[ExI] Gaian Bottleneck

[spike]

-----Original Message-----
From: extropy-chat [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf
Of Anders Sandberg
Sent: Sunday, January 24, 2016 4:29 AM
To: extropy-chat at lists.extropy.org
Subject: Re: [ExI] Gaian Bottleneck

On 2016-01-24 06:48, Stuart LaForge wrote:
> The extent of the of the dip has been measured to be about .193 magnitude
over the observed span.
>
> Thoughts? Anders?

>>...Confusion. 

Me too, oy vey.

>>...Meanwhile Phil Plait claimed the dimming was too *fast* to be Dyson
construction, and I felt obliged to calculate some limits on Dyson
construction:
http://aleph.se/andart2/space/what-is-the-natural-timescale-for-making-a-dys
on-shell/

Ja.  Before it becomes a viable notion to create a Dyson shell or MBrain,
the builders would already need replicating assemblers (we might think.)
Alternative: without replicating assemblers, the progress on the MBrain
would be too slow to map a change on our timescale.  Second alternative:
construction on the MBrain began, then the replicating assembler was
discovered, at which time the transition (causing the dimming) kicked into
high gear.  Problem: that we should happen to catch that transition in
progress is quite unlikely.

>>...So what do I think it is? I suspect it is natural, but perhaps a rare
phenomenon. Maybe there is a small and dense cloud of interstellar dust
drifting past? -- Dr Anders Sandberg
_______________________________________________

Ja, as much as I would like to jump up and down and point to an MBrain in
the process of being built, it is far easier for me to imagine not an
interstellar dust cloud but a huge dust cloud in the gravity well of this
star.  It could span a tenth of a radian of arc from the point of view of
the star and be far enough out to have a several tens of thousands year
orbit.  Then it could take a couple centuries to transit. and we just
happened to be here in the line of sight when it began to transit.

Considering the multiple possible orbit planes, this scenario would be
extremely rare, but if the phenomenon of a dust cloud a light month in
diameter is physically possible (that too strains the imagination) then
there would be a lot of them out there, and this is the first one we were
lucky enough to find one.  My task now is to calculate to see if it is at
all reasonable to hypothesize a dust cloud a light-month in diameter to see
if it would be gravitationally stable and estimate how it would block light.


Even as I write about it, that enormous dust cloud scenario is making my
puzzler sore.  It doesn't seem right at all.  We would need a lot of angular
momentum to keep it even a vaguely stable, and I am having a hard time
imagining where all that angular momentum would have come from.

spike