Nemesis-Sun Companion

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vandivx

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"a nemesis star is not necessarily a pre ordained event. Pre ordained implies that an intelligence is behind the stars cycle. A Nemesis star could be a possibility with the passages through the Oort cloud causing disrupted material to head inward towards earth. All part of just a regular cycle."<br /><br />ok, I that's what I wanted to say by 'preordained' - a 'regularly ocuring' event on which you could count to come and it would come no two ways about it (I think comets are quite different thing, those can come irregularly I suppose due to big orbit perturbation on sun's approach which is due to their small mass), after all don't large celestial bodies come and go on quite precise schedule, I mean you can't have that rogue body come around once after 25 mill yrs and next time after say 18 mill yrs and next again say after 22 or 29 mill yrs<br /><br />I can see that on some orbit it would bring in smaller shower of bombarding small bodies than on others but even then the mass extinction would be very regular with some 'slots' left empty (no extinction on some periods, that would still leave those extinctions based on period with some beats left out here and there, ie there would be regularity in the irregularity but apparently that is not the case<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>
 
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vandivx

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"Your idea about some kind of genetic disease or "time bomb" (if I got that right) would have a direct effect on only one species at a time. It's true that there are keystone species whose disappearance will lead to a chain of extinction, for instance if bees disappeared many species of flowers will also disappear, but it's rather difficult to imagine such a thing causing such an all-encompassing event as the K-T or P-T extinctions."<br /><br />I don't think about it in terms of 'keystone' idea, more like that we humans now (for example) share basic genetic fundamental make up with apes and to some extent with all mamals qua mamals, with some we share more, with other we have in common less but because we are all mamals, we all share some fundamental genetic basis that makes us mamals in the first place and if something went wrong with that basic makeup on the base level, then all mamals will come to the end of line, not just humans, it might be drawn out proces lasting long time and would be hard to notice that it is happening<br />but those historic extinctions weren't apparently governed along these lines, like 'mamals' going, it was something else<br /><br /><br />I was hesitating using that word 'species' since I am definitely no biologist, perhaps dinousaur extinction wasn't species extinction but many species in the first place, also I think that extinction went beyond species in the sense that what went weren't species as such but BIG species, same like those huge plants in carboniferous period went and were replaced by normal sized plants (by today's measure), that's what makes me think of something fundamental within the 'structure', genetical structure that is<br /><br />after all if some cosmic disaster had done away with dinosaurs, why didn't new ones continue, why did it have to be distinctly smaller mamals and only smaller mamals from there on, why didn't nature make something different but also BIG, similar to what she did the first time, tell me that<br /><</safety_wrapper> <div class="Discussion_UserSignature"> </div>
 
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qso1

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vanDivX:<br />"a nemesis star is not necessarily a pre ordained event.<br /><br />Me:<br />Large bodies go on as precise a schedule as its possible to predict and your right, if Nemesis comes around every 26 million years...it will be 26 million years unless something disturbs its orbit, such as the hypothesized passing star that supposedly changed Nemesis orbit. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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vandivx

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when that perturbing star is brought in to help make theory fit the facts, that to me is a tell tale sign the whole theory of Nemesis won't hold<br /><br />in that case I'd be more inclined to go with those asteroids hitting Earth and climate changes, that idea of 'gene that went wrong' I just threw in, I suppose even if there was something to it, we are long ways yet from being able to determine that or even start understanding something like that<br /><br />bottom line is that I find it hard to believe that a whole line of creatures like dinosaurs vanishes due to climate conditions (due to any cause) that make it hard for them to fend for fodder and I would like to see some more fundamental cause that would be sure to decimate uncompromisingly, else I can always imagine some heards of dinosaurs surviving in some places and so surviving past the period of deprivation<br /><br />but I may be quite wrong on that count, I am just layman when it comes to these things<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>
 
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qso1

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vanDivX:<br />but I may be quite wrong on that count, I am just layman when it comes to these things<br /><br />Me:<br />You n me both. I agree with pretty much your whole comment. I too would be more inclined to think asteroids or climate change were responsible for a few mass extinctions. The gene that went wrong is still a possibility unless or untill proven otherwise. The main problem with proving it is having the human race conduct research on a species over a long enough time to see it actually happen. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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search

