Subject: Re: Thermodynamic definition of life (was Could intelligent extraterrestrial life exist in our galaxy?)
From: "John D. Gwinner" <75162.514@compuserve.com>
Date: Tue, 12 Nov 1996 09:36:11 -0500
Erik Max Francis wrote:
> Thus, my preferred definition of life is the thermodynamic one: Any process
> which involves a steady, local decrease in entropy*. That is, anything that
> gradually creates order from disorder would be considered alive.
I've always liked this definition. One could even put it into religious
or fantasy relgiion
settings by saying that 'chaos' is Entropy, and 'order' is non-entropy,
i.e. life.
And intelligence may eventually give us the tools to either
1) Widen the 'system' or
2) Beat thermodynamics
so that non-entropy will win in the end.
The heat death of the Universe depresses me! Perhaps the Big bang is
the answer to that problem
== John ==
Subject: Re: Unit system based on physical constants -- was: When will the U.S. finally go metric?
From: adam.morris@octacon.co.uk (Adam Morris)
Date: Wed, 13 Nov 96 11:46:10 GMT
>>> For example, you can base a system on the speed of light,
>>> Planck's constant, the gravitational constant, and the charge of the
>>> electron. You can easily define mass, length, time, energy,
>>> and electrical units with these four constants.
But how, because speed is currently defined as distance covered in a given
time (metres per second) the speed of light is a constant, but has to be given
in units... to use the speed of light to define a unit of distance you need
to have a unit of time... and to use the speed of light to define a unit of
time, you need a unit of distance.
Adam
Subject: Re: A photon - what is it really ?
From: "Robert. Fung"
Date: Wed, 13 Nov 1996 07:44:46 -0500
Peter Diehr wrote:
>
> Robert Fung wrote:
> >
> > But isn't a photon a wave ? Mathematically a wave packet
> > built up from a superposition of a certain spectral distribution
> > of wave frequencies ?
> >
>
> No, a photon does not consist of bits and pieces of an electromagnetic
> wave. The photon is a quantum object; it is the quanta of the electromagnetic
> field. As such, it has both wave and particle attributes. It is also subject
> to the Heisenberg Uncertainty Principle (HUP).
HUP seems to be subordinate to the Fourier uncertainty since this
uncertainty is relavant whether matter is present or not. Whereas HUP is
valid only for EMR hitting matter, the Fourier uncertainty is
derivable mathematically based on abstract waves. For the case of free
EMR the uncertainty is in the position of the wave-packet when its
wave-length lengthens.
The introduction of Planck's constant is an addition to this uncertainty
as a limiting case.
Is it possible to affect the Bohr radius/Planck's constant ?
Can an "h" be derived strictly from abstract wave theory ?
The closest I've read to this effect is by Dirac something like:
theta * E - E * theta = ih for a component of
the superposition.
I don't know what the assumptions are in this case.
The wave-packet definition I'm working from being:
E'=E * integral { dk * f(k) * e ^-i*(wt-kx) }
f(k)=a gaussian spectral funtion of the wave-number k, w=c|k_o|
>
> If you are able to fully specifiy the electromagnetic field, then one of
> the quantum properties is that you no longer know how many photons you have!
> That is, the photon number is not an eigenvalue of the electromagnetic field.
I guess this is the case when the source is switched on and off and
the resulting wave packet contains energy larger than one hbar*w_o
yielding many coherent, phase-related photons ?
>
> When you think of a photon as having wave properties, the waves in question
> are probability amplitudes ... and these are going to tell you the likelihood
> of finding the photon here or there.
And this seems to match what I'm reading in terms of locating the photon in
some symmetric region k +- delta k/2 by treating the abs-squared
spectral function f(k) as the probability density P(k) for the wave-number
lying within the region.
> Best Regards, Peter
Subject: Russian Mars 96 spacecraft to study stellar oscillations
From: richmond@Princeton.EDU (Stupendous Man)
Date: 13 Nov 1996 07:04:57 -0600
I just discovered that the Mars 96 planetary spacecraft, scheduled
for launch on November 16, has a high-precision photometer on board.
The Mars 96 home page, http://www.iki.rssi.ru/mars96, describes the
instrument as follows:
> MAIN PURPOSE OF THE EXPERIMENT:
> Investigation of pulsation, rotation and internal
> structure of stars, measuring photometric
> microvariabilities induced by these oscillations.
> Characteristics of the oscillations (frequency, amplitude
> and coherence time) are used to probe the physical
> stage of the stellar interiors, i.e., the equation of state,
> the convective energy transport and the angular momentum distribution.
>
> INVESTIGATION METHODS:
> long--time, continuous, high--precision photometric observations
> of several bright stars during the cruise of the Russian
> MARS-96 spacecraft from Earth to Mars. The instrument
> composed of a photometer and a stellar sensor is
> installed in a pointing platform PAIS. The photometer
> is a 9 cm telescope with a photomultiplier, working in
> photon counting mode. The stellar sensor measures the position
> of the star with a CCD matrix and transfers this information to PAIS.
By golly, this instrument should perform some very important research
on several stars during the long trip to Mars. What a good place to put
a little telescope!
Oh, and by the way, the Russian spacecraft will be the only one of the
three Mars missions launched this year to carry a gamma-ray burst
detector. The combination of Mars 96, Ulysses, and BATSE should provide
precise positions for bright gamma-ray bursts over the next year or two.
