After a year of observations the Hubble Space Telescope has once again proved scientists that Pluto is a mysterious planet. The planet’s small moons which are known so far, Hydra, Nix, Styx and Kerberos, have an unexpected behavior. According to a report published in the journal Nature the moons form an elaborated gravitational dance.
It seems that the moons are permanently toppled and turned in their attempt to fight the gravitational forces of Pluto and its most important moon, Charon. Astronomer Mark Showalter from the SETI Institute in Mountain View (California) explained that Charon and Pluto resemble two unbalanced weights which are at the end of a dumbbell which is rotating. As a consequence the four moons react to the gravity field of both Pluto and Charon. Hubble’s findings could help scientists discover more about how Pluto and its moon formed and also how the solar system originated.
Hydra and Nix are thought to be too small for their own gravity so they cannot be pulled into spheres. Instead they are elongated in the shape of a potato or a football. Hydra measures almost 36 by 21 miles and Nix is smaller, having approximately 35 miles by 16 miles. The other two moons, Tryx and Kerberos are so small that Hubble cannot accurately establish their shape and size. However they are as well considered to be elongated.
The moons are supposed to be held in place by their long axes which are directed towards the central body and they orbit their primary ax. However the new data from Hubble indicates that the moons are in fact moving in a chaotic way. The cause of it is the complex gravitational interactions which occur between Pluto, Charon and the small four moons.
Showalter commented on the findings:
“It’s a very strange world. You literally would not know if the sun is coming up tomorrow. The sun might rise in the west and set in the east … or the north. If you have real estate on the north pole of Nix, you might suddenly discover one day that you’re on the South Pole instead.”
The New Horizons probe will fly past Pluto and its moons on July 14. Scientists will then have more data which will enable them to identify the celestial bodies’ structure and composition. John Spencer from the Southwest Research Institute believes that the probe will revolutionize the knowledge the scientists have about the moons.
Image Source: Sci News
