The installation of the Pluto plaque has been delayed so you will not currently find it where the map indicates - please accept our apologies for any troubles this may have caused you! Pluto itself has been a topic of controversy since the beloved planet was demoted by the International Astronomical Union to a dwarf planet in 2006 and in this case, it seems that art really does imitate life. Due to it's large distance from the Sun, Pluto is the only solar system object is not located on University of Arizona property. Delays in our agreements with property owners have temporarily hindered the placement of the Pluto plaque, but we are actively working to resolve this issue and aim to have it installed in the near future. Thank you for your patience!
Every planet orbits the Sun in an orbit that is very slightly elliptical. Ellipticity refers to far away from circular an orbit is. The placement of all the objects is as close as possible to their semi-major axis, which is basically the average distance from the Sun. An elliptical orbit means that sometimes the planet is closer to and sometimes it is further away from this distance. All the stanchions have been placed within the inner and outermost edges of this region.
AU stands for an astronomical unit and represents the average distance between the Earth and the Sun. One au is equal to 150 million kilometers.