WHAT LIES BEYOND NEPTUNE
Pluto may no longer be considered a planet, but that doesn’t mean it wants for company. Since Pluto’s discovery in 1930, scientists have discovered over 1,200 Trans-Neptunian Objects, listed here:http://bit.ly/9wt4Rt
Though Pluto’s reclassification was controversial among those who had grown up knowing it as one of the nine planets, its position in the Kuiper belt places it in the company of several other smaller bodies. The qualifications for a Trans-Neptunian Object incorporates a broad volume of space that plays host to bodies of wildly varying sizes—the Kuiper Belt, the scattered disc, and the Oort cloud.
Of these, scientists have discovered a number of distant icy worlds that are either classified or vying for classification as dwarf planets. Pictured here are 8 of the brightest, though not necessarily the largest, TNOs discovered.
Eris is the largest, at 27% more massive than Pluto, and possesses a tiny moon only 150 km across known as Dysnomia. [1] The name is fitting—Eris was the Greek goddess of discord, and the similarity of this dwarf planet to Pluto was a major contributing factor to the former 9th planet’s demotion.
Makemake is the 3rd largest after Pluto, and appears to have neither satellites nor an atmosphere. [2] Haumea’s unique ellipsoid shape, rapid orbit, and two tiny moons Hiʻiaka and Nāmaka, are all believed to be the result of collisions that created much of this debris-littered volume of space. [3]
Sedna is one of the most distant known objects in the Solar system, orbiting at three times the distance from Pluto to Earth. Because of its small size, it is not recognized by the IAU as a dwarf planet and its status—like Pluto’s—is hotly contested. Its extremely elliptical orbit at the very fringes of the Solar system have led some astronomers to believe that Sedna is the first directly observed body in the hypothetical Oort cloud. [4]
Orcus, orbited by its moon Vanth, is often referred to as the “anti-Pluto.” Due to Neptune’s gravitational influence, both objects have the same orbital period but are locked in opposite phases of their orbits—when one is at its closest to the sun, the other is at its furthest. [5]
Both Quaoar and 2007 OR10 are believed to be covered in water ice, but observation has revealed that their surfaces are reddish in color. It’s believed that radiation from space converted the methane that remained in their atmospheres to hydrocarbon chains that give the ice its rosy color. The water ice itself is thought to have spewed from cryovolcanoes long ago. [6] Quaoar’s tiny moon, Weywot, is estimated to be only 74 km across. [7]
Both the distance and small size of these icy microworlds present challenges for researchers who study Trans-Neptunian Objects, but further observation of the debris that lies at the outer edges of our Solar System will give us important clues regarding its formation.
-RLO
This post originally appeared at The Universe on Facebook
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