Nemesis, the Sun's Binary Star Companion? 271
0xC2 writes "The Binary Companion or 'Nemesis' theory asserts that a yet-to-be discovered companion to our Sun may actually exist. Recent observations of two nearby stars (assumed companions) show debris disks 'strikingly like the Kuiper Belt int the outer part of our Solar System'. The Binary Research Institute site is devoted to the theory, and presents a concise introduction, list of evidence, and sample calculations in support of the theory. A fascinating read, although the physics and related calculations are not trivial." Has the 'unique theory on the internet' vibe to it, but interesting nonetheless.
Not likely (Score:4, Interesting)
Re:Listen (Score:3, Interesting)
NASA might have been a better choice for inclusion in your parent post, or better yet a astonomological group.
Re:Not likely (Score:3, Interesting)
Good thing for us that there isn't another object the mass of the sun within about 3.8 light years of earth. Even as it is, the planets do influence one another's orbits, but their masses and spacing are such as to keep the earth's orbit from getting too elliptical. Because of the nearly circular orbit, the distance to the sun is constant enough keep the temperature within the bounds needed for life. Another object approaching the mass of the sun would force the orbit to be more elliptical, which would make this planet unsuitable for life as we know it. About half of the known stars are too close to each other for any of those to have a planet that could keep its temperature in the very narrow range wherein water exists in its liquid form. The temperature specs for higher life forms are considerably narrower than this. The nearest star to earth is Alpha Centauri, a nice safe 4.2 light years distant.
Re:How in the world... (Score:3, Interesting)
They kept looking for Pluto because Neptune kept exhibiting weirdness. Pluto wasn't anywhere near the size they were looking for. I'm not sure if they eventually decided that all those calculations were erroneous or whether there are really perturbations in Neptune and Uranus' orbit that could be caused by a tenth planet.
Anyway, those mathematical planet discoveries were accidents.
Oh, come on. (Score:3, Interesting)
"STAAAAAAARRRSS...."
Maybe Asimov was a genuis after all! (Score:1, Interesting)
Recursion (Score:2, Interesting)
Re:Nemesis Blamed for Periodic Extinction (Score:4, Interesting)
This theory is testable (Score:5, Interesting)
It is, however, about an unseen Sun companion responsible for the precession of the equinox. The precession of the equinox is the observation that as the Earth orbits the Sun, after a full year around the Sun the Earth does not realign itself with the distant stars, there is a difference of about 50 arcseconds. This correspond to a period of about 24,000 years.
Current theory for precession says the phenomenon is due to tidal effects due to the Moon acting on the non-perfectly-spherical Earth.
TFA makes the simple point that this could be also more easily explained if the Sun was revolving around an heretofore unseen companion for the same period. This would also explain a number of other more complex phenomena, such as why this the precession rate seems to slowly, but undoubtedly change with time, why the angular momentum of the Sun appears to be so low compared to that of the planets, etc.
TFA goes on to make prediction where this companion might be in the sky, and how far away it should be (between 0.01 and 0.03 of a LY), using nothing more complicated than basic Newtonian celestial mechanics.
Well, time will tell, and I'm not an astronomer, but the theory is actually very simple and testable (in the mid to long run), so either evidence will mount in this direction or it will be disproved.
For example we could measure precession rates on Mars. Since Mars has no large satellite, if it is found to have a precession rate similar to that of the Earth, then this will be very strong evidence that the tidal theory cannot be correct, and that the distant companion one is more likely to be. On the other hand if precession on Mars is very low, then this theory cannot be correct.
In short I think the guy might be wrong but he is no crackpot.
Re:Nemesis Blamed for Periodic Extinction (Score:4, Interesting)
Re:cool! (Score:3, Interesting)
Take a look at Structure and Interpretation of Classical Mechanics by Sussman and Wisdom. On page 255 they mention a published result from 1964 by Henon and Heiles. They found some trajectories were chaotic while others are regular. More specifically they found the solutions clustered in phase space into regions of regular and regions of chaotic motion. In other words I believe you are leaning too heavily on popular notions of nonlinear dynamics and chaos (which tends to find chaos everywhere). It is not that I am automatically accepting the Nemesis hypothesis. Only that it is a reasonable theory that would have to be proven or disproven by careful observation.
The Nemesis hypothesis includes the constraint that the Sun and this object are separated on a scale that is larger than the Solar System and the period could well be millions of years. That would make detecting it challenging given the limited time scale over which we have any observational data.