Michael Richmond
--
-----
Michael Richmond "This is the heart that broke my finger."
richmond@astro.princeton.edu http://astro.princeton.edu/~richmond/
Subject: Re: 7 November, PLutonium Day is the only future holiday
From: JC
Date: Wed, 13 Nov 1996 13:03:04 +0000
Zdislav V. Kovarik wrote:
>
> In article <55tll9$f39@dartvax.dartmouth.edu>,
> Archimedes Plutonium wrote:
> :In the future there is no other holiday, just one, plutonium day. It
> :comes 7 November, today.
> :
> :Unlike the other useless holidays of bygone days, of Xmass of
> :commercial crap. Of Easter silliness of an Easter bunny and painted
> :eggs. Of New Years get drunk and useless fireworks. Of National
> :holidays and a nation is born false allegiances, of presidents day, of
> :memorial day glorifying war and dying and politicians of dubious merit.
> : Or past holidays of yore of wasteful libations or animal slaughter or
> :virgin sacrifice. All of these holidays worship or praise or celebrate
> :things of non-importance. Holidays should be pragmatic, should be spent
> :with time and energy from the soul of a person. Such as a poem.
> [...]
> Right on! November 7 is the 79th anniversary of the Great October
> Socialist Revolution in Russia. It turned out to be a colossal failure,
> too.
Let's not encourage AP to further delusions of grandeur.I for one
refused to go to work on 7th November on the grounds that it was
a public holiday, referring my employers to AP for further
information. Now they want to offer him my job...
JC
Subject: Re: Lunar base
From: Michael Martin-Smith
Date: Wed, 13 Nov 1996 12:59:51 +0000
In article <56a1cv$bkm@news.ysu.edu>, Valerie Walko
writes
You're quite right. I feel also that our next step should be a lunar
base. apart form science and astronomy, the moon can be a source of
rocket propellants (oxygen and powdered aluminium) 20 times cheaper than
the same materials ferried from earth. Also, lunar materials could be
used to manufacture solar power satellites which could beam clean , non-
global warming energy to us in the next century. New technologies being
developed can ship lunar materials into high orbit for processing far
more cheaply than rocketry, and so, in future decades, free floating
gian tisland colonies could be bult, giving humaanity a longterm
expanding presence in space, relieving the Earth of some of our industry
and population, if we can mass produce cheaper space shuttle successors.
The so-called Two Planet Economy has great potential, and would become
the basis of a true Extraterrestrial civilization. Right now, the youth
of the world needs a new idealism and vision of the future; this is it!
You might like to visit
http://people.delphi.com/astronist/index.html and join in the
gigantic task of putting this vision to the people of the world, or, for
more research details, contact ssi@ssi.org - the Space Studies Institute
are doing key research to make it happen
--
Michael Martin-Smith
Subject: Re: Direction of aberration.
From: "Robert. Fung"
Date: Wed, 13 Nov 1996 08:23:45 -0500
glird@gnn.com wrote:
>
> In article <3284B8F5.7951@citicorp.com> Robert Fung wrote:
> >Brian Jones wrote:
> >> glird@gnn.com () wrote[in part]:
> >>> Upon drawing a simple picture, it became self evident that
> >>>since the angle of incidence is a function of the velocity of
> >
> >> If the earth is moving toward the star, no aberration is
> >>observed. The max aberration occurs when earth moves perp to
> >>star. And light is equivalent to rain when it comes to
> >>aberration.
> >
> > The definition of a photon is something like: a wave-packet with
> >a Gaussian spectral function f(k), total energy hv, v=c|k| where
> >|f(k)|^2 is the measure for the probability P(k) of the wave
> >number of the photon... How would this apply to aberration ?
> Let's consider the issue two ways:
> 1. Light as a bunch of particles pouring down to us from a given
> star.
> 2. Light as a series of plane waves reaching us one after the
> other, as in Bragg's thesis. (Each plane is perpendicular to the
> direction of propagation.)
> Drop 1, moving aslant to our left, is from the left ear of a
> person on the left side of the room. We point our telescope aslant
> to the right, whereupon THAT drop hits the middle of the viewpiece.
> Meanwhile, the rest of the drops from the left ear, each moving
> aslant at the same angle relative to us, hits the side of the
> moving, tilted telescope.
Sort of like a shot-gun microphone ? What if the inside of the
eyepiece is mirrored ? I'd imagine the telescope would have to
be very long to match a newtonian's surface area. But the view
would be narrow ?
> 2) Earth moving to right compared to star. Plane wave 1 from entire
> Let the plane waves be moving on a line
> from us to the star, per instant. Tho perpendicular to such lines,
> each plane will thus be moving aslant relative to us. Once it
> enters the material medium comprising Earth, each such wave IS
> moving at an angle to our left.
This is very interesting. Is the the speed of light relative
based on what direction you choose or are forced to choose to
measure the wavelength ? I thought one typically measures the
wavelength relative to the direction of the wave normal, but
that seems to have changed by aberration, along with the Doppler
frequency and wavelengths. The the angle of the Doppler shifted
wavelength must change in order for the speed c to remain
constant ? Sounds fishy, like saying light slows down in matter.
> The aberration takes place very far from Earth's surface. Some of
> it even as the star's light escapes the star's own envelope. Some
> of it as that star's light later escapes it's parent-galaxy's
> envelope.
> (Eventually, our maps of the universe will have to take
> these things into account, and - among other things - correct the
> presently somewhat distorted mapped-positions per heavenly body.)
If you mapped every position of every visble stellar object
with their relative distances calculated from Earth, where is
the center of mass of all these objects in relation to the Earth ?
