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28 units available
6 categories total
To convert tropical years to days: multiply by 365.24219. To Julian years: multiply by 365.24219/365.25.
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.
For example, 1 Year (Tropical) (yr (Trop)) = 3.155693e+22 Femtosecond (fs).
| Year (Tropical) (yr (Trop)) | Femtosecond (fs) |
|---|---|
| 0.1 | 3.155693e+21 |
| 0.5 | 1.577846e+22 |
| 1 | 3.155693e+22 |
| 2 | 6.311385e+22 |
| 5 | 1.577846e+23 |
| 10 | 3.155693e+23 |
| 25 | 7.889231e+23 |
| 50 | 1.577846e+24 |
| 100 | 3.155693e+24 |
| 500 | 1.577846e+25 |
| 1000 | 3.155693e+25 |
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.
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.



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