Hubble finds a tiny fourth moon around Pluto

[4th and Long]

(Reuters) - The Hubble Space Telescope has discovered a tiny fourth moon orbiting the distant icy dwarf planet Pluto, NASA said on Wednesday.

http://www.reuters.com/resources/r/?m=02&d=20110720&t=2&i=462581009&w=320&fh=&fw=&ll=&pl=&r=2011-07-20T154739Z_01_BTRE76J17VI00_RTROPTP_0_SPACE-PLUTO
The most detailed view to date of the entire surface of the
dwarf planet Pluto as constructed from multiple NASA Hubble
Space Telescope photographs taken from 2002 to 2003 and
released on February 4, 2010.

Credit: Reuters/NASA, ESA, and M. Buie (Southwest Research Institute)/Handout


The space telescope was searching for rings around the planetary oddball at the edge of our solar system when it came across P4, the temporary name for the newly discovered moon.

With an estimated diameter of 8 to 21 miles, P4 is the smallest of Pluto's four moons, the U.S. space agency said in a statement.

Pluto's largest moon, Charon, is 648 miles across, and its other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter.

"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, California, who led this observing program with Hubble.

The observation by Hubble is part of ongoing work to support NASA's New Horizons mission, scheduled to have a close encounter with Pluto and its moons in 2015.

P4 is located between the orbits of Nix and Hydra, both of which were discovered by Hubble in 2005. Charon was discovered in 1978 at the U.S. Naval Observatory.

All four of Pluto's moons are believed to have formed when Pluto and another planet-sized body collided in the early history of our solar system. Earth's Moon may have formed the same way.

P4 was first seen in a photo taken by Hubble on June 28 and was confirmed in subsequent Hubble pictures taken July 3 and July 18, NASA said.

http://blogs.nature.com/news/P4%20Large.jpg

http://www.reuters.com/article/2011/07/20/us-space-pluto-idUSTRE76J4L020110720

[Frazod]

So is Pluto still not considered a planet, or have they changed it again?

Seems like anything with multiple moons should get a free pass. :D

[Rooster]

So is Pluto still not considered a planet, or have they changed it again?

Seems like anything with multiple moons should get a free pass. :D

I agree. Pluto got the shaft IMO.

[Dave Lane]

So is Pluto still not considered a planet, or have they changed it again?

Seems like anything with multiple moons should get a free pass. :D

I'm kinda with you on this. If it's got more moons than earth it should be a planet.

[tooge]

just because you've got clingons circling uranus doesn't mean you are a planet. It could mean you just need to wipe better. Hear that Pluto?

[4th and Long]

I'm kinda with you on this. If it's got more moons than earth it should be a planet.
I'm with you guys but,

1. This guy's mission in life was to have Pluto declassified
http://www.haydenplanetarium.org/tyson/media/photos/portraits/neilParaphernalia.jpg
Neil deGrasse Tyson

and he talked to the folks at the IAU (International Astronomical Union) and

2. he conviced them that Pluto be declassified after a vote.

Here’s the problem, according to the IAU. Astronomers had been turning up larger and larger objects in the Kuiper Belt. 2005 FY9, discovered by Caltech astronomer Mike Brown and his team is only a little smaller than Pluto. And there are several other Kuiper Belt objects in that same classification.

Astronomers realized that it was only a matter of time before an object larger than Pluto was discovered in the Kuiper Belt.

And in 2005, Mike Brown and his team dropped the bombshell. They had discovered an object, further out than the orbit of Pluto that was probably the same size, or even larger. Officially named 2003 UB313, the object was later designated as Eris. Since its discovery, astronomers have determined that Eris’ size is approximately 2,600 km (1,600 miles) across. It also has approximately 25% more mass than Pluto.

With Eris being larger, made of the same ice/rock mixture, and more massive than Pluto, the concept that we have nine planets in the Solar System began to fall apart. What is Eris, planet or Kuiper Belt Object; what is Pluto, for that matter? Astronomers decided they would make a final decision about the definition of a planet at the XXVIth General Assembly of the International Astronomical Union, which was held from August 14 to August 25, 2006 in Prague, Czech Republic.

Astronomers from the association were given the opportunity to vote on the definition of planets. One version of the definition would have actually boosted the number of planets to 12; Pluto was still a planet, and so were Eris and even Ceres, which had been thought of as the largest asteroid. A different proposal kept the total at 9, defining the planets as just the familiar ones we know without any scientific rationale, and a third would drop the number of planets down to 8, and Pluto would be out of the planet club. But, then… what is Pluto?

In the end, astronomers voted for the controversial decision of demoting Pluto (and Eris) down to the newly created classification of “dwarf planet”.

For an object to be a planet, it needs to meet these three requirements defined by the IAU:

It needs to be in orbit around the Sun – Yes, so maybe Pluto is a planet.

It needs to have enough gravity to pull itself into a spherical shape – Pluto…check

It needs to have “cleared the neighborhood” of its orbit – Uh oh. Here’s the rule breaker. According to this, Pluto is not a planet.

What does “cleared its neighborhood” mean? As planets form, they become the dominant gravitational body in their orbit in the Solar System. As they interact with other, smaller objects, they either consume them, or sling them away with their gravity. Pluto is only 0.07 times the mass of the other objects in its orbit. The Earth, in comparison, has 1.7 million times the mass of the other objects in its orbit.

Any object that doesn’t meet this 3rd criteria is considered a dwarf planet. And so, Pluto is a dwarf planet. There are still many objects with similar size and mass to Pluto jostling around in its orbit. And until Pluto crashes into many of them and gains mass, it will remain a dwarf planet. Eris suffers from the same problem.

[4th and Long]

just because you've got clingons circling uranus doesn't mean you are a planet. It could mean you just need to wipe better. Hear that Pluto?
Klingon, petaQ!

[Fish]

Also....

http://img855.imageshack.us/img855/8774/tumblrlgbqrkchlh1qzqua1.jpg

[Dave Lane]

Tyson is one of the funniest most knowledgeable astronomers out there. Compared to the dry boring astrophysicists out there he is entertaining and great for astronomy. I agree with his assessment but hate to see it happen.