I was talking to a friend of mine today, she's a medical something. 
Among other things we talked about new born babies and she explained 
that pre-birth they were in a less-weight situation, being in the 
placenta and in fluid, and then when they were born the poor buggers had 
all the difficulties in the world to raise their arms in 1g and it took 
them a while to build up themuscles and get the hang of it. Seemed 
logical and I do not demur with thatn but it made me think (it happens): 
how come humans take so long in comparison with other mammals to become 
autonomous, or at least capable of standing on their own two/four feet? 
Is it because we can protect ourselves in other ways so the pure 
necessity of the thing is less, or are we just slow arseholes compared 
with the rest of the animal kingdom?

John of Aix  wrote:

> or are we just slow arseholes

Did you see that fartcakes xpost the other day?
 I guess that would answer your question.

-- 
^Ï^                               Sn!pe  

 <:>-[  On the Internet, nobody knows that you're a wading bird. ]-<:>

"John of Aix"  wrote in message

> how come humans take so long in comparison with other mammals to >become 
> autonomous, or at least capable of standing on their own two/four feet? Is 
> it because we can protect ourselves in other ways so the pure necessity of 
> the thing is less, or are we just slow arseholes compared with the rest of 
> the animal kingdom?
>

Apes, on the other hand, seem to develop the ability to hold on, straight 
from birth.
I guess the few who failed to do so, fell from the trees and became ........
our ancestors?

Bertie

On Fri, 25 Jul 2008 23:16:52 +0200, John of Aix wrote:

> I was talking to a friend of mine today, she's a medical something. 
> Among other things we talked about new born babies and she explained 
> that pre-birth they were in a less-weight situation, being in the 
> placenta and in fluid, and then when they were born the poor buggers had 
> all the difficulties in the world to raise their arms in 1g and it took 
> them a while to build up themuscles and get the hang of it. Seemed 
> logical and I do not demur with thatn but it made me think (it happens): 
> how come humans take so long in comparison with other mammals to become 
> autonomous, or at least capable of standing on their own two/four feet? 
> Is it because we can protect ourselves in other ways so the pure 
> necessity of the thing is less, or are we just slow arseholes compared 
> with the rest of the animal kingdom?

IIRC it's because of the size of the head. Babies are born when the head
can still fit through the relevant orifice.


-- 
"Why not toss onto a green salad..."

In uk.misc,  (Hot Badger Deluxe) wrote in
::

>On Fri, 25 Jul 2008 23:16:52 +0200, John of Aix wrote:
>
>> I was talking to a friend of mine today, she's a medical something. 
>> Among other things we talked about new born babies and she explained 
>> that pre-birth they were in a less-weight situation, being in the 
>> placenta and in fluid, and then when they were born the poor buggers had 
>> all the difficulties in the world to raise their arms in 1g and it took 
>> them a while to build up themuscles and get the hang of it. Seemed 
>> logical and I do not demur with thatn but it made me think (it happens): 
>> how come humans take so long in comparison with other mammals to become 
>> autonomous, or at least capable of standing on their own two/four feet? 
>> Is it because we can protect ourselves in other ways so the pure 
>> necessity of the thing is less, or are we just slow arseholes compared 
>> with the rest of the animal kingdom?
>
>IIRC it's because of the size of the head. Babies are born when the head
>can still fit through the relevant orifice.

The limiting factor is the pelvic girdle- walking upright can only be
done if the pelvis is not too wide, beyond a certain point it's too
unstable.  Human babies emerge half-baked, compared to the young of some
animals, before the head gets too big.  It's particularly important for
herbivores (i.e. prey species) to be able to walk as soon as possible
after being born- carnivores can afford to take it a bit easier.
-- 
Marc

Tidying the house while the children are growing 
is like shovelling snow while it's still snowing.

John of Aix formulated the question :
> I was talking to a friend of mine today, she's a medical something. Among 
> other things we talked about new born babies and she explained that pre-birth 
> they were in a less-weight situation, being in the placenta and in fluid, and 
> then when they were born the poor buggers had all the difficulties in the 
> world to raise their arms in 1g and it took them a while to build up 
> themuscles and get the hang of it. Seemed logical and I do not demur with 
> thatn but it made me think (it happens): how come humans take so long in 
> comparison with other mammals to become autonomous, or at least capable of 
> standing on their own two/four feet? Is it because we can protect ourselves 
> in other ways so the pure necessity of the thing is less, or are we just slow 
> arseholes compared with the rest of the animal kingdom?

Little kids get bollockings for stretching in school.  Every other 
animal will have a good stretch when it needs to.  The domestic cat is 
but one example.

-- 
Count Baldoni

On Mon, 28 Jul 2008 12:09:46 +0100, Baldoni wrote:

<snip>

> Little kids get bollockings for stretching in school.  Every other 
> animal will have a good stretch when it needs to.  The domestic cat is 
> but one example.

I suppose it depends on what they're stretching...


-- 
Ingenious Q. It's a bomb, but also a rucksack.

In article <488a42ba$0$942$ba4acef3@news.orange.fr>, 
j.murphy@libertysurf.fr says...
> I was talking to a friend of mine today, she's a medical something. 
> Among other things we talked about new born babies and she explained 
> that pre-birth they were in a less-weight situation, being in the 
> placenta and in fluid, and then when they were born the poor buggers had 
> all the difficulties in the world to raise their arms in 1g and it took 
> them a while to build up themuscles and get the hang of it. Seemed 
> logical and I do not demur with thatn but it made me think (it happens): 
> how come humans take so long in comparison with other mammals to become 
> autonomous, or at least capable of standing on their own two/four feet? 
> Is it because we can protect ourselves in other ways so the pure 
> necessity of the thing is less, or are we just slow arseholes compared 
> with the rest of the animal kingdom? 

It takes them time to build up muscles to raise their arms? Has she 
watched newborn babies, at all?

