I am trying to develop a plausible universe for a story in which
observations confirmed Aristotle’s speculations on the structure of
the universe.  There would be several basic differences from our own,
but I am not quite sure where to begin except that gravity would most
likely not reach out very far. (I’m thinking not much farther than the
radius of the Sun.)  Although the story is obviously fantasy, it is
set in a present day to near future mileu and scientific details
should be believable.  If anyone could point me to where I could
direct my research, I would appreciate it.  Consider that my
scientific literacy is of a level that I read, understand, and enjoy
Scientific American.

Thank you,

Ami Chopine
a…@vcode.com

Math on website details relationship between orbits.
It is accurate (0.2%), but not fully understood by the author.
Some say it is due to chance, and it is generally unexplained.
Any experts to offer any help ?
Mail address is on page.
http://members.aol.com/astroequation carries full details of the math.
I am particularly concerned about the so called ‘Venus Equation’
Is it due to chance ?
What is the probability ?
Etc Etc.
Hope for some help.
Regards
E.Curtis
(Discovered Astroequation)

[Mod. note: web pages are not moderated, read at your own risk -- mjh]

Does anybody know where the results of some statistical
studies of local (with global expansion removed) velocities
of galaxies can be found? (Or maybe someone just knows
what is the average velocity of galaxies and what is the
standard deviation).

I found accidentally that local velocities depend on the
density of the universe and I’d like to check how close
to the real world my results are (if at all).

Any help will be appreciated.

– Jim

I’ve set the scene with a very short story because a mental picture
must be worth almost a thousand words.
——-

A space traveler heading to a destination on the Earth’s surface
approaches the Earth and the Moon, and while still some distance
away, will be drawn to the barrycenter of the Earth-Moon orbits,
which is of course the pivot point about which the two components
are in freefall around each other. That point being somewhere near
1700km beneath the Earth’s surface. But the traveler will be
increasingly drawn toward the Earth’s center as he approaches the
Earth.

The traveler’s destination is a point on the equator which is
exactly aligned through the barrycenter along a line which is
perpendicular to a line scribed between the Earth-Moon centers.

        . . I
      .     I .
 Earth.   –I-.——————OMoon
        . . I
            ^Destination

When the traveler arrives at his destination he knows that he is
not in freefall around the pivot point and thus expects that gravity
will not be pulling him directly to the Earth’s center, but will be
pulling him to a point slightly shifted toward the Moon, located
somewhere along the line joining the Earth-Moon centers.

With the apparatus described below, my intention was to pinpoint
the location of that point.

                           UP
                Mirrors / – - / -<<<HeNe laser source.
                        .     x
 < WEST  S =            .     .   EAST >
         c =    =       .     .
         r =   =   = ()=/ – - /
        ee =    =            <->
         n =
                          DOWN

       " () " is a fiber optic collimator lense.
       " x " represents the knife edge pivot point for the
             pendulum that carries the movable mirror.

>From the diagram it should be fairly obvious that if the mirror

which is carried on the movable arm shifts 633nm, that action will
record one fringe shift on the screen. The arm length was .3 meters.
A 633nm shift over the .3 meter arm length expands to 13.5 meters
at the Earth’s center. Through one complete revolution of the
Earth’s surface (with the apparatus) I had expected to find **many**
more than one fringe shift across the screen.

Seismic activity was reasonably overcome by suspending the whole
apparatus between tension springs. The springs were covered with
grease to stop an endless resonance within the spring setup.
Induction motion dampeners succeeded in bringing the never ending
movement of the arm and the suspended apparatus into some sort of
order.

There were some positive readings, but they were canceled by just
as many negative readings. The inaccuracy could all be attributed
to temperature variation. With that problem under control, I could
now have confidence in what I was seeing.

As the apparatus passes through one alignment with the barrycenter
the pendulum will be leaning slightly toward the Moon, and will have
caused a fringe shift in one direction. The barrycenter alignment
on the other side of the Earth finds the apparatus pointing in the
opposite direction relative to the Moon, so the fringe shift is in
the opposite direction. In a 24 hour test, movement of the pendulum
couldn’t be detected, within the accuracy of the setup. The pendulum
was clearly pointing to a point near the Earth’s center which hadn’t
moved more than a few meters from the center. I found this quite
bewildering.

Disregarding the fact that the Moon’s influence on the arm would
be reduced according to the arm’s pointing angle when the apparatus
intersects with the barrycenter line. This is my rather simplistic
math justification for all of this;
Since there are 81 Moon masses per 1 Earth mass, the Moon’s gravity
rate at an Earth distance from the Moon is  ((1/81)*9.8)/384403^2
 =  8.188E-13 m/sec^2.  The ratio between the pull of gravity
between the two is  8.188E-13/9.8  =  8.355E-14 to 1 . The mirror
at the end of a 1 meter pendulum would be shifted toward the Moon
by 8.355E-14m. That only represents 535 nanometers at the Earth’s
center, which isn’t even 1 HeNe laser wave length. It seems
ridiculously minute.

I’m posting this prior to dismantling the setup just in case I’ve
missed something.

–
Max Keon

The following is an almost exact copy of a message I posted a few
months ago at soc.history.ancient, but it turned out to be the wrong
place.

