Pluto/Neptune resonance question

Given that :
A.) Pluto crosses Neptune's orbit.
B.) Pluto's orbital plane is offset from the major planets.
C.) Neptune's moon Triton has a retrograde orbit, and is apparently a
gravitationally captured object.
Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time? Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

Pat

Pat Flannery wrote in
:

Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time? Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

Neptune and Pluto have a 3:2 resonance; Neptune completes 3 orbits to
Pluto's 2. I assume the dog wags the tail in this case, and that may
help to make the case that Pluto should not be considered a planet.

http://en.wikipedia.org/wiki/Pluto

--Damon

Damon Hill wrote:
Pat Flannery wrote in
:

Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time? Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

Neptune and Pluto have a 3:2 resonance; Neptune completes 3 orbits to
Pluto's 2. I assume the dog wags the tail in this case, and that may
help to make the case that Pluto should not be considered a planet.

http://en.wikipedia.org/wiki/Pluto

--Damon

In the current era, the resonance works in such a way that Neptune is
never near the point of its orbit when Pluto crosses it. Also, it's not
so apparent in 2D pictures, but due to Pluto's inclination, when it
crosses Neptune's orbit in terms of solar distance, it is many AUs
above or below that orbit.

You'll have someone else about how the situation has evolved over time.

On Sat, 26 Aug 2006 02:37:22 -0500, Damon Hill
wrote:

Pat Flannery wrote in
:

Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time? Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

Neptune and Pluto have a 3:2 resonance; Neptune completes 3 orbits to
Pluto's 2. I assume the dog wags the tail in this case, and that may
help to make the case that Pluto should not be considered a planet.

http://en.wikipedia.org/wiki/Pluto

--Damon


Is there a chance of them ever colliding?

NoBody Here wrote in message
...
Neptune and Pluto have a 3:2 resonance; Neptune completes 3 orbits to
Pluto's 2. I assume the dog wags the tail in this case, and that may
help to make the case that Pluto should not be considered a planet.

http://en.wikipedia.org/wiki/Pluto

--Damon


Is there a chance of them ever colliding?

Not in any timeframe we can accurately predict.

Greg D. Moore (Strider) wrote:

Is there a chance of them ever colliding?



Not in any timeframe we can accurately predict.



I still think the reason Pluto's orbit is odd is that some point in the
past it did have a close encounter with Neptune that shifted its orbit.

Pat

"Pat Flannery" wrote in message
...
I still think the reason Pluto's orbit is odd is that some point in the
past it did have a close encounter with Neptune that shifted its orbit.

And, shortly thereafter, Checkov failed to remember he'd been there before,
and he was then captured by Khan and friends (notice that, during their
stay, the planetary conditions favored the survival of youthful-looking
Caucasians; the strain of leadership must have aged Khan).

In article ,
Pat Flannery wrote:
A.) Pluto crosses Neptune's orbit.

Only in a 2-D plot. Not in three-dimensional space.

Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time?

Yes. As noted above, the orbits don't actually intersect. Also, they are
in a 3:2 resonance such that Pluto avoids Neptune -- the "crossings" occur
near Pluto's perihelion, but Pluto's closest approaches to Neptune occur
at Pluto aphelion.

There are 40ish other "Plutinos", KBOs in similar 3:2 resonances with
Neptune. Plus some other KBOs in more distant resonances.

Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

The past history of resonant systems is difficult to determine, because
settling into the resonance tends to destroy the evidence. :-) But KBO
orbital inclinations vary a lot more than those of the major planets, so
there is no obvious *requirement* for such an encounter to have occurred.
Pluto's orbital plane looked strange when it was the only one of its
kind, but is now seen as nothing very unusual.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

Henry Spencer wrote:
In article ,
Pat Flannery wrote:
A.) Pluto crosses Neptune's orbit.

Only in a 2-D plot. Not in three-dimensional space.

Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time?

Yes. As noted above, the orbits don't actually intersect. Also, they are
in a 3:2 resonance such that Pluto avoids Neptune -- the "crossings" occur
near Pluto's perihelion, but Pluto's closest approaches to Neptune occur
at Pluto aphelion.

