I love the idea of Planet Nine, but have seen other "planets" disappear (cough, cough Vulcan cough, cough Nemesis).
How likely is it that it actually exists? If it is real, what are the prospects of confirming it in my lifetime (I am 58 years old)?
Established Member
I love the idea of Planet Nine, but have seen other "planets" disappear (cough, cough Vulcan cough, cough Nemesis).
How likely is it that it actually exists? If it is real, what are the prospects of confirming it in my lifetime (I am 58 years old)?
Order of Kilopi
We do not yet have enough evidence to answer those questions. As I see it, it is not as clear cut as the anomalies in the motion of Uranus that led to finding Neptune.
Order of Kilopi
Hold on to your hats, there might even be planet 10, planet 11 ......... . The jury is still out. What is important for now is to get precise data on the motions of the extreme trans-Neptunian objects to be able to adjust the calculations that should lead the way to the location of Planet Nine.Originally Posted by Tom Mazanec
http://www.spacedaily.com/reports/Ex..._Nine_999.html
According to this new study, also based on numerical (N-body) simulations, the orbit of the new planet proposed by Batygin and Brown would have to be modified slightly so that the orbits of the six ETNOs analysed would be really stable for a long time.
These results also lead to a new question: Are the ETNOs a transient and unstable population or, on the contrary, are they permanent and stable? The fact that these objects behave in one way or another affects the evolution of their orbits and also the numerical modelling.
"If the ETNOs are transient, they are being continuously ejected and must have a stable source located beyond 1,000 astronomical units (in the Oort cloud) where they come from", notes Carlos de la Fuente Marcos. "But if they are stable in the long term, then there could be many in similar orbits although we have not observed them yet".
In any case, the statistical and numerical evidence obtained by the authors, both through this and previous work, leads them to suggest that the most stable scenario is one in which there is not just one planet, but rather several more beyond Pluto, in mutual resonance, which best explains the results. "That is to say we believe that in addition to a Planet Nine, there could also be a Planet Ten and even more," the Spanish astronomer points out.
Mostly HarmlessTimely Astronomy Cast plug. Planet 9: Facts and Fiction.
Solfe
Banned
Extra chances for gravity assist.
Order of Kilopi
Batygin and Brown describe their work in the current issue of the Astronomical Journal and show how Planet Nine helps explain a number of mysterious features of the field of icy objects and debris beyond Neptune known as the Kuiper Belt.
http://www.dailygalaxy.com/my_weblog...ce%2C+Tech.%29
"This is the only exoplanet that we, realistically, would be able to reach using a space probe," says Alexander Mustill, astronomer at Lund University. "It is almost ironic that while astronomers often find exoplanets hundreds of light years away in other solar systems, there's probably one hiding in our own backyard."
Through a computer-simulated study, astronomers at Lund University in Sweden show that it is highly likely that the so-called Planet 9 (also known as Planet X) is an exoplanet. This would make it the first exoplanet to be discovered inside our own solar system. The theory is that our sun, in its youth some 4.5 billion years ago, stole Planet 9 from its original star.
An extrasolar planet, or exoplanet, is by definition a planet located outside our solar system. Now it appears that this definition is no longer viable. According to astronomers in Lund, there is a lot to indicate that Planet 9 was captured by the young sun and has been a part of our solar system completely undetected ever since.
Stars are born in clusters and often pass by one another. It is during these encounters that a star can "steal" one or more planets in orbit around another star. This is probably what happened when our own sun captured Planet 9.
Established Member
A couple of things about that article (post #6).
(1) The planet has not been "discovered" like they imply in certain places.
(2) If the stellar system Planet 9 came from was made from the same molecular cloud as our system, would it have a different composition? I would've thought its isotope ratios would be indistinguishable from ours, so it's not a provable hypothesis.
Order of Kilopi
If planet 9 exists than it might explain the tilt of the planets.
https://www.newscientist.com/article...xcept-the-sun/
A jealous Planet Nine may have shoved its siblings for attention. If a massive ninth planet exists in our solar system, it might explain why the planets are out of line with the sun.
The eight major planets still circle the sun in the original plane of their birth. The sun rotates on its own axis, but surprisingly, that spin is tilted: the axis lies at an angle of 6 degrees relative to a line perpendicular to the plane of the planets.
There are a few theories to explain this jaunty slant, including the temporary tug of a passing star aeons ago, or interactions between the magnetic fields of the sun and the primordial dusty disc that formed the solar system. But it is hard to account for why the sun’s spin is aligned the way it is relative to the planets.
Two teams of astronomers have just announced a new explanation: a hypothetical massive planet in the outer solar system could be interfering with all the other planets’ orbits.
