HDTenEightyP/NetNews huggingface dataset:
Newsgroups: rec.arts.sf.science
Subject: Re: Evolution under High Gravity
From: jjfink@skcla.monsanto.com
Date: 17 Aug 92 09:38:47 GMT
Organization: Searle, Skokie, IL
Nntp-Posting-User: kvitek

In article <doom.714038580@elaine36.Stanford.EDU>, doom@leland.Stanford.EDU (Joseph Brenner) writes:
> egl1@cunixf.cc.columbia.edu (Elizabeth G. Levy) writes:
> 
>>Short.  Very short.
> 
>>Actually, take a look at Forward's _Dragon's Egg_, about creatures
>>living on the surface of a neutron star (the ultimate in high gravity).
> 
> You can also take a look at Hal Clement's _Mission of
> Gravity_, a classic work about aliens on a high gravity
> planet.  Once again, Clement votes for "short": they're
> around the size and shape of Scorpions. 

Sure the tendency will be for ground hugging, but remember that anything which
DOES overcome the height limitations will have an advantage (as well as a
vantage), in that it can spot enemies and prey, can expand to absorb more
radiation, etc.

Besides, look at our own world.  We have creatures that hug the ground, and
hundreds-feet high trees.  What is tall or short?  Why aren't there
40-foot-high dinos anymore?  We can't blame that on gravity.

Joel
-- 
jjfink@skcla.monsanto.com
------------------------------------------------------------------------------
"Portions of the preceding were recorded.  As for the rest, I quite fear that
 it was all in your mind" -- Alfred Hitchcock
Newsgroups: rec.arts.sf.science
From: robert@cs.anu.edu.au (Robert Cohen)
Subject: Re: Evolution under High Gravity
Organization: Computer Science Dept., Australian National University
Date: Tue, 18 Aug 1992 15:50:58 GMT

LAAAA43@cc1.kuleuven.ac.be (Peter Arien) writes:

>In article <gapdrr.714069394@gsusgi1.gsu.edu>, gapdrr@gsusgi2.gsu.edu (Daniel R
>T Rothman) says:
>>
>>No, seriously. I haven't just pulled this out of the ether. Babies very
>>seldom hurt themselves when they fall. They've simply got less room to
>>accelerate in. In a high-g environment, that'd mean tremendously smaller
>>numbers of broken bones for the short of stature.

>I thought breaking bones when falling had more to do with tensing your
>muscles than with being short or tall... That's why babies and drunks
>don't break bones that easy.

I don't know about drunks but a major reason that babies are
fairly invulnerable to falling over is the square/cube law.

The reasoning is that as a "person" gets bigger the force applied by
falling over goes up with the mass ie height cubed but the strength
of the bones goes up with the cross sectional area of the bone ie 
height squared. Therefore the ratio of falling damage/bone strength
is much higher for an adult than a baby.
Hmm, its worse than that. As the first poster pointed out for
falling damage the distance fallen factors in as well. So its
more like falling damage goes up with the potential energy stored
in in the upright person or the height times the mass. I think
I just invented the square/quad law :-)

Of course this only applies perfectly if you scale proportionately which
may not be the case between babies and adults but the principle
should basically apply. But when you start considering "people" who
have adapted for high G by only scaling the vertical dimension of
a "normal" person then is starts getting tricky.

Robert

-- 
Robert Cohen		email: robert@cs.anu.edu.au
PhD Student,  Dept of Computer Science
Australian National University
Neuron not responding, still meditating.  - "BrainOS" error message
Newsgroups: rec.arts.sf.science
From: mfriedma@uucp (Michael Friedman)
Subject: Re: general relativity
Organization: Oracle Corporation
Date: Sat, 15 Aug 1992 22:41:33 GMT
X-Disclaimer: This message was written by an unauthenticated user
              at Oracle Corporation.  The opinions expressed are those
              of the user and not necessarily those of Oracle.

