space & time

Matters relating to length and duration in physics and transportation

Time, space, and station

I’ve been revising the glossary lately, see above. This required adjusting the post on Foundations of mechanics for time-space, among others. Here is an explanation: Ordinary 3D space is measured by distances. Correspondingly, 3D time is measured by durations. That is, 3D time is a space of times. Call this time space. Ordinary 1D time […]

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Reality and conventions #5

This post continues a series of posts. The previous one was here. I’ve noted before that the one-way speed of light is a convention (see John A. Winnie, Philosophy of Science, v. 37, 1970). The two-way (round-trip) speed of light is known to equal c, but the one-way speed may vary between c/2 and infinity,

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Direction and time

The measurement of the length of a motion follows the course of motion at its own pace. It is a measurement of something passive, and the motion may be past when the measurement takes place. Cartesian space lacks direction. The independent axes are just coordinates that describe a passive space. The origin is arbitrary and

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Introduction to duration space

Since Newton, time has been the usual and ultimate independent variable for physics. This contrasts with problems in transportation, where time is often optimized. Whether transporting goods across the world, commuters across town, or athletes to the finish line, length is the independent variable against which time is measured and optimized. If length is taken

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Temporo-spatial units

The temporo-spatial kinematic units are straightforward opposites of spacio-temporal units: Dischronment has units of seconds, minutes, hours, days, or years. Pace and lenticity have units of distance over duration: s/m or min/km or min/mile. Compare speed and velocity with their units of m/s, km/hr, or mi/hr. Relentation has units of s/m² or min/km² or min/mile². Compare

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Time and light

This post continues on the subject of light conventions, see here. In ordinary life today clocks are very common and portable. Time is everywhere and is everywhere the same (apart from adjustments for longitude, that is, time zones). It’s as if the signals from clocks arrived instantaneously everywhere, near or far. This is equivalent to

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Distance, duration, and angles

Let’s follow the orbit of a particle or the route of a vehicle as a curvilinear function with associated directions at every point. Measurement produces travel distance r, travel time t, with directions θ and φ. The directions may be considered as functions of either travel distance or travel time: θr, φr, θt, or φt.

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