From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Xenophile

> > For example, let's say that every race, creed, and culture on Earth
> > agrees to ZPG and a moratorium on space travel, with the single
> > exception of Albania. The obvious outcome millennias hence is a
Milky
> > Way overrun with Albanians.
>
> The obvious outcome in a couple of decades or less is the Albanians
> blown away for not going along. Any philosophy with that moch
> lock-step agreement behind it (at least outside of Albania) is not
> likely to be very tolerant of those not toeing the line.

OK, let's say we have a divided culture, with a colonizing minority and
a majority willing to practice genocide to stop it. For the colonizing
minority, obviously stepping up their colonization efforts is their best
chance for preserving their people. The more colonies they can create
in as many far-flung places as they can reach, the greater the odds that
no matter how much effort the majority culture puts into it, they'll
still miss some small, obscure colony somewhere. One from which the
minority culture can once again begin growing.

To assume that the explanation for the Fermi paradox is restrictive
cultures which are willing to annihilate those who aspire to
colonization, we have to assume 100%, unfailing competency on their
part.

Regards,

Mike Combs

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert

> 3) if they build space habitats there would be little reason
> to head out to the next star for much longer than 1000 years.

Probably true. But an important difference is that by that time
potential colonists might be pouring out of the system by the many
trillions. I think that would make a big difference in spread rates.

Another point is that in a space habitat future, we might see political
reasons providing the impetus for interstellar migrations, even if
literal crowding couldn't plausibly have anything to do with it.

Regards,

Mike Combs

Well, I don't really explain the Fermi Paradox with Albanian-nuking
anti-expansionists. Just pointing out that simply BEING expansionist
doesn't gauruntee victory. Being *successful* expansionists does.

Now, your idea that the Albanians would step up their colonization
program in the hopes that at least some of them would survive is
probably right. So whether or not they rule the galaxy in the future
would largely depend on whether the rest of the lock-stepping world
nuked them before or after they got that first off-Earth colony going.
The genocidists don't have to 100% competent; they just have to be
competent enough.

Indeed, this could well be the reason we don't see any aliens from Civ
K9R7MN89-A. The reason I wouldn't suggest this as an explanation of
the Fermi Paradox is because it leaves the anti-expansionists of Civ
K9R7MN89-A pretty helpless to stop the colonization program of Civ
M6F4IU56-Z, which is three star systems over. If Civ K9R7MN89-A never
leaves their planet, they can't do much about those ALREADY off of
their planet.

On 7/27/06, Combs, Mike wrote:
(...)
> Another point is that in a space habitat future, we might see political
> reasons providing the impetus for interstellar migrations, even if
> literal crowding couldn't plausibly have anything to do with it.
(...)

That's what I tried to illustrate with my Jew immigration example.

the thing is that by the time they have too many people to build
homes for in their solor system, where are they going to get the
material for the ships. basically the only difference in the ships
and the stations is the ability of the ship to move. they would not
hae the ability to move enough people out of the system fast enough
to overcome the crowding in the system soon they would have every
single asteroid, planet and other peice of useable material used in
the building of their habatats. they would not have enough left over
to build ships to go to new stars. they would have to stop their
population growth to allow new ships to be made. If they are going to
stop the growth anyway, why bother sending out part of their
population.

basically they would end up with a war for resourses, one side saying
they need to send off colonies, the other demanding the resourses be
used for new homes. since its most likely the group wanting to
colonize would be smaller, they would most likely lose.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert
>
> > 3) if they build space habitats there would be little reason
> > to head out to the next star for much longer than 1000 years.
>
> Probably true. But an important difference is that by that time
> potential colonists might be pouring out of the system by the many
> trillions. I think that would make a big difference in spread
rates.
>
> Another point is that in a space habitat future, we might see
political

On Jul 27, 2006, at 2:36 PM, Robert wrote:

> basically they would end up with a war for resourses, one side saying
> they need to send off colonies, the other demanding the resourses be
> used for new homes. since its most likely the group wanting to
> colonize would be smaller, they would most likely lose.

