Does Nemesis Exist? Has it Ever?

mikeemmert · Jan 19, 2006

Dear All: Space.com has presented this story about the dust discs of other stars. It turns out several of them have something in common with the Sun. The Kuiper Belt in our own solar system has an edge (see Edge of the Classical Belt link on the left hand column of links) at about 47 A.U. So do many of the other stars examined in the Space.com article. Could another star have carved out the edge of the Edgeworth-Kuiper Belt? The evidence is slim, but tantalizing. There is Buffy, which has a circular orbit around the sun at a distance that puts it right at the edge of the Kuiper Belt but has an inclination of 46.7 degrees. Then there's Sedna which is not part of the Kuiper belt. And there is the fact that the aphelia of a lot of long-period comets cluster at 50,000 A.U. But is this hypothetical Nemesis of the Sun still there? The serious scientists who proposed that figured it could have receded to as much as 1.5 A.U. from the sun, which means a passing star could have ripped it away. Alternatively, many of the observations can be explained by some massive object on a parabolic trajectory that never orbited the Sun. Or, there might be some other explanation altogether. Here's a brand new thread on the Death Star. Hopefully the material that belongs in Free Space or Phenomenon will stay in those realms. <img src="/images/icons/smile.gif" />

SpaceKiwi · Jan 19, 2006

This kind of topic fascinates the heck out of me. As potentially 'unsolved mysteries' go, this one is right up there in my book. At what point do you think this one will be definitively solved to even the most skeptical person's satisfaction, or have we long since reached that point? As a casual observer of this issue, I am inclined to believe a Nemesis companion star would have been discovered by now if it existed. If I can also ask a newbie-type question ... presumably the most 'likely' place to find a companion would be in the same plane as the Solar System? But, I guess astronomers have had a look everywhere, including perpendicular locations for example? <div class="Discussion_UserSignature"> Who is this superhero? Henry, the mild-mannered janitor ... could be!-------------------------------------------------------------------------------------------Bring Back The Black! </div>

harmonicaman · Jan 19, 2006

"Hopefully the material that belongs in Free Space or Phenomenon will stay in those realms." Get real! This thread will inevitably degenerate into an unfortunate stream of cromulent Bozo flux despite your noble plea for serious discussion... I think Gliese 710 is our best candidate to date for being the "Great Perturber" of the Solar System's Oort Cloud; but its period seems to be too long and it really doesn't get close enough to be a "Planet X" candidate. I don't think these newly discovered objects carry enough mass to really shake up the Oort Cloud, but if there are a lot of these things in highly irregular orbits, then maybe they are causing the periodic disturbances of the Oort Cloud. I think there's a lot of Brown Dwarf sized stuff out there just beyond the Solar System that may gravitationally interact with us from time to time that we have no idea about. These objects may be as big a danger to the Earth as Earth crossing asteroids because they have the potential of sending Oort Cloud debris into the inner Solar System. I don't think we've discovered the mythical Planet X yet but I do believe there is something out there that periodically upsets the delicate balance of the Oort Cloud.

mikeemmert · Jan 19, 2006

Hi, SpaceKiwi; I already gave this link to Nemesis, but right above that (just scroll up) is a link to Planet X. It is a fascinating discussion about attempts to find a large mass perturbing Uranus and Neptune. Ultimately, it was determined that the mass used for Neptune was incorrect. Nevertheless, it is a historical fact that Urbain de Leverrier and John Couch Adams tracked down Neptune through it's gravitational effects on Uranus. Today, everybody and his brother has a powerful computer, which was not avaliable to the Planet X searchers. Telescopes have become vastly more powerful; today, over a thousand KBO's are known, whereas in November 1994, only 20, including Pluto and Charon, were known. Additionally, SOHO has picked up a large number of comets falling into the sun. Each of these is a piece of evidence. I think there's enough pieces to form a puzzle.

