More undiscovered bodies out there?

Outer edges of our solar system were disturbed by passing star, may
contain more bodies out there-
http://www.spaceflightnow.com/news/n0412/01passingstar/

Didn't Ahad say something similar in his Oort cloud mission to Alpha
Cen back in August:

"From a dynamical perspective, as predicted by Isaac Newton's well
known gravity equation:

F=G(m1*m2)/r^2

the Sun's sphere of influence reaches well beyond the distance of
Alpha Centauri. Add to this the fact that the Sun has made some 20
revloutions around the Milky Way galaxy since its formation [4,500
million years (age) / 225 million years (galactic rotation period)]
and within that time, it is certain to have passed through dense gas
clouds, star and planet forming regions, brushing the outer edges of
proto-planetary disks of other stars, attracting and shedding swarms
of comets... There is every reason to be hopeful of swarms of comets
existing much further out than those within current detection range of
our instruments. "

This quote from:
http://uk.geocities.com/aa_spaceagen...ropulsion.html

"dreamer" wrote in message
m...
Outer edges of our solar system were disturbed by passing star, may
contain more bodies out there-
http://www.spaceflightnow.com/news/n0412/01passingstar/

Didn't Ahad say something similar in his Oort cloud mission to Alpha
Cen back in August:

"From a dynamical perspective, as predicted by Isaac Newton's well
known gravity equation:

F=G(m1*m2)/r^2

the Sun's sphere of influence reaches well beyond the distance of
Alpha Centauri.

The Sun's gravitational sphere of influence ends when the
infuence of other bodies becomes greater than its own. What's
the density of stars in the neighborhood of the Sun? It's
roughly 25 star systems in a volume of roughly 10,000 cubic
light years. So we have about 13.6 cubic light years per star
on average. Mean distance between stars will be given by the
cube root of the volume per star, or about 7.2 light years.

Assuming an average mass for the stars, then the gravitational
sphere of influence won't extend past the halfway point to the
next star. So in our stellar neighborhood the radius of the
sphere of influence will be about 3.6 ly, which is not quite as
far as Alpha Centauri at 4.3 ly.

Add to this the fact that the Sun has made some 20
revloutions around the Milky Way galaxy since its formation [4,500
million years (age) / 225 million years (galactic rotation period)]
and within that time, it is certain to have passed through dense gas
clouds, star and planet forming regions, brushing the outer edges of
proto-planetary disks of other stars, attracting and shedding swarms
of comets... There is every reason to be hopeful of swarms of comets
existing much further out than those within current detection range of
our instruments. "

The above seems to assume that the rest of the galaxy is motionless
while the Sun sails through it. The stars and other contents of the
local volume of space surrounding the Sun can have similar periods
of revolution around the galactic core, and so it is possible that
the Sun takes its environment with it as it goes. Now, this is not
necessarily true, but it is possible. Declaring that "it is certain
to havbe passed through dense gas clouds, star and planet forming
regions,..." seems to be taking a bit of a leap.


This quote from:
http://uk.geocities.com/aa_spaceagen...ropulsion.html

But if we're to believe the cosmologists, stars only represent about 1%
of the total matter. Another 4% is interstellar gas and neutrinos, and
the remaining 95% is Unobservium. Deep thinkers and mathematicians tell
us Unobservium is made up of 23% dark matter, and 72% dark energy. The
dark matter cannot be observed, but it supposedly has profound
gravitational influence. And the all-important dark energy is crucial as
it fills an empty spot in the curvature equations.

So your stellar "spheres of influence model" must be adjusted
accordingly. As we sit here today, a lump of dark matter may be tugging
at ol' Sol's happy little orbit, or stirring the Oort cloud into mischief!

Personally, I'm a little skeptical of the latest theories. I prefer the
traditional model where the universe is carried on the back of a rather
large turtle.



Greg Neill wrote:

"dreamer" wrote in message
m...

