Thursday, July 21, 2011

What's Pluto Got That Earth Doesn't?

Well according to this article on NASA's site Three more moons is what. Now I hear ya saying, hey wait, Pluto only has 3 moons. Wrongo! Hubble just found the smallest Pluto moon so far still designated P4.

From the NASA article:
  • The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles. By comparison, Charon, Pluto's largest moon, is 648 miles across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter.
The new moon is located between the orbits of Nix and Hydra and is believed to have formed by a collision between Pluto and another planet-sized body early in the history of the solar system, as were the other three Plutonian moons.

All this work is support work to support NASA's New Horizons mission, scheduled to fly through the Pluto system in 2015.

photo computer generated from Hubble photos - complete gif and info here


Bob W said...

Neophyte comment. If Pluto is not a planet then by definition how can these be called moons?

Beam Me Up said...

Moon is a generic label but still even many of the objects in the asteroid belt have moons.

Rosehippi said...

They just declared Pluto is a moon not a Planet, now they say Pluto has Moons... How can a MOON have 3 moons+ ???
I have always been taught Pluto is the smallest, farthest planet and I will continue to believe it... What if some of these moons are hollow generational ships and hosting life within?
what a thought... wouls make a nice story, eh?

Beam Me Up said...

Pluto is a dwarf planet not a moon. They needed the clarifications because we were about to have not 10 planets but something in the 20s or 30s, which I know is ridiculous but if we were to be honest in our classification then at the very least Vesta and Ceres become planets as well and then we have to start looking at other equally large objects. But if we apply the same rules then only the planets from Neptune in are planets in the true sense. The rest, due to size, and orbit do not meet all of the requirements.

Dave Tackett said...

That argument (planetary definition) is far from settled, though.

The idea that the quantity of items should be a factor in a definition is incredibly unscientific. Do we need a new definition of "insect" because there are millions of different species? A new definition of star because there are "billions and billions" of them?

I Know, it's an old tired argument, though I do believe the definition of "planet" should be based upon its intrinsic properties and not its location.

By the current definition, if the Earth and Pluto were to suddenly change places through some staggeringly implausible quantum fluctuation, the Earth would instantly be a dwarf-planet and Pluto would instantly be a full planet. Now that is ridiculous.

Oh and to continue to be a cantankerous nuisance, I do think we need a new definition of moon. :-)

Homer said...

Personally I am more intrigued by Ceres. I've seen pictures (both enhanced and not) from the Hubble that present it as more of a planet that just a hunk of rock orbiting out there in the belt. Hopefully Dawn will return some awesome pics and data when it gets there in a few years (as well as New Horizons when it gets to Pluto).

Question though - isn't one of the qualifications of being a planet the fact that it does not share its orbit with any other bodies such as asteroids? Wasn't this one of the reasons Pluto was downgraded? The fact that is in the Kuiper belt along with Haumea, Makemake, Eris, etc. Or maybe I'm quoting one of the older classifications.

Beam Me Up said...

Pluto in Earth's orbit yes would make it a planet. That says something about it's present orbit. Pluto is not a planet because it is small but that it does not have a circular orbit and has not cleared it's orbital path of all other bodies in its' path and I think it is based on if it is the major body in that orbit...but that may have been thrown out and the clearing of the orbit brought in. Now Earth in Pluto's orbit.... and everything else stays the same? Would it be a planet under the present definitions? Well it would have the same problems as Pluto the only thing would be that it would have size....that and it has crushed it's shape to that of a sphere.

Now the thing is, the redefining was not just to move Pluto out but to keep the planets to a reasonable number. The Dawn spacecraft is on a mission to visit two that were on a fast track to be called planets because of size. Ceres at one time WAS a planet for that very reason. Is the system perfect? No, but it does go a long way towards defining just how we should look at orbital bodies and dynamics... Plus I am better at remembering eight names instead of twenty or so.... but then that is just lazy.

Beam Me Up said...

Oh Homer you just have to KNOW they will be spectacular! I can not wait...

Dave Tackett said...

A very timely comic on the subject of Pluto. I think you'll like it.

Beam Me Up said...

Dave now that is just plain funny! Thanks!