SpaceKiwi · Jan 19, 2006

Awesome mike, thanks! I'm going to go chew on that link for a while. <div class="Discussion_UserSignature"> Who is this superhero? Henry, the mild-mannered janitor ... could be!-------------------------------------------------------------------------------------------Bring Back The Black! </div>

dragon04 · Jan 19, 2006

I think harmonicaman has it right. Gliese 710 is the "best" candidate for a Nemesis. If a massive trans Neptunian body existed, it would have gravitaionally shown itself long ago. <div class="Discussion_UserSignature"> "2012.. Year of the Dragon!! Get on the Dragon Wagon!". </div>

mlorrey · Jan 20, 2006

You talking about bozo flux? Gliese 710 is many light years from here, and with a velocity that is above solar escape velocity. It is not in solar orbit. I've read all of Muller's papers available on the subject, as well as a number of others by other scientists. To clarify the record: Mikeemmert, the other day you said Alvarez has nothing to do with Nemesis. This is false, as he and Muller were the other team that proposed it. Muller was a protege of his. Rather than yakking on and on about this, I'd suggest first that people actually read the science papers available on the topic. They are easily googlable. A real scientist does his or her homework before forming an opinion. Muller's team believes that the evidence shows that while Nemesis was originally in a circular orbit, shepherding the Oort Cloud and Kuiper Belt, about 600 million years ago (based on impact rate analysis derived from lunar dust and rock returned by Apollo missions, this was the fourth set of data I forgot to mention the other day) there was a major change in Nemesis' orbit, likely due to a flyby of another star, which triggered a massive spike in impacts on the moon and likely elsewhere. Nemesis is now in a 26 million year elliptical orbit that ranges from ~.1 ly at perigee to about 2-2.5 ly at apogee. This perigee triggers swarms of up to 100,000 comets to come into the solar system, many of which are absorbed by the Jovians, but enough get through to that an impact rate of 1 major cometary body every million years for 1-3 million years after perigee events results in one or more extinctions of various types. Given the last impact and extinction was about 5 million years ago, Muller believes Nemesis is about 1 ly away at the moment, and heading outward. Now, one reason I like the idea of Nemesis isn't just that it explains a lot of things with geology and evolution and so forth that couldn't be explained previously, but it also means THERE COULD BE A STAR

mikeemmert · Jan 20, 2006

<blockquote>In reply to:<hr />I do believe there is something out there that periodically upsets the delicate balance of the Oort Cloud.<hr /></blockquote>Let me ask you; do you think mass extinctions are periodic? What would that period be? For that matter, do you think all, most, or only one or no mass extinctions had an extraterrestrial cause?

mikeemmert · Jan 20, 2006

Thanks, Dragon04 I just got back from my hotmail site, where I have my Hubble Space Telescope press releases sent. This is a much better and more detailed explanation of the trimmed dust discs than the Space.com article listed above. Some excerpts (in yellow): "Kalas and Graham speculate that stars also having sharp outer edges to their debris disks have a companion - a star or brown dwarf, perhaps - that keeps the disk from spreading outward, similar to the way that Saturn's moons shape the edges of many of the planet's rings. "The story of how you make a ring around a planet could be the same as the story of making rings around a star," Kalas said. Only one of the nine stars is known to have a companion, but then, he said, no one has yet looked at most of these stars to see if they have faint companions at large distances from the primary star. He suggests that a stray star passing by may have ripped off the edges of the original planetary disk, but a star-sized companion would be necessary to keep the remaining disk material, such as asteroids, comets and dust, from spreading outward." So our Kuiper belt has been kept trimmed? I would presume you've noticed that Gliese 710 is now over 60 light years out and that means that you feel that stars flying by the solar system. OK, there's lots of good reasons for that. In our own Kuiper Belt, the planitessimals have been trimmed off. What the Hubble is seeing, however, is dust. We have, since 1993 or 1994, picked up an ever increasing number of planitessimals. But the dust? "A key uncertainty, Kalas said, is that while we can see many of the large planetesimals in our Kuiper Belt, we can barely detect the dust. "Ironically, our own debris disk is the closest, yet we know the least abou

nexium · Jan 20, 2006

The mainstream opinion is red dwarf stars do not have planets in the habitable zone which is less than a million miles from the center of the star. This is well inside the Roeche limit, so the planet could not be formed there. If the planet had high cohesion and adhesion it could possibly hold together, but it would likely keep one face toward the star. The unlighted side would be very cold, trapping the water in a great ice cap, unless the atmosphere is very thick, which means a mass several times that of Earth. Most red dwarf stars have powerful CME = corronal mass ejections, which could be a disaster for any life on such a planet. Please comment, refute and/or embellish. Neil