None of the plans for settlements rely on individual settlement
structures lasting forever. Being man-made, they will have to be
replaced from time to time. If they last >1000 years, settlers can
concentrate on building new settlements. If they last <100 years,
much of their time/energy/resources will be spent building/rebuilding
their own station. Also, if they last <100 years, they will have the
perhaps very difficult problem of having to rebuild/renovate their
colony out in interstellar space. Right now we can really only guess
how easy that may be.

Can we build them strong enough to last more than 100 years without a
major overhaul? Obviously there will be ongoing maintenance, but how
often will the population have to be removed from part or all of the
station so major renovations can take place? Keep in mind that as
technology evolves, the initial systems (life support, propulsion,
etc) will also have to be replaced with better, shinier ones. Not
very many naval vessels, aircraft, or even buildings go more than 30
years or so without being drydocked for major work (I guess you don't
drydock a building, but you know what I mean). This could be a
limiting factor on colonizing to the stars. At least for now.

doug

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert

> the thing is that by the time they have too many people to build
> homes for in their solor system, where are they going to get the
> material for the ships. basically the only difference in the ships
> and the stations is the ability of the ship to move. they would not
> hae the ability to move enough people out of the system fast enough
> to overcome the crowding in the system soon they would have every
> single asteroid, planet and other peice of useable material used in
> the building of their habatats.

I see your points, but I think the only thing we can get out of them is
that, in exactly the same way that habitats in HEO are not ultimately a
solution to overpopulation on Earth, interstellar colonization is not
ultimately a solution to the problem of solar system overcrowding. In
both cases, the solution would have to involve limiting population
growth rather than plans to siphon off excess population.

But I think my point is still valid. Let me elaborate. If we assume a
Zubrin future, then we're assuming one in which perhaps 10 or 20 billion
people live on Earth, and perhaps half than many on Mars. Some fraction
of these billions go out into that small minority of solar systems which
happen to contain planets which are sufficiently Earthlike to be
terraformed in the same manner in which Mars was. Given time, those
extrasolar colonies might come to have populations rivaling that of
Earth/Mars (never more than 10 or so billion, remember), and begin
seeding additional colonies.

But if we assume an O'Neill future, then we're assuming hundreds of
trillions of people living throughout the solar system. Imagine how
many interstellar colonists that would result if only one out of 200 or
300 happen to feel the wanderlust. Now imagine them going not just to
certain solar systems with Earthlike planets, but /every/ solar system
within reach of their starships, regardless of the presence or absence
of Earthlike planets, or planets of any type at all (and even without
regard to the sun's spectral type). Imagine the populations of every
one of these settled solar systems in turn growing into the hundreds of
trillions.

To summarize, allowing the High Frontier scenario has a /powerful/
affect on assumed interstellar growth patterns. In a Zubrin scenario,
the spread of humanity across the Milky Way might be a slow smolder. In
an O'Neill scenario, humanity will be a galactic wildfire, for the
simple reason that planetary limits to growth will have been removed
from the equation.

Regards,

Mike Combs

On 7/27/06, Douglas May wrote:
(...)
> Can we build them strong enough to last more than 100 years without a
> major overhaul? Obviously there will be ongoing maintenance, but how
> often will the population have to be removed from part or all of the
> station so major renovations can take place? Keep in mind that as
> technology evolves, the initial systems (life support, propulsion,
> etc) will also have to be replaced with better, shinier ones. Not
> very many naval vessels, aircraft, or even buildings go more than 30
> years or so without being drydocked for major work (I guess you don't
> drydock a building, but you know what I mean). This could be a
> limiting factor on colonizing to the stars. At least for now.
(...)

I would take buildings out of the examples. There are buildings with
concrete of even steel structure that are holding up perfectly for
over a hundred years. And there are stone cathedrals from the Middle
Ages that are over a thousand years old. And this without structural
need of major overhauls.

