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28 units available
6 categories total
To convert as to seconds: multiply by 10⁻¹⁸. To convert as to femtoseconds: divide by 1,000.
1 as = 10⁻¹⁸ s = 0.001 fs. Light travels only about 0.3 nm (the width of a water molecule) in one attosecond.
For example, 1 Attosecond (as) = 3.168754e-26 Year (Sidereal) (yr (Sid)).
| Attosecond (as) | Year (Sidereal) (yr (Sid)) |
|---|---|
| 0.1 | 3.168754e-27 |
| 0.5 | 1.584377e-26 |
| 1 | 3.168754e-26 |
| 2 | 6.337507e-26 |
| 5 | 1.584377e-25 |
| 10 | 3.168754e-25 |
| 25 | 7.921884e-25 |
| 50 | 1.584377e-24 |
| 100 | 3.168754e-24 |
| 500 | 1.584377e-23 |
| 1000 | 3.168754e-23 |
The attosecond is a unit of time equal to 10⁻¹⁸ seconds — one quintillionth of a second.
1 as = 10⁻¹⁸ s = 0.001 fs. Light travels only about 0.3 nm (the width of a water molecule) in one attosecond.
To convert as to seconds: multiply by 10⁻¹⁸. To convert as to femtoseconds: divide by 1,000.
No everyday applications yet. Research applications include tracking electron motion and developing future ultrafast electronics.
An attosecond is to one second as one second is to about 31.7 billion years — roughly twice the age of the universe.
Confusing 'as' (attosecond) with the English word 'as'. In scientific texts, context and formatting prevent ambiguity.
The 2023 Nobel Prize in Physics was awarded for attosecond pulse generation — this field is at the frontier of ultrafast science.
The sidereal year is the time for Earth to complete one orbit relative to the fixed stars — approximately 365.25636 days (31,558,149.7632 seconds).
1 sidereal year ≈ 365.25636 days ≈ 365 d 6 h 9 min 10 s. About 20 min 24 s longer than the tropical year.
To convert sidereal years to days: multiply by 365.25636. To tropical years: multiply by 365.25636/365.24219.
Tracking stellar positions, calculating satellite orbital decay, and determining long-term star catalog corrections.
The ~20-minute difference between sidereal and tropical years is caused by axial precession — Earth's axis traces a full circle every ~25,772 years.
Using sidereal year when tropical year is intended (or vice versa) in calendar calculations.
Think of it this way: the sidereal year measures Earth's orbit relative to stars. The tropical year measures relative to seasons. Precession makes them differ.



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