But you've not addressed my questions, particulary the second one:
But what about the color of the light due to the transverse
doppler effect ? When you put aberration together with the
Doppler shift, it sounds like dispersion due the motion
of a source ?
Subject: Re: Thermodynamic definition of life (was Could intelligent extraterrestrial life exist in our galaxy?)
From: suk@pobox.com (Peter Kwangjun Suk)
Date: Wed, 13 Nov 1996 10:39:19 -0400
In article <56b15v$p88@ccshst05.cs.uoguelph.ca>, devens@uoguelph.ca (David
L Evens) wrote:
> Erik Max Francis (max@alcyone.com) wrote:
> : David L Evens wrote:
>
> : > Isolated viri don't carry out any life processes, however. They just sit
> : > there, close to chemically inert.
>
> : And there are spores and seeds that sit, inert, for years or decades, before
> : finding the right environment to come alive. If viruses aren't alive, it's
> : probably not fair to consider those alive either.
>
> A virus needs a host that everyone agrees is alive in order to do its
> life cycle. A spore merely needs a suitable non-living environment.
But this introduces some circularity in the definition. To decide whether
or not something is alive, you have to decide if its "host environment" is
alive or not. So you are defining "alive" in terms of youir definition of
alive. (Not really pick a nit, but I like this self-reference stuff.)
Of course you say: "a host that everyone agrees is alive", which implies
that certain organisms are axiomatically considered alive in your
definition. Namely, everything that can be infected by a virus. That's
an awful lot of axioms there. How's this qualitatively different from:
"life = everything I point to and call alive" or "life = well, we all know
what that means, so why argue about it?"?
(Note: hacker usage of punctuation throughout.)
--PKS
--
There's neither heaven nor hell
Save that we grant ourselves.
There's neither fairness nor justice
Save what we grant each other.
Peter Kwangjun Suk
Musician, Computer Science Graduate Student
[finger suk@pobox.com for PGP public key]
Subject: Re: Thermodynamic definition of life (was Could intelligent extraterrestrial life exist in our galaxy?)
From: suk@pobox.com (Peter Kwangjun Suk)
Date: Wed, 13 Nov 1996 10:47:24 -0400
In article <32888B5B.19A5@compuserve.com>, 75162.514@compuserve.com wrote:
> Erik Max Francis wrote:
> > Thus, my preferred definition of life is the thermodynamic one: Any process
> > which involves a steady, local decrease in entropy*. That is, anything that
> > gradually creates order from disorder would be considered alive.
>
> I've always liked this definition. One could even put it into religious
> or fantasy religion settings by saying that 'chaos' is Entropy, and 'order'
> is non-entropy, i.e. life.
The equivalence makes the above definition of life circular.
> And intelligence may eventually give us the tools to either
> 1) Widen the 'system' or
> 2) Beat thermodynamics
>
> so that non-entropy will win in the end.
What exactly do you mean by this? Why would that be desirable? (Why
wouldn't that be boring?)
> The heat death of the Universe depresses me! Perhaps the Big bang is
> the answer to that problem
Nah. Just make a bet with somebody that the universe will end. So even
if it does, you still win! (And if that money is put into an
interest-bearing saving account, then you're going to win a whole lot!)
--
There's neither heaven nor hell
Save that we grant ourselves.
There's neither fairness nor justice
Save what we grant each other.
Peter Kwangjun Suk
Musician, Computer Science Graduate Student
[finger suk@pobox.com for PGP public key]
Subject: Re: Thermodynamic definition of life (was Could intelligent extraterrestrial life exist in our galaxy?)
From: Erik Max Francis
Date: Wed, 13 Nov 1996 08:03:29 -0800
Peter Kwangjun Suk wrote:
> A combination of the thermodynamic definition with a requirement for
> reproduction and a capacity to "evolve" comes very close to a universal
> definition of life. So how about it? I posit this as "THE definition".
> This would include viruses, but preclude candle flames and formaldehyde
> blobs.
Your requirement for reproduction is not required for life; it is required
for naturally evolving life. Individuals who cannot reproduce (through
accident or genetic defect) are certainly still alive.
There are two types of "life" here. The first, which I'll call
"macrolife," is the characteristic that a species or ecology or biosphere
exhibits over time: It evolves, adapts to changes, and often tends to grow
more complex. (This is not always the case, of course, but the general
trend of all life on Earth has been toward more complex organisms.)
Then there's the second type, which I'll call "microlife," which concerns
the individual. Individuals consume foods, excrete wastes, grow, and tends
to increase order in themselves (with the thermodynamic definition, all but
the last are _side effects_ of life, not symptoms of life itself -- though
they are often good clues).
To have evolving macrolife, you need reproduction with mutation (or some
other way to have genes change over time). To have viable microlife,
reproduction is not necessary. (And in some cases, doesn't occur; mules
can't reproduce, but they are most certainly alive.)
--
Erik Max Francis | max@alcyone.com
Alcyone Systems | http://www.alcyone.com/max/
San Jose, California | 37 20 07 N 121 53 38 W
&tSftDotIotE; | R^4: the 4th R is respect
"But since when can wounded eyes see | If we weren't who we were"
Subject: Re: analemna ?
From: Steve Jolly
Date: Wed, 13 Nov 1996 13:11:45 -0400
The analemma is a graphical way of showing the apparent movement of the
Sun north and south in the sky as the seasons change, along with the
advance or retardation of the Sun's time at "high noon" each day. The
analemma looks like a somewhat assymetrical figure-eight.