In fact, the longevity of buildings, particularly the ones made of
concrete and stone, are the main argument in favor of space colonies
made of concrete or perhaps some synthetic stone (like cast basalt).

actually with O'Neil type civiliations there is another factor. one
of moving the materials to build a new station. also as someone else
pointed out, they would have to rebuild the stations periodiacally.
this will have the same effect on populations as the planets lack of
more usable resources do. the only difference would be the size of
the population.

the problem colonizing groups from O'Neil type civiliations would
have is getting the resourses, since the same resourses would be
needed to maintain and build new homes. It would not be an easy,
cheap fix for those who are bit by the wonderlust bug. Most likely
they would have to deal with people not willing to risk the resources
on a possible suicidal colonizing attempt. meaning that first there
would have to be scouts sent out to see if a planet was colonizable,
or if the system had the resourses to handle a O'Neil type
civiliation. then after spending all that energy and resourses to
send out a new colony the old system would demand that the new one
send back resourses to pay for the effort. this would limit the
ability of the new system to build its own civiliation, leading to a
slowing of its growth for sometime.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert
>
> > the thing is that by the time they have too many people to build
> > homes for in their solor system, where are they going to get the
> > material for the ships. basically the only difference in the
ships
> > and the stations is the ability of the ship to move. they would
not
> > hae the ability to move enough people out of the system fast
enough
> > to overcome the crowding in the system soon they would have every
> > single asteroid, planet and other peice of useable material used
in
> > the building of their habatats.
>
> I see your points, but I think the only thing we can get out of
them is
> that, in exactly the same way that habitats in HEO are not
ultimately a
> solution to overpopulation on Earth, interstellar colonization is
not
> ultimately a solution to the problem of solar system overcrowding.
In
> both cases, the solution would have to involve limiting population
> growth rather than plans to siphon off excess population.
>
> But I think my point is still valid. Let me elaborate. If we
assume a
> Zubrin future, then we're assuming one in which perhaps 10 or 20
billion
> people live on Earth, and perhaps half than many on Mars. Some
fraction
> of these billions go out into that small minority of solar systems
which
> happen to contain planets which are sufficiently Earthlike to be
> terraformed in the same manner in which Mars was. Given time, those
> extrasolar colonies might come to have populations rivaling that of
> Earth/Mars (never more than 10 or so billion, remember), and begin
> seeding additional colonies.
>
> But if we assume an O'Neill future, then we're assuming hundreds of
> trillions of people living throughout the solar system. Imagine how
> many interstellar colonists that would result if only one out of
200 or
> 300 happen to feel the wanderlust. Now imagine them going not just
to
> certain solar systems with Earthlike planets, but /every/ solar
system
> within reach of their starships, regardless of the presence or
absence
> of Earthlike planets, or planets of any type at all (and even
without
> regard to the sun's spectral type). Imagine the populations of
every
> one of these settled solar systems in turn growing into the
hundreds of
> trillions.
>
> To summarize, allowing the High Frontier scenario has a /powerful/
> affect on assumed interstellar growth patterns. In a Zubrin
scenario,
> the spread of humanity across the Milky Way might be a slow
smolder. In

On Jul 27, 2006, at 3:39 PM, Lucio de Souza Coelho wrote:

> I would take buildings out of the examples. There are buildings with
> concrete of even steel structure that are holding up perfectly for
> over a hundred years. And there are stone cathedrals from the Middle
> Ages that are over a thousand years old. And this without structural
> need of major overhauls.
>
> In fact, the longevity of buildings, particularly the ones made of
> concrete and stone, are the main argument in favor of space colonies
> made of concrete or perhaps some synthetic stone (like cast basalt).

Yes, buildings aren't as good an example. The structures of older
buildings do last longer, but the infrastructure of modern buildings
(I.E. plumbing, wiring, communications, elevators, etc) still becomes
increasingly inadequate and eventually wears out. But even the older
buildings eventually crumble. Only the pyramids remain of the 7
ancient wonders. Earthquakes, volcanoes, and wars will (hopefully)
not affect the settlements, but there will be other perils. We don't
really know what kind of damage to expect on the structure of the
settlements from radiation. The radiation shield will last a long
time, but solar panels and other weak points may experience trouble
after a few decades. We don't know how dense the meteor material is
in interstellar space. The Oort cloud is full of dust and rocks.
Major collisions would be very rare, but smaller ones could be
common. The accumulation of years of sand sized meteors striking the
settlement while the settlement is traveling several million miles
per hour would certainly cause wear and tear on certain parts of the
craft.

