[meteorite-list] Nemesis

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Mon, 6 Sep 2010 19:23:07 -0500
Message-ID: <C3D1A8E4D9584D6C87C0478902E16AFD_at_ATARIENGINE2>

Hi, Rob, Steve, List,

> In other words, the orbit would not be stable...

    The originator of the Nemesis hypothesis says exactly
the same thing: not stable. What Richard Muller has
proposed is that our Sun has a small stellar companion
that becomes more eccentric with each of the many local
perturbations by passing stars through the life of the
solar system.
http://muller.lbl.gov/pages/lbl-nem.htm

    The orbit gets "longer" and the timing of passages
through Oortville varies as the aeons pass. (THAT'S
a clever touch.) That's why the periodicity varies the way
that it does. In the early days of the solar system, the
passages did not "dig into" the Oort Cloud, but as the
orbit elongates, the passages get "deeper" and the
disturbances of objects greater and change frequency.

    The picture it suggests to me is that Life was content
to spend its days at the beach of shallow warm tropical
seas, reading the latest best-seller, for billions of slowly
evolving years, until things got nasty enough to stimulate
some genetic response to the increasing upset, forcing a
complexity to arise.

    As it happens, the solar system impact rate has shot
back up over the last 400 to 600 million years to early-days
rates, another "fit," or circumstantial evidence, take your pick:
http://muller.lbl.gov/papers/Lunar_impacts_Nemesis.pdf

    So, the "non-stability" of the orbit is part and parcel
of the theory. If the Boogie Man Star is out there, WISE
should spot it. But it's going to take a long time to process
all that data and then acquire parallax data on all the
candidates.

    Even then, if the current orbital motion is opposite to the
direction of parallax shift, no accurate estimate of distance
will be calculated right now. It could take a few years to get
it right.

    Nemesises can be tricky.


Sterling K. Webb
----------------------------------------------------------------------------------
----- Original Message -----
From: "Rob Matson" <mojave_meteorites at cox.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Monday, September 06, 2010 2:52 PM
Subject: Re: [meteorite-list] Nemesis


> Hi Steve,
>
>> I Just read "Rocks from space" and in the end of the book they
>> mention
>> Nemesis in the Oort cloud as being a red dwarf with a cycle of 26 to
>> 30 million years.
>
> The theory that the sun has a long period, highly eccentric, red dwarf
> or brown dwarf companion is based on a ~perceived~ periodicity in
> earth's mass extinction record. From a strictly dynamical standpoint,
> it is a rather unlikely theory, IMO, since the dwarf orbit's required
> semi-major axis is so great that it would be subject to perturbations
> by nearby stars. In other words, the orbit would not be stable.
>
> Thanks to WISE (the Wide-field Infrared Survey Explorer), we shall
> soon be able to confirm or discard this theory. WISE is sensitive
> enough to detect any red dwarf or brown dwarf out to distances
> an order of magnitude greater than Nemesis' greatest possible
> distance. Even a Jupiter-mass object would be detectable at a
> distance of 1 light year, while a three-Jupiter-mass object
> would be detectable at 10 light years' distance.
>
> Realistically, if Nemesis exists it is almost certainly not a red
> dwarf as it would already have been discovered. A brown dwarf is
> the largest realistic candidate, and some Nemesis proponents
> theorize that its mass is only 3-5 times that of Jupiter -- too
> small to even be categorized as a brown dwarf. (Brown dwarf
> minimum size is 13 Jupiter masses -- the minimum mass to fuse
> deuterium.)
>
> So far WISE has discovered two unambiguous brown dwarfs (and a
> number of brown dwarf candidates), although their distances are
> not yet known. Follow-up measurements must be made by other
> instruments to measure their parallaxes, but I suspect these
> first two are more than 3 light years away (too distant to be
> Nemesis candidates).
>
> --Rob
>
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Received on Mon 06 Sep 2010 08:23:07 PM PDT