SECONDS
The atom of all temporal measurement. Every clock — from a wristwatch to an optical lattice — is just a count of one specific oscillation. Below, every second TIME CORE tracks, ticking live since the Unix epoch (1970-01-01 UTC).
Today's Natural Second
Mean solar day adjusted for Earth's actual rotation
LOD excess
+1.2080 ms
fallback value
Today's day
86400.001208 s
SI seconds in one mean solar day
1 natural s =
1.000000013981 s
SI seconds (today)
SI Second
1 s = 1.000000000 SI s
s since 1970-01-01
—
Ratio to SI1.000000000
vs SI1.000×
Today's Natural Second
1 s⊕ = 1.00000001 SI s
s⊕ since 1970-01-01
—
Ratio to SI1.00000001
vs SI1.00000×
Quartz Second
1 s_Q = 0.30517578 SI s
s_Q since 1970-01-01
—
Ratio to SI0.30517578
vs SI0.305176×
Cesium Second
1 s_Cs = 1.08782776 SI s
s_Cs since 1970-01-01
—
Ratio to SI1.08782776
vs SI1.08783×
Ytterbium Second
1 s_Yb = 1.55733768 SI s
s_Yb since 1970-01-01
—
Ratio to SI1.55733768
vs SI1.55734×
Aluminum-Ion Second
1 s_Al = 0.89204841 SI s
s_Al since 1970-01-01
—
Ratio to SI0.89204841
vs SI0.892048×
Mars Second
1 s_♂ = 1.02749125 SI s
s_♂ since 1970-01-01
—
Ratio to SI1.02749125
vs SI1.02749×
Planck Second
1 s_P = 5.39124700 SI s
s_P since 1970-01-01
—
Ratio to SI5.39124700
vs SI5.39125×
Conversion Reference
All ratios expressed against 1 SI second
| System | Symbol | SI s per 1 | Per 1 SI s | Oscillator (Hz) |
|---|---|---|---|---|
| SI Second | s | 1.000000000 | 1.0000000 | 9.1926e+9 |
| Today's Natural Second | s⊕ | 1.00000001 | 0.99999999 | — |
| Quartz Second | s_Q | 0.30517578 | 3.2768000 | 3.2768e+4 |
| Cesium Second | s_Cs | 1.08782776 | 0.91926318 | 9.1926e+9 |
| Ytterbium Second | s_Yb | 1.55733768 | 0.64212150 | 6.4212e+14 |
| Aluminum-Ion Second | s_Al | 0.89204841 | 1.1210154 | 1.1210e+15 |
| Mars Second | s_♂ | 1.02749125 | 0.97324430 | — |
| Planck Second | s_P | 5.39124700 | 0.18548584 | — |
Live SI clock: 0.000 s since 1970-01-01 UTC · Cs reference 9.1926e+9 Hz · Quartz reference 32,768 Hz