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Nemesis and Planet X

  1. Jan 1, 2006 #1


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    The former is a hypothesis that originated with observations of (apparent) periodicity in the extinction record, and has had its share of fame and controversy; the latter began as an innocent follow-on to the discovery of Pluto ('that puny little thing, a planet??') but in the late 20th century was kidnapped by a tribe of anti-science Californians.

    But can either be 'ruled out'? More precisely, in what regions of parameter space may such objects still lurk, awaiting discovery?

    Of the many techniques that could be used to discover any such 'hidden perturbers' (lovely phrase, donchathink?), which are the most powerful (in principle)? I mean this in the sense of 'straight-forward application with today's technology, at modest cost, could put much improved constraints on the existence of such objects in vast realms of parameter space'.
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  3. Jan 1, 2006 #2
    Hi Nereid, long time no see. Happy New Year.

    Richard Muller "invented" Nemesis based on both that extinction pattern and the perceived asteroid impact history of the moon derived from spherule research:


    However, new scrutinized reseach shows a different cyclic extinction pattern (same author) of 62 million years instead of the previous 26 million years.



    Now check that this is about marine micro fossil extinctions and the last one seemed to have been 65 Mya


    So a new extinction seems overdue or perhaps not and the Mid Pleistocene Stilostomella extinction has been overlooked?


    Anyway, there seems to be no more reason for a 26 My orbit of Nemesis, making it chances of it's existence more remote.
  4. Jan 2, 2006 #3
    Nice thread Nereid!

    Something else to consider... the Galactic Orbit model as it applies to the periodic extinctions of (most of) life on earth. Please excuse the long quote:

  5. Jan 2, 2006 #4
    186:62=3.0000. Curious.
  6. Jan 3, 2006 #5


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    Interesting comments, but not (apparently) directly addressing my question (Of the many techniques that could be used to discover any such 'hidden perturbers' (lovely phrase, donchathink?), which are the most powerful (in principle)?)

    That an examination of the fossil record of mass extinctions is a method for such discovery, I'd comment that it is a particularly poor one, for at least the following reasons:

    -> mass extinctions in the fossil record (difficult to determine in any case) leave - in the fossil record itself - only the most indistinct of signals concerning Nemesis (or other causes of periodic bombardment) - the fossils themselves don't say "bombardment" or "plate tectonics" or "methane burps" or "flood vulcanism", or ...

    -> periodic mass extinctions tell us nothing of where 'Nemesis' is (or even what it is)

    But perhaps you meant to say something like "a full analysis of the rocks at the times of identified mass extinctions"? Even allowing this, I don't feel it's a particularly powerful method, if only because there are so many links in the 'chain of evidence' that need to be locked solid before the nature of any 'hidden perturber' could be established.

    In any case, isn't it so that there is very little in the rocks indicating KT-style impacts (no Ir spikes, no shocked quartz, precious few craters, ...)? IIRC, other than for the KT impactor, there's very little that relates any observed mass extinction to such evidence, with a sufficiently close temporal correspondence (back to the late Cambrian, there's only one, n'est pas?)
  7. Jan 3, 2006 #6


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    True Nereid, mass extinctions are very ambiguous.

    Some time ago it was suggested (In Monthy Notices RAS but I've lost the reference) that the periodicity of such was about 32Myrs, so the dinosaurs suffered from one three cycles ago, with the last about 1Myr ago at the time of the onset of the Ice Ages.

    What intrigued me about this figure was that it is also the period of an Oort comet with SMA of 105 AU. Coincidence or Nemesis?

    Last edited: Jan 3, 2006
  8. Jan 3, 2006 #7
    I have no answer to Nereids question but, then again how big are the chances of Nemesis existing in the 26My orbit when it's supposed to explain the cycles in biodiversity.
    Would it help if we look at this overview of our current understanding of major and minor extinctions, bolide impacts and trap volcanism?

    Would an orbit of 32 My still be stable enough?

    Attached Files:

  9. Jan 3, 2006 #8
    Happy 2006... here is the link to where I scooped the "Galactic Model" of extinction events:


    Thanks to Nereid I may not get sued for copyright infringement... and if I do I will try to hold the court in appeal for 62 million years.

