[ExI] tabby's star dimming again

[Stuart LaForge]

John Clark wrote:

>On Mon, May 22, 2017 at 1:23 AM, Stuart LaForge <avant at sollegro.com>
wrote:
​>> Well somebody had to be first and so maybe we are the second.
>
>​So in a observable universe ​
> 27,600,000,000 light years in diameter the only other technological
> civilization just happens to be only 1480 light years away and Kepler just
> happened to find it even though it was looking at 1/400 of the sky and it
> just happened to find it when ET had the technological chops to build 5%
>of a Dyson Sphere but no more? Doesn't seem very likely. ​

On the contrary, a combination of the anthropic principle and the theory
of galactic habitable zones suggests that life would tend to live in
Goldilocks clusters because conditions nearby are more likely to be
permissive of life than conditions far away.

> That's another problem, Tabby's Star​
> it's not a G class yellow star like our sun, it's a larger F class white
> star with about 1.43 times the mass of the sun. Even a small increase in
> mass causes a star to burn a lot bright and die much younger.

Life became apparent on earth about 4 billion years ago essentially as
soon as the earth cooled enough from the late heavy bombardment to allow
it to. Then 2.5 billion years ago, about 1.5 billion years after life
began, cyanobacteria invented photosynthesis. The oxygen made by
photosynthesis enabled multicellular life which appeared in the fossil
record about 600 million years ago after about a 1.9 billion year gap.

Perhaps a brighter star increases the rate of photosynthesis such that the
gaps between the appearence of photosynthesis and the advent of
intelligent life are shortened by 50%. More sunlight means more
reproduction, more reproduction means faster mutation. Faster mutation
means faster evolution.

​> and ​it said the lifetime of a star of that mass would only be about 40%
> that of our sun, so
> Tabby's Star must be much younger than our sun, too little time I think
>for Evolution to produce beings smart enough to build 5% of a Dyson
>Sphere.

How old is Tabby's star? What about its companion star the alleged red
dwarf? How do astronomers distinguish between red and brown dwarfs or
Dysoned stars any how? Could not some red dwarfs be much brighter stars
that have been Dysoned and only look dim and red because that is the waste
heat we are seeing? ​

Stuart LaForge