First Ark to Alpha Centauri

"Tim Auton" wrote in message
...
(AA Institute) wrote:
"George Dishman" wrote:

Your web page said 50,000 years, that's between 2000 and
2500 generations.

Out of interest, what formula do you use for this? I just did a
simplistic 50,000/100 to get 500 generations! (Assuming a lifespan per
person of 100 years)

It's not that simple , right?!

You don't plan to have children when you're 100? I'll be happy if I
hold out that long; I expect my balls will have shriveled long before
then. 25 years is, very roughly, a generation. People tend to have
kids around that time (+/- 10 years, very roughly). That may not be
all that's important evolutionarily, but the genetics are fixed at
conception, and that's what we're talking about.

Until quite recently in our history the average age for
starting a new generation was about 16. You started there
and kept at it until you or the missus dropped dead of old
age at about 35 (Well, disease actually; bodies wore out
pretty quickly from malnutrition and constant battles with
disease).

Tim Auton wrote in message:
snip

then. 25 years is, very roughly, a generation.

I thought as much. So 50,000/25 = 2000. I stand duly corrected, the
2,000th generation will eventually get greeted by the warm sunshine
from Alpha Centauri!

With an initial crew make-up of just 900 people, they will have
"inbred" hundreds of times over that expected for natural conditions
on Earth, right? And there'll be all diseased and weak, etc when they
arrive at New Earth...

There is a way around this: you can take frozen eggs and sperm from a
much wider gene pool on reserve from Earth; the Centauri Princess'
(name of the starship) computer monitors births and deaths along the
voyage for each person/family. It calculates roughly after how many
natural births one needs to expand one's gene pool. The ship's medical
team then advise their passengers *when* they should start drawing on
the frozen fertility ingredients...

So there is a solution (assuming frozen genetic material can keep for
50,000 years of course!)

One question: when the 50,000th year party celebrations are to be
thrown on the ship right at the end... what would you call that? It's
not the 50,000th "centenary"? A new word is needed in the future
spaceflight dictionary...

Abdul

"AA Institute" wrote in message
om...
Tim Auton wrote in message:
snip

then. 25 years is, very roughly, a generation.

A few hundred years ago, it was common for the woman
to get pregnant and then get married, just to check
there were no problems. This might have been in the
late teens and typical family size was roughly 5 to
10 children with two year gaps. Mean age of the
parents at birth was around 22.

Then social attitudes changed and being born "out of
wedlock" was the worst thing possible. Better health
care meant fewer infant deaths and high living standards
meant less dependence on your children in old age so
family size tended to fall. A later start but fewer
children meant a slight rise in average age of the
parents.

Currently, there is a problem. In many countries the
average family is less than 2.4 children, which is not
even sustainable, and couples are waiting until their
thirties so that they have their careers established
before taking a break for a family.

You need to consider how attitudes and lifestyle will
be affected to work out the average age, and of course
over so many generations, there will be many changes.

I thought as much. So 50,000/25 = 2000. I stand duly corrected, the
2,000th generation will eventually get greeted by the warm sunshine
from Alpha Centauri!

With an initial crew make-up of just 900 people, they will have
"inbred" hundreds of times over that expected for natural conditions
on Earth, right? And there'll be all diseased and weak, etc when they
arrive at New Earth...

They would probably be producing children so deformed
that they would be sterile, or even be dieing before
puberty, within a few dozen generations.

There is a way around this: you can take frozen eggs and sperm from a
much wider gene pool on reserve from Earth; the Centauri Princess'
(name of the starship) computer monitors births and deaths along the
voyage for each person/family. It calculates roughly after how many
natural births one needs to expand one's gene pool. The ship's medical
team then advise their passengers *when* they should start drawing on
the frozen fertility ingredients...

So there is a solution (assuming frozen genetic material can keep for
50,000 years of course!)

The couples involved would ignore that advice completely
because they want to have _their_ children, not someone
else's. The first generation or two might stick to it
because they started the voyage knowing what was needed.
After that, why should kids stick to rules made by their
great-great-grandparents? They have the right to choose,
etc.

If a couple does ignore the advice, what could be done?
Enforced abortion followed by enforced artificial
insemination? I don't think so. Then again, who would
enforce it? If that was done to one couple, would they
then apply those rules to their children and grand-
children? It seems highly unlikely and remember the
problems don't show up until several generations later.

The solution is to have a population the size of
"Babylon 5". You should also consider that a population
the size you propose wouldn't have enough people to have
a league in most sports and couldn't support much of an
entertainment industry. It's going to be a very boring
place. The majority are going to be simple farmers, what
else is there to do?

