Conversions

• 10,000 metres
• 6.2 miles
• 1 mil, unit of measure commonly used and Sweden

Sports

• 42.195 km — length of the Marathon,

Human-defined scales and structures

• 18 km — cruising altitude of Concorde
• 27 km — circumference of the Large Hadron Collider, the largest and highest energy particle accelerator
• 34.668 km — highest manned balloon flight (Malcolm D. Ross and Victor E. Prather on May 4, 1961)
• 38 km — Length of the world's longest bridge, the Second Lake Pontchartrain Causeway in Louisiana, USA
• 39 km — undersea portion of the Channel tunnel

Natural lengths on Earth

• 10 km — Height of Mauna Kea in Hawaii, measured from its base on the ocean floor
• 11 km — deepest known point of the ocean, Challenger Deep in the Mariana Trench
• 11 km — average height of the troposphere
• 21 km — length of Manhattan
• 23 km — depth of the largest earthquake ever recorded in the United Kingdom, in 1931 at the Dogger Bank of the North Sea
• 34 km — narrowest width of the English Channel at the Strait of Dover
• 50 km — approximate height of the stratosphere

Astronomical

• 10 km — diameter of the most massive neutron stars (3 – 5 solar masses)
• 13 km — mean diameter of Deimos, the smaller moon of Mars
• 20 km — diameter of the least massive neutron stars (1.44 solar masses)
• 20 km — diameter of Leda, one of Jupiter's moons
• 20 km — diameter of Pan, one of Saturn's moons
• 22 km — diameter of Phobos, the larger moon of Mars
• 27 km — height of Olympus Mons above the Mars reference level, the highest known mountain of the solar system
• 43 km — diameter difference of Earth's equatorial bulge
• 66 km — diameter of Naiad, the innermost of Neptune's moons

See also

Notes

References