Meter Prefixes and Other Units
This section introduces prefixes used on 'meter' to represent decadic multiples or fractions of a meter. It also covers other standard units to measure distances like foot, mile, nautical mile and lightyear.
For the convenience of measuring a very long or very short distance,
some prefixes have been defined on "meter" to be decadic multiples or fractions of a meter.
Here are some commonly used meter prefixes and their abbreviated symbols:
Prefix Name Symbol Definition
peta petameter Pm 1 000 000 000 000 000 meters
tera terameter Tm 1 000 000 000 000 meters
giga gigameter Gm 1 000 000 000 meters
mega megameter Mm 1 000 000 meters
kilo kilometer km 1 000 meters
meter m 1 meter
deci decimeter dm 0.1 meter
centi centimeter cm 0.01 meter
milli millimeter mm 0.001 meter
nano nanometer nm 0.000 000 001 meter
pico picometer pm 0.000 000 000 001 meter
femto femtometer fm 0.000 000 000 000 001 meter
Beside "meter", other standard units are also used to measure distances.
- "foot" - "foot" was originally defined as the average foot (shoe include) length of Europeans.
It is standardized now that 1 foot = 0.3048 meter.
- "yard" - "yard" is defined as 3 times of 1 foot.
That means 1 yard = 0.9144 meter.
- "inch" - "inch" is defined as 1 12th of 1 foot.
That means 1 inch = 0.0254 meter.
- "mile" - "mile" was originally defined as 1,000 paces,
where each pace (about 5 feet) is the distance covered by two steps of a marching Roman soldier.
It is standardized now that 1 mile = 1,609 meters.
- "nautical mile" - "nautical mile" was originally defined as one minute arc length along any meridian line.
Since a meridian line has 360 degrees and each degree has 60 minutes,
so the entire length of a meridian line is 21,600 (360*60) nautical miles, which is about 40,000,000 meters.
Based on this, 1 nautical mile is about 1,852.85185 meters by the original definition.
It is standardized now that 1 nautical mile = 1,852 meters.
- "lightyear (ly)" - "lightyear" is defined as the distance that light travels in vacuum in one year.
We know the speed of light is 299,792,458 meter per second.
So a lightyear is about 9,454,254,955,488,000 meters, clost to 10 petameters.
Last update: 2014.
Table of Contents
About This Book
►Introduction of Space
What Is Space?
What Is Distance?
Meter Based on Earth's Meridian
Meter Based on Seconds Pendulum
►Meter Prefixes and Other Units
List of Various Distances and Lengths
Introducion of Frame of Reference
Introducion of Time
Introduction of Speed
Newton's Laws of Motion
Introduction of Special Relativity
Time Dilation in Special Relativity
Length Contraction in Special Relativity
The Relativity of Simultaneity
Introduction of Spacetime
Minkowski Spacetime and Diagrams
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