Does being a fluid-filled environment actually make you weightless? 
Serious question.

On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
 wrote:

>Does being a fluid-filled environment actually make you weightless? 
>Serious question.

No. Gravity is still exerting a force on you and that's what we call
weight.  The downwards thrust of gravity can be cancelled out by the
upthrust due to the buoyancy of the solution in which the baby or
person is immersed (saline solutions ie denser solutions are more
bouyant).  However, the solution will offer some resistance to the
movment of the baby's limbs.

In uk.misc,  (Oxford comma) wrote in
::

>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
> wrote:
>
>>Does being a fluid-filled environment actually make you weightless? 
>>Serious question.

Effectively- you can try this in your local baths.  That's why they
recommend aquatic exercise for those with damaged joints, or who are
morbidly obese.

>No. Gravity is still exerting a force on you and that's what we call
>weight.  The downwards thrust of gravity can be cancelled out by the
>upthrust due to the buoyancy of the solution in which the baby or
>person is immersed (saline solutions ie denser solutions are more
>bouyant).  However, the solution will offer some resistance to the
>movment of the baby's limbs.

Weightless != inertialess.

Mind you, that's true even in freefall.
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

On 2008-07-28, Marc Wilson  wrote:
> In uk.misc,  (Oxford comma) wrote in
>::
>
>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>> wrote:
>>
>>>Does being a fluid-filled environment actually make you weightless? 
>>>Serious question.

What happens when you drop a spanner in a submarine?

-- 
          "Be thankful that you have a life, and forsake your vain
                 and presumptuous desire for a second one."
               [email me at huge {at} huge (dot) org <dot> uk]

In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::

>On 2008-07-28, Marc Wilson  wrote:
>> In uk.misc,  (Oxford comma) wrote in
>>::
>>
>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>> wrote:
>>>
>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>Serious question.
>
>What happens when you drop a spanner in a submarine?

Fatuous question.  Spanners are much denser than air.  Being in a
submarine is irrelevant.
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

On 28 Jul 2008 14:48:47 GMT, Huge <Huge@nowhere.much.invalid> wrote:

>On 2008-07-28, Marc Wilson  wrote:
>> In uk.misc,  (Oxford comma) wrote in
>>::
>>
>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>> wrote:
>>>
>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>Serious question.
>
>What happens when you drop a spanner in a submarine?

The captain throws a wobbly.

A body in water retains the same mass, so a 3kg baby remains 3kg.
Its weight is just under 30 Newtons.
But a body in water weighs its own weight minus the weight of the water it
displaces (Archimedes principle).  A human body has about 95% of the density
of water, so *the baby would experience its own weight *in the womb* as
about 1.5 N (0.15kg)*.

As for the other bit about babies being weak.  Put your finger across a
new-born baby's palm.  It will cling on as if your hands are made of
chocolate.  You can lift up a baby less than an hour old like this.  And if
you'd like some evidence of our simian heritage, try the same thing across
the palm of its feet, and watch those toes curl up.
-- 
JAF anarchatntlworldfullstopcom
     Sapere Aude

In article <g6km8f$9b3$1@anubis.demon.co.uk>, Huge@nowhere.much.invalid 
says...
> On 2008-07-28, Marc Wilson  wrote:
> > In uk.misc,  (Oxford comma) wrote in
> >::
> >
> >>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
> >> wrote:
> >>
> >>>Does being a fluid-filled environment actually make you weightless? 
> >>>Serious question.
> 
> What happens when you drop a spanner in a submarine?
> 
The Nazis hear it on their sonar and fire torpedoes at you, OBVIOUSLY
Did you drift off to sleep during "Grey Lady Down" ?
-- 
People all over the world
Join hands
Start a love train
Love train

In uk.misc,  (JAF) wrote in
::

>On 28 Jul 2008 14:48:47 GMT, Huge <Huge@nowhere.much.invalid> wrote:
>
>>On 2008-07-28, Marc Wilson  wrote:
>>> In uk.misc,  (Oxford comma) wrote in
>>>::
>>>
>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>> wrote:
>>>>
>>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>>Serious question.
>>
>>What happens when you drop a spanner in a submarine?
>
>The captain throws a wobbly.
>
>A body in water retains the same mass, so a 3kg baby remains 3kg.
>Its weight is just under 30 Newtons.
>But a body in water weighs its own weight minus the weight of the water it
>displaces (Archimedes principle).  A human body has about 95% of the density
>of water, so *the baby would experience its own weight *in the womb* as
>about 1.5 N (0.15kg)*.
>
>As for the other bit about babies being weak.  Put your finger across a
>new-born baby's palm.  It will cling on as if your hands are made of
>chocolate.  You can lift up a baby less than an hour old like this.  And if
>you'd like some evidence of our simian heritage, try the same thing across
>the palm of its feet, and watch those toes curl up.

Though I wouldn't advocate anyone doing this, especially with the
parents watching, you can apparently hang a small baby from a
washing-line by its hands.

However, this reflex does disappear after a short time, so better sooner
than later.
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

On Mon, 28 Jul 2008 16:42:23 +0100, Marc Wilson
 wrote:

> you can apparently hang a small baby from a
>washing-line by its hands.