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As requested and for those who do not have much time to see all the websites I posted:<br /><br />The first link is the latest I found related with the Nemesis subject. What I would like to point out is that the Binary Research Institute (founded in 2001) is dedicated to the Binary theory (do not let the name impress you. The founder Walter W. Cruttenden is an amatuer astronomer and archaeoastronomer, however many discoveries were done by amatuers)<br />Link: <br />http://www.sciencedaily.com/releases/2006/04/060424180559.htm<br />"From April 24, 2006<br />Evidence Mounts For Sun's Companion Star<br />The Binary Research Institute (BRI) has found that orbital characteristics of the recently discovered planetoid, "Sedna", demonstrate the possibility that our sun might be part of a binary star system. A binary star system consists of two stars gravitationally bound orbiting a common center of mass. Once thought to be highly unusual, such systems are now considered to be common in the Milky Way galaxy.<br />Walter Cruttenden at BRI, Professor Richard Muller at UC Berkeley, Dr. Daniel Whitmire of the University of Louisiana, amongst several others, have long speculated on the possibility that our sun might have an as yet undiscovered companion. Most of the evidence has been statistical rather than physical. The recent discovery of Sedna, a small planet like object first detected by Cal Tech astronomer Dr. Michael Brown, provides what could be indirect physical evidence of a solar companion. Matching the recent findings by Dr. Brown, showing that Sedna moves in a highly unusual elliptical orbit, Cruttenden has determined that Sedna moves in resonance with previously published orbital data for a hypothetical companion star.<br />In the May 2006 issue of Discover, Dr. Brown stated: "Sedna shouldn't b
 
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mikeemmert

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Hello, SEARCH <img src="/images/icons/laugh.gif" /><br /><br />Thank you for digging up this link:<br /><br />http://arxiv.org/PS_cache/astro-ph/pdf/0502/0502390.pdf <br /><br />What this is is a paper by Varun Bhalerao and M. N. Vahia on whether or not we can find this "Nemesis", assuming that it exists. They have constructed a table of expected brightnesses vs. their mass. They made an assumption about the distance of the object and checked to see if there were databases which would have uncovered the object.<br /><br />The main conclusion that they reach is that if the object was about 45 times the mass of Jupiter, that it would have been uncovered by various surveys done in visible light, 0.4 (blue) to 0.7 (red) microns. They also gave the brightnesses in the infrared J band, about 1.24 +or- 0.1 microns, which would detect smaller objects. I don't know if infrared surveys in that band have been completed yet, but assuming a limiting magnitude of about 25, they conclude that such an object could be no bigger than about 28 Jupiter masses. They said they chose not to characterize such objects, but they would be brown dwarfs.<br /><br />My interest in Nemesis came about when I reviewed damage to the Kuiper belt and objects that don't fit into the Kuiper belt, as I have described in this thread in an earlier post. Earlier speculations about Nemesis centered on perturbations of the Oort cloud of comets. The density of the Oort cloud is probably too low for intense comet showers unless the object is fairly massive. As Bhalerao and Vahia point out, such an object would have been discovered by now.<br /><br />But if the comet showers come from the material in the Kuiper belt, a considerably smaller object can do the perturbing. Posted below is an image from a simulation I did on GravitySimulator, where a "Kuiper belt" was created with objects out to about 100 AU. These were created in a flat
 
