NASA's Hubble Discovers Another Moon Around Pluto

http://www.newswise.com ^ | 7/20/2011 9:00 AM EDT | Staff

[Red Badger]

Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny, new satellite -- temporarily designated P4 -- was uncovered in a Hubble survey searching for rings around the dwarf planet.

The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km).

"I find it remarkable that Hubble's cameras enabled us to see such a tiny object so clearly from a distance of more than 3 billion miles (5 billion km)," said Mark Showalter of the SETI Institute in Mountain View, Calif., who led this observing program with Hubble.

The finding is a result of ongoing work to support NASA's New Horizons mission, scheduled to fly through the Pluto system in 2015. The mission is designed to provide new insights about worlds at the edge of our solar system. Hubble's mapping of Pluto's surface and discovery of its satellites have been invaluable to planning for New Horizons' close encounter.

"This is a fantastic discovery," said New Horizons' principal investigator Alan Stern of the Southwest Research Institute in Boulder, Colo. "Now that we knoW there's another moon in the Pluto system, we can plan close-up observations of it during our flyby."

The new moon is located between the orbits of Nix and Hydra, which Hubble discovered in 2005. Charon was discovered in 1978 at the U.S. Naval Observatory and first resolved using Hubble in 1990 as a separate body from Pluto.

The dwarf planet's entire moon system is believed to have formed by a collision between Pluto and another planet-sized body early in the history of the solar system. The smashup flung material that coalesced into the family of satellites observed around Pluto.

Lunar rocks returned to Earth from the Apollo missions led to the theory that our moon was the result of a similar collision between Earth and a Mars-sized body 4.4 billion years ago. Scientists believe material blasted off Pluto's moons by micrometeoroid impacts may form rings around the dwarf planet, but the Hubble photographs have not detected any so far.

"This surprising observation is a powerful reminder of Hubble's ability as a general purpose astronomical observatory to make astounding, unintended discoveries," said Jon Morse, astrophysics division director at NASA Headquarters in Washington.

P4 was first seen in a photo taken with Hubble's Wide Field Camera 3 on June 28. It was confirmed in subsequent Hubble pictures taken on July 3 and July 18. The moon was not seen in earlier Hubble images because the exposure times were shorter. There is a chance it appeared as a very faint smudge in 2006 images, but was overlooked because it was obscured.

Hubble is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy Inc. in Washington.

For images and more information about Hubble, visit:

http://www.nasa.gov/hubble and http://hubblesite.org/news/2011/23

[Straight Vermonter]

Cerberus?

[Clara Lou]

LOL!

[Red Badger]

Good choice!...............

[Mannaggia l'America]

[NonValueAdded]

I say we name it Goofy.

[Ruy Dias de Bivar]

****They also discovered another moon around Uranus.***

Ohh let me guess! They named it...HEMEROID!

[blueunicorn6]

Oh, my....but that is a good one.

[Boiling point]

Why do other planets get to have multiple moons but we only have one? It isn’t fair! I am for moon redistribution! I must send an urgent letter to Sheila Jackson Lee so she can sponsor a bill. (and watch the hilarity begin)

[Red Badger]

We should be thankful we have a moon at all!............... If it weren’t for our Moon, we might not be here!...........

[6SJ7]

P4? Having three moons and denying planetary status is one thing, but 4 moons! It is just wrong to deny Pluto a return to planetary status.

And “P4”? Not very romantic. How about Persephone, queen of the underworld in Greek mythology, and the original name proposed for Pluto’s moon Charon.

[Red Badger]

Another good choice!.........

[lonevoice]

[SunkenCiv]

Thanks Red Badger! I sure am glad Pluto's still a planet.

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[SunkenCiv]

How big is Pluto?
http://www.mikebrownsplanets.com/2010/11/how-big-is-pluto-anyway.html

So is Pluto a planet after all? (he sez no)
http://www.mikebrownsplanets.com/2010/11/so-is-pluto-planet-after-all.html

The seven planets
http://www.mikebrownsplanets.com/2010/12/seven-planets.html

There is something out there — parts 1, 2, 3
http://www.mikebrownsplanets.com/2010/10/there-is-something-out-there.html
http://www.mikebrownsplanets.com/2010/10/theres-something-out-there-part-2.html
http://www.mikebrownsplanets.com/2010/11/theres-something-out-there-part-3.html

http://www.mikebrownsplanets.com/

[SunkenCiv]

"To Pluto And Far Beyond" By David H. Levy, Parade, January 15, 2006 -- We don't have a dictionary definition yet that includes all the contingencies. In the wake of the new discovery, however, the International Astronomical Union has set up a group to develop a workable definition of planet. For our part, in consultation with several experienced planetary astronomers, Parade offers this definition: A planet is a body large enough that, when it formed, it condensed under its own gravity to be shaped like a sphere. It orbits a star directly and is not a moon of another planet.