#+TITLE: QUANTUM CALENDAR
The same moment.
A different unit.
Your everyday clock, translated into caesium-133 periods. A small experiment in seeing the quantum definition behind every second.
Source: your device clock calculated equivalent, millisecond-based timestamps
Local civil time your time zone
Date appears when JavaScript runs
—:—:—
The time zone configured on your device.
Universal reference UTC
UTC date appears when JavaScript runs
—:—:—
The same instant, independent of your time zone.
Calculated Cs-period equivalent
Unix epoch → nowWaiting for your device clock…
— periods of the defining Cs-133 transition
;; precision note More digits do not mean a more accurate clock. The result depends on your device time; no atomic-clock feed or quantum measurement is used.
* THE MATHEMATICAL FOUNDATION
One second.
9,192,631,770 periods.
The SI second is defined using a specific transition in the caesium-133 atom. Quanlendar uses that exact defining frequency as a conversion factor for Unix time.
1970-01-01 00:00:00 UTC
using integer arithmetic
not detected atomic cycles
Cs_Hz = 9_192_631_770
Q = floor(Unix_milliseconds × Cs_Hz / 1_000)
UTC_day = floor(Unix_milliseconds / 86_400_000)
1 second = 9,192,631,770 period-equivalents
1 day = 794,243,384,928,000 period-equivalents** What the number means
A different unit for the same device timestamp. The UTC day is a count of complete 86,400-second Unix days since the epoch, starting at day zero. It changes at UTC midnight, which may differ from your local date boundary.
** Where the precision ends
JavaScript timestamps use milliseconds. Each millisecond represents about 9.19 million Cs periods. BigInt preserves the calculated integer; it does not improve the clock that supplied the timestamp.
** Unix time and atomic time
Unix time does not count UTC leap seconds. This conversion is therefore not a measurement of all physically elapsed atomic periods since 1970, nor a realization of International Atomic Time (TAI).
** Why “quantum”?
The connection is the atomic transition underlying the SI second. “Observation” and the Org-mode presentation are a design language; this page does not simulate superposition or wave-function collapse.
* BEYOND THE CLOCK
Prepare for uncertainty.
Do not put a date on it.
A sufficiently capable quantum computer could threaten widely used public-key cryptography. When that capability will arrive remains unknown. Preparation can start before the date is known.
A planning horizon: 2030
The original Quanlendar counted down to “Q-Day”. We retain 1 January 2030 as an illustrative planning date, not a prediction of a cryptographic breakthrough.
Enable JavaScript for countdown
2030-01-01 00:00 UTCKnow what you depend on.
Identify cryptography, trust relationships and data that must remain confidential for years.
Build room for change.
Plan for crypto-agility and review vendors’ support for standardized post-quantum algorithms.
Follow evidence, not countdowns.
Use current standards and migration guidance to set your own priorities and timelines.
* THE PROJECT
Keep the source open.
Keep the claims precise.
Dr. Šarūnas Grigaliūnas
Concept creator. Cybersecurity researcher and educator exploring the relationship between quantum technologies, time and trust.
Explore the author’s workA small, inspectable experiment
Plain HTML, CSS and JavaScript. The clock runs in your browser. No accounts, analytics scripts or cookies are used by this application.
Download the source code (.zip)- Source code
- MIT License — the software that runs this site.
- Observation outputs
- The project’s original QGPL v2.0 notice is retained for calculated outputs. This is separate from the source-code license.
The QGPL link above is a preserved version-specific text. Visit qgpl.org for the wider project and its current editions.