The planet's second

Universal Time

One agreed second. Several clocks. Hold this instant, walk the day, or read the stars over Greenwich — all on this device.

Coordinated Universal Time

—:—:—

Universal civil date

UTC at this device · Montréal keeps civil time

Gold follows solar UTC. The inner mark is Greenwich sidereal — about four minutes faster each day.

Episode 05 notes

The same second, elsewhere

Greenwich sits at +0.0° · —:—:— civil

TAI

—:—:—

UTC + 37 s

GPS

—:—:—

UTC + 18 s

GMST

—:—:—

Stars over Greenwich

LST

—:—:—

Sidereal at Montréal

Julian Date

—

MJD —

Unix

—

ISO week

The leap second

UTC is atomic time, occasionally stepped so that it stays within 0.9 seconds of UT1 — Earth rotation. The last leap second was 31 December 2016. TAI remains 37 seconds ahead. The IAU intends to freeze further leaps by 2035.

DUT1 (UT1 − UTC)+0.00 s

Inside the allowed window. No leap is required.

Equation of time: +0.0 min
This device: UTC

DUT1 here is an educational control, not an IERS bulletin.