Established Member
I thought that current accepted theories had Saturn and Jupiter forming much closer to the Sun and moving outward to their current positions.
Order of Kilopi
Axial tilt, elliptical inclined orbits, angular momentum, cometary wakes, retrograde motions, mathematical modeling, etc.
These things have been adding up for years... I'd opine it's almost certain.
Where the telescope ends, the microscope begins. Which of the two has the greater view?
Banned
It should be hard to form gas giants closer to the Sun, so I think the leading idea now is the "Grand Tack", where they form far out, move in and smash up all the super-Earths, and then move back out again. But I think it's fair to say we have little idea yet what actually happened in our solar system.
Established Member
Post a link for that concept, please.
Mostly Harmless"Jupiter's decisive role in the inner Solar System's early evolution." From Caltech Authors page.
Solfe
Established Member
Thanks for the link. What gravitational forces would be present for Jupiter to move, after forming at >5 AU to <+1.5 AU? And then move outward to its current location(average 5.2 AU)?
Order of Kilopi
If I am not mistaken, it would be interaction with zillions of primordial planetesimals with a significant total mass in proportion to Jupiter. Once all but a tiny trace of them have been either ejected or accreted, Jupiter will stop migrating.
Established Member
Are you suggesting that the inward and outward movements were as a result of the " interaction with zillions of primordial planetesimals"?
Order of Kilopi
Yes.
Established Member
Inward forces I can be persuaded, however after the rocky masses closer to the sun were destroyed, kicked out, how can the remaining masses "repulse" Jupiter to its current location?
Order of Kilopi
According to the authors of the linked paper, it was a complex interaction with the remaining planetesimals and Saturn. I do not have the mathematical knowhow to elaborate on or clarify what they wrote.
Established Member
I didn't read all of the articles and like you I don't possess the physical knowledge to do the calculations. Perhaps the Juno mission will reveal whether the core is liquid hydrogen or more rocky. Only time will tell.
Mostly HarmlessI am probably wrong, but it's the interaction between two large planets and the disc material. The planets create one force that opens a gap in the disc while disc is itself is subject to forces attempting to close that gap. The net result is outward migration via local torque.
Last edited by Solfe; 2016-Jul-26 at 02:41 PM.
Solfe
Order of Kilopi
There is a celestial treasure hunt going on. The prize is Planet 9. While we speculate, professional astronomers are getting time on some of the world's most powerful telescopes to carry out their search.
One thing the search might give is more precise definitions of the orbits of the seven objects as well as finding more objects that have similar orbits. This could help narrow the search region.
http://www.npr.org/2016/08/13/489815...ze-planet-nine
Nobody's actually seen the new planet. The reason astronomers think it's out there is the strange behavior of some smallish objects in the Kuiper Belt, a collection of celestial objects orbiting in the outer reaches of the solar system.
"The seven most distant of these objects, when they go really far away, they all go in the same direction," says Mike Brown, professor of planetary astronomy at the California Institute of Technology (Caltech).
That's one hint there's a planet tugging on them, but there are others. "They're all also tilted, compared to the planets in the solar system," says Brown. "They're tilted about 20 degrees, and they're all tilted in nearly exactly the same direction."
There's a third oddity about these objects: They never come closer to the sun than Neptune, "as if they'd been pulled away from the sun by something," he says.
In 2014, Scott Sheppard of the Carnegie Institution for Science and his colleagues proposed that a large planet orbiting way beyond the orbit of Neptune, might account for the strange behavior of these objects.
Earlier this year, Brown and his Caltech colleague Konstantin Batygin developed a computer model that actually made predictions about where this new planet might be. Since there's still a great deal of uncertainty about the precise orbits of the seven objects, the model's predictions of the possible location of the new planet covers a large swath of sky.
Order of Kilopi
The search for planet 9 is as expected turning up many more new objects.
http://www.universetoday.com/130524/...-new-objects/#
This survey is intended to find more objects that show the same clustering in their orbits, thus offering greater evidence that a massive planet exists in the outer Solar System. As Sheppard explained in a recent Carnegie press release:
“Objects found far beyond Neptune hold the key to unlocking our Solar System’s origins and evolution. Though we believe there are thousands of these small objects, we haven’t found very many of them yet, because they are so far away. The smaller objects can lead us to the much bigger planet we think exists out there. The more we discover, the better we will be able to understand what is going on in the outer Solar System.”
Their most recent discovery was a small collection of more extreme objects who’s peculiar orbits differ from the extreme and inner Oort cloud objects, in terms of both their eccentricities and semi-major axes. As with discoveries made using other instruments, these appear to indicate the presence of something massive effecting their orbits.