One question: when the 50,000th year party celebrations are to be
thrown on the ship right at the end... what would you call that? It's
not the 50,000th "centenary"? A new word is needed in the future
spaceflight dictionary...

50000th anniversary
500th centenary or centennial
50th millennium

There may be new words in their vocabulary though. Consider
what we call the time 50000 years ago:

Lower Paleolithic -- (the oldest part of the Paleolithic
Age with the emergence of the hand ax; ended about 120,000
years ago)

Middle Paleolithic -- (the time period of Neanderthal man;
ended about 35,000 years BC)

Upper Paleolithic -- (the time period during which only
modern Homo sapiens was known to have existed; ended about
10,000 years BC)

What arrives in your story will have evolved to be quite
different to the humans that get there by faster (unmanned)
means and spent 45000 years exploring and adapting to an
alien planet.

George

"AA Institute" wrote in message
om...

snip

One question: when the 50,000th year party celebrations are to be
thrown on the ship right at the end... what would you call that? It's
not the 50,000th "centenary"? A new word is needed in the future
spaceflight dictionary...

Abdul

It would be the 5,000th centenary, since centenary means something that
occurs every 100 years.

"Laura" wrote in message
...

"AA Institute" wrote in message
om...

snip

One question: when the 50,000th year party celebrations are to be
thrown on the ship right at the end... what would you call that? It's
not the 50,000th "centenary"? A new word is needed in the future
spaceflight dictionary...

Abdul

It would be the 5,000th centenary, since centenary means something that
occurs every 100 years.


Oops... too quick for my own good :-)
500th, of course.

"George Dishman" wrote:

snip
...
I wonder if cosmic rays can make objects of certain chemical
composition "glow in the dark"? So the ship might pass through a zone
of glowing gas or icy meteoroids acting as substitute for shooting
stars on Earth!

http://www-ssg.sr.unh.edu/tof/Outrea...nterdepth.html

75% hydrogen, 25% helium, both transparent, at about 1 atom
per cc, and a tiny amount of fine, black dust. Although the
density is very low, you may still need to consider drag
over such a long voyage.


Very interesting.

"Our sun (and solar system) are currently moving through a cloud of
interstellar gas." - quote from the above article.

As far as I know, the so-called "Pioneer effect" was never
satisfactorily resolved and I think both probes were retarded by
microscopic amounts in their solar system escape trajectories out
towards interstellar space. Do you suspect the interstellar
winds/medium could have had a part to play in this?

Thanks
AA

"George Dishman" wrote:
snip
snip
You should also consider that a population
the size you propose wouldn't have enough people to have
a league in most sports and couldn't support much of an
entertainment industry. It's going to be a very boring
place. The majority are going to be simple farmers, what
else is there to do?

My story shows never a dull moment. Mining comets, shopping, boating
trips along the river in the sky, taking shuttles out on starship fly
arounds, 360-degree night sky views (24 hour astronomy!), having the
freedom of job rotations, as well as catching up on all the local
gossip and mischief that's part of being who we are... There was even
going to be a "Miss Centauri Princess" competition... which I've had
to cut short due to time pressure...

There'll be sports facilities onboard too. No, it's a "miniature
Earth" alright albeit in a fantasy land...


What arrives in your story will have evolved to be quite
different to the humans that get there by faster (unmanned)
means and spent 45000 years exploring and adapting to an
alien planet.

These *faster* means of interstellar travel are still equally in the
realm of theoretical spaceflight, otherwise we would have launched a
few unmanned flights by now...

It's all in the future.

"Laura" wrote:


Oops... too quick for my own good :-)
500th, of course.

Thank you Laura. Very well, "500th Centenary Celebrations" it shall be!

Abdul

Rob Dekker wrote:
"AA Institute" wrote in message om...

"Rob Dekker" wrote in message news:XMjpd.26786


since the population should be in
the tens of thousands.

Cheers, Rob. You need such a large number of people to keep the gene
pool wide over 500 generations, right?



Right. Otherwize you will end up with a bunch of mutants and sick people,
or most likely they will just die out before they make it even halfway.
Nature is pretty harsh when it comes to small gene pools.

Incidentally, most so are most human social and religious rules :
It is NOT acceptable behavior to marry your cousin.


Why not eliminate the men entirely and take along, oh, a gallon or so
of frozen sperm?

"Rob Dekker" wrote:

P.S. You got me curious about the ending now ! Let me guess : the New Earth
is already inhabited (by humans?), and they are building an ark which is
about to set course for Earth since New Earth was treated the same way as we
treat Earth ?!!

Not quite... keep on guessing.

AA