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To convert fs to seconds: multiply by 10⁻¹⁵. To convert fs to picoseconds: divide by 1,000.
1 fs = 10⁻¹⁵ s = 0.001 ps = 1,000 as. Light travels about 0.3 µm in one femtosecond.
For example, 1 Femtosecond (fs) = 3.168877e-23 Year (Tropical) (yr (Trop)).
| Femtosecond (fs) | Year (Tropical) (yr (Trop)) |
|---|---|
| 0.1 | 3.168877e-24 |
| 0.5 | 1.584438e-23 |
| 1 | 3.168877e-23 |
| 2 | 6.337753e-23 |
| 5 | 1.584438e-22 |
| 10 | 3.168877e-22 |
| 25 | 7.922191e-22 |
| 50 | 1.584438e-21 |
| 100 | 3.168877e-21 |
| 500 | 1.584438e-20 |
| 1000 | 3.168877e-20 |
The femtosecond is a unit of time equal to 10⁻¹⁵ seconds — one quadrillionth of a second.
1 fs = 10⁻¹⁵ s = 0.001 ps = 1,000 as. Light travels about 0.3 µm in one femtosecond.
To convert fs to seconds: multiply by 10⁻¹⁵. To convert fs to picoseconds: divide by 1,000.
LASIK eye surgery uses femtosecond lasers. Also used in precision micro-machining and optical frequency combs.
A femtosecond is to one second as one second is to about 31.7 million years. The fastest chemical reactions occur on femtosecond timescales.
Confusing femtoseconds with picoseconds. Remember: fs is 1,000× shorter than ps.
Ahmed Zewail's Nobel-winning work proved we can 'photograph' chemical reactions happening in femtoseconds using ultrafast laser pulses.
The tropical year is the time for the Sun to return to the same equinox point — approximately 365.24219 days (31,556,925.216 seconds).
1 tropical year ≈ 365.24219 days ≈ 365 d 5 h 48 min 45 s. Shorter than the sidereal year by about 20 minutes due to precession.
To convert tropical years to days: multiply by 365.24219. To Julian years: multiply by 365.24219/365.25.
Calendar design — the Gregorian calendar's average year (365.2425 days) approximates the tropical year to within 26 seconds.
The tropical year is slowly shortening — by about 0.53 seconds per century. In the year 1900, it was 365.24220 days.
Confusing tropical year with sidereal year — the tropical year is ~20 minutes shorter due to axial precession.
The tropical year governs seasons. If we used the sidereal year for calendars, seasons would slowly drift through the months over ~26,000 years.



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