In article <5755@m1.cs.man.ac.uk> phl@fiveg.icl.co.uk ( Peter H Liyanage) writes:
>Just something I need to clear up. 

>	If a large object(ie. an aircraft) was travilling at the 
>speed of light, 

Large objects - in fact, anything with mass - can't travel at the
speed of light.  

>and is on a direct path to collied with a tall
>building. At the time of collision, what would happen to the building/
>aircraft ??.

Since it can't be at the speed of light, let's assume that it's almost
at the speed of light - say .9999c.  The answer:  An absolutely
enormous, god-awful explosion that would produce light, ultraviolet,
and if the object was moving fast enough, even x-rays and gamma rays.
There could also be fusion.

>		(I ask this cause in a science program I saw a few
>weeks ago, it said that the object would go through the building
>without damaging either its self or the building)

What was the science program?  Because whoever produced it had his
head firmly inserted about two feet up his anus.
-- 
-------------------------------------------------------------------------------
I am not an official Oracle spokesman.  I speak for myself and no one else.
From: sl25@emu.pmms.cam.ac.uk (Steve Linton)
Newsgroups: rec.arts.sf.science
Subject: Re: Superconductors
Date: 21 Aug 92 15:52:28 GMT
Organization: Cambridge University DAMTP


|>    Electron beams, actually. I don't think electron lithography is in
|> commercial use but it's been being researched for a good while.
|

I think it's used a lot for prototyping and such like, as it's easy to computer steer the beam and cut chips from a software design. Its less popular for production because it's hard to make a mask that you can use for quickly exposing a whole chip or wafer.

|> 
|>    I wonder where people will go after electrons? Maybe you could fire
|> cannonballs at the microchip and count on their short de Broglie 
|> wavelength ;-) 

Muons seem like an obvious choice.
From: dillard@ccwf.cc.utexas.edu (Alex Dillard)
Newsgroups: rec.arts.sf.science
Subject: Re: Hydro energy storage systems
Date: 23 Aug 92 05:43:13 GMT
Organization: The University of Texas at Austin, Austin TX

In article <hl71572@pro-smof.cts.com> wixer!cactus.org!wixer!pro-smof.cts.com!rfletcher@cactus.org (Robert Fletcher) writes:
>
>  Is there or is there not a loss of energy when water is pumped up a hill
>in the day and the letting it run down at night.

   Under ideal conditions (no friction, perfect motors(no energy lost in 
turning electricity into motion), no flow irregularaties(turbulence) in the
water, etc.) it would be possible to lose no energy in this process. That is,
you could get back out the energy put in to pump the water uphill.
   In the real world, however, some energy is lost due to 'friction' in the
water, heat generated by the motors pumping the water up the hill, cavitation
in the pump impellers and turbines (cavitation is the formation of gas bubbles
on the surface of the impeller or turbine blade), et cetera, leads to some loss
of energy.  I would guess at an overall efficency of about 60%, but I have 
little experience in an actual system, so this is a guess.
   Amazingly enough, it is possible to make _money_ doing this.  Power companies
sometimes sell electricity at a higher rate during peak load periods and give
a discount at night.  If the power generated by the water during the peak load
is more valuable (even if there is less of it) than the power used to lift the
water, then you could make a profit by pumping the water.
 

-- 
 \ _
 - o  We were once so close to Heaven, Peter came out and gave us medals,
  ^   declaring us the nicest of the Damned. - They Might Be Giants
        Alex  dillard@ccwf.cc.utexas.edu
From: gapdrr@gsusgi2.gsu.edu (Daniel R T Rothman)
Subject: Re: dragons were dinosaurs?
Organization: Georgia State University
Date: Sat, 22 Aug 1992 16:12:39 GMT

>How many cave paintings are there?  Maybe the places where cave paintings
>exist didn't have any dinosaurs that survived.  

>I guess I was envisioning a "lost world" scenario where some dinosaurs 
>survived in a very small area of the world.  This would explain why the
>fossil record doesn't reveal anything.  You'd have to find fossils in
>a very specific place and it may not have ever been dug up.  Asia, 
>where dragons seem to have been "invented", is a big place.  

