Time (disambiguation)

Time is a common term for the experience of duration and a fundamental quantity of measuring systems.

Time also may refer to:

Other matters of temporal measurement

Businesses

Education

Computing

Entertainment

Titled works

Film and television

The Time Machine

The Time Machine is a science fiction novel by H. G. Wells, published in 1895. Wells is generally credited with the popularization of the concept of time travel by using a vehicle that allows an operator to travel purposely and selectively forwards or backwards in time. The term "time machine", coined by Wells, is now almost universally used to refer to such a vehicle (Also see "the anacronopete").

The Time Machine has since been adapted into two feature films of the same name, as well as two television versions, and a large number of comic book adaptations. It has also indirectly inspired many more works of fiction in many media.

History

Wells had considered the notion of time travel before, in a short story titled "The Chronic Argonauts" (1888). This work, published in his college newspaper, was the foundation for The Time Machine.

Wells frequently stated that he had thought of using some of this material in a series of articles in the Pall Mall Gazette, until the publisher asked him if he could instead write a serial novel on the same theme. Wells readily agreed and was paid £100 (equal to about £10,000 today) on its publication by Heinemann in 1895, which first published the story in serial form in the January to May numbers of The New Review (newly under the nominal editorship of W. E. Henley).Henry Holt and Company published the first book edition (possibly prepared from a different manuscript) on 7 May 1895; Heinemann published an English edition on 29 May. These two editions are different textually and are commonly referred to as the "Holt text" and "Heinemann text", respectively. Nearly all modern reprints reproduce the Heinemann text.

Time travel

Time travel is the concept of movement (often by a human) between different points in time in a manner analogous to moving between different points in space, typically using a hypothetical device known as a time machine. Time travel is a recognized concept in philosophy and fiction, but travel to an arbitrary point in time has a very limited support in theoretical physics, usually only in conjunction with quantum mechanics or Einstein–Rosen bridges. Sometimes the above narrow meaning of time travel is used, sometimes a broader meaning. For example, travel into the future (not the past) via time dilation is a well-proven phenomenon in physics (relativity) and is routinely experienced by astronauts, but only by several milliseconds, as they can verify by checking a precise watch against a clock that remained on Earth. Time dilation by years into the future could be done by taking a round trip during which motion occurs at speeds comparable to the speed of light, but this is not currently technologically feasible for vehicles.

Coronary circulation

Coronary circulation is the circulation of blood in the blood vessels of the heart muscle (myocardium). The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries. The vessels that remove the deoxygenated blood from the heart muscle are known as cardiac veins. These include the great cardiac vein, the middle cardiac vein, the small cardiac vein and the anterior cardiac veins.

As the left and right coronary arteries run on the surface of the heart, they can be called epicardial coronary arteries. These arteries, when healthy, are capable of autoregulation to maintain coronary blood flow at levels appropriate to the needs of the heart muscle. These relatively narrow vessels are commonly affected by atherosclerosis and can become blocked, causing angina or a heart attack. (See also: circulatory system.) The coronary arteries that run deep within the myocardium are referred to as subendocardial.

The coronary arteries are classified as "end circulation", since they represent the only source of blood supply to the myocardium; there is very little redundant blood supply, which is why blockage of these vessels can be so critical.