A big problem with attempting interstellar repairs on a settlement:

If a comet/asteroid/brown dwarf or whatever were needed for material
to repair a settlement, as far as we know right now, we would have to
change course and slow down to get it. To slow down in deep space
somewhere between here and another star would require a lot of time
and energy. Reaccelerating would also require time and energy. A star
faring civ would likely have both time and energy available, but
neither would be unlimited. A journey to say Alpha Centauri of 50
years could be extended to 100 years or more if we had to stop for
repairs. Kind of a bummer for those who hoped to see another star
before they died. Also that could mess up our planning on how long
our recycling program can run before certain items run out.

Reliable, long lasting electronics are a must for interstellar
travel. Also, we should probably get pretty good at making electronic
and mechanical components out of a variety of different materials,
just in case we can't find the normal elements at a critical time
when repairs are needed and supplies are low. Manufacturing chemical
elements is probably not going to be an option for an early type I
Civ (at least for an isolated, brokedown settlement), since the
amount of energy required to fuse mid-size atoms requires something
with the energy of a supernova.

Basically, my point is just that I believe we are still a long way
off from being able to consider star travel. If we launched a mission
100 years from now, I doubt it could survive. I have no idea how long
it will be before we are ready, but it will require new construction
techniques, new knowledge of physics, new sources of energy, and a
new attitude and perhaps new physiology of humans.

Most important: it will require LOTS of experience with space
settlements here in the solar system.

doug

IMHO, in 100 years the an attempt to settle another star would have a
fairly good chance. they would have to have a lot of redundances,
including multiple ships, on slightly different paths. also they
would have to plan on losing 90 percent or more of their resourses
along the way, yet still have the resourses to maintain their life
for sometime after reaching the star. In addition, i dont think any
attempt would be made to send a colony out, unless there was enough
data about the star before they left to know that it had a fair
chance.

--- In spacesettlers@yahoogroups.com, Douglas May wrote:
>
> On Jul 27, 2006, at 3:39 PM, Lucio de Souza Coelho wrote:
>
> > I would take buildings out of the examples. There are buildings
with
> > concrete of even steel structure that are holding up perfectly for
> > over a hundred years. And there are stone cathedrals from the
Middle
> > Ages that are over a thousand years old. And this without
structural
> > need of major overhauls.
> >
> > In fact, the longevity of buildings, particularly the ones made of
> > concrete and stone, are the main argument in favor of space
colonies
> > made of concrete or perhaps some synthetic stone (like cast
basalt).
>
> Yes, buildings aren't as good an example. The structures of older
> buildings do last longer, but the infrastructure of modern
buildings
> (I.E. plumbing, wiring, communications, elevators, etc) still
becomes
> increasingly inadequate and eventually wears out. But even the
older
> buildings eventually crumble. Only the pyramids remain of the 7
> ancient wonders. Earthquakes, volcanoes, and wars will (hopefully)
> not affect the settlements, but there will be other perils. We
don't
> really know what kind of damage to expect on the structure of the
> settlements from radiation. The radiation shield will last a long
> time, but solar panels and other weak points may experience
trouble
> after a few decades. We don't know how dense the meteor material
is
> in interstellar space. The Oort cloud is full of dust and rocks.
> Major collisions would be very rare, but smaller ones could be
> common. The accumulation of years of sand sized meteors striking
the
> settlement while the settlement is traveling several million miles
> per hour would certainly cause wear and tear on certain parts of
the
> craft.
>
> A big problem with attempting interstellar repairs on a settlement:
>
> If a comet/asteroid/brown dwarf or whatever were needed for
material
> to repair a settlement, as far as we know right now, we would have
to
> change course and slow down to get it. To slow down in deep space
> somewhere between here and another star would require a lot of
time
> and energy. Reaccelerating would also require time and energy. A
star
> faring civ would likely have both time and energy available, but
> neither would be unlimited. A journey to say Alpha Centauri of 50
> years could be extended to 100 years or more if we had to stop for
> repairs. Kind of a bummer for those who hoped to see another star
> before they died. Also that could mess up our planning on how long
> our recycling program can run before certain items run out.
>
> Reliable, long lasting electronics are a must for interstellar
> travel. Also, we should probably get pretty good at making
electronic
> and mechanical components out of a variety of different materials,
> just in case we can't find the normal elements at a critical time
> when repairs are needed and supplies are low. Manufacturing
chemical
> elements is probably not going to be an option for an early type I
> Civ (at least for an isolated, brokedown settlement), since the
> amount of energy required to fuse mid-size atoms requires
something
> with the energy of a supernova.
>
> Basically, my point is just that I believe we are still a long way
> off from being able to consider star travel. If we launched a
mission
> 100 years from now, I doubt it could survive. I have no idea how
long
> it will be before we are ready, but it will require new
construction