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mikeemmert

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Hi, SEARCH <img src="/images/icons/laugh.gif" /><br /><br />Thank you for posting about Sedna. This is one of the pieces of evidence that I was going to post about for the existence of a Kuiper belt grazing Nemesis. I might get back to that one some day soon, but for now I would like to post about another object: 2004 XR190, which has been named Buffy (the vampire {theory} slayer).<br /><br />"<font color="yellow">2004 XR190 is particularly unusual for two reasons. With an inclination of 47 degrees, it is the most "tilted" object discovered thus far, traveling further "up and down" than "left to right" around the Sun when viewed edge-on along the ecliptic. Second, it has an unusually circular orbit for a scattered disc object. While it has been hypothesized that Scattered Disc Objects (SDOs) have been ejected into their current orbits by gravitational interactions with Neptune, the low eccentricity of its orbit and the length of its perihelion (SDOs generally have highly eccentric orbits and perihelions less than 38 AU) seems hard to reconcile with such celestial mechanics. This has led to some uncertainty as to the current theoretical understanding of the outer Solar System<font color="white">".<br /><br />It's one of those things like Sedna which just shouldn't be there. But if you check out the image I posted from GravitySimulator, you can see analogues of it there.<br /><br />Some of my simulations (not the one posted) were given objects of their own and in some cases transferred from one object (Nemesis or the Sun) to another. I only did a couple of those because there is a file in GravitySimulator called "sedna" in which somebody simulated a flyby of a brown dwarf past the sun in which exactly the same phenomenon was observed.<br /><br />I think, from viewing the simulation, that the author was thinking the brown dwarf formed in the same molecular cloud as the Sun, which would account for the relatively l</font></font>
 
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search

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From above link of M.<br />The simulation on Buffy<br />http://www.cfeps.astrosci.ca/4b7/Buffy-simulation.mpg<br /><br />Continuation on the links I posted earlier:<br /><br />Regarding future surveys that can bring some answers on a Nemesis or any Brown Dwarf possible sun companion.<br /><br />If Nemesis exists, it may be detected by the planned Pan-STARRS or LSST astronomical surveys, or similar future projects. If Nemesis is a brown dwarf as proposed by Whitmire and Jackson then the upcoming WISE mission (scheduled for June 2009) should easily find it.<br /><br />"Pan-STARRS (an acronym for Panoramic Survey Telescope And Rapid Response System) is a planned astronomical survey that will conduct astrometry and photometry of much of the entire sky on a continuous basis. By detecting any differences from previous observations of the same areas of the sky, it is expected to discover a very large number of new asteroids, comets, variable stars and other celestial objects. Its primary mission is to detect near-Earth objects that threaten to cause impact events. It is expected to create a database of all objects visible from Hawaii (three-quarters of the entire sky) down to apparent magnitude 24."<br />http://www.answers.com/topic/pan-starrs<br /><br />The Large Synoptic Survey Telescope (LSST) is a planned wide-field "survey" reflecting telescope that will photograph the available sky every three nights. Construction should start in 2009 with completion in 2012.<br />Particular scientific goals of the LSST include:<br />1.Measuring weak gravitational lensing in the deep sky to detect dark energy and dark matter.<br />2. Mapping small objects in the solar system, particularly Near-Earth asteroids and Kuiper belt objects.<br />3. Detecting transient optical events such as Novae and Supernovae.<br />4. Mapping the Milky way.<br />5. It is also
 
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alokmohan

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Brown dwarfs are comparatively less researched on.I love to see nemesus as a brown dwarf.Possibily it is so.
 
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MeteorWayne

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Very interesting post, thanks.<br />I did notice one contradiction in the statements.<br /><br />Early on "There's no way to put Sedna where it is. It never comes close enough to be affected by the sun, but it never goes far enough away from the sun to be affected by other stars... Sedna is stuck, frozen in place; there's no way to move it, basically there's no way to put it there -- unless it formed there. But it's in a very elliptical orbit like that. It simply can't be there. There's no possible way - except it is. So how, then?" <br /><br />Then later ""It is hard to imagine that Sedna would retain its highly elliptical orbit pattern since the beginning of the solar system billions of years ago. Because eccentricity would likely fade with time, it is logical to assume Sedna is telling us something about current, albeit unexpected solar system forces, most probably a companion star". <br /><br />These two don't add up. The first says that Sedna never comes close enough to the sun to be affected (and in fact is far enough out that it really wouldn't be affected by the rest of the planets), while the second says the eccentricity would "fade" over time. Why would it fade?<br /> AFAIK, eccectricity is reduced by interactions with matter surrounding an orbit, since there is almost none, why would it fade?<br /><br />Just pondering here.<br /><br />MW<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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search

