Pluto was first recognized as a body in our Solar System by Clyde Tombaugh who was studying pairs of photographic plates, attempting to locate Planet X. Just over a month after its initial discovery, after suggestions for names were submitted, the Lowell Observatory staff voted for “Pluto”, a name suggested by an eleven-year old schoolgirl by the name of Venetia Burney in Oxford, England, who was interested in classical mythology as well as astronomy.
Pluto is a member of the Kuiper Belt, the largest known Kuiper Belt Objects (KBOs), denizens which reside in a region that extends from Neptune’s orbit of about 30 AU to approximately 55 AU (where 1 AU is the mean distance from the Sun to the Earth). A distant and cold world, Pluto has held fascination for astronomers for decades, as repeated attempts have been made to study it’s surface, in order to find out more about this elusive little planet.
Pluto is markedly different from all the other planets in the Solar System (which is why it was redesignated a Dwarf Planet, and not a full planet). First off, it is smaller than all the other ‘regular’ planets. Secondly, all the planets in the Solar System orbit the Sun in a plane called the ecliptic, never venturing more than a few degrees above or below as they wing around our star. Pluto’s orbit is inclined over 17 degrees from the ecliptic. Thirdly, Pluto’s orbit is highly eccentric (elliptical), moreso by far than any of the other planets, ranging from just over 29 AU from the Sun to a hair over 49 AU from the Sun. Even Mercury, whose orbit is relatively eccentric compared to the other planets, only ranges from 0.3 to 0.47 AU away from the Sun.
Pluto rotates on its axis in 6 days 9 hours and 17.5 minutes. It orbits our Sun every 248.09 years. It boasts three moons. The first, Charon, is the largest and was discovered in 1978, and the other two, Nix and Hydra, were discovered in 2005 by astronomers using the Hubble Space Telescope.
Pluto was found to have an atmosphere during an occultation observation in 1985, and reconfirmed by a second occultation observation in 1988. Further studies have shown that this thin envelope of gas consists of nitrogen, methane, and carbon monoxide. When Pluto is closest to the Sun in its orbit, the atmosphere is create by sublimation of the ices on Pluto’s surface. As Pluto moves towards the outer portion of its orbit, the atmosphere gradually freezes and falls back to the surface as an ice mist.
As of the publication of this cache, only the Hubble Space Telescope, in 1996, has been able to image the surface of Pluto, but the resolution is rather poor: 1 pixel is approximately the equivalent of 300 miles (no reading of Plutonian license plates here!). Enough to discern light and dark areas, but little else. To further our understanding and knowledge of our Solar System, NASA launched the New Horizons space probe in January of 2006. It swung by Jupiter in February 2007, getting a gravity boost to fling it at Pluto. It did its flyby of the Pluto-Charon system on July 14th, 2015 (without the gravity boost assist, New Horizons would not have reached Pluto until 2020 or later). On board the spacecraft are some of Clyde Tombaugh’s ashes. Clyde had passed away in 1997.
This cache is part of a series of caches of objects in our Solar System, scaled to fit within the state of Maryland. 1 mile is the equivalent of 1 AU (astronomical unit). The cache you are seeking here is a micro, and is about 30 or so miles (AU) from The Solar System Tour: The Sun cache (GC10HDR). For the seasoned cacher, the hide should be pretty straight-forward. There is room in the cache for the reduced-size logsheet and little else. Bring your own pen/pencil. The cache starts out with a micro geocoin and a fossilized mako shark tooth.