On 7/27/06, Douglas May wrote:
(...)
> If a comet/asteroid/brown dwarf or whatever were needed for material
> to repair a settlement, as far as we know right now, we would have to
> change course and slow down to get it. To slow down in deep space
> somewhere between here and another star would require a lot of time
> and energy. Reaccelerating would also require time and energy. A star
> faring civ would likely have both time and energy available, but
> neither would be unlimited.
(...)

Of course all those logistic problems would be avoided if interstellar
colonization were done by pure diffusion instead of intentional
star-to-star trip. As you hinted, the interstellar space is full of
objects (comets, rogue planets, brown dwarfs, etc) and instead of
saying "lets go to Alpha Centauri" a colony could simply say "lets go
to the next comet", with no plan whatsoever of interstellar travel.
However, by hoping from object to object, refueling, repairing itself
and producing new colonies by consuming new sources of raw materials,
eventually one of those interstellar wanderers would get to another
planetary system. This method is admittedly the slowest one - an
expanding shell of interstellar wanderers would likely take tens of
thousands of years to grow a few light years - but on the other hand
it is fail-proof, relying on sheer power of huge numbers.

problem with this is that the space between stars has few comet and
such

--- In spacesettlers@yahoogroups.com, "Lucio de Souza Coelho"
wrote:
>
> On 7/27/06, Douglas May wrote:
> (...)
> > If a comet/asteroid/brown dwarf or whatever were needed for
material
> > to repair a settlement, as far as we know right now, we would
have to
> > change course and slow down to get it. To slow down in deep space
> > somewhere between here and another star would require a lot of
time
> > and energy. Reaccelerating would also require time and energy. A
star
> > faring civ would likely have both time and energy available, but
> > neither would be unlimited.
> (...)
>
> Of course all those logistic problems would be avoided if
interstellar
> colonization were done by pure diffusion instead of intentional
> star-to-star trip. As you hinted, the interstellar space is full of
> objects (comets, rogue planets, brown dwarfs, etc) and instead of
> saying "lets go to Alpha Centauri" a colony could simply say "lets
go
> to the next comet", with no plan whatsoever of interstellar travel.
> However, by hoping from object to object, refueling, repairing
itself
> and producing new colonies by consuming new sources of raw
materials,

> From: Robert
> meaning that first there
> would have to be scouts sent out to see if a planet was colonizable,
> or if the system had the resourses to handle a O'Neil type
> civiliation. then after spending all that energy and resourses to
> send out a new colony the old system would demand that the new one
> send back resourses to pay for the effort.

This assumes that construction of a Daedalus probe would be extortionately
expensive for an O'Neil type civilisation. I really don't think it will be.
(They will after all be used to building large effecient rocket engines.)
Especially if many of them were built at once. A generation or two after
NASA's current proposal for planet finders, telescopes might be able to make
the same observations from a distance.

John

On 7/28/06, Robert wrote:
(...)
> problem with this is that the space between stars has few comet and
> such
(...)

Certainly the density is lower than inside the Solar System, but even
though it is a perfectly adequate density for space habitats. The Oort
cloud is estimated to have *trillions* of comets, separated by
interplanetary-like distances - which means that it would take months
or at most years for a habitat to hop from one to another - and
extending as far as two light years - which means that our own
cometary cloud may touch those of other systems. Also, relatively
recent discoveries regarding brown dwarfs and rogue planets point out
that they are probably far more numerous than stars, and between here
and Alpha Centauri you may find several (or even many) of them (though
in this case they may be light-months from each other).