    The author of that quote I gave is selling his idea and you can put it in a shopping cart. He is also looking for similar ideas and people who might want to write about them.

    I have seen mention of a galactic model to explain periodic near extinction in other texts and contexts as well. I will search these out of the library. I think they're recent references and may even point back to the source I have linked above.

    I do remember that the model in the book in question showed an occillation that occurs where our part of the gallaxy, (aproximal position on a spiral arm) travels in and out of some areas that are denser with stars and debri than others as the galaxy spirals.

    It is difficult to prove the theory because we can't compare signature trace deposits of elements to original elements from the area our solar system has alledgedly passed through. This is because we are not in any of the areas at this time and supposedly won't be for another few million years.

    There are stratified layers of the earth that display changes due to radiation and so forth but, as the article says, the origin of these readings could be any number of events.

    The debris from the 65mya (astroid?) event may hold an answer to Nereid's question. Perhaps using spectographic telescopy to find a match to the composition of such debris would tell us where we're headed and what's in store for the humans that may or may not be on earth when earth gets there.
  10. Jan 6, 2006 #9
    I didn't know that Jack Sepkowski had passed on. I took paleontology from him when he and Dave Raup first published their hypothesis. Last I saw him he was in strapping good health. Only age 50. . . . . . .
  11. Jan 16, 2006 #10


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    You must have seen him not long before the heart attack which killed him, in 1999 - Journal of Paleontology memorial.
  12. Jan 16, 2006 #11


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    So searching the fossil record - even combined with looking for craters, Ir spikes, shocked quartz, etc - isn't a very powerful way to find (or rule out) a Nemesis (or Planet X).

    How about a survey of parallaxes? How powerful a technique would that be?
    The most recent, and perhaps best known, such survey was HIPPARCOS; what regions of parameter space* do the results from this mission leave open for a Nemesis (both the HIP and Tycho catalogues)?

    *let's assume any such unseen companion is in an orbit around (or with, if you prefer) the Sun, and has been in such an orbit for at least a billion years.
  13. Jan 16, 2006 #12


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    Searching the IRAS data might have proved more fruitful, only it didn't find Nemesis. Astrometric micro-lensing might also prove fruitful: Astrometric Microlensing Constraints on a Massive Body in the Outer Solar System with Gaia but I think if a brown dwarf was out there we would have found it in the IR by now.

  14. Jan 16, 2006 #13
    Wow, thanks for the link. Actually, the last time I saw Jack, and I'm really dating myself now, was back in the mid-1980's. I also went on one of those spring break field trips. In 1985 we went to the Turks and Caicos. Jack was a nice guy. Once the sea was pretty rough, and I was having a hard time making it back to shore. Jack didn't have to help me, but he was right there in case I needed it. His legacy lives on though.
  15. Jan 18, 2006 #14


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    Thanks Andre.

    Is there some explanation to go with this summary? For example, what's the difference between 'CRATERS - CLOSE' and 'Crater - other'? And what are 'IMPACTS - NO CRATER'?

    Also, do you know if anyone has a chart of (well documented) iridium spikes, shocked quartz, tektites, etc?

    Finally, what is the cratering history on the Moon, over the last ~600 million years? Especially of large (>50km) craters.

    PS I did some surfing on the 'Bedout/PT?' crater - it sure isn't a Chicxulub, is it!
  16. Jan 18, 2006 #15
    Sorry, it was a rush post. But here is the source with great links, like this one

    It appears that the "Close" refers to a geologic boundary associated with extinctions.

    If it exists, it would probably be here, or here

    But I haven't been exploring there since "To google" hasn't earned its status as verb for nothing. :wink:

    This narrative about the dating of a few lunar spherules (also on the former chart) shows a market increase of impacts around 400 Mya was one of the two incentives for the Nemisis hypothesis of Richard Muller.

    Not sure if my former link still works.

    The real biggies appear to be rather old, ~3,85 - 3,9 Bya according to this page

    Indeed it's rather unlikely that the bedout event went by unnoticed. :smile:

    All: there is still time to submit your abstracts here.
    Last edited: Jan 18, 2006
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