The Sun runs ahead--or behind--of the "expected" time it would reach
high noon, each day, because the Earth's orbit is an ellipse, not a
perfect circle. Because the orbit is an ellipse, and the Earth is
somewhat nearer the Sun at some points in its orbit than at others, the
Earth's speed in orbit varies (and, more to the point, the angular
distance it moves around its orbit each day, seen from the Sun, varies).
So, sometimes, the Earth runs a bit "ahead" or "behind" where it would
be in a perfectly circular orbit, making the Sun appear to be a bit
late--or early-- in crossing the meridian, or "high noon."
The same effect--the Sun seeming to run a bit ahead or behind where it
"should be" in the the sky--produces earlier and later sunrises and
sunsets than would be expected in a perfectly circular orbit. Both are
offset in the same direction, time-wise, as the "high noon" (if the high
noon is "late," then sunrises and sunsets are also offset "late" that
day--and the same is true for when the high noon is "early"). The sun
runs "early" for roughly half of the year, and "late" approximately half
of the year (I said "approximately," because, actually, the earth's
speed-changes in its orbit causes one effect to predominates for
somewhat more than half of the year, as you'll notice when you actually
_see_ an "analemma" diagram).
Since the Earth is nearest the Sun in its orbit in late December and
early January, and is moving the most quickly in its orbit (it's nearer
the sun, and speeds up), the Sun appear the most "behind" at high-noon
time during that part of the year. So, the days of latest
sunrise/earliest sunset are offset--by more than a week!--ahead of and
behind the date of the "shortest day" (that's, by definition, the day
with the minimum time interval between sunrise and sunset, which, as you
know, is near December 21st, but it doesn't mean that that same day also
has the latest sunrise or the earliest sunset, just that the time
between them is at a minimum).
The same thing happens at mid-summer, when the days of earliest sunrise
and latest sunset--again, on different days--are offset from the
"longest day."
Take a moment to make certain that you see that this is true: if a day
has its "high noon" and sunset offset later than you'd otherwise expect,
the "shortest day" wouldn't be the same day that has the earliest
sunset.
Since all of this might be a little bit unclear to you without some
diagrams, you might want to use one of the Web search engines and do a
search on "analemma." My personal preference is Infoseek Ultra at
http://ultra.infoseek.com/
You'll get lots of "hits" that guide you directly to sites with a fuller
explanation and some diagrams, including your mysterious analemma, of
how the Sun--and sunsets and sunrises--runs a bit late or early at
various times of year. You'll also find a full description in many
introductory astronomy books, especially those for kids 10-and-up.
Hope that helps!
Hope that helps!
Subject: Re: Thermodynamic definition of life (was Could intelligent extraterrestrial life exist in our galaxy?)
From: Doug McKean
Date: Wed, 13 Nov 1996 11:41:06 -0500
Erik Max Francis wrote:
> Thus, my preferred definition of life is the thermodynamic one: Any process
> which involves a steady, local decrease in entropy*. That is, anything that
> gradually creates order from disorder would be considered alive.
>
> -----
> * This does not violate the second law of thermodynamics because I did not
> put the restriction "in a closed system" on my statement. So long as, when
> taken as a whole closed system, there is an increase of entropy which
> outstrips the local decrease, the second law still holds firm. This
> happens, in the case of life on Earth, because lifecycles are powered by the
> Sun's light and heat, which is created through thermonuclear reactions in
> its interior. (The Earth-Sun-Moon system can approximately be considered a
> closed system for these purposes.) In this case, the increase in entropy
> caused by thermonuclear reactions _far_ outweighs the tiny local decrease
> caused by the evolution of life on Earth.
>
> --
> Erik Max Francis | max@alcyone.com
> Alcyone Systems | http://www.alcyone.com/max/
> San Jose, California | 37 20 07 N 121 53 38 W
> &tSftDotIotE; | R^4: the 4th R is respect
> "But since when can wounded eyes see | If we weren't who we were"
Although I like the brevity, I for one am having difficulty with this definition.
I can't say absolutely that an organism is negative entropic. They're just
so complicated that I would have to say they're positive if anything, or
at best very close to zero entropic at some point in it's lifetime.
And leaving a closed system for an open system would appear to
throw out lots of assumptions leaving the 2nd law open for debate,
i.e. you're ability to 'reclaim' energy, so to speak, is lost leaving
you with a positive entropic condition.
Interesting point. I really don't know.
*******************************************************
Doug McKean
doug_mckean@paragon-networks.com
-------------------------------------------------------
The comments and opinions stated herein are mine alone,
and do not reflect those of my employer.
-------------------------------------------------------
*******************************************************
Subject: Re: 2nd law of thermo -PRETENTIOUS!
From: redsox3@ibm.net (Wayne Delia)
Date: 13 Nov 1996 16:02:23 GMT
In <3286DD62.775C@eurocontrol.fr>, Steve Jones - JON writes:
>Hindsight is a wonderful thing, take Lord Byron who said of Dickens
>"Future generations shall wonder why we held him so high". Or NY Times
>article on Twain which said "In a 100 years time only the 'Jumping Frog'
>will be remembered". 100 years ago Jules Verne wrote "From Earth to the
>Moon".
Dickens? Twain? Verne? Never heard of 'em. :-) Actually, I'm currently
re-reading Twain's "Letters from the Earth" and other censored short stories,
and my wife is getting annoyed at my constant muttering "This man is a genius."
>Small minds can never envisage change, they cling to the "now"
>as perfect. If you want a modern example, just look at IBMs latest
>assertion that the year 2000 won't be a problem for them.