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert

> the problem colonizing groups from O'Neil type civiliations would
> have is getting the resourses, since the same resourses would be
> needed to maintain and build new homes. It would not be an easy,
> cheap fix for those who are bit by the wonderlust bug. Most likely
> they would have to deal with people not willing to risk the resources
> on a possible suicidal colonizing attempt. meaning that first there
> would have to be scouts sent out to see if a planet was colonizable,
> or if the system had the resourses to handle a O'Neil type
civiliation.
> then after spending all that energy and resourses to send out a new
> colony the old system would demand that the new one send back
resourses
> to pay for the effort. this would limit the ability of the new system
> to build its own civiliation, leading to a slowing of its growth for
sometime.

I think the problem here is that you seem to always assume that the
O'Neill civilization will not begin to engage in interstellar
colonization until resources are beginning to run out in the home
system. As I've mentioned elsewhere, I don't think overcrowding will be
the impetus for interstellar migrations. It will, I think, be done for
political reasons (the desire to create new societies free from
interference).

As for sending out scouts to see if a system had the resources needed to
support an O'Neill civilization, it's very difficult to see how a system
could possibly lack the resources needed. That would have to be a
system with no asteroids or comets at all. On the other hand, it might
be the exceedingly rare solar system that has a planet with all the
right characteristics to make terraforming viable.

Also, you seem to assume that the home civilization will need to fund
the colonization effort, and then demand a return on their investment.
I'd assume that the interstellar colonists themselves would be funding
the effort, since they (and their children) would be the only
conceivable beneficiaries. I think such colonization will be funded by
people who for one reason or another want to leave their parent
civilization and make a clean break from it.

Regards,

Mike Combs

On Jul 28, 2006, at 7:15 AM, ANTIcarrot wrote:

> A generation or two after
> NASA's current proposal for planet finders, telescopes might be
> able to make
> the same observations from a distance.

I read or heard once that out in either the Kuiper Belt or Oort cloud
somewhere at a certain distance there is a gravitational focus
created by our suns gravity that would make any telescope much more
effective. Telescopic observation of extrasolar planets could then be
much easier if that's true. By the time we are colonizing the dark
part of the solar system, we surely will have no trouble analyzing
other star systems.

Also, until we get out there, we really can't tell how densely packed
the Oort cloud is, or whether or not it is actually touching another
star's cloud. We're not even sure what percentage of stars actually
have such clouds, but by the time we need to know, we will know.

doug

On Jul 28, 2006, at 8:39 AM, Combs, Mike wrote:

> Also, you seem to assume that the home civilization will need to fund
> the colonization effort, and then demand a return on their investment.
> I'd assume that the interstellar colonists themselves would be funding
> the effort, since they (and their children) would be the only
> conceivable beneficiaries. I think such colonization will be funded by
> people who for one reason or another want to leave their parent
> civilization and make a clean break from it.

Given the travel times, that's probably the only economic model that
can work, and that would require high-quality spaceships that can be
built at low prices (prices=material+energy+labor+time). Sailing a
few weeks across the ocean on a wooden ship would be comparatively
easy and forgiving compared to setting off on a "home-made" world for
several generations.

Not that it won't happen, but construction quality standards on an
interstellar spaceship would have to be extremely high compared to
anything we do on Earth. It's difficult to imagine a group of
political refugees building a ship fit enough to go to Tau Ceti or
someplace, when they could just build one strong enough to orbit
right here in our solar system. Few of these political "Utopias"
would be wealthy enough to spawn new colonies to diffuse outward.

Of course I'm thinking shorter term. It's not possible and perhaps
not very constructive to try to imagine what it will be like in
thousands of years. Fun, maybe, but not very constructive.

doug

im not sure where you got the idea that the oort cloud spread out
that far into interstellar space. when i was reading about the object
they are calling the 10th planet, it was discussing the fact that
that was very near the point where solar gravity would no longer keep
the planets in orbit. there was some discussion on wheither or not it
was really a rogue object that happen to be passing though the fringe
of our solar system. orbits around the sun dont extend as far as one
light year, let alone two.

