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bruno
2016-Oct-28, 05:50 PM
Hi All,
Did anyone see this article yet

http://www.astronomy.com/news/2016/10/the-outer-solar-system-keeps-getting-weirder

is it my lack of knowledge that makes me feel this is bad or am I right? I still having trouble understanding the solar system.

Thank You

grant hutchison
2016-Oct-28, 06:11 PM
I can't see what you'd think was bad about it. We're getting evidence of a massive body a long way out on the edge of the solar system. It has presumably been there for the entire history of the solar system.

Grant Hutchison

bknight
2016-Oct-28, 06:17 PM
Yes, the JWST may even detect more objects.

bruno
2016-Oct-28, 06:17 PM
Sorry Grant I should clarify which parts I am confused about. I am not sure what they mean by the below

"Several newly discovered objects on the outskirts of the solar system suggest that something strange is afoot." and "“There are all these different, slightly odd things,” she said. “No one piece of evidence is really convincing me that for sure there is a planet there, [but] the fact that there are multiple things probably says something is happening.”

Swift
2016-Oct-28, 06:22 PM
I think any reason you might have for concern comes from the way the article is written, and not any actual events. The author is trying to be a little sensational. As Grant said, there is nothing to feel bad about.

Any mention of the solar system getting "weird" isn't an implication that the solar system was normal for billions of years, and now something has changed or gone wrong. What is changing is our knowledge of the solar system. As our observing tools improve, we are discovering objects that we never knew existed, or only had hypothesized the existence of. And like with many things, nature isn't always as we expect.

bruno
2016-Oct-28, 06:57 PM
Thank you Swift, the concerining part was the paragraphs below I am not sure what they mean

And L91’s distant path is shifting.

“It’s orbit is changing in quite a remarkable way,” astrophysicist Michele Bannister told scientists last week at the American Astronomical Society’s Division for Planetary Sciences in Pasadena, California. Bannister, an astrophysicist at Queen’s University Belfast, identified minute changes in the object’s orbit that could come from the passing gravity of other stars or interactions with the hypothetical Planet Nine. Simulations by the team suggest that the tiny tugs are more likely to come from beyond the solar system, whether distant stars or galactic winds.

and

‘Something is happening’

L91 isn’t the only new object in the sky. Another team of astronomers reported a handful of smaller icy bodies traveling beyond Neptune. Similarities in the orbits of objects like these led to the proposal of Planet Nine.

“A lot is going on in the outer solar system,” said Scott Sheppard of the Carnegie Institution for Science in Washington, D.C. Sheppard is part of a team of astronomers conducting the largest, deepest survey of trans-Neptunian objects, whose orbits take them farther out than Neptune. The team found several new objects clustered in the outer edges of the solar system.

One of these objects, 2014 FE72, is the first known to come from the Oort Cloud, the icy shell around the solar system where comets are born. With an orbit that takes it out more than 3,000 AUs, it may also suffer from the influence of passing stars or the gravity of Planet Nine

Sheppard and his colleagues have been mapping the sky in detail since 2007. So far, they’ve only covered about 10 percent of what he calls “the most interesting part of the sky.”

But not all scientists are convinced that the increasing number of odd orbits points to Planet Nine.

“We did search some parts of the sky more thoroughly than others,” says astronomer Katherine Volk, a planetary scientist at the University of Arizona. Volk analyzed the growing studies offered up as evidence for the hypothetical planet, and remains skeptical that it is the only conclusion. “You find things where you’re looking,” she says.

She pointed out that the similarities in orbits, or clustering, of the objects could be related to their similar positions in the sky.

“If the clustering persists at the end of [Sheppard’s] survey, it will be more convincing,” she said.

George
2016-Oct-28, 07:09 PM
I think any reason you might have for concern comes from the way the article is written, and not any actual events. The author is trying to be a little sensational. Yes, and the statement, 'While some scientists point to the odd behavior of the newfound residents as further proof for the existence of the hypothetical Planet Nine (a yet-unseen superEarth proposed to inhabit the outskirts) not everyone is convinced." It should read "further evidence", since if we allow the use of "proof" in the first place, and we shouldn't, then we no longer would have a hypothetical planet.