mikeemmert · Jan 20, 2006

<blockquote>In reply to:<hr />...you said Alvarez has nothing to do with Nemesis.<hr /></blockquote>That's not quite accurate, I said Alvarez has nothing to do with the bozoflux surrounding Nemesis. Anyway, that was another thread. And you know, I said Walter Alvarez should have gotten a Nobel Prize. I think his was one of the most significant discoveries of the 20th Century.<blockquote>In reply to:<hr />...I like the idea of Nemesis ...(because)... it explains a lot of things with geology and evolution and so forth that couldn't be explained previously...<hr /></blockquote>You see, this is where I'm terribly conflicted. I am highly impressed with that evidence. Really I am. I wish you would take just a few minutes and google that to show to harmonicaman and Dragon04 because they're not really as fully engaged in geology, etc., being on the Space Science and Astronomy board, so why should they look it up? Here's what they're worried about, I think:<blockquote>In reply to:<hr /> Nemesis is now in a 26 million year elliptical orbit that ranges from ~.1 ly at perigee to about 2-2.5 ly at apogee. <hr /></blockquote>I'm afraid I have to agree if they think that such an orbit could not possibly last four and a half billion years.

mlorrey · Jan 20, 2006

I can appreciate that, Mike. I think as time passes we will find more and more evidence that corroborates the thesis, even if we don't find the star until we get a really good IR scope, or else Muller finally finishes the distance survey of the red dwarf population. There are some 5,000 known red dwarves in the night sky whose distance is not known. More red dwarves are being found. Moreover, if it is a brown dwarf, it will be even tougher to find, but even if we don't find it for a while, the evidence piling up is getting to the point that equals what would be considered sufficient in court to convict without a reasonable doubt, or at least on preponderance of evidence. Which particular evidentiary standard do you consider acceptable for scientists? Generally it seems to tend toward the weight of published papers one way or the other. In regards to the orbit, according to Muller and others, the orbit is expected to be stable for another billion years, on average. Here's some info: http://muller.lbl.gov/pages/lbl-nem.htm This page has some good info on the periodicity and the disputes over popular perceptions of orbital stability of Nemesis. WRT the periodicity: there are two perigee periods that did not see a significant enough impact event to cause an extinction. That is to be expected, as given x-many comets driven into the solar system, if, on one pass through there are as many as 3 or more impacts, odds are that there will likely also be flybys in which no comets manage to strike Earth. Also here is the paper on the lunar impact rate evidence: http://muller.lbl.gov/papers/Lunar_impacts_Nemesis.pdf

mikeemmert · Jan 20, 2006

Thank you, mlorrey I get from the paper on the lunar impact rate that their conclusion is that there has been a significant increase in the rate of cratering in the last 400 million years. The explanation that I see from the papers for that is that Nemesis was in a circular orbit originally and was perturbed into an eccentric orbit 400 million years ago. Your post did not make this clear (please reread). That would go a long way towards answering the objections of a lot of people that such an orbit can't last long enough. I liked the idea of dating glass spherules created by craters to date the cratering rate. And that was pretty clever using the ejecta blanket from the Cone crater to get a mixed sample from various depths. It's too bad Muller couldn't get an accuracy better than 130 million years, since that would answer the periodicity question directly. Nevertheless, I think the hypothesis that the cratering rate on the moon and therefore presumably on Earth has increased in the last 400 million years works fairly well. It would have been nice if he could have gotten more than two grams of material. 155 spherules is not a very robust statistical sample.

harmonicaman · Jan 20, 2006

"Let me ask you; do you think mass extinctions are periodic?" Yes, and I believe these recurring extinctions are also related to Earth's periodic Ice Ages. As we learn more, I think a lot of these cataclysmic events will be connected together... (Although some of Earth's cyclic Ice Ages may have been triggered by comet storms; they can also be caused by terrestrial phenomena such as a detonation of the Yellowstone Cauldara. Geologists can count Earth's Ice Ages; but only a few are attributed to known cataclysmic events.

mikeemmert · Jan 20, 2006

<blockquote>In reply to:<hr />Yes, and I believe these recurring extinctions are also related to Earth's periodic Ice Ages<hr /></blockquote>The extinction that matters the most to humanity - the megafaunal extinction 8500 years ago which took out the woolly mammouth, the wolly rhinocerous, the giant ground sloth, and (gulp!) the PaleoIndian, was definitely an Ice Age phenomenon. I got a meeting in 30 minutes, I'll post more on that later. They have searched high and low for iridium, shocked quartz, and tecktites and have come up dry. I dont' think that the detonation of the Yellowstone caldera will create an Ice Age, but that's pretty much just an opinion. The ash would be too coarse and clump together and so it would be a purely regional event. Unfortunately, I live close to that region (Texas)...I believe I'd survive it. However, one of the datapoints in the Raup/Sepkoski/mlorrey graph of mass extinctions is the Permian-Triassic extinction, the worst one. They have a tiny trace of iridium and a few tectites; the main cause is thought to be the Siberian Traps volcanic event. However, the mechanism wasn't an Ice Age. The vast lava flow was an oxygen sink and the oxygen content of the atmosphere fell to 6%. Thank you for your post. <img src="/images/icons/laugh.gif" />. I'll be back.