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Hello MeteorWayne<br /><br />For example, the eccentricity of the Earth's orbit today is 0.0167. Through time, the eccentricity of the Earth's orbit slowly changes from nearly 0 to almost 0.05 as a result of gravitational attractions between the planets<br /><br />Since I did not write the article I can only presume that they refer to the original disk of solar system matter. Meaning that there was more interaction in the primordial solar system and the eccentricity would fade over time.<br /><br />Just guessing but good point from you
 
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MeteorWayne

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Eris is also in a highly inclined orbit of 44.2 degrees<br />There is also 2006 HH123, at 44.1 degrees. Both of these however are in highly eccentric orbits ( /> 0.4) whereas Buffy's is 0.111<br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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MeteorWayne

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Perhaps that is correct, search. <br />Clearly Sedna is a major oddball that we can not explain yet. The hardest part is figuring out the perihelion of 76 AU, the most distant of any solar system object so far.<br />Form in place? Way out there? That's tough.<br />Captured free floating object? Highly unlikely (but not impossible)<br />Perhaps it was ejected with other KB objects and had some sort of unique interaction with another large outer Solar system object?<br />Nemesis? (Brown Dwarf, hidden Jupiter mass object?)<br /><br />Lots of ideas in play here, with not much clear evidence.<br /><br />That's what makes the future so exciting! <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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mikeemmert

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<blockquote><font class="small">In reply to:</font><hr /><p>These two don't add up. The first says that Sedna never comes close enough to the sun to be affected (and in fact is far enough out that it really wouldn't be affected by the rest of the planets), while the second says the eccentricity would "fade" over time. Why would it fade? <br />AFAIK, eccectricity is reduced by interactions with matter surrounding an orbit, since there is almost none, why would it fade?<p><hr /></p></p></blockquote>Thank you for asking this question. First of all, here's a link to Gliese 710, kindly provided by harmonicaman on the last Nemesis thread:<br /><br />"<font color="yellow">With a possible stellar companion in a wide orbit, this currently dim star lies about 63.0 light-years from Sol. It is located in the eastern part (18:19:50.8-1:56:19.0, ICRS 2000.0) of Constellation Serpens (Cauda or the Tail), the Snake -- west of Alya (Theta1,2 Serpens), northeast of Eta Serpens, east of Cebalrai (Beta Ophiuchi) and Gamma Ophiuchi, and north of the Wild Duck Cluster (M11) and M26. Based on proper motion and more recent radial velocity data from the HIPPARCOS space satellite mission, Gliese 710 is expected to come within 1.1 light-years (0.34 pc) of Sol in less than 1.4 million years, but astronomers do not expect it to "perturb the Solar System's Oort Cloud sufficiently to create a substantial increase in the long-period comet flux at Earth's orbit" (García-Sánchez et al, 1999; and Weissman et al, 1997). At its closest approach, Gl 710 will rival the brightness of the red supergiant Antares, although it is currently not even visible to the naked eye of Earth-bound Humans<font color="white">".<br /><br />Our Sun is orbiting the galaxy along with a large number of other stars. Sometimes stars pass close by each other. This will be the case with Gliese 710. Also, Alpha Centauri, currently the closest star, is approaching our Solar syst</font></font>
 
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qso1

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mikeemmert:<br />"Close" is relative, of course. With the vast gap between stars, actual collisions are highly unlikely.<br /><br />However, with an object that's way out there, like Sedna or Nemesis, there is a good chance that if the object is far from the Sun out in the weak part of the Sun's gravitational field, that the passing star will affect the orbit of such objects. <br /><br />Me:<br />The problem here is that despite Sednas maximum distance of almost 1,000 au and close approaching stars we know about so far passing well over a light year distant (62,366 au) or almost 63 times the maximum distance Sedna is from the sun. Its hard to imagine a star, much less a red dwarf or brown dwarf star having more gravitational effect on Sedna and other KBOs. If Sedna were much much further out or the passing star much closer, I could see this being possible. Otherwise, I would think if Sednas orbit has been changed by a passing star, it was an event in which the star came well within a light year of the sun. Perhaps within .25 to .5 ly <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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mikeemmert

