length · International · Modern
SI base unit of length. Its definition fixes the speed of light in vacuum at exactly 299,792,458 m/s, with the second defined from the caesium-133 hyperfine frequency.
Converter
length · Various · Modern
attoparsec
informal
- Record
- M360
- Definition quality
- Informal / humorous mathematically defined
- Conversion mode
- multiplicative
- Calculator
- Fully calculable
Definition
Jargon File: 10^-18 parsec, about 3.1 cm.
Reference value
One attoparsec is equal to 0.0308568 metres.
History & use
Jargon File: 10^-18 parsec, about 3.1 cm.
Modern use
Used mainly as an informal, humorous, or illustrative reference rather than an official measurement standard.
Did you know?
The Jargon File notes a delightful coincidence: an attoparsec is about an inch, and one attoparsec per microfortnight is about one inch per second.
Sources & evidence
Source tier Tier A — government / museum / authoritative institutional source · confidence High
Related measurements
length · International · Modern
1 km = 1000 m by the SI prefix kilo-.
length · International · Modern
1 cm = 0.01 m by the SI prefix centi-.
length · International · Modern
1 mm = 0.001 m by the SI prefix milli-.
inch
inlength · UK / US · Modern / historical
1 international inch = exactly 0.0254 m.
foot
ftlength · UK / US · Modern / historical
1 international foot = exactly 0.3048 m.
yard
ydlength · UK / US · Modern / historical
1 international yard = exactly 0.9144 m.
mile
milength · UK / US · Modern / historical
1 international mile = exactly 1609.344 m = 1760 yd.