mlorrey · Jan 20, 2006

I too wish Muller had more material to work from. However, I think the results of his work clearly demonstrate that the dust/glass fallout/ejecta record on the moon is an immensely important geological database, and IMHO justifies going back there with a substantial geological science team. I believe the conclusive answer to whether Nemesis exists is on the moon, even if it takes us a longer while to actually locate it in the sky.

mikeemmert · Jan 21, 2006

I have spent an interesting evening perusing the Holocene extinction event. And, of course, the question of evidence has come up. Here is a link to the Blytt-Sernander classification, or sequence, is a series of north European climatic periods or phases based on the study of Danish peat bogs by Axel Blytt (1876) and Rutger Sernander (1908), from wikipedia. "Layers in peat were first noticed by Dau in 1829. A prize was offered by the Danish academy to anyone who could explain them. Blytt hypothesized that the darker layers were deposited in drier times; the lighter, in moister times, using the terms atlantic (warm, moist) and boreal (cool, dry). Weber noticed the sharp boundary horizons, or grenzhorizont, in German peat, which matched Blytt’s classification. Sernander added the subboreal and subatlantic periods, as well as the late glacial periods. Other scientists have since added other information..." There is a large section in the article about "Problems". These fell under the category of "dating and calibration" and "cross-discipline correlation". The reason I'm posting this is to show that even here on earth, with prizes offered, thousands of paleontologists and laborers working on it, modern carbon-14 dating, and easy transportation and logistics, they are still scratching their heads over light and dark layers of peat in Denmark. The mystery has spread throughout the world as investigators have zeroed in on the "Sixth extinction", the Holocene extinction event. Muller's work with two grams of lunar soil, while interesting and laudable, has serious problems. As I said, his dating is no closer than 130 million years. As a result, no direct correlation with a proposed 26 -30 million year extinction cycle can be made.

mlorrey · Jan 21, 2006

Two grams of material can be a lot. As an example, my cousin, a geologist/climatologist currently at U of Aukland, did a fantastic paper back when he was working on his masters at U Maine/Orino, in which he analysed the snowpack on top of Sugarloaf Mountain one winter, sectioning the snow to centimeter thicknesses, samples of less than a gram, and analysing the dust in the snow (each sample thus measuring in micrograms) was able to determine the originating region of every snowstorm that dropped snow on "the Loaf" that winter. This sort of work in the future will help scientists do the same by analysing very thin slices of arctic and antarctic glacial ice cores going back thousands of years in time to actually determine not just general climate, but from where each and every storm that year orginated from, and from that, what actual weather patterns were. As I learned from him about his work, I am not nervous about basing a major thesis upon a few grams of material. A microgram of DNA can convict a murderer today, or determine what weather patterns were thousands of years in the past. I am not shocked to learn they can tell what impact rates were over a long period. At a resolution of 130 million years, his study only serves to prove that there was a major blip in impact rates 400 million years ago, with materials of cometary origin, thus indicating that there was some major change in the KB/OC region at that time. That the periodicity of extinction rates seen since then has not been found in records prior to that time, this correlation is indicative of a new cyclic rather than random impact rate. Marcy and Butler are announcing the existence of new planets based on less distinct patterns in star doppler shifts.

mikeemmert · Jan 21, 2006

<blockquote>In reply to:<hr />Two grams of material can be a lot... my cousin... was able to determine the originating region of every snowstorm that dropped snow on "the Loaf" that winter.<hr /></blockquote>Your cousin was able to do that because he had excellent, layered samples to work with. As a result, I would find his work considerably stronger than Muller's. Muller's honest, no doubt, he himself went to considerable lengths explaining that the sample was mixed up in weird ways. For instance, he acknowleged that constant furrowing will result in younger spherules being overrepresented in his sample because material from the latest impact events will land on the top. Indeed, the far-right hand side of his graph, the youngest material, shows a strong spike. That's not bad science, it's the opposite, it's good science. It allows truthful analysis. Some projects are just plain easier than others, that's all.<blockquote>In reply to:<hr />This sort of work in the future will help scientists do the same by analysing thin slices of arctic and antarctic glacial ice cores going back thousands of years in time<hr /></blockquote>I see your cousin is part of a large effort and that his role is calibration. That's vital. Unfortunately for Muller, there was little calibration in his work. As I said, some projects are just easier than others.<blockquote>In reply to:<hr />... there was a major blip in impact rates 400 million years ago (and) in the KB/OC region at that time...<hr /></blockquote>This has piqued my curiosity. I would sure like to see better evidence. I see a hint in Muller's work, an indication.<blockquote>In reply to:<hr />Marcy and Butler are announcing the existence of new planets based on less distinct patterns in star doppler shifts. <hr /></blockquote>It is po