Ironically, the weirdness is actually the orderliness of a handful of objects that have very similar orbital characteristics, which triggered the idea for planet nine. An alternate hypothesis is that there are other dwarf planets or smaller objects, along with these objects (IIRC), that together provide the gravitational forces that would explain their orbits. These hypotheses are testable and one will be favored over the other, if not already. Planet nine seems to be the better bet, apparently.

Swift
2016-Oct-28, 07:40 PM
And L91’s distant path is shifting.

“It’s orbit is changing in quite a remarkable way,” astrophysicist Michele Bannister told scientists last week at the American Astronomical Society’s Division for Planetary Sciences in Pasadena, California. Bannister, an astrophysicist at Queen’s University Belfast, identified minute changes in the object’s orbit that could come from the passing gravity of other stars or interactions with the hypothetical Planet Nine. Simulations by the team suggest that the tiny tugs are more likely to come from beyond the solar system, whether distant stars or galactic winds.

With regard to this (the apparently changing order of L91), this is the first I've heard about it. Without more details, it is hard to know exactly what to make of it, though none of it is alarming. I do wonder about the details - are the changes in orbit because improved observations have changed it from what we thought it was, or has it actually changed? But as far as your concern, the key words are "minute changes". It isn't like L91 is about to be flung at the Earth. Astronomers have predicted for a long time that interactions with other stars might make tiny shifts in the orbits of objects very far out in the solar system; the remarkable part is that we may be observing it for the first time.

As far the other "new" objects, I think George covered it. There is also this thread in Astronomy (https://forum.cosmoquest.org/showthread.php?161608-Is-Planet-Nine-almost-certain-probable-possible-or-unlikely) with more information about the evidence for the hypothetical Planet Nine.

Swift
2016-Oct-28, 07:43 PM
I found this new article from the journal Nature (http://www.nature.com/news/astronomers-spot-distant-world-in-solar-system-s-far-reaches-1.20831), with more information about L91.


Astronomers have spotted a distant world that orbits far beyond Pluto, in the extreme reaches of the Solar System.

The object, known informally as L91, may be in the process of gradually shifting its way inward from the Oort cloud — a reservoir of comets and other icy bodies — into the nearby, equally icy Kuiper belt. No object has ever been seen doing this.

The discovery of L91 reveals more about the extreme worlds whose orbits lie beyond the gravitational influence of Neptune, the most distant giant planet in the Solar System. Researchers have yet to fully explain how these bodies end up in their current orbits. “Every time we find another one of these objects, it adds another piece to the puzzle,” says Meg Schwamb, a planetary scientist at the Gemini Observatory in Hilo, Hawaii.

L91 may have been tossed into its remote orbit by gravitational interactions with Neptune in the distant past. “This one is right on the hairy edge of everything,” says Nathan Kaib, an astronomer at the University of Oklahoma in Norman.

Bannister and her colleagues think the object may have been banished as far as 2,000 au from the Sun before it began easing its way back towards the star’s gravitational pull. L91’s orbit “is changing in quite a remarkable way”, she said.

But Konstantin Batygin, an astronomer at the California Institute of Technology in Pasadena, isn’t so sure. He thinks Bannister’s suggestion that L91 was first tossed towards the Oort cloud and is now moving inward is too complicated. He argues that an unseen giant planet — such as Planet Nine, which he and a colleague proposed in January — might instead be shepherding L91’s orbit more simply and directly.

Ken G
2016-Oct-28, 10:05 PM
Bottom line: we don't yet understand the influences going on in the distant reaches of the solar system. Many of the questions might be answerd by a planet Nine, or maybe the answer will come from some deeper understanding of what is going on out there that changes our picture in more subtle ways than another planet. We will have to wait for more information to be sure. Lack of knowledge isn't bad-- if we have no lack of knowledge, that's bad, for it means we have stopped looking.

John Mendenhall
2016-Oct-29, 08:54 AM
Sensationalism. Sensationalism draws readers. Read some of the headlines here. They are ofen ridiculous.

DaveC426913
2016-Oct-30, 06:11 PM
The object, known informally as L91, may be in the process of gradually shifting its way inward from the Oort cloud — a reservoir of comets and other icy bodies — into the nearby, equally icy Kuiper belt. No object has ever been seen doing this.


