Chronometry (from Greek χρόνος chronos, "time" and μέτρον metron, "measure") is the science of the measurement of time, or timekeeping. Chronometry provides a standard of measurement for time, and therefore serves as a significant reference for many and various fields of science.
The importance of the accuracy and reliability of measuring time provides a standardized unit for chronometric experiments for the modern world, and more specifically scientific research. Despite the coincidental identicality of worldwide units of time, time produces a measurement of change and is a variable in many experiments. Therefore, time is an essential part of many areas of science.
It should not be confused with chronology, the science of locating events in time, which often relies upon it. Also, of similarity to chronometry is horology, the study of time; however, it is commonly used specifically with reference to the mechanical instruments created to keep time, with examples such as stopwatches, clocks, and hourglasses. Chronometry is utilised in many areas, and its fields are often derived from aspects of other areas in science, for example geochronometry, combining geology and chronometry.
Early records of time keeping are thought to have originated in the Paleolithic era, with etchings to mark the passing of moons in order to measure the year. And then progressed to written versions of calendars, before mechanisms and devices made to track time were invented. Today, the highest level of precision in timekeeping comes with atomic clocks, which are used for the international standard of the second.
Etymology
Chronometry is derived from two root words, chronos and metron (χρόνος and μέτρον in Ancient Greek respectively), with rough meanings of "time" and "measure". The combination of the two is taken to mean time measuring.
In the Ancient Greek lexicon, meanings and translations differ depending on the source. Chronos, used in relation to time when in definite periods, and linked to dates in time, chronological accuracy, and sometimes in rare cases, refers to a delay. The length of the time it refers ranges from seconds to seasons of the year to lifetimes, it can also concern periods of time wherein some specific event takes place, or persists, or is delayed.
The root word is correlated with the god Chronos in Ancient Greek mythology, who embodied the image of time, originated from out of the primordial chaos. Known as the one who spins the Zodiac Wheel, further evidence of his connection to the progression of time. However, Ancient Greek makes a distinction between two types of time, chronos, the static and continuing progress of present to future, time in a sequential and chronological sense. And Kairos, a concept based in a more abstract sense, representing the opportune moment for action or change to occur.
Kairos (καιρός) carries little emphasis on precise chronology, instead being used as a time specifically fit for something, or also a period of time characterised by some aspect of crisis, also relating to the endtime. It can as well be seen in the light of an advantage, profit, or fruit of a thing, but has also been represented in an apocalyptical feeling, and likewise shown as variable between misfortune and success, being likened to a body part vulnerable due to a gap in armor for Homer, benefit or calamity depending on the perspective. It is also referenced in the Christian theology, being used as implication of God's action and judgement in circumstances.
Because of the inherent relation between chronos and kairos, their function the Ancient Greek's portrayal and concept of time, understanding one means understanding the other in part. The implication of chronos, an indifferent disposition and eternal essence lies at the core of the science of chronometry, bias is avoided, and definite measurement is favoured.
Metron (μέτρον), is that by which anything is measured, a due, limit, or goal, also concerns a space that can be measured. It can regard instruments for measuring, or even the result of measuring.
Fields of chronometry
Biochronometry
Biochronometry (also called chronobiology or biological chronometry) is the study of biological behaviours and patterns seen in animals with factors based in time. It can be categorised into circadian and circannual rhythms (circatidal and circalunar can be included in this categorisation depending on the relevance). Examples of these behaviours can be: the relation of daily and seasonal tidal cues to the activity of marine plants and animals, the photosynthetic capacity and phototactic responsiveness in algae, or metabolic temperature compensation in bacteria.