mlorrey · Jan 21, 2006

Good question. Well, I would say the idea would be to determine all the different possible 'taggants' that would be found to indicate impact events: a) iridium isotope layers, indicative of cometary impacts b) helium 3 layers (as recently found in ocean dust sediments) indicative of impacts of asteroids receiving He3 from the sun, or of lunar or asteroidal regolith blasted into earth orbit by impacts by comets with those bodies. My friend Amara Graps, an astrophysicist in Italy who specialises in space dust (her nickname is "the dust bunny") has commented that, like my cousins work with dust laden snowpack, dust detectors in space can tell astronomers the origin of the dust they sense.. Ideally, outside of direct observation, we would want to find impact signatures indicative of bodies formed in the KB/OC region that were gravitationally perturbed into extremely eccentric orbits into the inner solar system, or detect such bodies still in orbit. What would an icy/dusty/rocky body exhibit as indicative that it had once had a close encounter with either a brown or red dwarf some 5 million years ago? We know that asteroids and the moon accumulate materials ejected by the sun on the solar wind. Would a brown or red dwarf have similar plasma emanations, and how would such 'wind' be different from our own sun's solar wind? For example, a brown dwarf fuses deuterium, not plain vanilla hydrogen. Would it emit the waste products of deuterium fusion, at a different proportion than the Sun? These are the sorts of questions I think will yield answers as to the sorts of taggants we should be searching for in glass beads, buckyballs, and other things that contain original event material.

mikeemmert · Jan 21, 2006

Well, as a general answer to several questions there, any "Nemesis" would be a member of our solar system and would be formed by the same material. So, unfortunately, material associated with it would have the same isotopic composition. Long period comets would therefore look the same, so the fact that they do in fact look the same is not a null result for the Nemesis hypothesis. If Nemesis is a red dwarf like in the original hyposthesis, then it would be a flare star. That might leave a signature in the hydrogen isotopes, I don't know. It would be an awfully small signature, though. It might show up in the Stardust analysis, which is pending, and not be strong enough for spectroscopic detection in comet tails. If it's a brown dwarf, it's been quiescent for three and a half billion years. I believe live brown dwarfs are flare stars, (if anybody knows, tell us), so they might leave a trace. If it's over 55 Jupiter masses, it would have burned out the lithium, so there's no trace there. However, if it's between 13 and 55 Jupiter masses, lithium might work as a tracer. If it's less than 13 Jupiter masses, there will be no tracer. You might e-mail Amara Graps with this tip if she can look at Stardust samples. We now know to look for iridium in rock samples more than 400 million years old. A lot there depends on the specific local geology of wherever you find rock that age. Mixed rock of various ages just might work, the (vague) idea here is that you look at 10 or 50 or 100 million years at a time for total iridium content. Helium 3 doesn't have much utility for earth rocks because it's hard to detect, being chemically inert. I don't know how it responds to neutron activation analysis. P.S. Lithium shows up real strong on neutron activation analysis. It produces tritium.

