Pluto's discovery started with Urban Le Verrier, a French mathematician that he was interested in celestial mechanics: performing some newtonian calculation, on on 31 August 1846, he announced the prediction of a planet beyond Uranus. This planet, Neptune, was discovered one month later by the astronomer Johann Gottfried Galle about 1° of the position predicted by Le Verrier. From further observation, astronomers supposed that there was another planet that perturbed Uranus' orbit.
about #Lovecraft, #Pluto, #Lowell and #Tombaugh
about #Lovecraft, #Pluto, #Lowell and #Tombaugh
a young boy growing with the passion of astronomy: Howard Phillips Lovecraft, in a letter to Rheinhart Kleiner on 16 November 1916, wrote:
In the summer of 1903 my mother presented me with a 2-1/2" astronomical telescope, and thenceforward my gaze was ever upward at night. The late Prof. Upton of Brown, a friend of the family, gave me the freedom of the college observatory, (Ladd Observatory) & I came & went there at will on my bicycle. Ladd Observatory tops a considerable eminence about a mile from the house. I used to walk up Doyle Avenue hill with my wheel, but when returning would have a glorious coast down it. So constant were my observations, that my neck became much affected by the strain of peering at a difficult angle. It gave me much pain, & resulted in a permanent curvature perceptible today to a close observer.(1)Thanks to this passion for cosmos, Lovecraft starting to write The Rhode Island Journal of Astronomy:
In January, 1903, astronomy began to engross me completely. I procured a small telescope, and surveyed the heavens constantly. Not one clear night passed without long observation on my part, and the practical, first-hand knowledge thus acquired has ever since been of the highest utility to me in my astronomical writing. In August 1903 (though I knew nothing of the press associations) I commenced to publish an amateur paper called The R.I. Journal of Astronomy, writing it by hand, and duplicating it on a hectograph. This I continued for four years, first as a weekly, later as a monthly.(1)he wrote in a letter to Maurice W. Moe, on 1 January 1915.
In this way he could perform a lot of observations and he also supposed the possible existence of a new planet beyond Neptune, like he wrote on a letter to the Scientific American: