Eternalism is a philosophical approach to the ontological nature of time, which takes the view that all existence in time is equally real, as opposed to presentism or the growing block universe theory of time, in which at least the future is not the same as any other time. Some forms of eternalism give time a similar ontology to that of space, as a dimension, with different times being as real as different places, and future events are "already there" in the same sense other places are already there, and that there is no objective flow of time. It is sometimes referred to as the "block time" or "block universe" theory due to its description of space-time as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time. [1]

Mechanical metronomes have a pyramid-like shape, with a swinging pendulum down the middle. The pendulum swings left to right, similar to a windshield wiper, and the metronome emits a clicking sound each time the pendulum passes the center of the device. [2]

You Jiangu's device consisted of six candles made from 72 pennyweights (24 grains each), of wax, each being 12 inches high, of uniform thickness, and divided into 12 sections each of one inch. Each candle burned away completely in four hours, making each marking 20 minutes. The candles were placed for protection inside cases made of a wooden frame with transparent horn panels in the sides. Similar methods of measuring time were used in medieval churches and earlier, famously by King Alfred the Great of England, first by counting the number of candles of a specific size burnt, and later by use of a graduated candle. [7]

Where flying isn't concerned, it isn't the length of the flight that matters... only the difference in time zones. Flying from Paris to Johannesburg, while it might take you 15–20 hours, wouldn't leave you very jetlagged because there's only 1 hour time difference. A flight from New York to Tokyo, on the other hand, leaves you with a 13-hour difference, which effectively means reversing your sleep/wake schedule. [4]

The smallest units, insignificant over a lifetime, are also the most stressful. The most frustrating. I was sick of it. I unsubscribed from the clock. Dropped my watch right into the garbage. Shut off the glowing green-blue digital clocks that seem to piggyback on every appliance known to man – microwave, stove, VCR. The one in the corner of my computer screen? Gone. On my iPhone, I changed it to a random timezone so, technically, it still has a clock, but at quick glance? Almost useless. [5]

When individuals observe a slow-motion movement, the central nervous system (CNS) speeds up or reduces the time in order to balance the movement feedback and visual perception [1]. In other words, when an individual watches a movie scene in slow-motion for a few seconds, the CNS reorganizes the time estimation according to the normal speed of movement; this leads to the impression of shortening of time. [8]

Today, all of our cell phones, smart watches and more rely on atomic master clocks to keep them in sync. The tabletop clock mechanically winds, sets and regulates an Urwerk watch that is paired with the clock. The new AMC is one of three complex editions that will be revealed between now and the year 2020. [3]

Mercury 1,408 hours
Venus 5,832 hours
Earth 24 hours
Mars 25 hours
Jupiter 10 hours
Saturn 11 hours
Uranus 17 hours
Neptune 16 hours [6]