--- In spacesettlers@yahoogroups.com, "Lucio de Souza Coelho"
wrote:
>
> On 7/28/06, Robert wrote:
> (...)
> > problem with this is that the space between stars has few comet
and
> > such
> (...)
>
> Certainly the density is lower than inside the Solar System, but
even
> though it is a perfectly adequate density for space habitats. The
Oort
> cloud is estimated to have *trillions* of comets, separated by
> interplanetary-like distances - which means that it would take
months
> or at most years for a habitat to hop from one to another - and
> extending as far as two light years - which means that our own
> cometary cloud may touch those of other systems. Also, relatively
> recent discoveries regarding brown dwarfs and rogue planets point
out
> that they are probably far more numerous than stars, and between
here
> and Alpha Centauri you may find several (or even many) of them
(though

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Douglas May

> Not that it won't happen, but construction quality standards
> on an interstellar spaceship would have to be extremely high
> compared to anything we do on Earth.

The nanotech people seem to think that we can get to a world where our
technology is built to molecular levels of precision.

> Of course I'm thinking shorter term. It's not possible and
> perhaps not very constructive to try to imagine what it will
> be like in thousands of years. Fun, maybe, but not very
> constructive.

Yeah, we're probably like 15th century navigators speculating on what
kinds of exceedingly light wooden ships and what kinds of exceeding
large sails would permit trips to the moon. (Probably not quite that
bad, but you get the idea.)

Regards,

Mike Combs

the reason that i would expect them to wait so long is that if there
is more resourse still in the solar system, there are likely places
where a new station could be built. this would put the new one far
enough away from the older station as to make it effectively as cut
off as going to a new star.

building a star crossing colonizing ship would be an extreamly
expensive undertaking. unless all the colonist were exceedingly rich,
its unlikely they could afford to finace it themselfs. If they cant,
then they will have to have some form of finacial arrangement, which
would likely be something along the lines of sending resourses back
to the home system. the only other way is that they become vertual
slaves for more than a generation to the company that is going to
build the ship for them.

at this point we dont know if all the stars have rings of asteroids
or planets around them. the only things we know of yet is the giant
planets like jupiter or saturn. Atleast in the early stages, they
would have to make sure there were materials needed for colonization.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> I think the problem here is that you seem to always assume that the
> O'Neill civilization will not begin to engage in interstellar
> colonization until resources are beginning to run out in the home
> system. As I've mentioned elsewhere, I don't think overcrowding
will be
> the impetus for interstellar migrations. It will, I think, be done
for
> political reasons (the desire to create new societies free from
> interference).
>
> As for sending out scouts to see if a system had the resources
needed to
> support an O'Neill civilization, it's very difficult to see how a
system
> could possibly lack the resources needed. That would have to be a
> system with no asteroids or comets at all. On the other hand, it
might
> be the exceedingly rare solar system that has a planet with all the
> right characteristics to make terraforming viable.
>
> Also, you seem to assume that the home civilization will need to
fund
> the colonization effort, and then demand a return on their
investment.
> I'd assume that the interstellar colonists themselves would be
funding
> the effort, since they (and their children) would be the only
> conceivable beneficiaries. I think such colonization will be
funded by

Funny that it's been estimated that one quarter of all asteroidal mass
*inside* our solar system is in its largest body Ceres, which is roughly
about one quarter *of* a quarter of our Moon's mass. However, beyond
Neptune's orbit we're finding many TNOs & KBOs larger than Ceres, some
larger than Pluto. The more we search this dark expanse, the larger our
estimates of how much mass is out there.
http://en.wikipedia.org/wiki/Solar_system#Layout_and_distances
http://en.wikipedia.org/wiki/Trans-Neptunian_object#Largest_discoveries

It is commonly believed that many water-ice comets lie waiting in the
Kuiper Belt and Oort Cloud, and that our gas giants Jupiter and Saturn
provide such perturbation to bringing in these comets, that these two
may be largely responsible for the life-giving levels of water on Earth.

So I suppose that the worry is not about finding useful matter inside
these belts, but in the darker reaches beyond.