H. Hunger, Astrological Reports to Assyrian Kings, Helsinki University
Press 1992. This is a collection of 567 tablets. The usual form is
first a portent in the sky and then some important event. It is
generally accepted that one tablet describes a real event at the
invasion of Elam in the 12th century BCE, because in this case the
name of the king is given. I have been in contact with the editor and
he don’t believe the rest describe anything real. He believes that
unrelated items are described on the same tablet.
   I disagree. To check the solar eclipses was easy because
calculations of ancient solar eclipses have been published. I think
those published on these tablets are based upon real cases. For a few
other phenomena I have made comparisons with other ancient material.
And again I believe we are dealing with phenomena which are real.
   Many tablets are so badly broken that they are useless, but even
as few as 10 good records would make a significant contribution to our
knowledge of ancient astronomy. So I think it would be a good idea if
more people bothered about this material.
   As usual, I welcome follow-up postings. Thank you very much in
advance. And again thanks for follow-up postings and messages to my
mailbox after my earlier postings.
G H I Johansson

Hi Ive been asked to write a short but comprehencive report and talk on the
below CMB (cosmic microwave backround) question. I would be extremely
grateful if someone could help, I’m having difficulty in understanding it
myself let alone write about it.

" Estimate the energy in a comoving volume and show that the energy is not
conserved. Where is the energy going ?

Thanks a lot

Luke

[Mod. note: as with the other homework question posted recently,
please try to give hints when following up rather than writing a
complete answer -- mjh]

Hey everyone,

I’m new here but looking for a quick fix.
Hope someone can help me answer this exam question,

1. Describe the evolutionary changes that the Sun will go through from
now until its final state. Be sure to discuss changes in both its
outward appearance and its internal structure. NOTE: Please limit
yourself to one side of a single page (single-spaced). Additional
material will not be marked! [total: 15 marks]

Thanks.
I’ve got lots of data on it but can’t seem to fit it on one page!
What’s important, what should I leave out????

THANKS!!!!!!

First, let me apologize for what I am about to say. My entire
education on astrophysics has been gleaned from decased of Cosmos
reruns, Star Trek, and Nova. I appreciate your patience in tolerating
this, and hopefully, providing some direction for my research.

I have a questions based on the following assertions:
1. The galaxy is spinning, ergo, the sun is moving through space
2. The earth as its moves about the sun is also moving through space
in the general direction of the Sun’s movement.
3. If these are true, it then follows that at times the earth passes
back over its path it once held in the past, as well as passes over
the path it will take in the future.
4. If the sun is circling the galactic center, then it must be
travelling in a curved trajectory.

So my questions are these:
1. At what rate does the sun pass through space, or orbit the galactic
center/locus? And what is its trajectory?
2. What is the rate that the earth orbits the sun?
3. How can I calculate when the earth passes over its past and future
positions?

Any and all help appreciated.

http://www.planetary.org/html/news/articlearchive/headlines/2001/neog…

Planetary Society Now Accepting Applications for the next round of
Shoemaker NEO Grants

by Melanie Melton
Planetary Society
December 3 , 2001

The Planetary Society is now accepting applications for the next round of
Shoemaker Near Earth Object (NEO) grants.

Those amateur or professional astronomers interested in studying Near Earth
Objects can apply for the grant by filling out an application form and sending
it to The Planetary Society by March 31, 2002.

The application form can by found here:

http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOG…

The Shoemaker NEO grant program was established by the Society in 1997, in an
effort to advance the study of Near Earth Objects. Grant recipients in the past
have been both individuals and groups, amateur and professional astronomers, all
interested in studying asteroids and comets in Earth’s vicinity.

For this round of grants, the Society’s international advisory group reviewing
the proposals will be considering three different categories: Observation
Programs, NEO Research Programs, and International Collaboration in NEO
Observations.

With several asteroid detection programs in place at major observatories around
the country, there has been a dramatic increase in asteroid detection within the
last year, creating a long list of objects in need of follow-up observations. As
a result, special consideration will be given to observers interested in
conducting follow-up NEO observations, especially those capable of detecting
objects fainter than magnitude V= 19.5 or so.

   * For more information about the Shoemaker NEO Grant Program:
     http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOG…
   * For NEO Grant Guidelines:
     http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOG…
   * For the application form:
     http://www.planetary.org/html/neo/SocietyProjects/ShoemakerGrant/NEOG…

At page 501 of Nature no 6863 29 Nov 2001
"A new spin on black-hole masses" we read:
"The apparent speed is a well-known optical illusion caused
by special relativity, but the true velocity of the jet material
is calculated to be greater than 90% of the speed of light"

IMO an optical illusion and SR have nothing in common.
The apparent speed is either an optical illusion or it can be
explained by SR but it can not be both

A different line of reasoning is that SR (part of)
is an optical illusion but I doubt that.

When you will go to my home page
http://users.pandora.be/nicvroom/
and you select train experiment part 1 or
program 4
I argue that when you move a rod away from you
its length appears shortened
and when you move a rod towards you
its length appears longer
however both effects are optical illusions.
The same for effects are for speed
ie it is an optical illusion and has nothing to do with SR

Or something of my understanding is wrong.

One very interesting piece of information
are the MEASURED delta z values from:
1  GRS1915+105 the source microquasar.
2. The approaching component
3. The receding component

The original article in Nature 6492 at page 48
I read:
"The spectral lines arising in the approaching and
receding components should have mean redshifts
of 0.75 and 2.36 respectivily (as a result of relativistic
effects both should appear redshifted)"

I interpret this as, that as of 1994, the redshift values
were not measured.

In relation to the Big Bang if you study the distance
as for example quasars at z=3 you should be carefull
not to measure the dz of the receding components
of the quasar but the dz of the real quasar

Nicolaas Vroom

[Mod. note: in quasars, as opposed to Galactic microquasars, the jets
are synchrotron emission and so do not contain spectral lines.
You're right, however, that the optical illusion that gives rise to
apparent superluminal motion has nothing much to do with SR. See
http://sciastro.astronomy.net/sci.astro.8.FAQ , question 8 -- mjh]