Planets and Moons  ID: 12082

Moons In Chaos

Story by Alison Takemura Released on February 16, 2016
Download Options
Pluto’s moons Nix and Hydra tumble unpredictably in their orbits.
How long a day lasts and where the sun rises and sets are impossible to forecast on one of Pluto’s five moons, Nix. When NASA’s Hubble Space Telescope observed odd changes in the sunlight Nix was reflecting, researchers realized that Nix does not rotate predictably like Earth’s moon. Instead, it tumbles chaotically as it revolves around Pluto. Nix’s erratic nature comes from orbiting a double planet: Pluto and its largest moon, Charon, which is about half Pluto’s size. The two swing around each other like a dumbbell with unequal weights, shifting the gravity field that Nix experiences and tugging the potato-shaped moon in different directions about its axis. The same chaos afflicts Hydra, another tiny Pluto moon. Watch the video to see an animation showing Nix’s wobbles as it orbits Pluto.
Download Options
This simulation shows how Nix might move as seen from Pluto. The video compresses four years of modeled motions into less than two minutes.
Download Options
This image of Nix was taken in 2015. The moon's chaotic movements were predicted by the way light reflected off its surface over a period of years.
Download Options
Similar observations show Pluto's moon Hydra (above) also wobbles chaotically on its axis.
Download Options
Orbit diagram showing the location of Nix and Hydra in relation to Pluto and its largest moon Charon.
 

Related Story

Pluto's Underground Ocean

Story Credits

Scientist:
Mark Showalter (SETI Institute)

Lead Writer:
Alison Takemura (USRA)

Please give credit for this item to:
NASA's Goddard Space Flight Center
Video courtesy of NASA/ESA/M. Showalter, SETI Institute/G. Bacon, STScI
Images courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Short URL to share this page:
https://svs.gsfc.nasa.gov/12082

Keywords:
SVS >> App
NASA Science >> Planets and Moons