All of these objects have been submitted to the International Astronomical Union’s (IAU) Minor Planet Center for designation. They include 2014 SR349, an extreme TNO that has similar orbital characteristics as the previously-discovered extreme bodies that led Sheppard and Trujillo to infer the existence of a massive object in the region.
Another is 2014 FE72, an object who’s orbit is so extreme that it reaches about 3000 AUs from the Sun in a massively-elongated ellipse – something which can only be explained by the influence of a strong gravitational force beyond our Solar System. And in addition to being the first object observed at such a large distance, it is also the first distant Oort Cloud object found to orbit entirely beyond Neptune.
Established Member
Sort of time-lagged double post, but as mentioned in the other P9 thread not only professionals are searching. There is also a cool (unofficial) Zooniverse citizen science project aimed at searching through existing images. Anyone can participate;
https://www.zooniverse.org/projects/...marks-the-spot
"Downwards is the only way forwards" Cobb
Noting in science is proven actual
Order of Kilopi
More evidence of the existence of Planet 9.
http://www.europlanet-eu.org/evidenc...outer-fringes/
However, there are a few known Kuiper Belt objects (KBOs) that are unlikely to be significantly perturbed by the known giant planets in their current orbits. Referred to as “extreme KBOs” (eKBOs) by the authors, all of these have extremely large orbital eccentricities, in other words, they get very close to the Sun at one point on their orbital journey, only to swing far out into space once they pass the Sun, on long elliptical orbits that take these strange mini worlds hundreds of AUs away from the Sun.
“We analyzed the data of these most distant Kuiper Belt objects,” Malhotra said, “and noticed something peculiar, suggesting they were in some kind of resonances with an unseen planet.”
In their paper, “Corralling a Distant Planet with Extreme Resonant Kuiper Belt Objects,” Malhotra and her co-authors, Kathryn Volk and Xianyu Wang, point out peculiarities of the orbits of the extreme KBOs that went unnoticed until now: they found that the orbital period ratios of these objects are close to ratios of small whole numbers. An example of this would be one KBO traveling around the Sun once while another takes twice as long, or three times as long, or four times as long etc., but not, say, 2.7 times as long.
According to the authors, such ratios could arise most naturally if the extreme KBOs’ orbital periods are in small whole number ratios with a massive planet, which would help to stabilize the highly elliptical orbits of eKBOs.
The findings bolster previous work by other scientists that showed that six of those bodies travel on highly eccentric orbits whose long axes all point in the same direction. This clustering of orbital parameters of the most distant KBOs suggested a large, planetary size body shepherding their orbits.
Banned
If so, this is a huge development, because the orbital periods are known. Hence, they can infer the orbital period of the extra planet. Is it consistent with expectations? It should be easier to find if they know its period, and hence its semi-major axis.
Established Member
Before we get too carried away, note that the orbital data for the most distant solar system bodies are .... not very well measured. In part, it's just a matter of time: we have observations over only a short portion (10 to 30 years at best, in most cases) of an orbit that might last for, well, thousands of years.
For example, one of the objects mentioned in the Malhotra paper (which is https://arxiv.org/abs/1603.02196) is 2010 GB174. The JPL Horizons systems provides this value for its period:
Period = 7101 +/- 816 years
If you are looking for relationships between orbital periods, and the uncertainties are 10 percent or so, you will find a boatload of relationships -- almost all of them false.
Order of Kilopi
More for the pile: Curious tilt of the sun traced to undiscovered planet.
Where the telescope ends, the microscope begins. Which of the two has the greater view?
Banned
Is there a danger that every unexplained phenomenon under the Sun is going to get attributed to the missing planet? (That article does make an interesting point though-- if planet 9 is 10 times the mass of Earth and 20 times the distance of Neptune, then its angular momentum is important. Jupiter has a mass that is about 300 times Earth, so planet 9 has a mass 1/30 of Jupiter, but a distance from the Sun about 160 times Jupiter. Angular momentum goes like mass times the square root of distance, so planet 9 has an angular momentum that is perhaps half or a third of Jupiter's. So it's not an insignificant contribution to the total angular momentum of the solar system.)
Last edited by Ken G; 2016-Oct-20 at 08:37 PM.
Order of Kilopi
Space.com: 'Planet Nine' Can't Hide Much Longer, Scientists Say
"I'm pretty sure, I think, that by the end of next winter — not this winter, next winter — I think that there'll be enough people looking for it that … somebody's actually going to track this down," [Mike] Brown said during a news conference Wednesday (Oct. 19) [...]
0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ...
Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan
Posting Permissions
Reply With Quote