I now have an image of a maternity ward, with no cots, just rows and rows of
babies hanging off washing lines in the corridor.
-- 
JAF anarchatntlworldfullstopcom
     Sapere Aude

"Amethyst Deceiver"  wrote in message 
news:MPG.22f7c85f80db3dba989aea@news.individual.de...
> In article <488a42ba$0$942$ba4acef3@news.orange.fr>,
> j.murphy@libertysurf.fr says...
>> I was talking to a friend of mine today, she's a medical something.
>> Among other things we talked about new born babies and she explained
>> that pre-birth they were in a less-weight situation, being in the
>> placenta and in fluid, and then when they were born the poor buggers had
>> all the difficulties in the world to raise their arms in 1g and it took
>> them a while to build up themuscles and get the hang of it. Seemed
>> logical and I do not demur with thatn but it made me think (it happens):
>> how come humans take so long in comparison with other mammals to become
>> autonomous, or at least capable of standing on their own two/four feet?
>> Is it because we can protect ourselves in other ways so the pure
>> necessity of the thing is less, or are we just slow arseholes compared
>> with the rest of the animal kingdom?
>
> It takes them time to build up muscles to raise their arms? Has she
> watched newborn babies, at all?
>
> Does being a fluid-filled environment actually make you weightless?
> Serious question.

NASA seem to think so as astronauts train underwater.

-- 
Chris, (on tour)
Intellect is invisible to the man who has none.
Schopenhauer

In message , Marc Wilson 
 writes
>In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::
>
>>On 2008-07-28, Marc Wilson  wrote:
>>> In uk.misc,  (Oxford comma) wrote in
>>>::
>>>
>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>> wrote:
>>>>
>>>>>Does being a fluid-filled environment actually make you weightless?
>>>>>Serious question.
>>
>>What happens when you drop a spanner in a submarine?
>
>Fatuous question.  Spanners are much denser than air.

Air is a fluid though, which makes a submarine a fluid filled 
environment, unless the submarine has been evacuated, of course.

-- 
bof at bof dot me dot uk

On Mon, 28 Jul 2008 17:17:29 +0100, "Cerumen" 
wrote:

>>
>> Does being a fluid-filled environment actually make you weightless?
>> Serious question.
>
>NASA seem to think so as astronauts train underwater.

They do some 'weightless' training under water, but mostly the underwater
stuff is to simulate walking under lunar gravity (1/6 that of earth).
-- 
JAF anarchatntlworldfullstopcom
     Sapere Aude

In uk.misc,  (JAF) wrote in
::

>On Mon, 28 Jul 2008 16:42:23 +0100, Marc Wilson
> wrote:
>
>> you can apparently hang a small baby from a
>>washing-line by its hands.
>
>I now have an image of a maternity ward, with no cots, just rows and rows of
>babies hanging off washing lines in the corridor.

Evolution in action?
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

In uk.misc,  (Cerumen) wrote in
<g6krh1$ucb$1@registered.motzarella.org>::

>
>"Amethyst Deceiver"  wrote in message 
>news:MPG.22f7c85f80db3dba989aea@news.individual.de...
>> In article <488a42ba$0$942$ba4acef3@news.orange.fr>,
>> j.murphy@libertysurf.fr says...
>>> I was talking to a friend of mine today, she's a medical something.
>>> Among other things we talked about new born babies and she explained
>>> that pre-birth they were in a less-weight situation, being in the
>>> placenta and in fluid, and then when they were born the poor buggers had
>>> all the difficulties in the world to raise their arms in 1g and it took
>>> them a while to build up themuscles and get the hang of it. Seemed
>>> logical and I do not demur with thatn but it made me think (it happens):
>>> how come humans take so long in comparison with other mammals to become
>>> autonomous, or at least capable of standing on their own two/four feet?
>>> Is it because we can protect ourselves in other ways so the pure
>>> necessity of the thing is less, or are we just slow arseholes compared
>>> with the rest of the animal kingdom?
>>
>> It takes them time to build up muscles to raise their arms? Has she
>> watched newborn babies, at all?
>>
>> Does being a fluid-filled environment actually make you weightless?
>> Serious question.
>
>NASA seem to think so as astronauts train underwater.

If you can adjust your density to close to the density of the medium,
you are essentially weightless.
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

On 2008-07-28, Marc Wilson  wrote:
> In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::
>
>>On 2008-07-28, Marc Wilson  wrote:
>>> In uk.misc,  (Oxford comma) wrote in
>>>::
>>>
>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>> wrote:
>>>>
>>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>>Serious question.
>>
>>What happens when you drop a spanner in a submarine?
>
> Fatuous question. 

Actually it's a true and complete answer to your question, but as you wish.

-- 
          "Be thankful that you have a life, and forsake your vain
                 and presumptuous desire for a second one."
               [email me at huge {at} huge (dot) org <dot> uk]

In article ,
Marc Wilson   wrote:

>>> Does being a fluid-filled environment actually make you weightless?
>>> Serious question.

>>NASA seem to think so as astronauts train underwater.

>If you can adjust your density to close to the density of the medium,
>you are essentially weightless.

However the medium is dense and viscous, which makes the simulation
less than perfect.

-- Richard

-- 
Please remember to mention me / in tapes you leave behind.

"Amethyst Deceiver"  wrote in message

> Does being a fluid-filled environment actually make you weightless?
> Serious question.

When I was a diver, I could adjust my bouyancy to rise and fall with my 
breathing, so it felt pretty damn close to me, but I've never experienced 
'freefall' or zero g, so I don't know.

In uk.misc,  (Huge) wrote in <g6kqik$agq$2@anubis.demon.co.uk>::

>On 2008-07-28, Marc Wilson  wrote:
>> In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::
>>
>>>On 2008-07-28, Marc Wilson  wrote:
>>>> In uk.misc,  (Oxford comma) wrote in
>>>>::
>>>>
>>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>>> wrote:
>>>>>
>>>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>>>Serious question.
>>>
>>>What happens when you drop a spanner in a submarine?
>>
>> Fatuous question. 
>
>Actually it's a true and complete answer to your question, but as you wish.

