Representation theory of the Poincaré group. Spacetime. In non-relativistic classical mechanics, the use of Euclidean space instead of spacetime is appropriate, as time is treated as universal and constant, being independent of the state of motion of an observer.

[disambiguation needed] In relativistic contexts, time cannot be separated from the three dimensions of space, because the observed rate at which time passes for an object depends on the object's velocity relative to the observer and also on the strength of gravitational fields, which can slow the passage of time for an object as seen by an observer outside the field. Until the beginning of the 20th century, time was believed to be independent of motion, progressing at a fixed rate in all reference frames; however, later experiments revealed that time slows at higher speeds of the reference frame relative to another reference frame.

Such slowing, called time dilation, is explained in special relativity theory. Spacetime in literature[edit] Mathematical concept[edit] Henri Poincaré. Jules Henri Poincaré (French: [ʒyl ɑ̃ʁi pwɛ̃kaʁe];[2] 29 April 1854 – 17 July 1912) was a French mathematician, theoretical physicist, engineer, and a philosopher of science.

He is often described as a polymath, and in mathematics as The Last Universalist by Eric Temple Bell,[3] since he excelled in all fields of the discipline as it existed during his lifetime. As a mathematician and physicist, he made many original fundamental contributions to pure and applied mathematics, mathematical physics, and celestial mechanics. He was responsible for formulating the Poincaré conjecture, which was one of the most famous unsolved problems in mathematics until it was solved in 2002–2003.

In his research on the three-body problem, Poincaré became the first person to discover a chaotic deterministic system which laid the foundations of modern chaos theory. Poincaré group. Basic explanation[edit]

Minkowski space. In theoretical physics, Minkowski space is often contrasted with Euclidean space.

While a Euclidean space has only spacelike dimensions, a Minkowski space also has one timelike dimension. Maxwell's equations. Maxwell's equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of classical electrodynamics, classical optics, and electric circuits.

These fields in turn underlie modern electrical and communications technologies. Maxwell's equations describe how electric and magnetic fields are generated and altered by each other and by charges and currents. They are named after the Scottish physicist and mathematician James Clerk Maxwell, who published an early form of those equations between 1861 and 1862.

The equations have two major variants. The "microscopic" set of Maxwell's equations uses total charge and total current, including the complicated charges and currents in materials at the atomic scale; it has universal applicability but may be unfeasible to calculate. The term "Maxwell's equations" is often used for other forms of Maxwell's equations. Anthony Grafton. Anthony Grafton, lecturing at the Gotha Research Center, 2010 Anthony Grafton (sometimes Anthony T.

Grafton; born May 21, 1950) is one of the foremost historians of early modern Europe and the current Henry Putnam University Professor at Princeton University. Timeline JS - Beautifully crafted timelines that are easy, and intuitive to use. Timeline. The bronze timeline "Fifteen meters of History" with background information board, Örebro, Sweden.

A timeline is a way of displaying a list of events in chronological order, sometimes described as a project artifact. It is typically a graphic design showing a long bar labelled with dates alongside itself and usually events labelled on points where they would have happened. Uses of timelines[edit] Timelines are often used in education to help students and researchers with understanding the order or chronology of historical events and trends for a subject.

Timeline. Minard.png 2,003×955 pixels. National and Public Holidays in Iceland in 2013. Symmetry group. Introduction[edit] The "objects" may be geometric figures, images, and patterns, such as a wallpaper pattern.

The definition can be made more precise by specifying what is meant by image or pattern, e.g., a function of position with values in a set of colors. For symmetry of physical objects, one may also want to take physical composition into account. The group of isometries of space induces a group action on objects in it. Two geometric figures are considered to be of the same symmetry type if their symmetry groups are conjugate subgroups of the Euclidean group E(n) (the isometry group of Rn), where two subgroups H1, H2 of a group G are conjugate, if there exists g ∈ G such that H1=g−1H2g.

One dimension[edit] See also symmetry groups in one dimension. Two dimensions[edit] Up to conjugacy the discrete point groups in 2-dimensional space are the following classes: For non-bounded figures, the additional isometry groups can include translations; the closed ones are: Time. The flow of sand in an hourglass can be used to keep track of elapsed time.

It also concretely represents the present as being between the past and the future. Time is a dimension in which events can be ordered from the past through the present into the future,[1][2][3][4][5][6] and also the measure of durations of events and the intervals between them.[3][7][8] Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars.[3][7][8][9][10][11] Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems.[12][13][14] Some simple, relatively uncontroversial definitions of time include "time is what clocks measure"[7][15] and "time is what keeps everything from happening at once".[16][17][18][19] Temporal measurement and history[edit]

Bezos-Backed 10,000 Year Clock Site Preparation and Fabrication Underway. If you were worth a million dollars, you might buy a fine watch to measure time.

Rolex, Breitling, Seiko, this watch could run a couple thousand dollars. If you’re Jeff Bezos, you spend $42 million on a 200-foot clock inside a mountain, engineered to withstand Armageddon and tick 10,000 years. That sounds like a lot of money, but compared to Bezos’ $25.2 billion, it’s akin to our millionaire buying a single Rolex. No big deal for Bezos. The last time we covered the 10,000 Year Clock project, Bezos was freshly aboard.

The 10,000 Year Clock will have an 8-foot face, 700-pound gear wheel, 300-pound steel pendulum, and a never-repeating set of 3.65 million distinct chime sequences programmed by 10,000 Year Clock inventor and co-founder, Danny Hillis. So how close is the foundation to fulfilling their vision? The winder and main differential, key components of the power storage system, were the first parts completed.