Nautical mile

The International Hydrographic Organization (IHO) is an intergovernmental organisation representing hydrography. As of May 2022, the IHO comprised 98 Member States.

The International Civil Aviation Organization is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international air transport to ensure safe and orderly growth. ICAO headquarters are located in the Quartier International of Montreal, Quebec, Canada.

The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronics engineering, electrical engineering, and other related disciplines with its corporate office in New York City and its operations center in Piscataway, New Jersey. The mission of the IEEE is advancing technology for the benefit of humanity. The IEEE was formed from the amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers in 1963.

The nanometre or nanometer is a unit of length in the International System of Units (SI), equal to one billionth of a metre and to 1000 picometres. One nanometre can be expressed in scientific notation as 1×10−9 m, and as 1/1000000000 metres.

Latin is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition.

In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is significant, and they are sometimes identified by their position in an ordered tuple and sometimes by a letter, as in "the x-coordinate". The coordinates are taken to be real numbers in elementary mathematics, but may be complex numbers or elements of a more abstract system such as a commutative ring. The use of a coordinate system allows problems in geometry to be translated into problems about numbers and vice versa; this is the basis of analytic geometry.

A circle of latitude or line of latitude on Earth is an abstract east–west small circle connecting all locations around Earth at a given latitude coordinate line.

In geography, latitude is a coordinate that specifies the north–south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or parallels, run east–west as circles parallel to the equator. Latitude and longitude are used together as a coordinate pair to specify a location on the surface of the Earth.

In geography and geodesy, a meridian is the locus connecting points of equal longitude, which is the angle east or west of a given prime meridian. In other words, it is a line of longitude. The position of a point along the meridian is given by that longitude and its latitude, measured in angular degrees north or south of the Equator. On a Mercator projection or on a Gall-Peters projection, each meridian is perpendicular to all circles of latitude. A meridian is half of a great circle on Earth's surface. The length of a meridian on a modern ellipsoid model of Earth has been estimated as 20,003.93 km (12,429.87 mi).

Longitude is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians are semicircular lines running from pole to pole that connect points with the same longitude. The prime meridian defines 0° longitude; by convention the International Reference Meridian for the Earth passes near the Royal Observatory in Greenwich, England on the island of Great Britain. Positive longitudes are east of the prime meridian, and negative ones are west.

In mathematics, a great circle or orthodrome is the circular intersection of a sphere and a plane passing through the sphere's center point.

The equator is a circle of latitude that divides a spheroid, such as Earth, into the northern and southern hemispheres. On Earth, it is an imaginary line located at 0 degrees latitude, about 40,075 km (24,901 mi) in circumference, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical.

An Earth ellipsoid or Earth spheroid is a mathematical figure approximating the Earth's form, used as a reference frame for computations in geodesy, astronomy, and the geosciences. Various different ellipsoids have been used as approximations.

The metre is the base unit of length in the International System of Units (SI).

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, larger only than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosphere and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes, and polar ice caps. Mars has two small, irregularly shaped moons, Phobos and Deimos.

Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space without having to rely solely on estimated positional calculations, commonly known as "dead reckoning", made in the absence of satellite navigation or other similar modern electronic or digital positioning means.

The idea of sending humans to Mars has been the subject of aerospace engineering and scientific studies since the late 1940s as part of the broader exploration of Mars. Some have also considered exploring the Martian moons of Phobos and Deimos. Long-term proposals have included sending settlers and terraforming the planet. Proposals for human missions to Mars came from e.g. NASA, Russia, Boeing, and SpaceX. As of 2023, only robotic landers and rovers have been on Mars. The farthest humans have been beyond Earth is the Moon.