No, it's a misleading question in response to someone else's question.
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

On Mon, 28 Jul 2008 19:41:43 +0100, Marc Wilson
 wrote:

>In uk.misc,  (Huge) wrote in <g6kqik$agq$2@anubis.demon.co.uk>::
>
>>On 2008-07-28, Marc Wilson  wrote:
>>> In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::
>>>
>>>>On 2008-07-28, Marc Wilson  wrote:
>>>>> In uk.misc,  (Oxford comma) wrote in
>>>>>::
>>>>>
>>>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>>>> wrote:
>>>>>>
>>>>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>>>>Serious question.
>>>>
>>>>What happens when you drop a spanner in a submarine?
>>>
>>> Fatuous question. 
>>
>>Actually it's a true and complete answer to your question, but as you wish.
>
>No, it's a misleading question in response to someone else's question.

But the spanner would fall faster if it was in a vacuum, so the same
principle of buoyancy still applies, only somewhat less noticeably so.
Although, you be awfully stretched to apply any claim of weightlessness.

-- 
JAF anarchatntlworldfullstopcom
     Sapere Aude

On Mon, 28 Jul 2008 20:06:40 +0100, JAF wrote:

>On Mon, 28 Jul 2008 19:41:43 +0100, Marc Wilson
> wrote:
>
>>In uk.misc,  (Huge) wrote in <g6kqik$agq$2@anubis.demon.co.uk>::
>>
>>>On 2008-07-28, Marc Wilson  wrote:
>>>> In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::
>>>>
>>>>>On 2008-07-28, Marc Wilson  wrote:
>>>>>> In uk.misc,  (Oxford comma) wrote in
>>>>>>::
>>>>>>
>>>>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>>>>> wrote:
>>>>>>>
>>>>>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>>>>>Serious question.
>>>>>
>>>>>What happens when you drop a spanner in a submarine?
>>>>
>>>> Fatuous question. 
>>>
>>>Actually it's a true and complete answer to your question, but as you wish.
>>
>>No, it's a misleading question in response to someone else's question.
>
>But the spanner would fall faster if it was in a vacuum, so the same
>principle of buoyancy still applies, only somewhat less noticeably so.
>Although, you be awfully stretched to apply any claim of weightlessness.

When submerged, your whole body might be supported by the water,
making the body as a whole move as if (nearly) weightless, but your
internal organs aren't.  In this respect, at least, it differs from
being in free fall.

-- 

Peter

I'm an alien
email: home at peteward dot gotadsl dot co dot uk
Squids have no blind spots? There goes that whole business plan, dammit.
- S. Checker

In article ,
Peter Ward   wrote:

>When submerged, your whole body might be supported by the water,
>making the body as a whole move as if (nearly) weightless, but your
>internal organs aren't.  In this respect, at least, it differs from
>being in free fall.

Is this noticable?  It would - from the point of view of your internal
organs - be comparable to the difference between lying down and
standing up, or half as much as standing on your head.  I imagine the
main difference would be to your stomach.

-- Richard
-- 
Please remember to mention me / in tapes you leave behind.

In uk.misc,  (Richard Tobin) wrote in
<g6l8av$2el1$1@pc-news.cogsci.ed.ac.uk>::

>In article ,
>Peter Ward   wrote:
>
>>When submerged, your whole body might be supported by the water,
>>making the body as a whole move as if (nearly) weightless, but your
>>internal organs aren't.  In this respect, at least, it differs from
>>being in free fall.
>
>Is this noticable?  It would - from the point of view of your internal
>organs - be comparable to the difference between lying down and
>standing up, or half as much as standing on your head.  I imagine the
>main difference would be to your stomach.

Your internal organs are held in place by muscles, which are differently
loaded when standing, sitting, lying etc.  All of these loads are
ultimately supported by the surface you are lying/sitting/standing on,
via whatever part of you is touching them.  Animals that spend all their
time in the water (e.g. cetaceans) don't have the same musculature to
support the organs, which is one reason whales and dolphins can't stay
out of water very long, and have to be very carefully supported when out
of water.  So the water *does* support you in a different way, including
your innards.
-- 
Marc

It is difficult to produce a television documentary that is both incisive  and probing when every twelve 
minutes one is interrupted by twelve dancing rabbits singing about toilet paper."  (Rod Serling)

"Marc Wilson"  wrote

>>>When submerged, your whole body might be supported by the water,
>>>making the body as a whole move as if (nearly) weightless, but your
>>>internal organs aren't.  In this respect, at least, it differs from
>>>being in free fall.
>>
>>Is this noticable?  It would - from the point of view of your internal
>>organs - be comparable to the difference between lying down and
>>standing up, or half as much as standing on your head.  I imagine the
>>main difference would be to your stomach.
>
> Your internal organs are held in place by muscles, which are differently
> loaded when standing, sitting, lying etc.  All of these loads are
> ultimately supported by the surface you are lying/sitting/standing on,
> via whatever part of you is touching them.  Animals that spend all their
> time in the water (e.g. cetaceans) don't have the same musculature to
> support the organs, which is one reason whales and dolphins can't stay
> out of water very long, and have to be very carefully supported when out
> of water.  So the water *does* support you in a different way, including
> your innards.

So we all agree, then?

Blimey. That was short.

In article <488e00b5$0$2928$fa0fcedb@news.zen.co.uk>, 
qrnq_znatyrq_cvtrba@zfa.pbz says...
> 
> "Amethyst Deceiver"  wrote in message
> 
> > Does being a fluid-filled environment actually make you weightless?
> > Serious question.
> 
> When I was a diver, I could adjust my bouyancy to rise and fall with my 
> breathing, so it felt pretty damn close to me, but I've never experienced 
> 'freefall' or zero g, so I don't know.
> 

Very different apparently. In water your motion is largely controlled by 
the resistance of the water. Start rotating, for instance, and the water 
will quite rapidly stop the rotation if you cease applying force. In 
micro gravity in air you'll keep rotating for quite a while.

So whilst astronauts and cosmonauts do some training in water, it only 
really relates to moving extremely slowly and carefully in micro gravity.