Outer edges of our solar system were disturbed by passing star, may
contain more bodies out there-
http://www.spaceflightnow.com/news/n0412/01passingstar/

Didn't Ahad say something similar in his Oort cloud mission to Alpha
Cen back in August:

"From a dynamical perspective, as predicted by Isaac Newton's well
known gravity equation:

F=G(m1*m2)/r^2

the Sun's sphere of influence reaches well beyond the distance of
Alpha Centauri.


The Sun's gravitational sphere of influence ends when the
infuence of other bodies becomes greater than its own. What's
the density of stars in the neighborhood of the Sun? It's
roughly 25 star systems in a volume of roughly 10,000 cubic
light years. So we have about 13.6 cubic light years per star
on average. Mean distance between stars will be given by the
cube root of the volume per star, or about 7.2 light years.

Assuming an average mass for the stars, then the gravitational
sphere of influence won't extend past the halfway point to the
next star. So in our stellar neighborhood the radius of the
sphere of influence will be about 3.6 ly, which is not quite as
far as Alpha Centauri at 4.3 ly.


Add to this the fact that the Sun has made some 20
revloutions around the Milky Way galaxy since its formation [4,500
million years (age) / 225 million years (galactic rotation period)]
and within that time, it is certain to have passed through dense gas
clouds, star and planet forming regions, brushing the outer edges of
proto-planetary disks of other stars, attracting and shedding swarms
of comets... There is every reason to be hopeful of swarms of comets
existing much further out than those within current detection range of
our instruments. "


The above seems to assume that the rest of the galaxy is motionless
while the Sun sails through it. The stars and other contents of the
local volume of space surrounding the Sun can have similar periods
of revolution around the galactic core, and so it is possible that
the Sun takes its environment with it as it goes. Now, this is not
necessarily true, but it is possible. Declaring that "it is certain
to havbe passed through dense gas clouds, star and planet forming
regions,..." seems to be taking a bit of a leap.


This quote from:
http://uk.geocities.com/aa_spaceagen...ropulsion.html

"Tim Killian" wrote in message
...
But if we're to believe the cosmologists, stars only represent about 1%
of the total matter. Another 4% is interstellar gas and neutrinos, and
the remaining 95% is Unobservium. Deep thinkers and mathematicians tell
us Unobservium is made up of 23% dark matter, and 72% dark energy. The
dark matter cannot be observed, but it supposedly has profound
gravitational influence. And the all-important dark energy is crucial as
it fills an empty spot in the curvature equations.

So your stellar "spheres of influence model" must be adjusted
accordingly. As we sit here today, a lump of dark matter may be tugging
at ol' Sol's happy little orbit, or stirring the Oort cloud into mischief!

If the background mass is more or less uniformly distributed, it will
not influence the spheres of influence (so to speak) of the "point source"
stars. If something substantial was tugging differentially on Sol, it would
have shown up in the Hipparcos results, no?


Personally, I'm a little skeptical of the latest theories. I prefer the
traditional model where the universe is carried on the back of a rather
large turtle.

:-)

On Mon, 13 Dec 2004 11:09:25 -0500, "Greg Neill"
wrote:

Personally, I'm a little skeptical of the latest theories. I prefer the
traditional model where the universe is carried on the back of a rather
large turtle.

:-)

Reminded me of this....
http://www.the-funneled-web.com/hawking.htm

On Mon, 13 Dec 2004 09:50:14 -0500, "Greg Neill"
wrote:

The Sun's gravitational sphere of influence ends when the
infuence of other bodies becomes greater than its own.

That is not really true. The sun actually exerts more than twice the
force on the moon as does the earth, but that doesn't mean the earth
has no influence on the moon. Gravity does go "forever". At some
point the effect of any one body is hard to pick out, but that doesn't
mean it doesn't exist.

William Hamblen wrote:
That is not really true. The sun actually exerts more than twice the
force on the moon as does the earth, but that doesn't mean the earth
has no influence on the moon. Gravity does go "forever". At some
point the effect of any one body is hard to pick out, but that doesn't
mean it doesn't exist.