mikeemmert · Jan 22, 2006

I'm baaaaccccckkkkkkkk!!!!!!!!!!!!!!!!!!!!! I decided to do some GravitySimulations concerning this project. But of course, when you start those, you usually don' t really know what to do. My first question had to do with the mass of Nemesis. Muller, et. al, figured about at least a tenth of a solar mass or more. Does it take an object that large to tear the Kuiper belt apart? The Oort cloud is considerably more delicate. But I decided to use a considerably smaller mass star. I chose 5000 Earth masses, about 16 Jupiter masses, a small brown dwarf and a nice round number. I put it in an orbit with a semimajor axis of 5000 AU and an eccentricity of 0.95. Distance is supposed to be much greater, but I got tired of waiting for the slow orbit to come to perihelion and, having decided to see if a smaller mass would tear up the Kuiper belt, a smaller orbit would be realistic enough. Other questions can be answered later. I created a group of 40 objects 1/1000 the mass of Triton. My first semimajor axis for this group was 20 billion kilometers, +/- 50%. Unexpectedly, I got an interesting result right away. "Nemesiss" grabbed one of the objects from the Sun and it went into orbit around Nemesiss (extra "s" = fictitious/hypothetical object). The orbit was not highly eccentric, about 3 billion x 6 billion kilometers. I though of Buffy. I hadn't put anything around Nemesiss because more objects slow down the simulation, which already takes quite a while even using the "don't plot" feature (if the machine doesn't have to make a graphic display every 1/25 sec., it runs faster. My machine is very basic, the VA got it for me.) A lot of orbits wound up a little eccentric. Rather than do 20 or 30 orbits, I made a new simulation. Nemesiss was the same, but the "Kooiper" belt had a semimajor axis of 45 billion kilometers (10 times as far as Neptune) +/- 70 %. Again, I got a result right away. One of the Kooiper o

mlorrey · Jan 23, 2006

Sounds like you are making some progress. Try this one on: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1985AJ.....90.1876H&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf This paper by JG Hills puts some nice constraints on allowing large mass objects (greater than 10 Jupiter masses) come in from the KB and pass through the inner system. He also precludes anything greater than 20 Jm (.02 solar masses) orbiting within the KB based on possible perturbation influences. He also says that .01 solar masses of dim companions with semi-major axis out to 20,000 AU is a minimum to create 'death showers' of comets. He also posits that Pluto is perturbed by Nemesis. Another interesting calculation he makes is that for any cometary object at the inner edge of the Oort Cloud (20,000 Au), the odds of passing at least once through the inner system in the 4.6 billion year life of the solar system is 56%, and these odds go up the closer you get. This explains why there is an inner edge: almost everything closer has long since fallen inward. KBOs that remain in orbit in the KB are the statistical flukes residing in resonant orbits.. This might point to another way to detect Nemesis: the more KBOs we know the orbits of will narrow down the number of possible orbits that a Nemesis-like object can pass through without perturbing them all into falling into the inner solar system. This will give a handle on where to look, unless this just indicates what the OLD orbit of Nemesis was, pre-400 Mya. Hills also says that cometary death showers persist for not much more than one orbital period from the Oort Cloud through the inner system (so it appears the solar system is pretty effective at sorting out most of the bad ones), given that J

mikeemmert · Jan 23, 2006

Howdy. I read your post, but it's after 2:00 A.M. and I see that the paper in the link is long. I'll have to read it later. OK, I have been running the simulation described above. So far, I have had five Kooiper (deliberate misspellings denote fictional objects) belt objects ejected and two which were perturbed inward enough to cut inside of Neptune. I decided to watch the last pass and the one object from the last post which had come within 3 billion kilometers was perturbed into an even more eccentric orbit. But I didn't measure it. Several more were ejected. The Nemesiss in this simulation approaches within 37.7 billion kilometers of the sun. KBO orbits out to about 30 billion kilometers have remained intact and fairly circular. Everything outside of that has been perturbed into an eccentric orbit; most so far barely so, but some considerably. It's pretty obvious watching this that if I let it keep running the outer part of this Kooiper belt will be trimmed off. However, it was not trimmed off in the four or five orbits that have been done so far. My conclusion is that Nemesis (one "s") could easily be a small brown dwarf. Of course, these were quick sims, kind of almost spur of the moment. I was pulling numbers to create this brown dwarf out of a brown hole somewhere. <blockquote>In reply to:<hr />Another tid bit: he says Nemesis would have caused any planets beyond Pluto "INTO HIGHLY ECCENTRIC AND HIGHLY INCLINED ORBITS". I believe this is the smoking gun: Xena exhibits this behavior and has an aphelion which would have put it in a region where it would be perturbed into its current orbit by a Nemesis encounter.<hr /></blockquote>Now, THERE's a system I have spent months modeling. I would say the statement you made absolutely 100% hits the jackpot. I have done any number of flybys of a Triton/Xena binary past Neptune. When Neptune captures Triton, Xena gains the energy Triton loses.

najab · Jan 23, 2006

>Were there such a large, dark body out there, the gravitationsl effects upon the outer Oort Cloud and the Kuiper would probably have been seen by now. Steve, did you read the thread? That is precisely what the principal posters have been discussing: the evidence/lack of evidence for Nemesis based on the observed behaviour and orbits of known objects in our Solar System.

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