Hi,

I wonder what kind of physical and brain adaptations would be need for
people to live directly in 3-d space cities without gravity.

Yes. I know normal, standard, current human beings can't stand zero g
for too long. But in the long term -I really mean long term- is there
any reason why human biology could not evolve (nature, artificially)
to beings that are able to live in zero g without consecuences?

Just for curiosity.

Regards,

Omar Vega

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Omar E. Vega

> Yes. I know normal, standard, current human beings can't stand
> zero g for too long. But in the long term -I really mean long
> term- is there any reason why human biology could not evolve
> (nature, artificially) to beings that are able to live in zero
> g without consecuences?

For those who have no concern for ever again going into gravity, one
might simply choose to regard the loss of bone and muscle mass as
appropriate adaptations to the new environment. However, there remain
other deleterious effects (chief among them a decline in the immune
system) which would have to be overcome somehow.

Marshall Savage, for one, was certainly sanguine about the prospects for
0-G space habitats, and even had their residents depicted as looking
pretty much like normal humans today. For myself, I would expect them
to look freakishly different.

Regards,

Mike Combs

Forget evolving into anything in the short term.

Geneticly, we start out pretty much the same. BUT, for pregnant women in
space, there could be a problem if the women spent a long time in zero-G.
Might have to spin her some before the birth. Some spinning would probably
be advised for early child development as well.

For one's own life, IF the person doesn't plan to return to earth or land on
any gravity rich object (ie. earth's moon, Mars, etc), and is shielded from
radiation, and doesn't sit in their butt all the time, the person will
probably live a full and satisfying life. The person's muscles and bones
will likely deteriorate over time but these are most essential for survival
on gravity rich surfaces, not absolutely needed in space.

George
http://www.cygo.com/

On 5/4/06, Omar E. Vega wrote:

>I wonder what kind of physical and brain adaptations would be need for
>people to live directly in 3-d space cities without gravity.

The unanswered question is whether 1g of simulated gravity resulting from
the spin of the habitat will make up for the lack of actual gravity. But
muscle mass and bone loss should not be a problem in Kalpana One, because
they are the body's reactions to the lack of force load on muscles and
bones. For example you can simulate the same bone and muscle loss an
astronaut suffers by weeks of strict bed rest here on earth, and needless to
say these bed rest subjects are still being effected by earth's gravity.
It's also been shown that weightlifters add both muscle mass (which is
obvious) and bone mass (not so obvious) as their bodies adjust to the
physical stresses of lifting heavy weights. And that hours of strenuous
exercise can reduce the bone and muscle mass loss for astronauts in orbit
(although the amount of work you have to do to completely stop the loss
while in orbit is impractically large). It's not that zero-g has magical
effects on bone and muscles that are not understood, it's that zero-g turns
one into a couch potato in a drastic way. Spin-simulated g forces should
counter that by causing occupants to reutrn to the physical exertions we go
through daily on earth just by sitting, standing, walking, etc.

But what about the immune system question? And other questions? Is there
something about gravity that centrifugal force can't simulate? Are there
subtle health effects of minor coriolis forces that we're not yet aware of?
The first orbital habitat occupants will be pioneers in many ways that are
not obvious to us now.

Brad W.

Brad Walsh wrote:
> It's not that zero-g has magical effects on bone
>and muscles that are not understood, it's that zero-g
>turns one into a couch potato in a drastic way.

I've always looked askance at ideas to alter us (or the idea that we
just might evolve into it some day) to live in microgravity. It's not
just that we'd be unable to return to higher G, but being a couch
potato has other effects, far more harmful than loss of muscle tone
and bone mass. Aside from the unanswerable (for now) questions about
immunodeficiency mentioned here, the main problem seems to be that
our heart shrivels up into a soft, weak shadow of a healthy person's.
You can't stay alive very long or be very healthy if your cardio-
pulmonary system is weak or underdeveloped.
Lets face it: a marathon runner is probably going to outlive and out
perform a sofa spud. Muscles and bodily structures like and need to
be stressed regularly to stimulate removal of old cells and regrowth,
and the whole system of moving construction materials around the body
needs to be worked, or it all goes soft and unresistant to stresses
and entropy.
Possibly the strongest and most healthy people in the future will
push the envelop of engineering and adapt to higher centripetal
forces as conveniently possible.
Evidence abounds for this in experiments of animals living in
centrifuges. (See the book "Great Mambo Chicken and the Transhumanist
Condition"). They're stronger and live longer lives in better overall
health than controls (more likely to mate and pass their genes
along?).

I resist speculation about becoming so dependant and symbiotic to
technology that we every day of our lives and fetuses of our babies
need adjusting with radical therapies or tinkering into something
that's not us, just to survive. As a lazy transhumanist, I don't have
much of a problem accepting that people will opt for just this kind
of thing someday, whether it's to do with microgravity or not, but
that's not my idea of perpetuating humanity and Gaian life across the
galaxy. Not when all it (apparently) takes is 1970s technology in
stressed cables in a 1+meter sinter-crete colony hull. (showing my
predilection in colony hull design again)

> Is there something about gravity that centrifugal
>force can't simulate?

I've often wondered about that, (something other than simple
mechanical stress of moving against a floor that's always pushing up
against your feet) but it's certainly not something we can point to
now. I'm confident that the "conservative engineering" they used in
the Summer Studies to make colonies that just about everyone could
adapt to is adequate to go ahead and plan as if we know that all we
need to do is spin it.
And I too was highly skeptical about Savage's assumptions (long
chains of assumptions) about living in microgravity.

> Are there subtle health effects of minor coriolis
>forces that we're not yet aware of?

In ignorance, I doubt that almost as much as I doubt that we'd ever
be able to live and evolve as healthy couch potatoes. Some evidence
is that people live aboard watercraft for years at a time. I know
it's not the same, but it's an indicator of living in conditions
where "down" wanders about under your floor.

Back around Y2K, I saw an article where they asked different people
about where we were at, compared to where we could be and what
different predictions about the 21st century had said. Arthur C
Clarke said that it's almost shameful that nobody has run long-term
studies in rotating environments in space.

I haven't heard anything lately from the Mars Society about
their "TransLife Biosatellite" experiment.
http://www.marsgravity.org/main/

as adaptable as humans are, and the way life acts as no barrier can
stop it, id say that is possibly, but i'm not a scientist or doctor

--- In spacesettlers@yahoogroups.com, "Omar E. Vega"
>
> Hi,
>
> I wonder what kind of physical and brain adaptations would be need
for
> people to live directly in 3-d space cities without gravity.
>
> Yes. I know normal, standard, current human beings can't stand zero
g
> for too long. But in the long term -I really mean long term- is
there
> any reason why human biology could not evolve (nature,
artificially)