A good guide to influence is tidal strength. For instance, the Sun's
force on the Moon may be twice that of the Earth's, but its tidal
influence is smaller by a factor of a couple of hundred. This suggests
(correctly) that the Earth-Moon system can, to a first approximation,
be considered in isolation, and then the Sun's influence can be counted
in as a perturbation.

The fact that the Sun's gravitation *force* is twice that of the Earth
merely means that the Earth-Moon system orbits the Sun. It could be
that it's directly related to the fact that the Moon's orbit around
the Sun is everywhere concave inward, but I haven't thought that through.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

On Tue, 14 Dec 2004 07:11:49 +0000 (UTC), (Brian Tung)
wrote:

The fact that the Sun's gravitation *force* is twice that of the Earth
merely means that the Earth-Moon system orbits the Sun. It could be
that it's directly related to the fact that the Moon's orbit around
the Sun is everywhere concave inward, but I haven't thought that through.

That's exactly the reason why. If the pull of the Earth were greater
than the pull of the Sun, the acceleration of the Moon at the time of
the New Moon would be toward the Earth, and the orbit would be curved
toward the Earth. If the pull of the Sun were greater than that of
the Earth, the acceleration of the Moon would be toward the Sun and
the orbit would be curved toward the Sun, which it is.

With you all the way on the Turtle model
"Tim Killian" wrote in message
...
But if we're to believe the cosmologists, stars only represent about 1% of
the total matter. Another 4% is interstellar gas and neutrinos, and the
remaining 95% is Unobservium. Deep thinkers and mathematicians tell us
Unobservium is made up of 23% dark matter, and 72% dark energy. The dark
matter cannot be observed, but it supposedly has profound gravitational
influence. And the all-important dark energy is crucial as it fills an
empty spot in the curvature equations.

So your stellar "spheres of influence model" must be adjusted accordingly.
As we sit here today, a lump of dark matter may be tugging at ol' Sol's
happy little orbit, or stirring the Oort cloud into mischief!

Personally, I'm a little skeptical of the latest theories. I prefer the
traditional model where the universe is carried on the back of a rather
large turtle.



Greg Neill wrote:

"dreamer" wrote in message
m...

Outer edges of our solar system were disturbed by passing star, may
contain more bodies out there-
http://www.spaceflightnow.com/news/n0412/01passingstar/

Didn't Ahad say something similar in his Oort cloud mission to Alpha
Cen back in August:

"From a dynamical perspective, as predicted by Isaac Newton's well
known gravity equation:

F=G(m1*m2)/r^2

the Sun's sphere of influence reaches well beyond the distance of
Alpha Centauri.


The Sun's gravitational sphere of influence ends when the
infuence of other bodies becomes greater than its own. What's
the density of stars in the neighborhood of the Sun? It's
roughly 25 star systems in a volume of roughly 10,000 cubic
light years. So we have about 13.6 cubic light years per star
on average. Mean distance between stars will be given by the
cube root of the volume per star, or about 7.2 light years.

Assuming an average mass for the stars, then the gravitational
sphere of influence won't extend past the halfway point to the
next star. So in our stellar neighborhood the radius of the
sphere of influence will be about 3.6 ly, which is not quite as
far as Alpha Centauri at 4.3 ly.


Add to this the fact that the Sun has made some 20
revloutions around the Milky Way galaxy since its formation [4,500
million years (age) / 225 million years (galactic rotation period)]
and within that time, it is certain to have passed through dense gas
clouds, star and planet forming regions, brushing the outer edges of
proto-planetary disks of other stars, attracting and shedding swarms
of comets... There is every reason to be hopeful of swarms of comets
existing much further out than those within current detection range of
our instruments. "


The above seems to assume that the rest of the galaxy is motionless
while the Sun sails through it. The stars and other contents of the
local volume of space surrounding the Sun can have similar periods
of revolution around the galactic core, and so it is possible that
the Sun takes its environment with it as it goes. Now, this is not
necessarily true, but it is possible. Declaring that "it is certain
to havbe passed through dense gas clouds, star and planet forming
regions,..." seems to be taking a bit of a leap.


This quote from:
http://uk.geocities.com/aa_spaceagen...ropulsion.html

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