Civilizations in star clusters

Star clusters contain hundreds to thousands of stars in a very small
volume. The stellar density of open clusters averages 1.5star/ cubic
light years whereas in the region of our sun it is about .1 star/cubic
light year. This means that interstellar travel within an open cluster
would be much easier than without. Globular clusters have much higher
stellar densities but generally contain very old stars and they are so
close that stable planets might be difficult. However, if a
civilization did arise in a globular cluster, you would expect it to
rapidly colonize the entire cluster, if there were any stable planets
worth doing so.
A civilization within a star cluster might have an entirely different
perspective on astronomy than we do because their sky would be filled
with so many stars that night would be nearly as bright as day. They
could be expected to rapidly find planets around the other very close
stars. However, once a civilization did fill such a cluster, it would
expand much more slowly because outside the cluster the stellar density
falls so that distances become extreme. Even worse, many globular
clusters are outside the plane of the Milky Way so that distances to
stars outside the cluster are much greater than around our sun.
SETI might emphasize looking at star clusters rather than individual
stars.

Good Point!

Carl

Although deep within a dense globular cluster, stellar distances are
only a few "light weeks", say .1 light year, on the outer fringes, the
average distances might be say .5 light year and the planetary lifetime
much longer. At such short distances, at only a speed of .01c, such an
interstellar trip might be feasible in a beings lifetime.
Deeper within the cluster, planetary lifetimes might be too short for
native life to arise but sufficiently long for any civilizations
purposes if the civilization arises near the edge of the cluster.
Furthermore, interstellar panspermia would be very likely in a globular
cluster.
I wonder what the phsychology of space travel would be like for beings
situated in a globular cluster situated far from the main galaxy.
Would they feel themselves to ultimately be isolated somehow?

wrote:

Star clusters contain hundreds to thousands of stars in a very small
volume. The stellar density of open clusters averages 1.5star/ cubic
light years whereas in the region of our sun it is about .1 star/cubic
light year. This means that interstellar travel within an open cluster
would be much easier than without. Globular clusters have much higher
stellar densities but generally contain very old stars and they are so
close that stable planets might be difficult. However, if a
civilization did arise in a globular cluster, you would expect it to
rapidly colonize the entire cluster, if there were any stable planets
worth doing so.
A civilization within a star cluster might have an entirely different
perspective on astronomy than we do because their sky would be filled
with so many stars that night would be nearly as bright as day. They
could be expected to rapidly find planets around the other very close
stars. However, once a civilization did fill such a cluster, it would
expand much more slowly because outside the cluster the stellar density
falls so that distances become extreme. Even worse, many globular
clusters are outside the plane of the Milky Way so that distances to
stars outside the cluster are much greater than around our sun.
SETI might emphasize looking at star clusters rather than individual
stars.


Makes sense to me. Things are more busy closer to the center of the (or any)
galaxy. Everytime I say closer to the center somebody immediately jumps in
thinking I mean the center. No, not the center I mean half way to the
center from the edge of the spiral arms. Or half way out from the center of
the galactic disc.

In article 4Csbg.663$nA2.87@trndny01, Nog wrote:

wrote:

Star clusters contain hundreds to thousands of stars in a very small
volume. The stellar density of open clusters averages 1.5star/ cubic
light years whereas in the region of our sun it is about .1 star/cubic
light year. This means that interstellar travel within an open cluster
would be much easier than without. Globular clusters have much higher
stellar densities but generally contain very old stars and they are so
close that stable planets might be difficult. However, if a
civilization did arise in a globular cluster, you would expect it to
rapidly colonize the entire cluster, if there were any stable planets
worth doing so.
A civilization within a star cluster might have an entirely different
perspective on astronomy than we do because their sky would be filled
with so many stars that night would be nearly as bright as day. They
could be expected to rapidly find planets around the other very close
stars. However, once a civilization did fill such a cluster, it would
expand much more slowly because outside the cluster the stellar density
falls so that distances become extreme. Even worse, many globular
clusters are outside the plane of the Milky Way so that distances to
stars outside the cluster are much greater than around our sun.
SETI might emphasize looking at star clusters rather than individual
stars.


Makes sense to me. Things are more busy closer to the center of the (or any)
galaxy. Everytime I say closer to the center somebody immediately jumps in
thinking I mean the center. No, not the center I mean half way to the
center from the edge of the spiral arms. Or half way out from the center of
the galactic disc.

Of course, we really don't know what the radiation levels are at the
center of the galaxy -- what with black holes, etc. in the region.

Unfortunately, the old globular clusters have only stars for,ed before
there was very much other than H and He, so they will only have gas
giants, no small planets, and any moons must also be metal poor.

But there are new globular clusters in the Magellianic clouds, see
APOD, not that many weeks ago.

Regards

Carsten Nielsen
Denmark

In article . com,
wrote:
Deeper within the cluster, planetary lifetimes might be too short for
native life to arise but sufficiently long for any civilizations
purposes if the civilization arises near the edge of the cluster.

Unfortunately, if I recall correctly, globular-cluster stars are thought
to generally have very elliptical(*) orbits. They don't stay at a
roughly-constant distance from the center, the way stars in a spiral
galaxy generally do; most of them make frequent passes through the dense
center. At any one time, there will be some in near-circular orbits, but
a particular star usually won't stay in such an orbit for billions of
years, because perturbing encounters are too frequent.

(* Actually the orbits aren't ellipses, because the cluster as a whole
does not behave like a point mass, but the general idea is right. )
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

dboh,
You're absolutely correct, except that club SETI/OSETI have actually
been a well established and otherwise perpetrated joke.
-
Brad Guth

In article . com,
"Brad Guth" wrote:

dboh,
You're absolutely correct, except that club SETI/OSETI have actually
been a well established and otherwise perpetrated joke.
-
Brad Guth

I believe that SETI has directed their antennae at "Brad Guth's" house
and detected no sign of intelligent life. ;)

Funny, real funny, Orval Fairbairn.
Gosh, got any other such topic constructive zingers?

Got proof that SETI/OSETI are not basically an ongoing ruse of mostly
tax avoidance?

Got any actual SETI/OSETI hard-science or even soft-science to show us?

Why would ETs worth their salt be so dumb enough as to allowing their
detection? especially by Earth heathens that would just as soon put
the likes of Jesus Christ back on another stick.
-
Brad Guth