American Astronomical Society: Whether you prefer “My very energetic mother just served us nine pickles” or “Make very easy money just save up new pennies,” there are plenty of mnemonics to help you remember the order of the nine planets in our solar system. You could also ask a member of the American Astronomical Society for the actual lineup: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. (We know, Pluto was downgraded to dwarf planet status in 2006, but humor us as we hold with tradition.)

Fédération Aéronautique Internationale: As of 2013, 536 people from 38 countries have gone into space, according to the Fédération Aéronautique Internationale, the international governing body for air sports, aeronautics, and astronautics world records. FAI defines spaceflight as any flight that goes 100 kilometers or 62 miles above Earth. The United States, meanwhile, defines outer space as everything above 80 kilometers or 50 miles.

Association of Space Explorers: Doesn’t matter if you call them astronauts or cosmonauts: To be a member of the Association of Space Explorers a person must have completed at least one orbit of Earth in a spacecraft. Every year ASE hosts an annual Planetary Congress where international space explorers gather to exchange space flight experiences and technical information about space operations, astronaut training, and more.

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