Convert Lightyears to Nautical Miles (ly to nmi) ▶
How to convert
1 nautical mile (nmi) = 1.95761E-13 lightyear (ly). Nautical Mile (nmi) is a unit of Length used in Standard system. Lightyear (ly) is a unit of Length used in Metric system.
Nautical Mile: A Unit of Length
A nautical mile is a unit of length that is used in air, marine, and space navigation, and for the definition of territorial waters. It is based on the Earth’s longitude and latitude coordinates, and is equal to one minute of arc along a meridian. In this article, we will explore the definition, history, uses, and conversions of the nautical mile.
Definition of the Nautical Mile
The nautical mile is defined as exactly 1,852 metres (6,076 feet; 1.151 miles) by the International Hydrographic Organization (IHO) since 1929. This definition is based on the length of one minute of arc along a great circle of a sphere having the same surface area as the Clarke 1866 ellipsoid, which approximates the shape of the Earth.
The nautical mile is not an SI unit, but it is accepted for use with the SI by the International Committee for Weights and Measures. The derived unit of speed is the knot, which is one nautical mile per hour.
History of the Nautical Mile
The concept of the nautical mile dates back to ancient times, when navigators used the stars and angles to measure distances at sea. The word mile comes from the Latin phrase mille passus, meaning a thousand paces.
The nautical mile was originally defined as the length on the Earth’s surface of one minute of arc along a meridian (north-south line of longitude). However, this definition varied depending on the latitude and the shape of the Earth assumed by different countries. For example, France defined a nautical mile as one ten-millionth of a quarter meridian using the original 1791 definition of the metre.The United States and the United Kingdom used an average arcminute based on the Clarke 1866 ellipsoid.
In order to standardize the nautical mile, the IHO adopted the current definition in 1929, which was later endorsed by other international organizations such as the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO). The United States adopted the international nautical mile in 1954 and the United Kingdom in 1970.
Where Nautical Mile is Used
The nautical mile is widely used in navigation, especially for maritime and aviation purposes. It is convenient to use because it corresponds to one minute of latitude, which can be easily measured with a sextant or a GPS device. It also allows for simple calculations of distances along great circles, which are the shortest routes between two points on a sphere.
Some examples of where nautical mile is used are:
How to Convert Nautical Mile
The nautical mile can be converted to other units of length using simple multiplication or division by a conversion factor. Here are some common conversion factors:
For example, to convert 10 nautical miles to kilometres, we multiply by 1.852:
10 NM × 1.852 = 18.52 km
To convert 50 kilometres to nautical miles, we divide by 1.852:
50 km ÷ 1.852 = 27 NM
Example Conversions of Nautical Mile to Other Units
Here are some example conversions of nautical mile to other units:
Lightyear: A Unit of Length
The lightyear is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (9.46 × 10^12 km), or 5.88 trillion miles (5.88 × 10^12 mi). As defined by the International Astronomical Union (IAU), a lightyear is the distance that light travels in a vacuum in one Julian year (365.25 days). The lightyear is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications.
In this article, we will explore the definition, history, usage and conversion of the lightyear as a unit of length.
Definition of the Lightyear
The lightyear is a unit of length that is equal to the product of the Julian year and the speed of light. The Julian year is a unit of time that is equal to 365.25 days or 31,557,600 seconds. The speed of light is a physical constant that is defined as 299,792,458 meters per second. The symbol for lightyear is ly.
The definition of the lightyear can be derived from the following formula:
1 ly = 1 Julian year × speed of light
1 ly = 31,557,600 s × 299,792,458 m/s
1 ly = 9,460,730,472,580,800 m
1 ly = 9.46 × 10^15 m
History of the Lightyear
The concept of the lightyear as a unit of distance was first proposed by the German astronomer Friedrich Wilhelm Bessel in 1838. He used it to estimate the distance to some nearby stars based on their parallax measurements. Parallax is the apparent shift in position of an object when viewed from different angles. Bessel calculated that the star 61 Cygni was about 10.3 lightyears away from Earth.
The term lightyear was popularized by the British astronomer James Bradley in his book Stellar Movements and the Structure of the Universe (1918). He used it to describe the distances to various stars and galaxies. He also introduced the term parsec as another unit of distance based on parallax.
The lightyear was officially recognized by the IAU in 1976 as part of its System of Astronomical Constants.
Usage of the Lightyear
The lightyear is a unit of length that is used for measuring astronomical distances that are too large to be expressed in other units such as kilometers or astronomical units (AU). An AU is equal to about 150 million kilometers or 93 million miles and is roughly the distance from Earth to the Sun.
The lightyear is commonly used in astronomy and cosmology to describe the distances to stars, galaxies, nebulae and other celestial objects. For example:
The lightyear can also be used to measure time intervals in cosmology by relating them to distances traveled by light. For example:
Example Conversions of Lightyear to Other Units
The lightyear can be converted to other units of length by using different factors and formulas. Here are some examples of conversion for different types of units:
1 ly × 9.46 × 10^12 = 9.46 × 10^12 km
1 ly × 5.88 × 10^12 = 5.88 × 10^12 mi
1 ly × 63,241 = 63,241 AU
1 ly / 3.26 = 0.31 pc
1 km / 9.46 × 10^12 = 1.06 × 10^-13 ly
1 mi / 5.88 × 10^12 = 1.70 × 10^-13 ly
1 AU / 63,241 = 1.58 × 10^-5 ly
1 pc × 3.26 = 3.26 ly
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