According to a synodic period program I have, Neptune and Pluto are in
conjunction once every 492.4 years. I haven't worked the numbers but
I'm curious about when the last such conjunction occurred and when the
next one will be.

Just ran another program and found the last Neptune/Pluto conjunction
to around mid May 1883. So the next one will be early in the 2376. Also
I noted that the conjunctions are moving three degrees toward Pluto
aphelion per conjunction, the last being at about 60 degrees and then
next at 57 degrees, whereas Pluto aphelion is about 45 degrees. All
degrees in heliocentric coordiantes with 0 degrees being the first
point of Aries.

Eric


There are 40ish other "Plutinos", KBOs in similar 3:2 resonances with
Neptune. Plus some other KBOs in more distant resonances.

Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

The past history of resonant systems is difficult to determine, because
settling into the resonance tends to destroy the evidence. :-) But KBO
orbital inclinations vary a lot more than those of the major planets, so
there is no obvious *requirement* for such an encounter to have occurred.
Pluto's orbital plane looked strange when it was the only one of its
kind, but is now seen as nothing very unusual.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

This lists my contribution/modification to an item
originally by Tony Hoffman:

What has resonance to do with if an object should be
considered a planet?
Earth and Mars are in an 2:1 resonance, does that mean
something other
than one orbits twice the time of the other? Of course not.
Clearing their space in orbit? Again not, look at Jupiter
and the difficulty it has
clearing the Trojan asteroids it orbits with. The earth has
a near miss with
asteroids every other day, I can email you the actual list.
Does that mean the
earth is not considered a planet? Of course not. What about

Jupiter-sized extrasolar planets that cross each other's
orbit in 2-D only and
exhibit resonance? Of course they are both planets. (DRL)

It's now been some time since the International
Astronomical Union
(IAU) stripped Pluto of its planethood. In choosing the
more
stringent of two competing definitions of the term planet,
the IAU
has booted Pluto into a new underclass of "dwarf planets",
and
seemingly capped the solar system's planet total at eight.
Many
scientists aren't pleased with the new solar-system order,
saying
it's imprecise and too restrictive.

The ancient Greeks called the points of light that roved
along the
zodiac planetes: wanderers. But despite the discovery of
several new
planets since the invention of the telescope, astronomers
never
defined what a planet actually was. When Ceres, Pallas,
Juno, and
Vesta were discovered in the early 1800s, they were
originally
considered planets, but later reclassified as asteroids.
Pluto,
discovered by Clyde Tombaugh of Lowell Observatory in 1930,
proved
to be much smaller than originally thought, smaller than
Earth's
moon, leading some astronomers to call for its demotion.
But it was
Caltech astronomer Mike Brown's discovery of an ice-world
slightly
larger than Pluto, which he nicknamed "Xena", that brought
the issue
to a head, many wondered whether Xena be classified as a
planet,
or a mere asteroid? And however Xena went, Pluto was likely
to follow.

The initial definition proposed by an IAU committee in
August
defined a planet as an object that orbits the Sun and is
large
enough so that its gravity holds it in a near-spherical
shape.
Opponents claimed that this definition would permit tens or
hundreds
of puny poseurs to become planets (though the proposal took
care to
distinguish the eight "classical planets" from Pluto and
the
upstarts), and it would be confusing to students and the
public.
Almost no one has to memorize the entire periodic table of
the
elements, yet everyone knows oxygen, carbon, iron, and
other key
elements. So, kids would learn of "Xena" (whatever it is
ultimately
named), as well as far-ranging, reddish Sedna, several
large,
exotically named iceballs (Quaoar, Ixion, Orcus, and
Varuna), a
football-shaped world known only as 2003 EL61, and other
worlds as
yet undiscovered. (TH)