- joel

Douglas May wrote:

On Jul 28, 2006, at 9:08 AM, Robert wrote:

> im not sure where you got the idea that the oort cloud spread out
> that far into interstellar space. when i was reading about the object
> they are calling the 10th planet, it was discussing the fact that
> that was very near the point where solar gravity would no longer keep
> the planets in orbit. there was some discussion on wheither or not it
> was really a rogue object that happen to be passing though the fringe
> of our solar system. orbits around the sun dont extend as far as one
> light year, let alone two.

There have been several planetoids called the 10th planet, most in
the Kuiper belt. Sometimes called TNO's (Trans-Neptune objects). The
Kuiper belt starts around 30 AU's out (just past Neptune) and drops
off pretty quickly at around 50 AU's (around 5 billion miles). The
Oort cloud doesn't begin until 50,000 AU's (5 Trillion miles). We
don't know where the Oort cloud ends. Probably different distances in
different directions thanks to new data from the Voyagers (yes,
they're still working hard out there). The Kuiper belt is a ring,
while the Oort cloud is a shell, completely surrounding the Sun. The
nearly 5 trillion miles of space in between is sometimes called an
"outer Kuiper belt" or an "inner Oort cloud". No Oort cloud object
has actually been seen at the Oort cloud distance. Its existence is
calculated by many different means. The small-moon sized object Sedna
is considered an Oort Cloud object even though it is in the empty
zone less than 1000 AU's out.

We don't know how many objects exist in this empty zone between the
Kuiper belt and Oort cloud, its simply too dark to see with a
telescope. Sedna could be an oddball planetoid adrift in the trans-
kuiper desert, or there could be many other objects floating around
out there waiting for us. Voyager is probably not sophisticated
enough to answer that, but within 50 years, we may know.

We have no visual sighting of any planetoid beyond 1000 AU's. The
Oort cloud goes out to at least 100,000 AU's, if not more, and Alpha
Centauri is just under 300,000 AU's away.

For those who don't know, 1 AU is the distance from the Earth to the
sun, about 93 million miles. The voyagers are still less than 100 AU
out I believe.

doug

Thanks for sparing me the work of pouring all this data and discussion
about the Oort Cloud, Doug! I would just like to add:

On 7/28/06, Douglas May wrote:
> No Oort cloud object
> has actually been seen at the Oort cloud distance. Its existence is
> calculated by many different means.
(...)

Remembering that everything started when Oort himself, back in the
50's, saw that if the comets that we see had always occupied their
observed orbits, all comets would have become extinct billions of
years ago because they would have passed close to the Sun too many
times. So in fact comets *have* to be constantly replenished in the
Solar System, and then Oort postulated that there was a huge comet
reservoir (obviously later called Oort Cloud) enveloping the Solar
Systems. From the trajectories and frequency of comets, the Oort Cloud
diameter and number of comets was estimated.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> To summarize, allowing the High Frontier scenario has a /powerful/
> affect on assumed interstellar growth patterns. In a Zubrin
scenario,
> the spread of humanity across the Milky Way might be a slow
smolder.
In
> an O'Neill scenario, humanity will be a galactic wildfire, for the
> simple reason that planetary limits to growth will have been removed
> from the equation.
>
> Regards,
>
> Mike Combs
>
I agree with you Mike. For anyone interested: The Mote In God's Eye
by
Niven and Pournelle is a great fictional example of the O'Neill
scenario using a race confined to a single star system for maybe
millions of years as an interplanetary race. They divide into
families
or tribes and are continually at war. Their basic drive is to
reproduce
because they die young and painfully if they don't breed.

We may not have the physical drive they have, but look at any area of
the world and you will find groups of people that continue to breed
beyond the capabilities of their environment to support the
population.
The children die of starvation or pestilence or plagues or warfare,
as
do their elders. This is not "civilized" behavior.

Look at the Middle East now with the Palestine and Israel and Lebanon
situation. People don't like to live next to 'different' people. The
Middle East was poorly divided up into nations in the 20th century
and
did not take into consideration the racial or religious groupings
that
were split into fragments in several nations, as also with the Balkan
nations.

Any group that wishes to have a 'new start' will need its own space
settlements. They can control population flow to their own
requirements.

Regards,
Harvey