I can't imagine how they can posit such a thing.

Pluto's orbit take 246 years; what's the orbital period of Kuiper Belt objects (Sedna is ~11,400y), let alone Oort Cloud objects?
How much have they seen so far since its been discovered? One degree of arc? A few minutes?

I'll bet they barely have enough to determine its current orbit with any degree of accuracy, let alone whether it's "gradually" deviating from that orbit.

Stroller
2016-Nov-06, 10:03 PM
Bottom line: we don't yet understand the influences going on in the distant reaches of the solar system. Many of the questions might be answerd by a planet Nine, or maybe the answer will come from some deeper understanding of what is going on out there that changes our picture in more subtle ways than another planet. We will have to wait for more information to be sure. Lack of knowledge isn't bad-- if we have no lack of knowledge, that's bad, for it means we have stopped looking.

I've been trying to understand resonance in the solar system as a force which shapes its planet-neighbour orbital parameters. A surprising finding I made is that the golden section - Phi is intimately involved. As an example, I derived this simple plot to illustrate the hypothesis.
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It appears that because neighbouring Fibonacci numbers 1:2, 2:3 etc form resonant ratios between planets that lead to orbit changing energy transfers, and are also approximations of Phi, which is the ratio offering the minimum gravitational interference (perturbation) condition, many planet pairs end up with orbital period ratios which lie between the two.

It's a good puzzle I'm still working on to see if I can tease out the underlying gravitational interactions which explain it.

Edit: I've attached newer version of the graphic, with the original in the thumbnail below.

Ken G
2016-Nov-07, 01:26 PM
You have something interesting there. Even if people point out that you are doing some selecting as to what objects you are deciding to include in the plot, still you have a good point that Bode's law does not have. Bode's law, which is of unclear importance, is a more complicated relation than the simple factor-change in distance from object to object that you use. For example, your graph shows that the ratio of the distance between the Sun and Mars to the Sun and Earth is about the same as that same ratio for Neptune and Uranus. That's not something that comes out of Bode's law, but it does come out of your relation. I think you can make a case that simple logarithmic spread is a more interesting distribution than Bode's law, though you don't say how you chose the phi parameter. It doesn't really matter what phi is chosen to be, your result is interesting as a simple statement of a logarithmic spreading with some gaps left by the planets that can be filled in by other objects. It's better than Bode's law.

George
2016-Nov-07, 02:58 PM
Very nice!! :clap: [If I were the sq. root of 5 I would be kinda proud right now. ;)]

It is interesting, though not likely significant, that the average of the variances in distance (known/yours) wash each other out (=99.3%).

Stroller
2016-Nov-08, 11:12 AM
Thanks for your responses gents. I was nervous about posting this here as I'm not a trained astronomer or astrophysicist, just a mechanical engineer.

It always seemed to me that Bodes Law is just a heuristic, and can't be made into anything more than a heuristic. While my distribution is only an empirical fit at this stage too, I do think the power-of-two progression is nice, as it hints at a gravitational or electro-magnetic force-relation lurking beneath, yet to be teased out. I'm hoping some finer minds than mine could be drawn into working on this one. :)

p=2^0, 2^1, 2^2,… 2^n for a sequence of planets and dwarf planets starting at Mercury.
φ=(1+√5)/2
Dist(AU) = (p^1/φ) (1/φ^2) ((1/φ+φ)/2)

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Edit to add: I think the reason Pluto doesn't fit the model may be because like many other TNOs, its it's a long way from the Sun's gravitational influence, making it easier for it to be locked into a ~3:2 resonance with Neptune.

Question for George: Do you mean that the separate sums of the 'overshoots' and 'undershoots' between the model and obs nearly cancel each other out? That's encouraging. I'll plot the variances and see if any pattern emerges. Thanks

Ken: regarding the selection of objects, I just looked around to see what the most significant bodies near the model-predicted distances were.

Vesta is one of the biggest and most massive objects in the asteroid belt, (525km diameter), second only to Ceres. Perhaps of more interest in terms of this discussion about resonance being responsible for the neighbour relations and distances is that Vesta lies at 2.36179 AU, which is the densest part of the asteroid belt.

