By John D. Cody
AS thunderous tones deepen, their power seemingly intensifies over frail barriers such as glass windows. Certain abrupt thunder peals often shatter windows into tiny fragments. In the apparent absence of thunderous tones we may observe the strong and continuous vibration of glass window panes during storms. A sudden eerie silence, and the window is shattered before our eyes.
Natural phenomena are prodigious generators of infrasound. The potent distal effects produced when natural explosions occur produce legendary effects. When Krakatoa exploded, windows were shattered hundreds of miles away by the infrasonic wave. Wind was not the causative agent of these occurrences, as no wind was felt or detected. Seismographic stations registered the blast, and barometers measured the shockwaves. The “ringing” of both earth and atmosphere continued for hours. It is believed that Continue reading
16TH CENTURY MATHEMATICS
The cultural, intellectual and artistic movement of the Renaissance, which saw a resurgence of learning based on classical sources, began in Italy around the 14th Century, and gradually spread across most of Europe over the next two centuries. Science and art were still very much interconnected and intermingled at this time, as exemplified by the work of artist/scientists such as Leonardo da Vinci, and it is no surprise that, just as in art, revolutionary work in the fields of philosophy and science was soon taking place.
It is a tribute to the respect in which mathematics was held in Renaissance Europe that the famed German artist Albrecht Dürer included an order-4 magic square in his engraving “Melencolia I”. In fact, it is a so-called “supermagic square” with many more lines of addition symmetry than a regular 4 x 4 magic square (see image at right). The year of the work, 1514, is shown in the two bottom central squares. Continue reading
Dürer’s polyhedron: 5 theories that explain Melencolia’s crazy cube
By Günter M Ziegler, 2014
In 1514 the German artist Albrecht Dürer (1471-1528) created the copper engraving Melencolia I. It was immediately recognised as a masterpiece, not only because of its remarkably fine and detailed execution and unsurpassed shadings, but also because of its unusual symbolism. Dürer was proud of his creation, carefully produced prints on the best paper he could get and gave them away as a proof for his artistry. But he was clever enough not to give any explanations. And thus even now, after 500 years of study (and certainly more than 500 interpretations, books, research papers, artistic essays and even blog entries about the piece), the mystery remains, and makes the piece as fascinating as ever. Continue reading
The study of celestial objects is an ancient one. Knowledge of the sun, moon, and stars, and their associated mythology, was passed from generation to generation but few conclusive records of prehistoric observations survive.
Constellations were part of the historical record in Mesopotamian culture around 4000 B.C. In the 8th century B.C. Homer mentioned a few now familiar constellations in his epic poem, the Odyssey. Four hundred years later Eudoxus of Cnidus wrote about 43 constellations (or 45 or 48 depending on one’s interpretation) which survive today. Eudoxus’ original work was lost but his ideas were kept alive by Aratus in a poem called Phaenomena (circa 270 B.C.). Continue reading
First printed edition, 1515
By Ian Ridpath
HERE is a page of the star catalogue from the first printed edition of Ptolemy’s Almagest, published in Venice in 1515. It is based on the Latin translation made by Gerard of Cremona (c.1114–1187) in Toledo, Spain, in 1175. Gerard worked from Arabic manuscripts, which were themselves translations of the Greek original.
Ptolemy’s original manuscript is thought to have been produced around AD 150 and was long lost by Gerard’s time, a thousand years later, although copies survived, both in Greek and in Arabic. Continue reading
QUANTUM PHYSICS: THE PHYSICS OF DREAMING
By Paul Levy, 2014
6. SELF-EXCITED CIRCUIT
Wheeler’s vision of the universe is like a “self-excited circuit,” to use a metaphor from electronics. To say the universe is “self”-excited is to say it is not “other”-excited, which is to say that rather than depending upon an external agent, god or deity, the universe is self-creating and self-referential─i.e., able to refer to, reflect and act upon itself, and hence, endlessly re-create itself anew.
Seen as a self-excited and self-actualizing circuit, the physical universe bootstraps itself into existence, laws and all. As a self-excited circuit, the universe gives rise to observers who, in completing the circuit, potentially give meaningful reality to the universe. Wheeler says,
“The universe is to be compared to a circuit self-excited in this sense, that the universe gives birth to consciousness, and consciousness gives meaning to the universe.”
From Physics Classroom
Kinetic energy is the energy of motion. An object that has motion – whether it is vertical or horizontal motion – has kinetic energy. There are many forms of kinetic energy – vibrational (the energy due to vibrational motion), rotational (the energy due to rotational motion), and translational (the energy due to motion from one location to another).
To keep matters simple, we will focus upon translational kinetic energy. The amount of translational kinetic energy (from here on, kinetic energy) that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object. The following equation is used to represent the kinetic energy (KE) of an object. Continue reading
Styx is a small natural satellite of Pluto whose discovery was announced on 11 July 2012. It is the fifth confirmed satellite of Pluto and was found approximately one year after Kerberos, Pluto’s fourth confirmed satellite.
Styx was discovered by a team led by astronomer Mark R. Showalter, using fourteen sets of images taken between 26 June and 9 July 2012 by the Wide Field Camera 3 fitted to the Hubble Space Telescope.
Styx is about half as bright as the dimmest previously known object in the system, Kerberos, and about one hundred thousandth as bright as Pluto. It was designated S/2012 (134340) 1, and informally referred to as P5. Continue reading
Two giant belts of radiation surround Earth. The inner belt is dominated by electrons and the outer one by protons. Image courtesy of NASA
Earth’s radiation belt: Van Allen probes reveal ‘zebra stripes’ in space
From Science Daily, March 19, 2014
Scientists have discovered a new, persistent structure in one of two radiation belts surrounding Earth. NASA’s twin Van Allen Probes spacecraft have shown that high-energy electrons in the inner radiation belt display a persistent pattern that resembles slanted zebra stripes. Surprisingly, this structure is produced by the slow rotation of Earth, previously considered incapable of affecting the motion of radiation belt particles, which have velocities approaching the speed of light. Continue reading