El Capitan and Yellow Pine

by
Reply

 

El Capitan is composed almost entirely of El Capitan Granite, a pale, coarse-grained granite emplaced approximately 100 mya (million years ago). In addition to El Capitan, this granite forms most of the rock features of the western portions of Yosemite Valley. A separate intrusion of igneous rock, the Taft Granite, forms the uppermost portions of the cliff face.

A third igneous rock, diorite, is present as dark-veined intrusions through both kinds of granite, especially prominent in the area known as the North America Wall.[3]

Along with most of the other rock formations of Yosemite Valley, El Capitan was carved by glacial action. Several periods of glaciation have occurred in the Sierra Nevada, but the Sherwin Glaciation, which lasted from approximately 1.3 mya to 1 mya, is considered to be responsible for the majority of the sculpting. The El Capitan Granite is relatively free of joints, and as a result the glacial ice did not erode the rock face as much as other, more jointed, rocks nearby.[4] Nonetheless, as with most of the rock forming Yosemite’s features, El Capitan’s granite is under enormous internal tension brought on by the compression experienced prior to the erosion which brought it to the surface. These forces contribute to the creation of features such as the massive Texas Flake, a large block of granite slowly detaching from the main rock face about halfway up the side of the cliff.

 

 

Jolene Inspects the Pandimensional Matter Tractors

by
Reply

While Team Sicore repeatedly tests the friction coefficient of the ice layer covering Badger Pass, Jolene and I explore the surrounding territory.  Here she diligently inspects the equipment for mission-worthiness.

An intriguing feature of string theory is that it predicts extra dimensions. In classical string theory the number of dimensions is not fixed by any consistency criterion. However, to make a consistent quantum theory, string theory is required to live in a spacetime of the so-called “critical dimension”: we must have 26 spacetime dimensions for the bosonic string and 10 for the superstring. This is necessary to ensure the vanishing of the conformal anomaly of the worldsheet conformal field theory. Modern understanding indicates that there exist less-trivial ways of satisfying this criterion. Cosmological solutions exist in a wider variety of dimensionalities, and these different dimensions are related by dynamical transitions. The dimensions are more precisely different values of the “effective central charge”, a count of degrees of freedom that reduces to dimensionality in weakly curved regimes.[14][15]

One such theory is the 11-dimensional M-theory, which requires spacetime to have eleven dimensions,[16] as opposed to the usual three spatial dimensions and the fourth dimension of time. The original string theories from the 1980s describe special cases of M-theory where the eleventh dimension is a very small circle or a line, and if these formulations are considered as fundamental, then string theory requires ten dimensions. But the theory also describes universes like ours, with four observable spacetime dimensions, as well as universes with up to 10 flat space dimensions, and also cases where the position in some of the dimensions is is described by a complex number rather than a real number. The notion of spacetime dimension is not fixed in string theory: it is best thought of as different in different circumstances.[17]

Nothing in Maxwell‘s theory of electromagnetism or Einstein‘s theory of relativity makes this kind of prediction; these theories require physicists to insert the number of dimensions manually and arbitrarily, and this number is fixed and independent of potential energy. String theory allows one to relate the number of dimensions to scalar potential energy. In technical terms, this happens because a gauge anomaly exists for every separate number of predicted dimensions, and the gauge anomaly can be counteracted by including nontrivial potential energy into equations to solve motion. Furthermore, the absence of potential energy in the “critical dimension” explains why flat spacetime solutions are possible.

This can be better understood by noting that a photon included in a consistent theory (technically, a particle carrying a force related to an unbroken gauge symmetry) must be massless. The mass of the photon that is predicted by string theory depends on the energy of the string mode that represents the photon. This energy includes a contribution from the Casimir effect, namely from quantum fluctuations in the string. The size of this contribution depends on the number of dimensions, since for a larger number of dimensions there are more possible fluctuations in the string position. Therefore, the photon in flat spacetime will be massless—and the theory consistent—only for a particular number of dimensions.[18] When the calculation is done, the critical dimensionality is not four as one may expect (three axes of space and one of time). The subset of X is equal to the relation of photon fluctuations in a linear dimension. Flat space string theories are 26-dimensional in the bosonic case, while superstring and M-theories turn out to involve 10 or 11 dimensions for flat solutions. In bosonic string theories, the 26 dimensions come from the Polyakov equation.[19] Starting from any dimension greater than four, it is necessary to consider how these are reduced to four dimensional spacetime.

 

Chas Pattern Instance: Taunting the Poloti

by
Reply

 

The Ahwahneechee people called the waterfall “Cholock” (“the fall”) and believed that the plunge pool at its base was inhabited by the spirits of several witches, called the Poloti.[4][5] An Ahwaneechee folktale describes a woman going to fetch a pail of water from the pool, and drawing it out full of snakes. Later that night, after the woman had trespassed into their territory, the spirits caused the woman’s house to be sucked into the pool by a powerful wind, taking the woman and her newborn baby with it.

Nummy Lift

by
Reply

Last run of the day at Badger Pass.  Chas, behind his board, is making and hoarding a battery of snowballs in preparation for Ford’s arrival off the bunny slope under the Bruin lift.  Chas refused to eat all day due to excitement.  So, he was punchy as hell.  On this day, both boys learned to snowboard in under two hours–now they take the lift on their own and make it down the hill without falling.  Not bad.

Jolene hit her wall and dropped her boot to get some end-of-day nummy.  There was nobody around to bother us, so Steph plopped down on the bench under the running lift.  We had several minutes to ourselves before Ford arrived to receive Chas’ surprise attack–a success.

The history of winter sports in Yosemite National Park is unique. Following the building of the Ahwahnee Hotel in 1925–1927,[4] came Yosemite’s first ski school in 1928 with Jules Fritsch as instructor.[5] Fritsch, a Swiss ski expert was part of a trained staff of winter sports experts available in Yosemite. Fritsch and the staff led six day snow excursions in Yosemite from the Ahwahnee to Tenaya Lake to bolster the ski school. Many believe this ski school was the first in California. In conjunction with the Curry Company, one of the first projects was the 1927 construction of a four-track toboggan slide near Camp Curry. Dr. Donald Tresidder, the first president the Yosemite Park & Curry Company and its guiding force, saw the visitor interest in winter sports and immediately formed the Yosemite Winter Club.[6] With the club’s enthusiast support, a small ski hill and ski jump near Tenaya Creek Bridge was built in 1928.[7]