On May 6, 2007, at 3:15 AM, Michel Jullian wrote:
No Jones, the 62My period "vertical" oscillation superimposed on
the "horizontal" circular orbit of the sun round the galactic
center has nothing to do with the inclination of the solar system
plane wrt the galactic plane. It is a purely gravitational effect
due to the galactic plane being denser. The "real nemesis" is more
likely to be the galactic plane itself, around which our solar
system is more likely to undergo collisions. Such collisions
explain why rotating clouds of matter always end up as planes BTW.
I think most of the oscillation is due to the sun's galactic orbit.
We have a 200 My galactic orbital period, so, given no matter at all
in the galactic plane, we should be in the galactic plane every 100 My.
Actually I believe we are still in the danger zone presently,
having crossed the plane only 1My ago or so. It seems to me this is
in favor of using solar sail reflectors to mitigate global warming
BTW: such reflectors could also be used occasionally to deviate
from very far away any asteroids detected to be on collision
course, using photon pressure as was discussed here some time ago.
It seems to me likely we are interacting with something that bobs
back and forth just like we do. Once two bodies in orbit closely
interact it is as if they were at one time a single body, and thus
they tend to interact more frequently and closely in the future (e.g
the Shoemaker-Levy Comets and Jupiter.) This is a reason why hitting
a golf ball off the space station may not have been a great idea!
On May 6, 2007, at 5:46 AM, Jones Beene wrote:
Also I think that the Menvedev idea might work with some variation
of Horace's 'nemesis cloud' idea in that we already have an Oort
cloud which can serve as a model, and both the cloud and the sun's
radiance would be affected by the "northern exposure" ...
The Oort cloud might indeed be the secondary source of the swarm. A
single large mass gravitationally linked to the sun, but having a
differing galactic orbit, will pass the sun roughly twice per
galactic orbital bobbing up and down period, i.e. about every 70-100
MY or so. A very roughly "close" passing would be sufficient to
disrupt the Oort cloud, placing many objects in orbits of extreme
eccentricity, and send them eventually pouring down toward the sun.
However, it could take a fairly random period of time for the few
larger Oort objects so disrupted to actually collide with the sun.
At 9:13 PM 3/20/4, Horace Heffner wrote:
It has been speculated at various times that a cloud or swarm of
asteroids
and/or comets exists which tends to all return at once. Such a
swarm could
be created by various means. One is that a heavy but fairly dark
object, a
dark or small star might periodically traverse or might have at
some time
traversed our neighborhood and disrupted the Ort cloud, sending
numerous
bodies sunward at the same time. ...
On May 6, 2007, at 5:46 AM, Jones Beene wrote:
... which BTW - and this is the most convincing detail of all to me
in the 'big picture' - as the so-called northernmost exposure out
of the Milky Way galactic plane puts the solar system facing
directly towards the "great attractor," which is probably the
source of the most intense cosmic rays ... plus one can assume (at
least I can), since we are strongly attracted to this feature in
space - that it was probably the very source from which our entire
local group was expelled 13-15 billion years ago - which - as it
turns out, fits into the argument for a succession of 'little
bangs' (supercluster size) in a non-expanding but pulsating
universe - and not a single big bang in an expanding universe..
The Norther exposure idea would require a full galactic N-S traversal
(bobbing up and down) period, or about 130-200 M years, while the
period between extinctions is often roughly half that.
Age Period Interval
Cambrian 570-500 70 *
Ordovician 500-430 70 *
Silurian 430-395 35
Devonian 395-345 50 *
Carboniferous 345-280 65
Permian 280-225 55 *
Triassic 225-195 30 *
Jurassic 195-136 56
Cretaceous 136-65 71 *
Tertiary 65-present 65
* general agreement on extinction
Fig. 1 - Ages, Periods, and Interval lengths (My)
Age Start Interval
============ ===== =======
Cambrian 570 70
Ordovician 500 105
Devonian 395 115
Permian 280 55
Triassic 225 89
Cretaceous 136 136
Fig. 2 - Extinctions Ages and Intervals (My)
It certainly is worrisome that it's been 136 My since the last go-
round! Cognitive dissonance tells me we missed it this time! 8^)
