Universal Time (UT) is a time standard based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time (GMT), i.e., the mean solar time on the Prime Meridian at Greenwich, and GMT is sometimes used loosely as a synonym for UTC. In fact, the expression "Universal Time" is ambiguous, as there are several versions of it, the most commonly used being UTC and UT1 (see below). All of these versions of UT are based on the rotation of the Earth in relation to distant celestial objects (stars and quasars), but with a scaling factor and other adjustments to make them closer to solar time.
Read more about Universal Time: Universal Time and Standard Time, Measurement, Versions
Famous quotes containing the words universal and/or time:
“The philosopher is like a man fasting in the midst of universal intoxication. He alone perceives the illusion of which all creatures are the willing playthings; he is less duped than his neighbor by his own nature. He judges more sanely, he sees things as they are. It is in this that his liberty consists—in the ability to see clearly and soberly, in the power of mental record.”
—Henri-Frédéric Amiel (1821–1881)
“Harvey: About this Voltaire.
Helene: What about him?
Harvey: How’d he ever get time to do all he did?
Helene: He lived to be old.
Harvey: Even so, how many letters did he write?
Helene: Oh, I don’t know exactly. Thousands.
Harvey: I can’t remember when I even wrote one.
Helene: You should try.
Harvey: It’s too late. I wouldn’t know where to send it.”
—Tom Waldman (d. 1985)