On behalf of the company that employs me, I can assure you that the year 2000
won't be a problem for IBM. It will, however, be a problem for anyone else who
uses IBM hardware and software... wait a minute... IBM's the biggest customer of
IBM hardware and software! Oh shit...
(Actually, and officially, I do not presume to speak for the brilliant upper-level
management of the I.B.M. Corporation, in whom I have the utmost confidence, as
far as they know.)
I once worked on a PL/I program in 1993 along with a good friend who had 25
years experience with IBM, which required modifying a sorting routine based on a
date field in the format YY/MM/DD. I pointed out that we needed to take the
turn of the century into account, but my friend said not to worry about it -
because he'd be retired by then. The scary part is he was dead serious.
Wayne Delia, redsox3@ibm.net
"Don't take me! I have a wife and kids! Take *them*!" - Homer Simpson
Subject: Re: Creationism VS Evolution
From: Alan \"Uncle Al\" Schwartz
Date: 13 Nov 1996 17:11:30 GMT
Jerry wrote:
>Tim Hollebeek wrote:
>>
>> In article <32853A38.38E7@gte.net>, Ash writes:
>> > I read in a science book that there is a greater posibility of a
>> > printinng press exploding and forming webster's dictionary completly by
>> > accident; as opposed to the world being created from some dead matter.
[snip]
>Comments from Jerry:
[snip
> However the story is more complex than that. Our universe is composed of a spectrum
>of energy from our light speed toward infinite light speed. Over an infinity of time,
>we get universes of God alone where all the energy is at the highest light speeds and
>only standing waves of energy form.
[snip]
"Never argue with an idiot. Casual passersby cannot tell the
difference."
1) "God did it." Where do you go from there? Supplication? 6000+
years of religion and a million-plus deities did not bring forth the
flush toilet. God turns a blind eye (or whatever) to Hitler's
concentration camps (12 million murders), Stalin's Gulag (20 million
including Mushik famine), Mao's Great Leap Forward killing 30 million by
famine, Africa right now... What makes you think It gives a shit about
smaller stuff?
2) "Science." The thing speaks for itself.
3) "Pseudoscience." Cargo cults only benefit the priests.
Thomas Aquinas can blather until the sun burns down. Anything which
accounts for the creation of the manufacturer can just as easily account
for building the package.
--
Alan "Uncle Al" Schwartz
UncleAl0@ix.netcom.com ("zero" before @)
http://www.ultra.net.au/~wisby/uncleal.htm
(Toxic URL! Unsafe for children, Democrats, and most mammals)
"Quis custodiet ipsos custodes?" The Net!
Subject: Re: analemna ?
From: willner@cfa183.harvard.edu (Steve Willner)
Date: 13 Nov 96 17:33:13 GMT
In article , Norbert Ebel writes:
> PS as far as I know the phenomenon has as a consequence that the earliest
> sun rising day (and the latest sun falling day) are not the 21th december (but
There is a short answer, with reference to a longer answer, in the
FAQ:
http://astrosun.tn.cornell.edu/students/lazio/sci.astro.3.FAQ
Note that both obliquity of the ecliptic and eccentricity of Earth's
orbit contribute to the shape of the analemma, with the former being
slightly the larger effect.
--
Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu
Cambridge, MA 02138 USA
(Bad news service; please email your reply if you want to be sure I see it)
Subject: Re: Gravity, speed of, and black holes: clueless questions
From: willner@cfa183.harvard.edu (Steve Willner)
Date: 13 Nov 96 17:28:47 GMT
In article , wa2ise@netcom.com (Robert
Casey) writes:
> It's said that light photons cannot escape the black hole, as
> the required escape velocity is higher than the speed of light.
> OK, does gravity "particles" travel at the speed of light?
See the FAQ, specifically
http://astrosun.tn.cornell.edu/students/lazio/sci.astro.4.FAQ
--
Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu
Cambridge, MA 02138 USA
(Bad news service; please email your reply if you want to be sure I see it)
Subject: Re: 2nd law of thermo -PR
From: john.pazmino@moondog.com (JOHN PAZMINO)
Date: Wed, 13 Nov 96 10:17:00 -0500
C > From: czar@freenet.edmonton.ab.ca ()
C > Subject: Re: 2nd law of thermo -PRETENTIOUS!
C > Date: 9 Nov 1996 14:42:30 GMT
C > Organization: Edmonton FreeNet, Edmonton, Alberta, Canada
C >
C > : : Two hundred years ago, we thought that there was a fundamental limit to
C > : : travel speeds because even the fastest horses couldn't go over 30 mph, no
C > : : matter how well they were bred, trained or jockeyed.
C >
C > : And with the advent of faster transportation, there were learned and
C > : highly degreed scientists who spouted all sorts of scientific reasons
C > : why we would never exceed the speed of sound, and so on.
C >
C > : The history of scientific "can't"'s is a long series of embarrassing
C > : statements by damn fools.
C >
C > Some favorites of mine:
C >
C > What can be more palpably absurd than the prospect
C > held out of locomotives traveling twice as fast as
C > stagecoaches?
C > The Quarterly Reviev, England, March 1825
C >
C > The ordinary "horseless carriage" is at present a
C > luxury for the wealthy; and although its price will
C > probably fall in the future, it will never, of course,
C > come into as common use as the bicycle.
C > The literary Digest, October 14 1899
C >
C > The actual building of roads devoted to motor cars is
C > not for the near future, in spite of many rumors to
C > that effect.