I would have to take this theory with a grain of salt. the myths and legends
of dragons are just too wide-spread (in various permutations) for me to buy
the fact that a small group in a distant area could have disseminated it
to all the various cultures that support this myth.


Newsgroups: rec.arts.sf.science
From: gapdrr@gsusgi2.gsu.edu (Daniel R T Rothman)
Subject: Re: Evolution under High Gravity
Organization: Georgia State University
Date: Mon, 17 Aug 1992 16:36:34 GMT

sks1@Ra.MsState.Edu (Sujay Shaunak) writes:

[stuff deleted]
>   I would think that structural and muscular strength would be increased
>so that the being could survive on the planet (or whatever). I would
>not be so quick on height and stockiness. I would think that since the 
>high-g environment would be natural for the being, that other effects
>would dictate growth patterns (like : Is basketball a planetary sport :).

>   Any other opinions on this ?

I'm not terribly certain on stockiness (although in many instances this is
linked with strength). On the other hand, short people have a great 
survival advantage in high-G environments. They don't have as far to fall.

No, seriously. I haven't just pulled this out of the ether. Babies very
seldom hurt themselves when they fall. They've simply got less room to
accelerate in. In a high-g environment, that'd mean tremendously smaller
numbers of broken bones for the short of stature.


Newsgroups: rec.arts.sf.science
From: iwsbarke@acs.ucalgary.ca (I W Scott Barker)
Subject: Re: dragons were dinosaurs?
Date: Sat, 22 Aug 92 05:58:23 GMT
Organization: The University of Calgary, Alberta, Canada
X-Newsreader: Tin 1.1 PL5

It would seem that a number of people have made the wrong assumptions regarding
my recent posts. So, to try to get everyone on track (including myself), here 
is a little explanation:

        I originally posted because someone essentially called another 
someone an idiot for believing that something "impossible" could happen. I
simply tried to explain that we are not qualified to determine what is
"impossible". I agree that the chances of the dinosaurs co-existing with
humans is nearly zero. I agree that apples will most likely continue to fall
*down*. I agree that a great many things have enough evidence to support
their existence/non-existence and that we should accept them as the only
current possibility. However, I strongly disagree that we can be sure of what
is "impossible". 

        Further, I agree that too much open-mindedness can lead to "one's 
brains falling out", as someone said so fittingly; and that we shouldn't hold
our breath for some highly unlikely events to occur. Just remember, we could
all get a good swift kick in the butt about everything we think we know at
some time in the future. We *could*. That doesn't mean we *will*. And most
of us like to think we "won't*, just to keep our sanity.

        Further, I *know* that I hit the brakes. I know because: first, I took
my foot off the gas, and continued to accelerate. I then put my foot on the
brakes. I slowed down momentarily, and then continued to accelerate. I looked
down to make sure I had my foot on the brakes. I shut the car off. The brakes
finally brought me to a stop. I still cannot explain what happened. And as to
what one person posted (that the brakes are required to provide more stopping
power than the accelerator can generate as forward power), every car I have
ever driven has been capable of accelerating if you push the gas all the way
and the brakes all the way - and yes, it's something I like to try.

        Finally, back to the topic of this thread: I would tend to agree with
either one of two proposals for the creation of the dragon myth:

        1. Someone discovered dinosaur remains at some time in the past, and
           "invented" dragons to explain the monstrous creature they had found
        2. Someone greatly exaggerated tales of crocodiles, or large lizards
           such as the komodo (sp?) dragon.

Both of these are more likely, I think everyone will agree, than humans and
dinosaurs co-existing.