Of course "weightless" is largely about perception rather than reality, 
so it's reasonably enough to describe being at zero buoyancy in water as 
being weightless. It's just a completely different kind of weightless 
from being in a falling lift or diving plane, as well as different from 
being in orbit.

-- 
eric
To a man who only has a hammer every job looks
like one for somebody with a proper toolkit.

On Mon, 28 Jul 2008 17:11:47 +0100, JAF 
wrote the following to uk.misc:

> On Mon, 28 Jul 2008 16:42:23 +0100, Marc Wilson
> wrote:
>
>> you can apparently hang a small baby from a
>>washing-line by its hands.
>
> I now have an image of a maternity ward, with no cots, just rows and rows of
> babies hanging off washing lines in the corridor.

Megadeth got there first:
http://upload.wikimedia.org/wikipedia/en/2/24/Megadeth-Youthanasia.jpg

mh.
-- 
http://www.nukesoft.co.uk
http://personal.nukesoft.co.uk

From address is a blackhole. Reply-to address is valid.

On 28 Jul 2008 17:13:09 GMT, Richard Tobin 
wrote the following to uk.misc:

> In article ,
> Marc Wilson   wrote:
>
>>>> Does being a fluid-filled environment actually make you weightless?
>>>> Serious question.
>
>>>NASA seem to think so as astronauts train underwater.
>
>>If you can adjust your density to close to the density of the medium,
>>you are essentially weightless.
>
> However the medium is dense and viscous

What does Mystic Meg have to do with this?

mh.
-- 
http://www.nukesoft.co.uk
http://personal.nukesoft.co.uk

From address is a blackhole. Reply-to address is valid.

In article , 
spam@nukesoft.co.uk says...
> On 28 Jul 2008 17:13:09 GMT, Richard Tobin 
> wrote the following to uk.misc:
> 
> > In article ,
> > Marc Wilson   wrote:
> >
> >>>> Does being a fluid-filled environment actually make you weightless?
> >>>> Serious question.
> >
> >>>NASA seem to think so as astronauts train underwater.
> >
> >>If you can adjust your density to close to the density of the medium,
> >>you are essentially weightless.
> >
> > However the medium is dense and viscous
> 
> What does Mystic Meg have to do with this?
> 
> mh.
> 
[applause]
-- 
People all over the world
Join hands
Start a love train
Love train

On 2008-07-28, Marc Wilson  wrote:
> In uk.misc,  (Huge) wrote in <g6kqik$agq$2@anubis.demon.co.uk>::
>
>>On 2008-07-28, Marc Wilson  wrote:
>>> In uk.misc,  (Huge) wrote in <g6km8f$9b3$1@anubis.demon.co.uk>::
>>>
>>>>On 2008-07-28, Marc Wilson  wrote:
>>>>> In uk.misc,  (Oxford comma) wrote in
>>>>>::
>>>>>
>>>>>>On Mon, 28 Jul 2008 13:13:53 +0100, Amethyst Deceiver
>>>>>> wrote:
>>>>>>
>>>>>>>Does being a fluid-filled environment actually make you weightless? 
>>>>>>>Serious question.
>>>>
>>>>What happens when you drop a spanner in a submarine?
>>>
>>> Fatuous question. 
>>
>>Actually it's a true and complete answer to your question, but as you wish.
>
> No, it's a misleading question in response to someone else's question.

As you wish.


-- 
          "Be thankful that you have a life, and forsake your vain
                 and presumptuous desire for a second one."
               [email me at huge {at} huge (dot) org <dot> uk]

On 2008-07-28, Marc Wilson  wrote:

> Your internal organs are held in place by muscles, 

No they aren't.


-- 
          "Be thankful that you have a life, and forsake your vain
                 and presumptuous desire for a second one."
               [email me at huge {at} huge (dot) org <dot> uk]

On Mon, 28 Jul 2008 14:44:13 +0100, Marc Wilson
 wrote:

>>No. Gravity is still exerting a force on you and that's what we call
>>weight.  The downwards thrust of gravity can be cancelled out by the
>>upthrust due to the buoyancy of the solution in which the baby or
>>person is immersed (saline solutions ie denser solutions are more
>>bouyant).  However, the solution will offer some resistance to the
>>movment of the baby's limbs.
>
>Weightless != inertialess.

Er, yes.  Is there something in my statement that makes you think I am
saying weightless = inertialess?

Huge <Huge@nowhere.much.invalid> wrote:

> On 2008-07-28, Marc Wilson  wrote:
> 
> > Your internal organs are held in place by muscles, 
> 
> No they aren't.

Skin, it's the thing that keeps your insides in.

Well that and connective tissue.

In uk.misc,  (Huge) wrote in <g6o39o$6j6$5@anubis.demon.co.uk>::

>On 2008-07-28, Marc Wilson  wrote:
>
>> Your internal organs are held in place by muscles, 
>
>No they aren't.

OK, technically you're right.  But they are *supported* by muscles.  
-- 
Marc

"Nobody is more dangerous than he who imagines himself pure in heart; for his purity, by definition, is unassailable." 
  --  James Arthur Baldwin

In uk.misc,  (Oxford comma) wrote in
::

>On Mon, 28 Jul 2008 14:44:13 +0100, Marc Wilson
> wrote:
>
>>>No. Gravity is still exerting a force on you and that's what we call
>>>weight.  The downwards thrust of gravity can be cancelled out by the
>>>upthrust due to the buoyancy of the solution in which the baby or
>>>person is immersed (saline solutions ie denser solutions are more
>>>bouyant).  However, the solution will offer some resistance to the
>>>movment of the baby's limbs.
>>
>>Weightless != inertialess.
>
>Er, yes.  Is there something in my statement that makes you think I am
>saying weightless = inertialess?