C > Harper's Weekly, August 2 1902
I have no actual quotations but in my little town we had sentiments
like:
Buildings on Broadway could never excede ten floors simply because
that's the limit for how high a hearty man can walk up the stairs.
The City can never excede some two million people because each person
must have his own horse. And two million horses will totally overwhelm
the streets and sewers.
That people will casually put themselves into steel cans and whoosh
thru pipes under the street is utterly absurd. (Such a air-powered
contraption was actually built in 1870 as a pilot project.)
But this pipe is SOLID; there's no hole down the center. How does the
light get thru it to the bulbs?
What a minute! You can't replace a guy's heart. that's the thing he
loves with!!
The only way to cross the ocean is by zeppelin or by steamer. An
airplane is too small, noisy, confined, boring, tiring to offer any
good alternative. (This one is arguable still true!)
---
* RoseReader 2.52B P005004
Subject: Re: Do You Know Anybody F
From: john.pazmino@moondog.com (JOHN PAZMINO)
Date: Wed, 13 Nov 96 10:48:00 -0500
BZ> From: bdzeiler@primenet.com (Brian Zeiler)
BZ> Subject: Re: Do You Know Anybody Famous? (was: Re: Space Summit (FWD from NSS)
BZ> Date: 9 Nov 1996 15:10:04 -0700
BZ> Organization: Project Sigma
BZ> >
BZ> >Not to defend the Soviet system, but this statement is at least partly
BZ> >falsified by Yuri Gagarin and the MIR space station. It seems to me
BZ> >that it might even be easier to invest resources in space if you're a
BZ> >monolithic totalitarian government than if you're accountable to your
BZ> >population (or stockholders) for how you spend your money.
BZ>
BZ> With a government like the Soviets' at the time, the main motivator
BZ> was furious competition with the US as well as ferocious nationalism.
BZ> Most countries seem to lack that sense of fierce pride these days, and
BZ> the culture of liberalism places a higher priority on cute social
BZ> programs than on long-term goals. So, not only do I not see a
BZ> motivation for US leadership in space exploration, but I see a lack of
BZ> interest from the entire population.
BZ>
BZ> In that sense, government is largely out of the picture. Private
BZ> funding is needed, or perhaps a philanthropic effort (like if Bill
BZ> Gates donated $1 billion for a Mars probe or something), or a
BZ> combination of both. The private support of SETI with Project Phoenix
BZ> is a good example of private wealth saving a project with eroding
BZ> government support and nonexistent public interest.
There IS a source of such huge donations just waiting to be accepted.
A cool one billion dollars was offered to America this past summer for
humane projects but the US State Dept rejected it. Perhaps if we ask
if we can use it for seeding a Mars exploration system, we can still
get that money.
---
* RoseReader 2.52B P005004
Subject: Re: When will the U.S. fi
From: john.pazmino@moondog.com (JOHN PAZMINO)
Date: Wed, 13 Nov 96 11:05:00 -0500
JL> From: jamesl@netcom.com (James Logajan)
JL> Subject: Re: When will the U.S. finally go metric?
JL> Organization: Lugoj Incorporated
JL> Date: Mon, 11 Nov 1996 01:15:47 GMT
JL> Finally, there are many subfields where the "base" units are not SI: the barn
JL> in nuclear physics; the Angstrom in atomic physics; setting c = 1 (speed of
JL> light) in relativistic kinematics; Parsec or light-year in astronomy, the
JL> electron volt in atomic/nuclear physics; and I'm sure one can find a few other
JL> examples like this in the sciences. And most of these are used universally in
JL> their respective fields.
In astronomy, such as for celestial mechanics within the solar system,
we use 'canonical units'. These are mass, length, &c; normalized to
'natural' units within the solar system. The Sun's mass is 1, the
Earth's orbit radius is 1, and so on. The equations for motion then
become simpler to manipulate and the results are often simpler to
interpret.
As for the lightyear, there is a mild agitation within the
profession to drop it in favor of straight metric measure. This isn't
getting nay great support, but once in a while I read a paper where
the distance to such and such a galaxy is some immense number of
meters.
Altho the lightyear is not a strict metric unit (nor is the
astronomical unit and the parsec, they are allowed as 'vernacular'
units. That is, they are defined in metric terms. This is different
from a 'deprecated' unit, which is a unit defined under an older,
like CGS, metric system.
You'll be surprised how many textbooks still use the CGS system,
because certainly in the high schools textbooks can be decades old.
When new books are purchased the trend is to replace the volatile
subjects, like social studies, and leave the static ones, like math
and physics, alone.
---
* RoseReader 2.52B P005004
Subject: Re: Moon Phases Inverted in S. Hemisphere???
From: pcp2g@karma.astro.Virginia.EDU (Twisted STISter)
Date: Wed, 13 Nov 1996 16:31:19 GMT
In article <3289436A.536E@ozemail.com.au>,
Jean-Joseph JACQ wrote:
>spooner wrote:
>>
>> rsmith@clysmic.com wrote:
>> >
>> > This has been diving me crazy! I need astronomical advise ...
>> >
>> > My question: are moon phases really "inverted" in the
>> > southern hemisphere? In other words, at the First Quarter moon,
>> > which side is lit, the right or left?? In the northern hemisphere,
>> > it's the right side. Is it really the left in Australia and points
>> > south? Do the local almanacs/calendars all reflect this, or use a
>> > "standard" moon picture (i.e. always the right side)?
>> >
>> > Thanks...Any help appreciated!