I disagree! (Score:2, Interesting)
Anyways, the punchline of all this is missing. Why was it that approximately every 30 million years (not quite the number, IIRC it's a bit more exact, but I forget the specifics) there were recurring catastrophes? Talk about a science mystery worthy of Science Fiction! My own thoughts were along the lines of some kind of statistical quirk of the setup of Earth over millions of years (things get strange characteristics over such timespans, much the way that the dynamics of situations look fundamentally different if you're looking at things recorded reeeeaaalllyyyy sssslllloooowwwwwwwwwwwwly or, trading time for space, under a microscope). But the book referenced an apparently widely-known theory, though hotly contested, that the Sun had a twin star, probably a brown dwarf, which orbited somewhere outside of the Oort cloud. Perhaps some characteristic of its orbit meant that around every 30 million years (or whatever it was) it would swing close enough for awhile to start disturbing the Oort cloud. With so many possibly dangerous objects being flung around, the likelihood of a cometary impact on Earth suddenly becomes relatively quite alot higher (though probably still unlikely enough that it's far from a reliable impact, perhaps explaining the wiggle room in the exact time of the recurrance of mass extinction). There were other bits of random evidence both astronomy-related and geology-related, I don't quite recall them. But whether the theory is true or bunk, the idea of Nemesis (which is also how it was referred to in the book and in other related literature that I read up on at the time) is at least a significant step about the stereotypical internet-theory.
One last sidenote, though it's somewhat OT: I had been thinking, back then, that if you do the rather simple math we're at least a handful of million years overdue for another mass extinction. Then I did a double take as I realized that we actually weren't! The way that these extinctions were measured, since the fossil record is far from play-by-play, is a sudden and drastic disappearence of biodiversity, with large numbers of species suddenly disappearing. And you know what? Not making any direct opinionated slant on this (though my stance is probably obvious), but humans have managed to wipe out enough in the way of species that we're already about on par with many of these rather significant (from a fossil-record viewpoint) extinctions. (Seen from a kind of statistical-determanistic point of view, then, we're just the inevitable comet-equivalent that would inevitably pop up sooner or later, give or take a handful of million years).
Sorry for waxing so arguably OT, but the theory of Nemesis is such an interesting science bit, what with how it manages to draw threads in from so many interdisciplinary puzzles and findings. And in such a more reasonable and non-paranoid way than those aforementioned internet theories!
Re:By now? (Score:2, Interesting)
For instance, see the Dogon's well documented belief in a binary system, that was later revealed to be true. http://en.wikipedia.org/wiki/Sirius#The_Dogons [wikipedia.org]
The Dogon issue is of course, debatable. Regardless, it is interesting to speculate about.
We now know that solar system travels up and down through the galactic plane in a regular cycle, and some have speculated that this particular cycle brings with it increased chances of asteroid impact, as well as yet unforseen forces (for instance, gravitational).
Who knows what odd galactic cycles we'll discover in the future? I, for one, don't find the intense ancient interest in the sky and its movements, to be something that we can mearly attribute to some sort of primitive fascination with bright and shiny things alone.
Rather, I think there is probably some truth to the many, many myths concerning disasters, floods, and dramatic climate changes, and these were in some way linked to observable heavingly events. That probably greatly contributed to almost every known culture having an intense interest in the sky, with the greatest well known ancient cultures having such well known, and seeminly overly complex, obsessions with the movements of the stars and planets.
Re:By now? (Score:4, Interesting)
I got the +17 number from here [bahnhof.se]. For the record, 17 is pretty damned dim: Proxima Centauri has an absolute magnitude of 15.49. But even if you unrealisticly want to bump up Nemesis' absolute magnitude to 30, at 100,000 AU (twice your largest claim) it'd still have an apparent magnitude from earth of 24, still 16 times brighter than what modern ground-based telescopes can see. All you'd be doing is limiting the data that should be available on Nemesis to 80 years instead of 120.
"Each of these brown dwarfs are warm objects that emit a reasonable amount of infrared radiation. If it is a cold black dwarf similar to a larger Uranus--~60 K (and less than 13 Jupiter masses so that it can't have fusion)"
Aside from the fact that we'd still be able to see it, with 13 Jovian masses at 25,000 AU (half your smallest claim), the gravitational attraction on the sun would be 0.117 pm/s^2 (that's picometers). The center of the galaxy exerts an acceleration on the sun of 19,330 pm/s^s. Nemesis' gravitational influence would be indiscernible and meaningless compared to the gravitational effect of the rest of the galaxy. Its influence on us would literally be background noise, unless one tries to claim it influences us in some way other than gravity (*cough* astrology *cough*)