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<blockquote><font class="small">In reply to:</font><hr /><p>... close approaching stars we know about so far...<p><hr /></p></p></blockquote>You're quite right that Gliese 710 is probably not going to affect our Solar system. It certainly won't affect Sedna, because the gravitational pull is inversely proportional to the square of the distance, so Gliese 710's pull on Sedna is 64 squared times less than the Sun's.<br /><br />However, our baseline using Gliese 710 is only 1.4 million years. The history of the Solar system is 3000 times longer than that. The odds of a closer encounter go way up over such a long time.<br /><br />I wouldn't know Nemesis' semimajor axis before the encounter. But my guess is that the perturber must have passed considerably closer than a quarter or a half a light year, even if it was a big star like the Sun or Alpha Centauri.<br /><br />Muller's evidence for the time of the encounter, unfortunately, is not very precise. He needed more spherules to work with (and IMHO he can find a better method of dating this event somewhere here on Earth). If it was 400 Mya and the perturber was travelling at the speed of Gliese 710 then today it is about 1800 light years away.
 
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qso1

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mikeemmert:<br />However, our baseline using Gliese 710 is only 1.4 million years. The history of the Solar system is 3000 times longer than that. The odds of a closer encounter go way up over such a long time.<br /><br />Me:<br />I agree with this in terms of it being possible Gliese 710 might have been that passing star many millions of years, or even a billion years ago. It gets more difficult to calculate a stars path around the galaxy in relation to our sun the further back you go in time as I'm sure your already aware. I sometimes wonder where Alpha Centauri was half a billion years ago in relation to sol.<br /><br />BTW, thanks for the math refresher. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
 
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MeteorWayne

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You quoted "Thank you for asking this question. First of all, here's a link to Gliese 710, kindly provided by harmonicaman on the last Nemesis thread: <br /><br />"With a possible stellar companion in a wide orbit, this currently dim star lies about 63.0 light-years from Sol."<br /><br />You are not suggesting this in Nemesis are you? As I understand it Nemesis would be a "Solar System" object.<br /><br />This is way out there, and unless I'm really wrong, this could not be gravitationally bound to the Sun. The Centauri system is only 4.3 light years away, so how could something 15 times further away be bound to the sun?<br /><br />Now, if it does indeed come that close, it could seriously perturb the Oort cloud. Good thing I'll have been dead for 1.4 million years <img src="/images/icons/smile.gif" /><br /><br />Wayne <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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search

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Regarding Nemesis what we should be asking is:<br />How do stars move in the Galaxy?<br />Answer:<br />http://curious.astro.cornell.edu/question.php?number=378<br /><br />"Our Galaxy, like all other spiral galaxies is rotating. The stars move on orbits around the centre of the Galaxy. It was the motions of stars in external galaxies that lead to the idea of dark matter in the universe - their motions indicated that there was more mass within their orbit than could be accounted for by visible matter alone. This is also true in our Galaxy.<br /><br />At the distance of the Sun from the centre of the galaxy (about 8 kpc or 24 thousand light years) we move at an orbital speed of about 220 km/s and take about 230 million years to make one revolution around the centre of the Galaxy.<br /><br />Stars also have some random motions - they don't orbit the galaxy in exact circles. This random motion usually amount to a few tens of km/s in some direction.<br /><br />As observers we see this motion of the stars as what's called 'proper motion' - the projection of their velocity onto the plane of the sky, and 'radial motion', which is the projection of their velocity along our line of sight. We can dectect radial motion by looking at the wavelength shifts it creates in the spectrum of the star. Proper motion we detect by plotting the position of the star over time and seeing how it moves relative to more distant "fixed" objects. The star with the largest proper motion is Barnard's star which moves about 10 arcseconds (0.003 degrees) per year. A more typical proper motion is about 0.1 arcseconds a year."<br /><br />The point I would like to make is regarding the fact that star movement is not necessarely the same at all times specially as you get further away from the center of the galaxy. <br /><br />Keplerian orbits can be found close to the center but in spiral arm like the sun this is not the case and the or
 