>> >
>> > Ralph Smith
>>
>> And also what happens at the equator? ;-)
>I can vouch that at the 1st quarter I see the moon's left side lit when
>I am standing up in Melbourne
This is correct. In the northern hemisphere (NH from here on out), the
Moon is always more or less to the south of the zenith. Facing south, the
Sun sets on your right, so the 1st quarter Moon is lit on the right.
In the SH, the Moon is more or less north of the zenith. Facing *north*,
west is on your left, so the left side of the Moon is lit at 1st quarter.
So it depends on which way you face to see the Moon. On the equator you can
take your pick! ;-)
Disclaimer: this assumes the Moon's orbit is the same as the ecliptic. It is
not, but is tipped by five degrees. Worse, the path of the ecliptic through
the sky appears to move as the year drags on; sometimes higher (winter nights
in NH), sometimes lower (summer nights in NH). At some northern latitudes
at certain times of the year the Moon can actually be north of the equator.
This confuses the issue somewhat. Caveat Emptor.
--
* Phil Plait, Pee Aytch Dee pcp2g@virginia.edu
* "Twinkies are not sentient in any way we can understand."
* My home page-- http://www.astro.virginia.edu/~pcp2g/home.html
* --> Humor, supernovae, Bad Science, and my daughter Zoe.
Subject: Re: Could intelligent extraterrestrial life exist in our galaxy?
From: JHOLL4@
Date: 13 Nov 1996 18:02:22 GMT
In <3288B7EB.4F8F@courier6.aero.org>, "Walter E. Shepherd" writes:
>JHOLL4@ wrote:
>> However, once a species becomes tool-using and
>> starts using tools to make better tools, a binary separation *does* form.
>But... I still think that even tool use comes in various shades.
>Chimpanzees use sticks to dig out termites... sea otters use rocks to
>crack shells... Moose use tree bark to help the shedding of their antlers.
Reread my quote. Once a species starts using tools *to make better
tools*, exponential growth occurs and quickly changes the behavior
of the toolmaker. The examples you give don't involve tools-to-make-
tools. A hammer, or a bellows, or a flint-and-steel are better examples
than a club or spear.
>We are definitely an impressive species, but not magical.
Of course not. There's nothing magical about it. But we
are still *qualitatively* different from other species on the planet.
I don't believe we're all that much more intelligent than the
highest primates in some abstract sense, but that small difference
has given us an incredible amount of control over our environment
in a way that even the highest ape could only fantasize about.
--Cathy Mancus
Subject: Re: Hale Bopp photos
From: pcp2g@karma.astro.Virginia.EDU (Twisted STISter)
Date: Wed, 13 Nov 1996 18:38:50 GMT
In article <01bbd0cf$ef55b5c0$98462399@default>,
Ray Laliberty wrote:
>Gary/Robyn Goodwin wrote in article
>...
>> In article <01bbd061$06d8d7a0$89462399@default>, "Ray Laliberty"
>> wrote:
>>
>> > From what I found by browsing through the Hubble datasets at
>> > http://marvel.stsci.edu,
>> > it appears that ALL Hubble Space Telescope datasets are subject to a
>> > wait period of 1 year. So exactly 1 year from the time the data
>> > was collected, NASA will release the data to the public,
>> > not necessarily including the finished photograph.
>>
>> there is a discrepancy in what you are saying. Last year the august,
>> september series of HB taken by the HST was posted within weeks. I agree
>> with Mark, the postings this year stop in May and those this year are
>> from ground based scopes.
>
>That may be true, but if you check the website, there is a release date of
>1 year after the date of observation. I think it's a dumb idea myself,
>but that's what I found.
Data taken by HST is indeed held private for 1 year. This 'embargo' gives
the astronomer that made the proposal a chance to reduce and analyze the data.
Time (and money!) on HST is very competitive, so it is in the community's
best interest to put the data on hold for a year. Getting a proposal passed
to observe on HST is an arduous and time-consuming task. If they simply
released the data immediately no one would ever propose anything!
Sometimes an image will be released before the year is up, but typically
that is an 8-bit JPEG or GIF image, which lacks the resolution of the
actual data. This makes for a pretty picture, and can even help other
astronomers, but keeps the actual high-resolution data in the hands of the
proposal astronomer. After a year the data are up for grabs.
The exceptions are when the astronomer releases the data early (rare), or
when a target or set of observations is taken for the general community.
Examples are the Deep Field image taken late last year that was immediately
released, or when a new camera goes on board and Early Release Observations
are made.
--
* Phil Plait, Pee Aytch Dee pcp2g@virginia.edu
* "Twinkies are not sentient in any way we can understand."
* My home page-- http://www.astro.virginia.edu/~pcp2g/home.html
* --> Humor, supernovae, Bad Science, and my daughter Zoe.
Subject: Re: Leonides
From: wayne.t.hally@tek.com (Wayne T. Hally)
Date: Wed, 13 Nov 1996 14:24:46 LOCAL
In article <56abe4$m73@dodge.eng.sc.rolm.com> lewisk@clipper.robadome.com (Lew Kurtz) writes:
>From: lewisk@clipper.robadome.com (Lew Kurtz)
>Subject: Re: Leonides
>Date: 12 Nov 1996 17:16:51 GMT
>In article <4OCpiXABtnhyEwvF@the-symposium.demon.co.uk>, Mandy Wright
> writes:
>>In article <32836F3B.631@platinum.com>, Phil Grainger
>> writes
>>>Hi all,
>>>
>>>Hopefully this is a relevant question for this newsgroup.......