There are no imaginable circumstances where there is no resistance to
movement, unless you're inertialess.  As far as we know, there is no way
to become so.
-- 
Marc

"Nobody is more dangerous than he who imagines himself pure in heart; for his purity, by definition, is unassailable." 
  --  James Arthur Baldwin

On Mon, 28 Jul 2008 23:15:07 +0100, Bing Trotsky wrote:

> Of course "weightless" is largely about perception rather than reality, 
> so it's reasonably enough to describe being at zero buoyancy in water as 
> being weightless. It's just a completely different kind of weightless 
> from being in a falling lift or diving plane, as well as different from 
> being in orbit.

Errr, the freefall of orbit is *exactly* the same as the freefall of a 
falling lift or diving plane.

-- 
One way ticket from Mornington Crescent to Tannhauser Gate please.

On Mon, 28 Jul 2008 17:42:12 +0100, JAF wrote:

> They do some 'weightless' training under water, but mostly the underwater
> stuff is to simulate walking under lunar gravity (1/6 that of earth).

Bzzzt!

The tank stuff is for training for stuff done on orbit.
http://www.nasa.gov/lb/centers/marshall/news/background/facts/nbs.htm

Lunar surface training (not that any has been done for a *long* time) 
was done using a trapeze like gizmo holding up the astronaut and suit.
You can see that in this picture.
http://space.about.com/od/apollomissions/ig/Apollo-13-Pictures-Gallery/Apollo-13-Astronaut-Fred-Haise.htm

Worth remembering that the moon-walking suits were really quite "heavy"
themselves, so it wouldn't have been that easy.

-- 
One way ticket from Mornington Crescent to Tannhauser Gate please.

Fevric J Glandules <fevric@invalid.invalid> wrote:

> Errr, the freefall of orbit is *exactly* the same as the freefall of a
> falling lift or diving plane.

Is that actually true? I though that in orbit there is a tidal force
which is not present in a falling lift or divign plane. i.e. both of the
latter are more 'free' fall than orbit.

On Wed, 30 Jul 2008 16:49:12 GMT, Fevric J Glandules
<fevric@invalid.invalid> wrote:

>On Mon, 28 Jul 2008 17:42:12 +0100, JAF wrote:
>
>> They do some 'weightless' training under water, but mostly the underwater
>> stuff is to simulate walking under lunar gravity (1/6 that of earth).
>
>Bzzzt!
>
>The tank stuff is for training for stuff done on orbit.
>http://www.nasa.gov/lb/centers/marshall/news/background/facts/nbs.htm
>
In which case NASA are contradicting themselves, as that's where I checked
that I was correct.

>Lunar surface training (not that any has been done for a *long* time) 
>was done using a trapeze like gizmo holding up the astronaut and suit.
>You can see that in this picture.
>http://space.about.com/od/apollomissions/ig/Apollo-13-Pictures-Gallery/Apollo-13-Astronaut-Fred-Haise.htm
>
. . .as well.

>Worth remembering that the moon-walking suits were really quite "heavy"
>themselves, so it wouldn't have been that easy.

Indeed, and just like the human body, less in the water/on the moon.
-- 
JAF anarchatntlworldfullstopcom
     Sapere Aude

On Wed, 30 Jul 2008 17:07:50 +0100, Marc Wilson 
wrote the following to uk.misc:

> In uk.misc,  (Huge) wrote in <g6o39o$6j6$5@anubis.demon.co.uk>::
>
>>On 2008-07-28, Marc Wilson  wrote:
>>
>>> Your internal organs are held in place by muscles, 
>>
>>No they aren't.
>
> OK, technically you're right.  But they are *supported* by muscles.

I wish my right arm was. 15 days to go until I can get rid of this sling.
It's bad enough getting a dead arm from holding a phone for too long, but
it's going to be great fun moving it after a month of being immobilized.

mh.
-- 
http://www.nukesoft.co.uk
http://personal.nukesoft.co.uk

From address is a blackhole. Reply-to address is valid.

In uk.misc,  (Steve Firth) wrote in
<1ikwkut.9murmgszwnq1N%%steve%@malloc.co.uk>::

>Fevric J Glandules <fevric@invalid.invalid> wrote:
>
>> Errr, the freefall of orbit is *exactly* the same as the freefall of a
>> falling lift or diving plane.
>
>Is that actually true? I though that in orbit there is a tidal force
>which is not present in a falling lift or divign plane. i.e. both of the
>latter are more 'free' fall than orbit.

There are tidal forces wherever you are.  Depending on where in space
you are, these could be greater or lesser than on Earth.

If you're in a spinning spacecraft, you'd also have to deal with
Coriolis "force" (which you do on Earth, but it's negligible over short
distances).
-- 
Marc

People must not do things for fun. We are not here for fun. There is no reference to fun in any Act of Parliament.

In article <kM0kk.35030$E41.550@text.news.virginmedia.com>, 
fevric@invalid.invalid says...
> On Mon, 28 Jul 2008 23:15:07 +0100, Bing Trotsky wrote:
> 
> > Of course "weightless" is largely about perception rather than reality, 
> > so it's reasonably enough to describe being at zero buoyancy in water as 
> > being weightless. It's just a completely different kind of weightless 
> > from being in a falling lift or diving plane, as well as different from 
> > being in orbit.
> 
> Errr, the freefall of orbit is *exactly* the same as the freefall of a 
> falling lift or diving plane.
> 

No it isn't. Not exactly. It's the same physics behind it, but when it 
comes to doing anything practical the simple fact that the forces are 
operating in different directions can make a huge difference. Or so I'm 
told. I've no direct experience of any of them, only what I've been told 
by people who have tried them. The big difference with the latter two is 
over time. One way or another the plane is imminently going to cease 
diving. So things don't stay in "freefall", making the risks and 
discomforts somewhat different. The difference between a falling lift and 
a diving plane is in what directions the forces act when "freefall" 
ceases.

No difference at all in terms of the physics of what is happening to a 
person, a massive difference in what that person needs to learn in order 
to cope with the situation.

