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[Chicago Astronomer - Astro Joe]

Hubble Confirms Two New Moons of Pluto

Credit: NASA, ESA, H. Weaver (Johns Hopkins University/Applied Physics Laboratory), A. Stern (Southwest Research Institute) and the HST Pluto Companion Search Team

Anxiously awaited follow-up observations with NASA's Hubble Space Telescope have confirmed the presence of two new moons around the distant planet Pluto. The moons were first discovered by Hubble in May 2005, but the science team probed even deeper into the Pluto system last week to look for additional satellites and to characterize the orbits of the moons.


The confirmation reinforces the emerging view that the Kuiper Belt, a swarm of icy bodies encircling the solar system beyond Neptune, may be more complex and dynamic than astronomers once thought. Pluto resides inside the Kuiper Belt and is about 3 billion miles from the Sun. Pluto was discovered in 1930.

The moons' orbits are in the same plane as the orbit of the much larger satellite Charon (discovered in 1978). This likely means the moons were not captured, but instead were born, along with Charon, in what is commonly theorized to have been a titanic collision between two Pluto-sized objects over 4 billion years ago.

Astronomers believe that the formation of the Pluto system is similar to that of our Earth and Moon. In both cases a comparable-sized body slammed into the parent planet. Simulations show that debris from the collision would go into an orbit around the planet and coalesce to form one or more satellites. Investigating how Pluto ended up with three moons while the Earth has only one should yield valuable insights into the processes by which satellite systems form around planets.

The team will use Hubble again on March 2 to study the new moons. They hope the follow-up observations will provide information on the moons' color, as well as their size and shape, which could yield further clues about the formation and evolution of the Pluto system.

In the Hubble image, Pluto is in the center and Charon is just below it. P 1 is to the right and just below Charon. P 2 is to the right of Pluto and Charon.

Source: Space Telescope Science Institute

Full story here: www.physorg.com/news11093.html

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I bet in 10 years, the old view of our solar system and space in general will be drastically different than is understood now.

It's a whole new universe...

[Al Degutis]

From Universe Today:

The International Astronomical Union approved new names for Pluto's recently discovered tiny moons. Previously designated S/2005 P 1 and 2, the moons will now bear the names Hydra and Nix. In mythology, Nix is the goddess of darkness and night, while the hydra is a monster with the body of a serpent and nine heads. Although they're faint dots right now, NASA's New Horizons probe will fly pas them in 2015, and map them in much more detail.

Rest of the story here:
www.universetoday.com/2006/06/22/plutos-new-moons-are-named-nix-and-hydra/

[Chicago Astronomer - Astro Joe]

Here, to follow up on Al's post...

Pluto's Newly Found Moons Named Nix, Hydra

Meet the newest kids in the solar system: Nix and Hydra. The pair of moons orbiting Pluto were officially christened last week by the International Astronomical Union, which is in charge of approving celestial names.

Until last year, scientists thought Pluto was accompanied by only one moon, Charon. But the Hubble Space Telescope spotted the two satellites - more than twice as far away as Charon and many times fainter.

The duo had been known by the tongue-twisting names S/2005 P 2 and S/2005 P 1. Earlier this year, the moons' discoverers, led by Alan Stern of the Southwest Research Institute in Boulder, Colo., submitted their choices to the IAU.

The names, with roots in Greek mythology, were selected in part because the first letter of each, "N" and "H," were a tribute to the New Horizons spacecraft, Stern said Wednesday.

New Horizons blasted off earlier this year on a nine-year mission to study Pluto, the last unexplored planet in the solar system. Stern is the mission's principal investigator.

Nix was originally spelled "Nyx" by Stern's group. Nyx is the Greek goddess of darkness and Hydra is the nine-headed serpent that guarded the underworld. Pluto is the Roman god of the underworld.

But since a near-Earth object was already called Nyx, the IAU decided to tweak the spelling to "Nix" to avoid confusion. The names passed by a majority vote, said Brian Marsden, a Harvard astronomer and IAU committee member. Stern said he wasn't disappointed by the spelling change because the pronunciation and significance of the names were still intact.

This summer, the IAU will debate whether Pluto should remain a planet. The discovery of an icy object slightly larger than Pluto in the Kuiper Belt last year reinvigorated the argument over whether to demote Pluto or add other planets.

Source: www.forbes.com/home/feeds/ap/2006/06/21/ap2831970.html

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I think the Solar System will be a larger one soon.

[Chicago Astronomer - Astro Joe]

Orbits of known Plutonian Satellites

Source: www.boulder.swri.edu/plutonews/