--
Scott Barker
barker@enel.ucalgary.ca

"If winning is not important, then commander, why keep score?"
   - Worf, Star Trek: The Next Generation
Newsgroups: rec.arts.sf.science
From: doom@leland.Stanford.EDU (Joseph Brenner)
Subject: Re: Evolution under High Gravity
Organization: DSO, Stanford University
Date: 17 Aug 92 08:03:00 GMT

egl1@cunixf.cc.columbia.edu (Elizabeth G. Levy) writes:

>Short.  Very short.

>Actually, take a look at Forward's _Dragon's Egg_, about creatures
>living on the surface of a neutron star (the ultimate in high gravity).

You can also take a look at Hal Clement's _Mission of
Gravity_, a classic work about aliens on a high gravity
planet.  Once again, Clement votes for "short": they're
around the size and shape of Scorpions. 

Seems plausible, if only because of the problems involved
with pumping circulatory fluids up a steep gravity well. 

Also, you have to worry about things like falling over. 


Newsgroups: rec.arts.sf.science
From: egl1@cunixf.cc.columbia.edu (Elizabeth G. Levy)
Subject: Re: dragons were dinosaurs?
Reply-To: egl1@cunixf.cc.columbia.edu (Elizabeth G. Levy)
Organization: Columbia University
Date: Thu, 20 Aug 1992 15:19:43 GMT

In article <1992Aug20.144627.24952@news.acns.nwu.edu> myboy@casbah.acns.nwu.edu (Lewis Murtaugh) writes:
>
>If enough dinosaurs did survive to ensure genetic diversity, where are they
>now?  Did primitive man kill them off?  Why aren't there any cave paintings of
>dinosaurs?

All the birdies.



--
But this is.
From: neufeld@helios.physics.utoronto.ca (Christopher Neufeld)
Newsgroups: rec.arts.sf.science
Subject: Re: Merpeople
Date: 18 Aug 92 14:43:13 GMT
Organization: University of Toronto Physics/Astronomy/CITA

In article <1992Aug18.101924.4130@aston.ac.uk> evansmp@uhura.aston.ac.uk (Mark Evans) writes:
>bjgaed@bb1t.monsanto.com writes:
>Are the neural processes of cold-blooded animals 
>: qualitatively different from those of warm-blooded animals?  Need a 
>: physiologist or zoologist here.  I'm just a dumb chemist.
>
>The terms warm vs cold blooded are confusing.
>Better terms are Endo-therm and Ecto-therm
>Warm blooded creatures have their body temperature kept constant by their
>metabolic processes.
>Cold blooded creatures must rely on external heat sources.
>
   This is not completely accurate. After all, the metabolic processes in
an endotherm are located inside the body, not scattered all over the
outside of it. There must necessarily be a higher temperature at the
centre of a lizard than at its skin once it has come into thermal
equilibrium with its surroundings (and assuming it is alive, naturally).
   The difference is that an ectotherm will do internal temperature
regulation, using an organic equivalent of a thermostat to govern
reactions which are run solely for the purpose of producing heat, while
an endotherm will notice that it feels cold and go look for a warm spot
to sit in.
   A creature with a large mean diameter, even a lizard, can get very
warm at the centre. The circulation of blood prevents a simple thermal
diffusion solution to the problem, but a dinosaur was likely quite warm
at the surface, as would be a modern lizard scaled [no pun intended] up.

>For an animal to generate heat internaly the metabolic cost is quite high,
>thus a mammal will require a much larger food/oxygen intake than a reptile
>or fish of the same body weight.
>
   In cold weather this is correct. In warm weather there isn't going to
be too much difference. It depends, of course, on the additional power
required to keep the body at the appropriate temperature. Up around
thirty-seven degrees your body's idea of temperature regulation is to sit
very still, out of the sun, and exude water through your skin. At this
point you're doing a credible imitation of a lizard (except for the bit
about the water through the skin).


