The time library
Articles
A thoughtful guide to the time we measure, the rhythms we live by and the hours we share. Practical examples, careful science and sources you can check.
Time now
3 guides
Time now · 4 min read
Why the Moon needs its own time standard
NASA's work on coordinated lunar time explains why future missions cannot simply use Earth clocks unchanged.
Read guide
Time now · 4 min read
The future of UTC: why leap seconds are under review
International timekeepers are reconsidering leap seconds. Here is what is decided, what remains open and why it matters.
Read guide
Time now · 4 min read
The year 2038 problem is being worked on now
Why a date more than a decade away already matters to the software and devices we use today.
Read guideTime standards
2 guides
Time standards · 3 min read
UTC vs GMT: what is the difference?
A clear guide to the international time standard, Greenwich Mean Time and why they are not quite interchangeable.
Read guide
Time standards · 4 min read
Leap seconds: why a minute can last 61 seconds
The difference between atomic time and Earth’s rotation, and the future of leap seconds.
Read guideTime zones
2 guides
Time zones · 4 min read
How time zones really work
Offsets, IANA place names and political decisions: the practical anatomy of a time zone.
Read guide
Time zones · 4 min read
Daylight saving time without the guesswork
Why clocks change, what happens to a missing hour and how to avoid scheduling mistakes.
Read guideSleep & biology
4 guides
Sleep & biology · 4 min read
Your body clock: a guide to circadian rhythms
How light, the brain and daily habits shape the body’s roughly 24-hour rhythm.
Read guide
Sleep & biology · 3 min read
Sleep timing: consistency before perfection
A realistic approach to sleep duration, regularity and planning your evenings.
Read guide
Sleep & biology · 3 min read
Morning light and the timing of your day
Why the timing of light matters to alertness and sleep, with practical daily habits.
Read guide
Sleep & biology · 3 min read
Early birds, night owls and chronotypes
What a chronotype means, why it is not a personality test and how to work with it.
Read guideTravel & planning
3 guides
Travel & planning · 4 min read
A practical, science-aware guide to jet lag
What happens when you cross time zones quickly and how light and scheduling may help.
Read guide
Travel & planning · 4 min read
Finding a fair time for a global meeting
A step-by-step approach to overlapping work hours, daylight saving and fair scheduling.
Read guide
Travel & planning · 3 min read
The International Date Line and the day next door
Why the calendar can change when you cross the Pacific and how to plan around it.
Read guideFocus & activity
3 guides
Focus & activity · 4 min read
The Pomodoro method: structure without the myth
How to use focused intervals and breaks while staying honest about what the evidence can tell us.
Read guide
Focus & activity · 3 min read
Better breaks: what short pauses can and cannot do
An evidence-aware guide to micro-breaks, fatigue and taking pauses that genuinely help.
Read guide
Focus & activity · 4 min read
Using an interval timer for exercise
Work and recovery intervals, sensible progression and what an exercise timer cannot tell you.
Read guideMeasurement
2 guides
Measurement · 3 min read
Why a reliable countdown uses an end time
How browsers keep a countdown meaningful when a tab sleeps or the device clock changes.
Read guide
Measurement · 3 min read
What does a millisecond stopwatch really measure?
Display precision, reaction time and a more honest way to interpret lap times.
Read guide