>>>
>>>Last year my wife and I spent a few evenings, nights (and mornings)
>>>watching the Leonides meteor showers (shooting stars) in mid-November
>>>and we were wondering what the prospects were for this year.
>>>
>>>Aparrently they will be getting better and better each year for the next
>>>few years, but I'd appreciate some 'professional' opinions.
>>>
>>>Also, if anyone can remind me of the appropriate dates I'd be very
>>>grateful.
>>>
>>>TIA
>>>
>>>Phil & Nikki
>>Peak occurs November 17/18 1996, at 0200 UTC: look North East.
>>Estimated peak 60 per hour. Have it from John Mason that it will be a
>>mediocre show this year. Wrap up warm :-)
>>Regards
>>Mandy
>However:
>>SKY & TELESCOPE NEWS BULLETIN
>>NOVEMBER 8, 1996
>>
>>
>>READYING FOR THE LEONIDS
>>
>>The annual Leonid meteor shower should peak on the morning of November
>>17th. This year conditions will be ideal, weather permitting. The first-
>>quarter Moon sets by about 11 p.m. local time on the night of November
>>16th, and peak activity should come around 7:00 Universal Time on the
>>17th. This is also when the Earth crosses the orbit plane of Comet
>>55P/Tempel-Tuttle, the comet that is slowly crumbling apart to form the
>>Leonid meteor stream. The timing is excellent for North America,
>>especially the East. Next year a waning gibbous Moon will compromise the
>>view, so now is the last good time to monitor the shower's behavior before
>>1998 and 1999, years in which a Leonid meteor storm may return.
>>
>So is it the night of 16/17, or the night of 17/18?
>Lew
Lew,
The peak will occur on the night of the 16-17th. Saturday night/Sunday morning.
The radiant rises around midnight for most of the US, so you can observe
from then (0500 UT in EST time zone, 0800 UT for PST) until nearly 6AM (1100
UT in EST, 1400 UT in PST zone).
Wayne T Hally
NAMN,IMO,ALPO (just so you know that I have some idea of what I'm talking
about)
Subject: Re: REDSHIFT ??
From: ZELLNER@GSVMS2.CC.GASOU.EDU (BENJAMIN_H. ZELLNER)
Date: 13 Nov 1996 19:47:35 GMT
In <566a8j$tb2@camel4.mindspring.com> egibson407@pipeline.com writes:
> 1. If the universe started out very dense after the Big Bang, though
> physically very small, How much expansion has occurred? What
> velocity is our Galaxy traveling outward from the point of the 'Bang"?
> How far has our galaxy travelled?
>
> 2. If the light from these images comes from objects with a small
> fraction of the universe's age ( 12 - 18 Billion years) then has this
> light been traveling for 10.2 - 15.3 billion years? and if so, HOW DID
> WE GET HERE AHEAD OF IT to 'see' it?
Well, we've always been right here. Where else would we have been?
It makes absolutely no sense to pick a direction and distance in space,
and say "We used to be over there." The same applies for every other
co-moving observer.
> Is the velocity of our galaxy +
> the expansoin rate of the universe close to c?
>
> 3. Is it possible that the high Redshifted "proto - galaxies' in the
> Hubble deep field photos ( and all high redshifted objects) could
> actually be on the other side of the point of the 'Bang' and therefore
> be much further away?
So long as you keep thinking of the Big Bang as objects "traveling
outward" from a definite point in space with a "this side" and an
"other side", you are going to keep stumbling over logical paradoxes.
You are trying to sneak in the concept of a "center of expansion" at
some definite, uniquely defined physical location relative to some
hypothetical absolute space, and that's a non-physical concept.
The expansion rate can only be described in a differential sense:
the Hubble constant in km per sec per megaparsec, as a function of
time. But a question like "is the expansion rate of the universe
close to c?" makes no sense.
Ben
Subject: Re: REDSHIFT ??
From: ZELLNER@GSVMS2.CC.GASOU.EDU (BENJAMIN_H. ZELLNER)
Date: 13 Nov 1996 19:47:35 GMT
In <566a8j$tb2@camel4.mindspring.com> egibson407@pipeline.com writes:
> 1. If the universe started out very dense after the Big Bang, though
> physically very small, How much expansion has occurred? What
> velocity is our Galaxy traveling outward from the point of the 'Bang"?
> How far has our galaxy travelled?
>
> 2. If the light from these images comes from objects with a small
> fraction of the universe's age ( 12 - 18 Billion years) then has this
> light been traveling for 10.2 - 15.3 billion years? and if so, HOW DID
> WE GET HERE AHEAD OF IT to 'see' it?
Well, we've always been right here. Where else would we have been?
It makes absolutely no sense to pick a direction and distance in space,
and say "We used to be over there." The same applies for every other
co-moving observer.
> Is the velocity of our galaxy +
> the expansoin rate of the universe close to c?
>
> 3. Is it possible that the high Redshifted "proto - galaxies' in the
> Hubble deep field photos ( and all high redshifted objects) could
> actually be on the other side of the point of the 'Bang' and therefore
> be much further away?
So long as you keep thinking of the Big Bang as objects "traveling
outward" from a definite point in space with a "this side" and an
"other side", you are going to keep stumbling over logical paradoxes.
You are trying to sneak in the concept of a "center of expansion" at
some definite, uniquely defined physical location relative to some
hypothetical absolute space, and that's a non-physical concept.
The expansion rate can only be described in a differential sense:
the Hubble constant in km per sec per megaparsec, as a function of
time. But a question like "is the expansion rate of the universe
close to c?" makes no sense.
Ben