Sylvia is the 8th-largest asteroid in the asteroid belt. She lies at 3.490 AU, the very outermost edge of the asteroid belt.

Both these locations seem relevant to resonance, one being where most asteroid belt objects are being pushed to, and the other being on the fringe before the void between the asteroid belt and Jupiter. The 'final Kirkwood gap' so to speak.

Chiron is noteworthy not just because it lies close to the model distance prediction, but perhaps also because its aphelion divided by its perihelion is 0.998 of root 5.

MakeMake I can't makemake anything of yet. :)

profloater
2016-Nov-08, 11:14 AM
Thanks for your responses gents. I was nervous about posting this here as I'm not a trained astronomer or astrophysicist, just a mechanical engineer.

It always seemed to me that Bodes Law is just a heuristic, and can't be made into anything more than a heuristic. While my distribution is only an empirical fit at this stage too, I do think the power-of-two progression is nice, as it hints at a gravitational or electro-magnetic force-relation lurking beneath, yet to be teased out. I'm hoping some finer minds than mine could be drawn into working on this one. :)

As another mechanical engineer, interesting ideas, thanks

Ken G
2016-Nov-08, 10:35 PM
Ken: regarding the selection of objects, I just looked around to see what the most significant bodies near the model-predicted distances were.Right, and that's really the only weakness. Had you selected a set of bodies first, prior to inspecting how they would fit the law, it would have been a more unbiased set of data. But still, you have all 8 major planets, and some significant asteroids, so it's hardly an arbitrary set of objects. It certainly suggests some kind of set of resonances or interactions, in a way that Bode's law just doesn't. Many places don't mention Bode's law either, but any that do, I think yours should replace it.


Both these locations seem relevant to resonance, one being where most asteroid belt objects are being pushed to, and the other being on the fringe before the void between the asteroid belt and Jupiter. The 'final Kirkwood gap' so to speak.Yes, the choices of objects is very far from cherry-picked to fit the data. They all have some meaningful relationships to each other, either as gravity sources, or test particles in important gravitational zones.

George
2016-Nov-09, 03:06 AM
Question for George: Do you mean that the separate sums of the 'overshoots' and 'undershoots' between the model and obs nearly cancel each other out? That's encouraging. I'll plot the variances and see if any pattern emerges. Thanks I noticed that the percentages of the known distances with your distances, when all were averaged, came close to canceling the highs with the lows. It's almost as if the wiggle differences in distance are still balanced, something one might expect in a resonance stability, even with Saturn off by 12%. I am not versed in celestial mechanics, however; I'm just an m.e. :)


MakeMake I can't makemake anything of yet. :)Yikes! A fellow puntificator.

Stroller
2016-Nov-10, 03:03 PM
It certainly suggests some kind of set of resonances or interactions, in a way that Bode's law just doesn't. Many places don't mention Bode's law either, but any that do, I think yours should replace it.

Thank you! That makes my day.

George
2016-Nov-10, 08:59 PM
Stroller, you should copy a version of our original post of your hypothesis in the astronomy forum to generate greater interest.

Have you tried it yet on any of the multi-exoplanet systems? [Perhaps a solar mass ratio coefficient will be required.]

Lucretius
2016-Nov-11, 02:17 PM
Stroller, you should copy a version of our original post of your hypothesis in the astronomy forum to generate greater interest.

Have you tried it yet on any of the multi-exoplanet systems? [Perhaps a solar mass ratio coefficient will be required.]

I agree. I'd like to see more on this.

Also, could you explain it in a way that the mathematically challenged among us can better understand?

Stroller
2016-Nov-15, 01:22 PM
Stroller, you should copy a version of our original post of your hypothesis in the astronomy forum to generate greater interest.

Have you tried it yet on any of the multi-exoplanet systems? [Perhaps a solar mass ratio coefficient will be required.]

George, that's very kind, but I'm nervous I'll get torn to pieces. Will you be my sponsor please? :)

I'm working abroad for the next fortnight with limited internet so maybe it's best to wait until I'm home again at the end of the month.

