[ExI] Old Chemically Mature Galaxies and Fermi Paradox

[BillK]

On Sat, Nov 5, 2011 at 9:07 AM, Anders Sandberg wrote:
> One reset mechanism that was suggested by Milan Circovic (and then, with
> some minor input from me, developed by him into a paper with Robert
> Bradbury) is that gamma ray bursts acts as the reset. The data suggests that
> gamma ray bursts were much more common in the past, and it is not hard to
> imagine that every time one hits a biosphere it slides back to a simple
> stage. If there is a number of "ladders" to climb and the GRBs act as
> "snakes", then a model with exponentially declining GRBs and lots of
> biospheres has a decently sharp transition from simple to complex
> biospheres. I don't think this is a good enough reset mechanism to answer
> the Fermi question, but it might be part of an answer.
>
>

This article from an astrophysicist says not to worry. Stars and
Galaxies formed quickly in the early universe and started the
recycling mechanism.

<http://scienceblogs.com/startswithabang/2011/11/the_heavy_metal_universe.php>
Quote:
This is the current record-holder for most distant galaxy ever:
UDFj-39546284, from when the Universe was only 480 million years old,
or 3.5% of its current age!
This galaxy is a small collection of hot, blue stars, with not even 1%
of the mass of the Milky Way! Is this where we were forming the first
stars? Or is this galaxy even typical of the galaxies that are out
there at this early stage in the Universe?

Our best theories tell us that we wouldn't be surprised if galaxies as
far back as this one were abundant, rich in metals, and -- in many
cases -- of comparable masses to our own Milky Way, already. But at
some point, some distant galaxy was first. And we want to know where
that was, and when that was.

At this point in time, there's only one plan in the works to find that out.
Add just one more reason to the list of why we need the James Webb
Space Telescope!

So until we get there, don't be surprised that the distant Universe is
full of heavy metals, evolved stars, or massive galaxies. The Universe
is a place where everything we know can not only happen, it happens
fast. It does make you wonder, though, just how long ago -- under the
right conditions -- planets, and even life, could have formed!
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BillK