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colesakick

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I have been rather persuaded that Mr. Cruttenden is spot on with his analysis of the data. Logic is on his side and nothing in known astronomy precludes us from having a brown dwarf companion. In fact, the statistics are heavily on the odds being in favor of the sun having AT LEAST one companion.<br /><br />There is a surprising amount of records from the ancients who describe in detail the chaos they experienced the last time planets from outside our solar system passed through the orbits of our home worlds. I happened onto the Binary Research Institute page after reading archeoastronomy material about ancient mythology. I wondered if anyone was seriously entertaining the idea of an undiscovered companion star with planets of its own orbiting a common center with our sun. I half hoped that the ancient stories from Sumer and Babylon were fictitious to the full, after all, their accounts are terrifying! <br /><br />The fact is that there is no better way to explain why our pole marks a circular pattern against the stars. The idea that earth must wobble (not the yearly wobble in relation to our sun, a large scale wobble in relation to the stars) seemed credible enough to believe, but only because no one bothered to confirm that we had that same large scale wobble against the local bodies in our system. Point in fact, the earth does not large scale wobble when compared to Venus, the sun, etc. The only rational answer is that our whole system tilts together. It does not stretch logic or imagination to conclude that just as earth has an intrinsic wobble in relation to the sun, the sun and her planets wobble together as it/we orbit about a center shared by a companion system. The physics remain true in both cases so why not?<br /><br />I’m guessing that we are approaching our sister system and in time its presence will become apparent as earth heats up. Earth has several periodicities that puzzle researchers; perhaps freezing and warming cycles are related, at least in part, t <div class="Discussion_UserSignature"> Intellectual honesty means being willing to challenge yourself instead of others </div>
 
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mikeemmert

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<blockquote><font class="small">In reply to:</font><hr /><p>You are not suggesting this in Nemesis are you?<p><hr /></p></p></blockquote>Absolutely not!<blockquote><font class="small">In reply to:</font><hr /><p>As I understand it Nemesis would be a "Solar System" object.<p><hr /></p></p></blockquote>This is correct, Nemesis would be a Solar system object. Gliese 710 is not a Solar system object. There's some confusion here.<br /><br />If you see yellow print in my posts, it usually (not always) means I am quoting from the link and it did in this case. What the link was referring to is that <i>Gliese 710</i> has a possible stellar companion in a wide orbit.<br /><br />I hope this clarifies, because calling Gliese 710 a Solar system object would, indeed, be "way out there" <img src="/images/icons/crazy.gif" /> . <br /><br />
 
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MeteorWayne

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Sorry, guess I got confused reading too much at once <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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mikeemmert

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<img src="/images/icons/laugh.gif" /><br /><br />I got a lot of reading to do tonight, too. I have to cram my calculus homework. So let me do the quick post, here...<br /><br />Alpha Centauri has been popping up in this thread a little. Everybody's heard of it, it's the nearest star system, comprising a binary pair 4.39 light years away and a red dwarf 4.26 light years away, 15,000 A.U. from the primary pair.<br /><br />It looks like this system has suffered an orbital mechanical disaster. The primary pair's orbit is highly eccentric, 0.52, with Alpha Centauri A and B approaching within 11.2 A.U., about the distance of Saturn, and receding out to 35.6 A.U., slightly farther than Neptune. You might expect two stars formed from the same disc of gas and dust to have more circular orbits. One possibility here is that B and C had a close encounter, which threw C ("Proxima Centauri", given a name of it's own because it is the closest known star) out to 15,000 A.U. Not enough is known about the system to say if Proxima really is in orbit around the other two stars, but the whole thing moves at the same speed in the same direction through space. The central pair (which is unresolvable to the naked eye, appearing as a single point) is separated from Proxima by 2 degrees.<br /><br />The system is thought to be about 6 billion years old. If Proxima has been orbiting in it's present orbit then it hasn't been plucked away by a passing star. If Proxima got tossed out by dynamical instability, then who knows when that happened?<br /><br />The Alpha Centauri system may have started out being dynamically unstable. For instance, Proxima could have started out making almost two orbits for every orbit of Alpha Centauri B. In this case, very slight perturbances add up over time, making C's orbit more and more eccentric, until there is a close encounter which flings C away in a gravitational slingshot. Or alternative
 
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yevaud

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A brief thought - perhaps Proxima was a capture? <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>
 
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