I've discovered something else unusual about Chiron's orbit which might be of use in trying to work out the underlying forces. Chiron is between Saturn and Uranus and has been squeezed such that its orbit has significant eccentricity. Its aphelion is close to Uranus' orbit and its perihelion is close to Saturn's. It may only be coincidence, but out of this relationship arises an eccentricity which exhibits a Phi ratio between perihelion distance and the SMA, and this gives an eccentricity of 0.382 - which is (1/Phi)^2.

Even more curiously the ratio of the number of syzygys between the pairs of this triplet is 9:16:25. Taking the square roots of those numbers we get 3,4,5 - the sides of a Pythagorean triangle. There is a relationship between pythagorean triangles from which many fibonacci series emerge.

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What does it all mean? :doh: :confused:

George
2016-Nov-15, 06:57 PM
George, that's very kind, but I'm nervous I'll get torn to pieces. Will you be my sponsor please? :) You will likely find others more helpful and constructive (KenG in particular), though the need for the underlying physics will be the biggest issue. Lemaitre's work, when he presented Einstein with his model for an expanding universe, was commented by Einstein as being fine in its math but abominable in its physics -- since Einstein was stuck in a static universe model. He apologized once he expanded his mind a little.

What kind of fit do we have with other objects, and does the fit make sense? Ceres fits using a non-integer value of 4.35, so is this a harmonic (resonance) of some sort as well? Perhaps. [This last S&T notes that Ceres likely migrated greatly due to the recent discovery of all the carbonates, though no clear answer is known yet. Maybe this matters, or maybe not.]


I'm working abroad for the next fortnight with limited internet so maybe it's best to wait until I'm home again at the end of the month.
Ok. You might want to clean-up the equation hiccups since you have three different equations shown for distance (the two charts and the one in the equation stated in the post). I chose the equation shown on the thumbnail chart, not realizing that all three were different. Is this the right one?


Even more curiously the ratio of the number of syzygys between the pairs of this triplet is 9:16:25. Taking the square roots of those numbers we get 3,4,5 - the sides of a Pythagorean triangle. There is a relationship between pythagorean triangles from which many fibonacci series emerge. Interesting but why is this so? Any numerology flavoring will be detrimental unless the "why" is demonstrated.

It is certainly deserving of its own thread. Heck, I did several threads on the Sun's true color and sure had fun with it. :)

Stroller
2016-Nov-15, 07:46 PM
George, thanks for all your helpful points and advice. Best keep it simple and avoid the unresolved numerology for sure!
All the equations are equivalent. I've just been fiddling around trying to make it look as neat, aesthetic and parsimonious as I can. I replaced root 5 over 2 with Phi+phi over 2 for aesthetic reasons (same result), and shifted to using (capital) Phi (~0.618) rather than its inverse (lower case) phi (~1.618) to reduce the number of parentheses and inverse clauses.

The underlying physics is what I'll be asking for help with...

See you at the end of the month.

George
2016-Nov-15, 09:12 PM
All the equations are equivalent. I've just been fiddling around trying to make it look as neat, aesthetic and parsimonious as I can. Ah, I see now the inverse approach for phi, and I missed that capital phi, which looked like a low rez. phi to me. To eschew obfuscation, I recommend the less aesthetic equation (thumbnail version) since many will not catch that cool nuance of the inverting and adding, literally, capital phi. It would be a nice side note, no doubt.


The underlying physics is what I'll be asking for help with... Yep, but regardless, your formula has a level of elegance that I doubt is found elsewhere, and it has more meat than the bare bones Bode's law -- broken at the hands of Neptune and subsequent others.


See you at the end of the month.Bon voyage, clear skies, and bueno suerte.

Stroller
2016-Nov-15, 11:09 PM
George, thanks for pointing out the lack of clarity. Here's the refreshed version before I go. Hopefully, it makes the definitions clearer.

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Print flight tickets - OK, see you later.

George
2016-Nov-16, 06:15 PM
George, thanks for pointing out the lack of clarity. Here's the refreshed version before I go. Hopefully, it makes the definitions clearer.

21856
A small nit, I think, that Phi was meant to be stated as (root 5 + 1)/2, not (root 5 - 1)/2.

BTW, the asteroid belt distribution is a very nice touch!

Stroller
2016-Nov-16, 11:57 PM
You're right George. I should have used lower case p

Phi = 1/phi

(root 5)/2 = phi + 0.5 = Phi - 0.5