-- 
 Christopher Neufeld....Just a graduate student  | Confidence is the feeling
 neufeld@helios.physics.utoronto.ca    Ad astra  | you have before you
 utzoo.utoronto.ca!generic!cneufeld              | understand the situation.
 "Don't edit reality for the sake of simplicity" |
From: fiddler@concertina.Eng.Sun.COM (steve hix)
Newsgroups: rec.arts.sf.science
Subject: Re: Merpeople
Date: 13 Aug 1992 23:57:38 GMT
Organization: Sun Microsystems, Mt. View, Ca.
NNTP-Posting-Host: concertina

In article <199208131941.AA25183@natinst.com> kathrynw@radian.UUCP (Kathryn Whitworth) writes:
>
>Okay, I admit it.  I'm too literal-minded to be happy about merpeople,
>and someone in my writing group just brought one into the story.
>
>My objections have to do with the standard type gills, mainly.  I'll
>explain my reasoning, then shoot me down if I'm wrong.  Hey, I'll
>learn something.
>
>Oxygen in air at atmospheric pressure runs about 12%.  

More like 21%?

Oxygen partial pressure at sea level is about 3 psi: you'd only need
that pressure to operate like at sea level (14.5psi) in normal air.

>  (I don't know how much of this we actually use -- postulating a normal,
>healthy adult male -- or how much O2 the blood contains, either in % or 
>mg/L.)

I seem to recall something like 20% of available oxygen used/breath...?

>Dissolved oxygen in water should average 4 - 5 mg/L to support fish.  Call
>this 0.045% O2.  Again, I don't know if this is the normal DO in sea-water,
>although Standard Methods for the Analysis of Water and Wastewater leads me
>to believe it might be.

what partial pressure of O2 does this give us?  The percentage of oxygen
in the medium is much lower, but the total mass of oxygen might not be so
bad.

Partial pressure is important; at pressures equal to depths of 500' or more,
adjusted breathing mixtures have very low percentages of oxygen...oxygen is
toxic at fairly low pressures above sea level.  I think that pure O2 at
2 atmospheres can do you in.

>We are now looking at gills that must be 267 times more efficient than lungs
>at extracting O2 in order to support the normal healthy adult male mentioned
>above, and I suspect that extracting the O2 from the water is not so easy as
>from the air.

I think it may not be so bad, since the pressure of the medium is higher,
and the density.

Some work has been done with liquid-filled lungs and breathing mammals at
various pressures.  Tiring, but mice, dogs, and goats have spent extended
periods breathing oxagenated water and other fluids.  Pumping the fluid
in and out is hard work, and exhaustion usually sets limits on how long
they can function.

--
-----------------------------------------------------------------------
Of making many books there is no end...  |  What's wrong with chasing 
                       -- Eccl. 12:12    |  nebulae till 3 am?  |-(
-----------------------------------------------------------------------
Organization: K.U.Leuven - Academic Computing Center
Date: Tuesday, 18 Aug 1992 15:01:57 +02
From: Peter Arien <LAAAA43@cc1.kuleuven.ac.be>
Newsgroups: rec.arts.sf.science
Subject: Re: Evolution under High Gravity

In article <gapdrr.714069394@gsusgi1.gsu.edu>, gapdrr@gsusgi2.gsu.edu (Daniel R
T Rothman) says:
>
>No, seriously. I haven't just pulled this out of the ether. Babies very
>seldom hurt themselves when they fall. They've simply got less room to
>accelerate in. In a high-g environment, that'd mean tremendously smaller
>numbers of broken bones for the short of stature.

I thought breaking bones when falling had more to do with tensing your
muscles than with being short or tall... That's why babies and drunks
don't break bones that easy.
Newsgroups: rec.arts.sf.science
Subject: Re: Niven's blunders (was:Superconductors + the 2nd law)
From: ecmtwhk@ccu1.aukuni.ac.nz (Thomas Koenig)
Date: Fri, 21 Aug 1992 10:19:57 GMT
Organization: University of Auckland, New Zealand.

wiml@milton.u.washington.edu (William Lewis) writes:

>In article <1992Aug11.101042.16489@ccu1.aukuni.ac.nz> ecmtwhk@ccu1.aukuni.ac.nz (Thomas Koenig) writes:
>>Rinworld stability (well, that's a classic; has anyone figured wether he
>>got it right the second time round?)