It is sad and pathetic that astronomy has become a war
between planetary
geologists, who study the structure and composition of
worlds, and
orbital dynamicists, who are concerned with planetary
motion. The
latter group forced the inclusion of a provision that to be
a
planet, an object must have "cleared the neighborhood
around [its]
orbit". This rules out Pluto which orbits amid a flock of
similar
(yet mostly smaller) iceballs in a region known as the
Kuiper
Belt. Ceres, the largest asteroid; both are being
reclassified as
dwarf planets. But what of Neptune? It hasn't cleared away
pesky
Pluto, nor the Kuiper-belt objects that cross its orbit.
Even
Jupiter has an array of Trojan asteroids before it and
after it cannot
seem to "clear the way" with gravity so strong that it is
almost a star.
It is not a star because it does not light up from
thermonuclear fusion.
So it seems that the IAU definition is not scientific
either, and
it is decidedly unpopular. That is because everyone reading
about it
seems to come to the same conclusion, that is, that the IAU
should have
better things to do with its time and more importantly "our
tax money"
that supports the grants received by astronomers in
general. (DRL)

And by the new definition, Earth, which lies in a cosmic
shooting
gallery of tens of thousands of asteroids that potentially
could
collide with us shouldn't be a planet. (As to whether
there's
intelligent life here, I'll leave that to a future
discussion.

The solar system was due for a reclassification, to keep up
with new
discoveries. It made sense for the IAU to call Pluto the
prototype
for a new type of "trans-Neptunian" object, world, or
planet,
but that and planethood need not be mutually exclusive.
Any definition of planet is some-what arbitrary; it's not
as if objects
are hung with tags that say "I'm a planet!" Faced with
competing definitions,
both with some scientific merit, the IAU went the
restrictive route. Even as
telescopes reveal new and exotic denizens of the outer
solar system,
we've gone and shrunk the solar system. Pluto's gotten the
boot, and
dwarf planets by definition aren't true planets. (Perhaps a
better
name for them would be planettes or worldlets.) Even many
of the
astronomers who supported the new order admit a twinge of
sadness
over Pluto's demotion. The new system is not only
imprecise, but
it's demoralizing. People are inspired by the idea of new
planets in
a way that they're never likely to be for lesser solar
system
bodies. (TH)

It might do well if astronomers borrowed from the
biologist's
species and genus system of organization of plants and
animals.
After all, no one has demoted mice from the animal kingdom
because they are small. Here we would have anything not a
star considered a planet and divided into classes.
Examples might be Ice Giant, Gas Giant, Solid,
Water, Ice, Proto, Extra-solar or Independent
(a planet not in a solar system at all but drifting between
stars).
Words like terrestrial type or lunar type or Mars Type come
to mind.
The relative orbital movement would not be important, that
is,
a planet in another solar system of 12 Jupiter masses
but in a highly elliptical orbit would not be disqualified.


Another simple way might include a defintion that if a
proposed
new object were viewed at the distance of Saturn from the
earth,
mathematically would the new object be readily visible to
the naked eye?
(at least 3rd Magnitude) Such math is very easy to do and
sounds better
than demoting existing planets. By the way, Saturn was the
most
distant planet the Greeks could see and it's their word we
are borrowing
just as I am borrowing part of Tony Hoffman's news item
here.(DRL)

Darrell Lakin
Smithfield, Virginia

Henry Spencer wrote:
In article ,
Pat Flannery wrote:
A.) Pluto crosses Neptune's orbit.

Only in a 2-D plot. Not in three-dimensional space.

Do Pluto and Neptune engage in some sort of long-term resonance
relationship so that Pluto never crosses Neptune's orbit while being in
the same plane and place as Neptune at the same time?

Yes. As noted above, the orbits don't actually intersect. Also, they are
in a 3:2 resonance such that Pluto avoids Neptune -- the "crossings" occur
near Pluto's perihelion, but Pluto's closest approaches to Neptune occur
at Pluto aphelion.

There are 40ish other "Plutinos", KBOs in similar 3:2 resonances with
Neptune. Plus some other KBOs in more distant resonances.

Is the reason that
Pluto's orbital plane is skewed from the other planets due to a close
encounter with Neptune in the distant past that put it into its present
orbit?

The past history of resonant systems is difficult to determine, because
settling into the resonance tends to destroy the evidence. :-) But KBO
orbital inclinations vary a lot more than those of the major planets, so
there is no obvious *requirement* for such an encounter to have occurred.
Pluto's orbital plane looked strange when it was the only one of its
kind, but is now seen as nothing very unusual.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |