New 'Planet' Discovered in Solar System

Greyfox writes: "This USA Today story tells us that astronomers have discovered a puny little "planet" between Neptune and Pluto. Significantly larger than your average asteroid, it falls just shy of qualifying as being planet sized." Plutino?

Comments

If a planet circles in darkness, does it exist?

[WillAffleck]

Seriously. Let's say you're in a solar system with twelve major planets, but two of them are airless, have less effect than asteroids and meteors, and pretty much are only found when you look really hard for them.

Are they planets? Or just statistical anomolies intended to distract us from sending extrasolar probes to avoid the inevitable destruction of this solar system? Because, if we don't get out of the solar system, human life is an historical footnote in the history of the universe, a leaf fluttering from a tree in a vast and empty forest, which falls and decomposes with noone ever seeing it.

hrmmm

[Nate Fox]

I wonder if it came out of Uranus? :)

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If Bill Gates had a nickel for every time Windows crashed...

Re:Other possible names

[Black Parrot]

> More?

Plutanium - naw, Intel already has that one.

Plu.net - naw, Micorsoft already has that one.

Plunix - naw, The Open Group already has that one.

Plutoe - naw, Dan Quayle already has that one.

I give.

well...

[zenith744]

it was bound to happen. time to sew another star into the flag...

wait a minute...

Isn't the moon a planet?

[cperciva]

Broadly, the IAU group agrees that a planet should independently orbit a star, possess enough gravity to shape itself into a sphere and weigh at least 100,000 billion billion grams. EB173 just misses the last mark, Boss says.

Judging by this definition, earth's moon should be considered a planet. It is easily massive enough, and it has greater gravitational attraction to the sun than it does to the earth.

A planet which shares the same orbit as the earth, sure, but still a planet.

Re:Isn't the moon a planet?

[KFury]

I don't know what the astronomical distinction is between an asteroid and a planet, but I know what defines a moon.

A moon is a natural object that orbits a planet, where the center of mass of the planet-moon system lies within the planet. the irony is that although 'the Moon' is the archetypical moon, it doesn't fit this definition, as both the Moon and Earth rotate around a point in space between the two and outside the Earth. In truth, the Moon-Earth system is a binary planetary system, as is Charon and Pluto. All other 'moons' in the solar system are true moons by this definition.

Kevin Fox

No, it orbits the Earth

[Lish]

Look at your quote. "... should independently orbit a star ...." Earth's moon does not orbit the sun independently, but rather as a satellite of Earth. If your interpretation were correct there would be no such thing as a large moon.

the Earth-at-the-center--of-the-universe issue

[Rob Cebollero]

One debunkable point that often comes up in various metaphysical/religious debates is the issue of the ancient belief in the sun orbiting the earth. In our society we are rather led to believe that this "Earth centered" view was the only one anyone around (along with the Flat Earth concept) until Copernicus came along and suggested the opposite arrangement. This is plainly untrue. To wit:

"Most people think the Earth lies at the center of the universe... but the Italian philosophers known as Pythagoreans take the contrary view. At the center, they say, is fire and the Earth is one of the stars, creating night and day by its circular motion about the center." - Aristotle, de caelo 293a

Note that here, even in the age of Pythagoras (sixth century BC), Earth is reduced to an insignificant star among the multitude, at least as far as philosophy was concerned. It even comes up, in slightly different form, in Ptolemy's Almagest, the standard astronomical text of the middle ages, a classic that was required reading for formally educated members of society, particularly clergy and government staff.

This theory has been known as one possibility among several ever since; it was not "discovered" by later astronomers as most textbooks would have us believe. Sure, mathematics and, later, telescopes helped to prove it correct, but the idea was current long before.

Images of EB173:

[Anne Marie]

Here're some clear images of EB173 captured by the Fort Bend Astronomy Club. It seems they imaged it without necessarily knowing EB173's significance at the time.

And while I'm at it, here's a considerably grainier shot taken at the Klet observatory.

Text of Rabinowitz's paper:

[Anne Marie]

The actual paper discussed in the article can be found here .