-- 
eric
Live fast, die only if strictly necessary.

On Wed, 30 Jul 2008 17:10:03 +0100, Marc Wilson
 wrote:

>>Er, yes.  Is there something in my statement that makes you think I am
>>saying weightless = inertialess?
>
>There are no imaginable circumstances where there is no resistance to
>movement, unless you're inertialess.  As far as we know, there is no way
>to become so.

Ah, I see.  You're having problems because I left out the word
'fluid'.  Sorry.

On Wed, 30 Jul 2008 16:36:32 GMT, Fevric J Glandules
<fevric@invalid.invalid> wrote:

>> Of course "weightless" is largely about perception rather than reality, 
>> so it's reasonably enough to describe being at zero buoyancy in water as 
>> being weightless. It's just a completely different kind of weightless 
>> from being in a falling lift or diving plane, as well as different from 
>> being in orbit.
>
>Errr, the freefall of orbit is *exactly* the same as the freefall of a 
>falling lift or diving plane.

Shoulders with fevric, pretty much

On Wed, 30 Jul 2008 18:05:49 +0100, %steve%@malloc.co.uk (Steve Firth)
wrote:

>> Errr, the freefall of orbit is *exactly* the same as the freefall of a
>> falling lift or diving plane.
>
>Is that actually true? I though that in orbit there is a tidal force
>which is not present in a falling lift or divign plane. i.e. both of the
>latter are more 'free' fall than orbit.

What do you mean by 'tidal force'?

On Wed, 30 Jul 2008 19:03:50 +0100, Bing Trotsky
 wrote:

>No difference at all in terms of the physics of what is happening to a 
>person, a massive difference in what that person needs to learn in order 
>to cope with the situation.

Oh, right, you meant a special kind of difference.

Oxford comma <malone@invalid.really.invalid.invalid> wrote:

> On Wed, 30 Jul 2008 18:05:49 +0100, %steve%@malloc.co.uk (Steve Firth)
> wrote:
> 
> >> Errr, the freefall of orbit is *exactly* the same as the freefall of a
> >> falling lift or diving plane.
> >
> >Is that actually true? I though that in orbit there is a tidal force
> >which is not present in a falling lift or divign plane. i.e. both of the
> >latter are more 'free' fall than orbit.
> 
> What do you mean by 'tidal force'?

When something orbits, the part of "it" that is closer to the thing it
is orbiting experiences a different force to the part furthest away. The
net result is a force that attempts to elongate the orbiting thingy
along a plane normal to the centre of the object being orbited.

That is a tidal force.

[s.s.h added]

On Wed, 30 Jul 2008 18:12:47 +0100, JAF wrote:

> On Wed, 30 Jul 2008 16:49:12 GMT, Fevric J Glandules
> <fevric@invalid.invalid> wrote:
> 
>>On Mon, 28 Jul 2008 17:42:12 +0100, JAF wrote:
>>
>>> They do some 'weightless' training under water, but mostly the underwater
>>> stuff is to simulate walking under lunar gravity (1/6 that of earth).
>>
>>Bzzzt!
>>
>>The tank stuff is for training for stuff done on orbit.
>>http://www.nasa.gov/lb/centers/marshall/news/background/facts/nbs.htm
>>
> In which case NASA are contradicting themselves, as that's where I checked
> that I was correct.

Well... I'm not aware of any lunar surface training done in the tank but
perhaps someone on ssh knows for sure.

>>Lunar surface training (not that any has been done for a *long* time) 
>>was done using a trapeze like gizmo holding up the astronaut and suit.
>>You can see that in this picture.
>>http://space.about.com/od/apollomissions/ig/Apollo-13-Pictures-Gallery/Apollo-13-Astronaut-Fred-Haise.htm
>>
> . . .as well.
> 
>>Worth remembering that the moon-walking suits were really quite "heavy"
>>themselves, so it wouldn't have been that easy.
> 
> Indeed, and just like the human body, less in the water/on the moon.

Less weight, same inertia.

-- 
One way ticket from Mornington Crescent to Tannhauser Gate please.

On Wed, 30 Jul 2008 18:05:49 +0100, Steve Firth wrote:

> Fevric J Glandules <fevric@invalid.invalid> wrote:
> 
>> Errr, the freefall of orbit is *exactly* the same as the freefall of a
>> falling lift or diving plane.
> 
> Is that actually true? I though that in orbit there is a tidal force
> which is not present in a falling lift or divign plane. i.e. both of the
> latter are more 'free' fall than orbit.

Depends on the frame of reference, I guess.

In any case, there is only one real force in operation; both in your
falling lift and your orbiting capsule, you are being accelerated towards
the centre of the earth.  And in both cases you are rotating around the
earth at the same time.

-- 
One way ticket from Mornington Crescent to Tannhauser Gate please.

In uk.misc,  (Steve Firth) wrote in
<1ikwrpw.1rq9n4u16oejk0N%%steve%@malloc.co.uk>::

>Oxford comma <malone@invalid.really.invalid.invalid> wrote:
>
>> On Wed, 30 Jul 2008 18:05:49 +0100, %steve%@malloc.co.uk (Steve Firth)
>> wrote:
>> 
>> >> Errr, the freefall of orbit is *exactly* the same as the freefall of a
>> >> falling lift or diving plane.
>> >
>> >Is that actually true? I though that in orbit there is a tidal force
>> >which is not present in a falling lift or divign plane. i.e. both of the
>> >latter are more 'free' fall than orbit.
>> 
>> What do you mean by 'tidal force'?
>
>When something orbits, the part of "it" that is closer to the thing it
>is orbiting experiences a different force to the part furthest away. The
>net result is a force that attempts to elongate the orbiting thingy
>along a plane normal to the centre of the object being orbited.
>
>That is a tidal force.

It's very tiny in Earth orbit- if you were orbiting a black hole it
would be a serious matter.

