I is for the International Astronomical Union

Have you ever wondered who gets to decide what or how to name a star? Or who names the craters and mountains on other planets? Who is in charge of defining all the astronomical constants. Who makes sure everything is consistent whether you are studying astronomy in America, or in Germany, or in Japan? The IAU does, that’s who.

The IAU, or the International Astronomical Union, is made up of professional astronomers who hold a PhD or higher and are active in research and education. They are the only internationally recognized authority for assigning names to celestial objects and their surface features. This means that any company offering to sell you the naming rights to a star, or to real estate on the Moon, that company is made up of a bunch of lying liars who lie.

If you have ever seen some of the names the IAU gives to these object you know they look very confusing and very boring but they have to be that way. In ancient times there weren’t many stars visible to the naked eye. Now we have telescopes, and now there are billions of stars visible to our eyes and we have to have a way to name them all that makes sense to everyone, all over the world/

Well known objects, and objects that are close to us, like the other planets in the solar system, or very bright stars can have proper names but that just doesn’t work on a large scale. The IAU uses the analogy or trying to find a person using just their name, or having their exact address.

“Finding Maria Gonzalez in Argentina or John Smith in Britain just from their names is pretty hopeless, but if you know their precise address (perhaps from their social security number) you can contact them without knowing their name at all.”

The IAU also has rules for the way certain object in space should to be named such as moons of other planets, dwarf planets, minor planets, planetary features, comets, nebulae, galaxies, exoplanets, and planets outside our solar system. In addition to that the IAU defines what exactly all of these things are.

Remember in 2006 when Pluto was demoted from it’s status as a planet and joined Ceres, Haumea, Makemake, and Eristo as a “dwarf planet”? Yeah, that was the IAU. I will never forget that when I was a kid, the solar system had 9 planets, not 8! The scientist in me understands though, Pluto had to be demoted or else Ceres, Haumea, Makemake, and Eristo would become planets, and as much as I liked Pluto being a planet, he didn’t really fit in with the other planets.

And maybe, just maybe, Pluto went on to be with other celestial objects who are like him and understand him. Maybe Pluto is happier now.

When the IAU isn’t naming things and making sure they are named in the right way, they are out there promoting education, research, and public outreach. They are proactive in approaching the authorities and governments of other countries to persuade them to join the IAU.

The IAU’s ultimate goal is to improve the astronomical education all over the world, especially in countries that have little to no astronomical education at all. They offer to train new teachers and supply them with teaching and tools and resources as well and translation services.


Image: “PIA01667-Io’s Pele Hemisphere After Pillan Changes“. Licensed under Public Domain via Wikimedia Commons.

This global view of Jupiter’s moon, Io, was obtained during the tenth orbit of Jupiter by NASA’s Galileo spacecraft. Io, which is slightly larger than Earth’s moon, is the most volcanically active body in the solar system. In this enhanced color composite, deposits of sulfur dioxide frost appear in white and grey hues while yellowish and brownish hues are probably due to other sulfurous materials. Bright red materials, such as the prominent ring surrounding Pele, and “black” spots with low brightness mark areas of recent volcanic activity and are usually associated with high temperatures and surface changes. One of the most dramatic changes is the appearance of a new dark spot (upper right edge of Pele), 400 kilometers (250 miles)in diameter which surrounds a volcanic center named Pillan Patera. The dark spot did not exist in images obtained 5 months earlier, but Galileo imaged a 120 kilometer (75 mile) high plume erupting from this location during its ninth orbit.


5 Replies to “I is for the International Astronomical Union”

  1. Well, I still think they’re spoilsports…

    But I do like the way you put it – I hope Pluto is in better company with his peers, and maybe he feels a bit bigger and better now, and less of a little outcast in the cold reaches of our solar system.


  2. I still don’t really like the current definition of “planet”, though.
    For one thing, it says “the sun”, not “a star”, which means that according to the IAU, exoplanets aren’t planets?


  3. I once named a star after a friend of mine. I don’t know whether it’s official, but my friend’s wife has the certificate to prove it.


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