Something else to think about or and factor in is Neptune tilted orbit. It had to have collided with a massive object in the past and Pluto and Charon could have been that objects, or Neptune moon...

Originally posted by ChrisRT
Something else to think about or and factor in is Neptune tilted orbit. It had to have collided with a massive object in the past and Pluto and Charon could have been that objects, or Neptune moon...

Not very propable, difference in mass is like between car and train.

(1.27e+22 kg vs 1.024e+26 kg)

Originally posted by SpookyVince
(...)
Also, it doesn't seem that other planets come to a strange behavior in that software (winstars, that is) unless maybe someone is patient enough to try it to years up to 12,000 or more...

Well, I've just been patient enough... It seems that after a while, there are several planets having strange behaviors:

- Pluto is continuously doing its strange orbits in horseshoe-like movements, larger and larger
- Neptune, though, stays perfectly on its orbit (up to 10000+, so far)
- Uranus starts around 4500+ to change its orbit to something more and more elliptical and excentric, then around 7000 starts to mix horseshoe-like movements together with an elliptical orbits, which gives it funny moves. It then goes more and more like Pluto, closer and further away from the sun.
- By the year 7000, it seems that Saturn changes slightly its orbit to be more elliptic (very slightly). This tendancy is confirmed later in time (10000+), and its orbit becomes quite erratic.
- Slightly after 7000, Jupiter seems to adopt the same change as Saturn, and becomes more elliptic (minor change)
- Over time, (5500+) Mars has changed its orbit also, so that it is more centered on the sun than now. It remains non elliptic (or unnoticeable), but over time (10000+) is de-centered again, but to the other side of the sun.
- Earth and Venus orbits are perfectly on what they are now.
- Mercury has changed also to a significantly more elliptic (6000+), but within Venus orbit.

I think it is all probably is calculation flaws, but then, why 3 bodies stay perfectly where they should and not the others? I mean, it still looks like well organized if you look at the animation in years over 10000.

Is it possible? I mean, has anyone ever wondered if the orbits could really change that significantly in 5 thousand years? Or is it pure sci-fi to imagine that? We don't know well Pluto btw. Its orbit is supposed to take it around the sun in roughly 250 years, and we know it now for just over 70 years...

E_T, I didn't have a look yet at the soft you mentioned, but I will do that later.

Not having looked at the software, take this with a grain of salt:

It sounds like classic numerical error. On computers decimal/fractional numbers are represented by what is known as floating point. On x86 (which is what your AMD or Intel CPU is) this is usually a 64 bit number that is broken up as follows:

1 bit for sign
11 bits for an exponent
52 bits for the 'Significand'

There is only so much that can be represented accurately in a binary based system, so as the difference between numbers becomes larger (say multiple 1000000001 by .0000000001) you can incorrect results (unless you go to EXTREME lengths to do all the math by hand in the code). Multiply that by a couple of million iterations and an error of .0000000000001 quickly becomes an error or .0001 which is not nearly as insignificant as some might naturally think it is.

Note: This information comes my real-world experience writing software that does numerical modelling on PCs for better than 10 years.

Osiris

Originally posted by UofCinLA


The analytical theory of Pluto's orbit is only accurate for
about ±150 years around 1950, so outside that range to avoid
displaying incorrect values, it isn't displayed at all.

Note that Pluto was only discovered in 1930 and with an
orbital period of 248 years has been observed over only a
fraction of its orbit.

i was actually going to submit that thought,
also that Pluto, being recently tracked/discovered...scientists aren't
certain if it is a 'excaped' moon? or a KBO KuiperBeltObject? that has
been ?assimiliated by the inner solar system

so unless a constant plotting (at some expense) of its orbital path is observed and recalculated then published periodically...we're just gonna have to rely on old inexact models...
i guess that would bother some scientific minds
of expected orbit....
Hope that helps....

[edit on 11-12-2004 by St Udio]

St Udio - yup, detailed orbital elements for Pluto have not been calculated yet.

It's hairy math with a 10 body integration and the off the shelf software only uses "mean orbital elements" with Sun as primary gravitational object and ignores all influence of other planetary interactions....

JPL kids have the calcs done for the objects we've traveled to but not the outer planets - since we've not needed them yet and as another post noted - even computers have trouble with the precision necessary for this....

a little off topic, but i saw on a tv show (for little kids) that pluto and its moon share what there is of their atmosphere.
Is this a known fact or were the show's creators lying to kiddies

Originally posted by llama009
a little off topic, but i saw on a tv show (for little kids) that pluto and its moon share what there is of their atmosphere.
Is this a known fact or were the show's creators lying to kiddies

Well Charon does orbit a mere 11,400 miles about Pluto's surface. Not to mention it's about hlf the size and one-fifth the mass of Pluto. The only thing though is that Pluto, since it is so bloody cold, has little to no atmosphre for most of its year. There is blieved to be a thin layer of frozen methane gas though, which during the summer decades of Pluto's orbit evaporates to form a thin, temporary atmosphere. Perhaps some of that is bled off onto Charon.

maybe we could colonise the moon like that, all we need is a big hose and a pump