For that matter, your head is that much further away from the Earth's
centre of mass than your feet- there is a small difference in the forces
acting.  For all normal purposes it's negligible, even for Masai
warriors and basketball players.
-- 
Marc

Books breed like rabbits, bookcases breed like elephants (NancyButton)

In uk.misc,  (Oxford comma) wrote in
::

>On Wed, 30 Jul 2008 17:10:03 +0100, Marc Wilson
> wrote:
>
>>>Er, yes.  Is there something in my statement that makes you think I am
>>>saying weightless = inertialess?
>>
>>There are no imaginable circumstances where there is no resistance to
>>movement, unless you're inertialess.  As far as we know, there is no way
>>to become so.
>
>Ah, I see.  You're having problems because I left out the word
>'fluid'.  Sorry.

Not at all.
-- 
Marc

Books breed like rabbits, bookcases breed like elephants (NancyButton)

In article , 
malone@invalid.really.invalid.invalid says...
> On Wed, 30 Jul 2008 19:03:50 +0100, Bing Trotsky
>  wrote:
> 
> >No difference at all in terms of the physics of what is happening to a 
> >person, a massive difference in what that person needs to learn in order 
> >to cope with the situation.
> 
> Oh, right, you meant a special kind of difference. 
> 

Nope. A general kind of difference. When it comes to the special theory 
regarding only the forces on the person at any time then there isn't a 
difference.

-- 
eric
In the beginning was the word, and the word was
"what happens if I press this button?"

On Wed, 30 Jul 2008 20:39:39 +0100, %steve%@malloc.co.uk (Steve Firth)
wrote:

>> >> Errr, the freefall of orbit is *exactly* the same as the freefall of a
>> >> falling lift or diving plane.
>> >
>> >Is that actually true? I though that in orbit there is a tidal force
>> >which is not present in a falling lift or divign plane. i.e. both of the
>> >latter are more 'free' fall than orbit.
>> 
>> What do you mean by 'tidal force'?
>
>When something orbits, the part of "it" that is closer to the thing it
>is orbiting experiences a different force to the part furthest away. The
>net result is a force that attempts to elongate the orbiting thingy
>along a plane normal to the centre of the object being orbited.

Mmm.  The equation for g involves 1/r^2.  You draw the graph for what
that means for an object with a larger r (e.g. something in orbit) as
opposed to an object with a smaller r (e.g. a falling plane or a chap
in a lift).  Of course, it's not strictly 1/r^2 due to all sorts of
planetary influences, but the general 1/r principle applies to that
understanding.

Not that I'm saying you're *wrong*, mind, merely that this definition
of tidal force would lead to an object *closer* to the planet
experiencing more of it compared to an object in orbit.

The key, really is to look at what happens over the length of the
object.  By your definition, it's going to be negligible for a person
sized object in orbit or in a lift.

On Wed, 30 Jul 2008 22:45:57 +0100, Bing Trotsky
 wrote:

>> >No difference at all in terms of the physics of what is happening to a 
>> >person, a massive difference in what that person needs to learn in order 
>> >to cope with the situation.
>> 
>> Oh, right, you meant a special kind of difference. 
>> 
>
>Nope. A general kind of difference. When it comes to the special theory 
>regarding only the forces on the person at any time then there isn't a 
>difference.

Oh bollox. I wasn't referring to relativity, I was referring to your
differences being *special*.

On 2008-07-30, Marc Wilson  wrote:
> In uk.misc,  (Huge) wrote in <g6o39o$6j6$5@anubis.demon.co.uk>::
>
>>On 2008-07-28, Marc Wilson  wrote:
>>
>>> Your internal organs are held in place by muscles, 
>>
>>No they aren't.
>
> OK, technically you're right.  But they are *supported* by muscles.  

No they aren't.

OK, I'll be a little kinder. Your internal organs are generally supported by
connective tissue, a little like cartilage. Not muscles. Except the lungs, which
are supported by air pressure (which is how they can collapse if the peritoneum
is punctured).


-- 
          "Be thankful that you have a life, and forsake your vain
                 and presumptuous desire for a second one."
               [email me at huge {at} huge (dot) org <dot> uk]

Fevric J Glandules <fevric@invalid.invalid> writes:

>[s.s.h added]

>On Wed, 30 Jul 2008 18:12:47 +0100, JAF wrote:

>> On Wed, 30 Jul 2008 16:49:12 GMT, Fevric J Glandules
>> <fevric@invalid.invalid> wrote:
>>>The tank stuff is for training for stuff done on orbit.
>>>http://www.nasa.gov/lb/centers/marshall/news/background/facts/nbs.htm
>>>
>> In which case NASA are contradicting themselves, as that's where I checked
>> that I was correct.

>Well... I'm not aware of any lunar surface training done in the tank but
>perhaps someone on ssh knows for sure.

	Sorry to be late answering this, but, I didn't have any good 
or clear references on-hand.  Luckily, I've been listening to _First 
Man_, James Hansen's biography of Neil Armstrong, as a book-on-CD in 
the car, and it just today got around to mentioning: there was indeed 
water tank training for some lunar surface activities.  In particular 
it mentions that Armstrong practiced hopping up the Lunar Module 
ladded and guiding his way back down (proving that if an astronaut 
were to trip he could right himself using the handrails).  

	Since I have the book-on-CD version, I don't have the reference 
*that* book used, although given the bulk of the text -- which answers 
every single question you might have ever had about Neil Armstrong, ever, 
in almost mind-crushing detail -- I'm inclined to trust it.  (For those 
with copies of the book and looking for the reference, it comes in the 
description of the end of the moonwalk, as Armstrong is re-entering the 
Lunar Module.  I think it's around chapter 29; certainly it's early in 
disc 21 of the audio version.)  

-- 
								Joseph Nebus
------------------------------------------------------------------------------