Understanding Time & Gravity

What Is Time?

Thomas Kitching, a cosmologist and astrophysics lecturer, looks at questions like: Does time have a beginning? Time's arrow? Will time end?

Written in non-technical language, this post gives you an idea of the questions scientists are looking at.

A Walk Through Time - Ancient Calendars

This on-line essay on the history of timekeeping was conceived and written by Kent Higgins and illustrated by Darwin Miner, of the Program Information Office of the National Bureau of Standards (now NIST). Originally penned in 1975, it has been updated numerous times over the years.

Time Zones

This site provides an overview of Time Zones, what are they and why we have so many of them.

Who knew the International Date Line created 3 extra time zones.

Does Time Really Flow? New Clues Come From a Century-Old Approach to Math

Strangely, although we feel as if we sweep through time on the knife-edge between the fixed past and the open future, that edge – the present – appears nowhere in the existing laws of physics. Albert Einstein wrote in 1955, "... the distinction between past, present and future is only a stubbornly persistent illusion." And yet, at the quantum level, outcomes are random and unpredictable, even as particle behavior collectively follows statistical patterns.

A Swiss physicist, Nicolas Gisin posits that the problem is in the math. If you reject existence of numbers with infinitely many digits (i.e., infinite precision) and use what's called intuitionist math, the strict determinism implied by Einstein's equations gives way to a quantum-like unpredictability. If numbers are finite and limited in their precision, then nature itself is inherently imprecise, and thus unpredictable.

Time as marked by the bells

You've heard the phrase, "8 bells and all is well." This resource shows you where that saying originated.

Not everyone uses a display to tell the time.

NIST

Major concepts and a history of time-keeping can be found at the NIST site.