Ceres is larger

[Jalal]

Pluto = 1440 miles in diameter

Ceres = 584 mi

EB173 (Plutino) = 373 mi

Pallas = 365 mi

Vesta = 358 mi

Not quite...

[isaac]

The barycenter (center of mass) of the earth-moon system is some 1707 km below Earth's surface. The Earth/Luna mass ratio is larger than any other planet/moon system in our solar system, bar Pluto/Charon, but I wouldn't go so far as to call the moon a planet.

Bottom line, your thesis is based on a faulty assertion. (i.e. Earth and Luna don't revolve around a common point in space - that point is comfortably beneath the earth's surface.)

See this link for greater detail.

-Isaac

A Little Light Astronomy

[JazzManJim]

Wow...finally a slashdot article that allows me to use a hobby of mine that's really obscure! Yay!

Okay, first, this object will probably not be called "Plutino", because that name's already pretty much taken and has been used for a class of objects which astronomers decide are larger than the average asteroid, but smaller than the traditional definition of a planet. They've been discovering plutinos for years now and there's even a circular which goes out in the astronomical community a couple times a year which outlines the information on all the plutinos.

These plutinos, and even Pluto itself, is believed to have come from, or may still be part of a large group of chunks of rock called the Kuiper Belt. This belt rings our solar system just beyond the orbit of Pluto. The important factor influencing these object is the planet Neptune which, because of its orbit, will occasionally pull an object from the Kuiper belt and drag it into the solar system proper. Also, bodies in the Kuiper Belt run into each other, and the collision will send a body into our solar system. This is where astronomers believe Pluto and this new rock may have come from. Astronomers believe that there are even more bodies orbiting more closely than the Kuiper Belt, probably tucked in between the orbits of Neptune and Pluto, and just beyond Pluto.

Beyond the Kuiper Belt is yet another conglomeration of chunks of rock and dust called the Oort Cloud. This also surrounds our solar system and may actually protect us from some of the things that could zip into the system and strike another planet or disrupt things. The Oort Cloud also provides us with debris which will come floating into the solar system from collisions with object in the cloud, or from objects that arrive in the cloud from outside. We don't quite know how large the cloud is, for sure, nor how many objects are in ot, mostly because the cloud doesn't reflect what little light it might get. We make our guesses based on fairly obscure measuring methods. It has been suggested that perhaps the Oort Cloud has a good amount of Dark Matter in it, but that's pretty much conjecture right now.

The upshot of the whole thing is that, the harder we look, the more we find in our own backyard. Our methods of studyign the heavens have gotten more and more sophisticated, and allow us to see smaller objects, orbiting farther away. I, personally, hope that we realize that, as long as we're looking out there anyhow, it wouldn't be a bad idea to look systematically, especially for objects that could pose some sort of threat to our planet directly. The tech is cheap, and what we'd need to build to deal with any intruder that might run into us is also quite cheap. Maybe it's not a bad idea at all.

-Jimmie

Planet Order Mnemonic

[empesey]

Now, the mnemonic to remember the order of the planets work any longer. I'll have to change My Very Easy Mother Justifies Sex, Unless Not Paid to something else.

&nbspMy Very Easy Mnemonic Just Sucks - Useless Now, Extra Planet.

The debate

[Veteran]

National Observatory Six astronomers were injured and two hundred were arrested when police had to step in to stop a riot at the observatory. Fighting broke out between the Politically Correct Revisionist Faction and the traditionalist branches of Astronomy.

Phillip Narf a spokesman for the P.C.R.F. said: "The traditionalists are pooh heads. Pluto is the smallest planet, and as such it needs to be called an asteroid". "Nonsense" replied Arnold Dweeb of the traditionalist school "if we call Pluto an asteroid it would be by far the largest asteroid ever discovered, and as such would automatically be promoted to planetary status."

In a related story computer nerds around the world were seen dancing in the streets. A post on Slashdot - the computer nerd news web site explained the jubilation: "Finally we have found a group even more pathetic than we are; at least we could go out at night if we wanted to. And everybody used to say that we needed to get lives."