>  What is there to get wrong? He had an active control system (the
>ramjets). Unless one could calculate that the ramjets wouldn't have enough
>thrust, or something, but I think ramjets are too theoretical
>to do that.

For one thing, he could have got the timeframe wrong. As far as I remember,
the City Builders used the ramjets as spaceship engines for thousands of
years before the fall. How long would it take for the Ringworld to collide
with the sun without attitude control, if a medium - sized asteorid like
the one which caused the 'Fist of God' hit it? Anyone done the calculation
on that?

Another thing - the notion that the Ringworld, by being built with its
edge towards the galactic core, will offer its inhabitants safety when
the shockwave from the explosion arrives (expressed towards the end in
Ringworld Engineers by Louis) is ludicrous. The visible angle of the
core explosion will be much larger than the angle of the opposite end of
the Ringworld.

-- 
Thomas Koenig, ecmtwhk@ccu1.aukuni.ac.nz, ib09@rz.uni-karlsruhe.de
The joy of engineering is to find a straight line on a double logarithmic
diagram.
From: dillard@ccwf.cc.utexas.edu (Alex Dillard)
Newsgroups: rec.arts.sf.science
Subject: Re: Superconductors
Summary: Wires on computer chips have already reached their physical limit
Date: 23 Aug 92 01:33:46 GMT
Organization: The University of Texas at Austin, Austin TX

In article <1992Aug20.032505.24142@u.washington.edu> wiml@milton.u.washington.edu (William Lewis) writes:
>In article <1992Aug13.122812.8253@monu6.cc.monash.edu.au> ins894r@aurora.cc.monash.edu.au (Aaron Wigley [Wigs]) writes:
>>When better lithography processes are used to layer chips, then this
>>benefit you mention about higher densities will come about, without the
>
>   Electron beams, actually. I don't think electron lithography is in
>commercial use but it's been being researched for a good while.
>
>   I wonder where people will go after electrons? Maybe you could fire
>cannonballs at the microchip and count on their short de Broglie 
>wavelength ;-) 

  If I recall correctly, IBM researchers manfactured a chip with 0.25 micron
wires, and they had trouble with the current leaking out of the wires, due to 
quantum effects.  I don't think the issue of what to use for lithography will
be important for conventional technology semiconductors.  However, some work
has been done on "quantum dot" devices, which use quantum effects to make 
devices.  I remember reading (in Scientific American, I think) about very tiny
Galium-Arsenide lasers, made from "quantum wells".  The most trouble they had
was connecting wires to the devices, because they were so small.
-- 
 \ _
 - o  We were once so close to Heaven, Peter came out and gave us medals,
  ^   declaring us the nicest of the Damned. - They Might Be Giants
        Alex  dillard@ccwf.cc.utexas.edu 
Newsgroups: rec.arts.sf.science
From: rob@watney.eng.ohio-state.edu (Rob Carriere)
Subject: Re: Superconductors
Organization: The Ohio State University Dept of Electrical Engineering
Date: Sat, 15 Aug 1992 04:54:26 GMT

In article <ins818e.713771986@aurora.cc.monash.edu.au>
ins450m@aurora.cc.monash.edu.au (T.F. Eccles) writes: 
>rob@watney.eng.ohio-state.edu (Rob Carriere) writes:
>>A superconductor is only a superconductor under some conditions.  That the
>>temperature has to be right is the most well-known one, but not the only one.
>
>Isn't there also a maximum magnetic field in which a material is a super-
>conductor?  Would this affect the current levels?

Yes, and yes.  You have three variables to play with: temperature, magnetic
field strength and current density.  You get superconductivity as long as you
stay within a bounded region of this 3-space.  For all known superconductors,
the bounded region is _not_ a right block aligned with the axes, so the value
you pick for one of the parameters affects the choice you have for the other
two.


SR
---