Dark matter

"moogle33" writes:

Is it possible to measure the average mass and density of the Oort cloud? I
would imagine that the mass would probably be the equivalent to a large
planet this alone would not make up enough mass to count for all the dark
matter.

The total mass of the Oort cloud is indeed small compared even to a large planet,
let alone a small star, and could not possibly account for the "Dark Matter,"
which exceeds the amount of "ordinary" matter by nearly ten to one.

Furthermore, there are very strong reasons to believe that _whatever_ the
"Dark Matter" is, one thing it _CANNOT_ possibly be is any form of "normal"
matter, because that much "normal" matter would screw up the observed
abundances of the lightest chemical elements and isotopes that were created
during the Big Bang, such as helium, lithium, and deuterium.


If our sun has a belt of asteroids that where ejected when our star ignited

That is =NOT= how the asteroids were formed! The asteroids are leftovers
from the protoplanetary disk that were prevented from coalescing into
larger objects because the giant planet Jupiter's gravitation perturbed
their orbits so badly that most of the matter in that region was ejected
before it could collide and merge into a protoplanet.


it is possible that every star has a belt of asteroids.

Highly unlikely, since it requires that a supergiant planet be in a nearly
circular orbit at roughly the right distance from its star. We now know
that, while many star systems contain supergiant planets as large or even
much larger than Jupiter, most of them are in highly eccentric orbits
that would hopelessly perturb the orbits of any asteroid belt, ejecting
most small objects from the star system.


I know one example is bad statistics but this made me think that maybe we
are not seeing all the light from the stars because a belt of asteroids
would be absorbing the light from the star so maybe every star is infact
larger than we think.

I'm sorry, but space is very, VERY, =VERY= big, and asteroids are
microscopiclly small compared to stars; they simply could =NOT=
"obscure" a significant amount of starlight!

Asteroid belts are =NOT= like the teeming bee-swarms of tumbling rocks
you see in bad SF movies and TV shows: Even if you were sitting in the
middle of the _densest_ part of the asteroid belt, you would need a
_VERY_ good telescope to resolve asteroids as anything but dim,
far-away pinpoints of light.

Furthermore, if you _really_ wanted to "obscure" the light of a star,
you would =NOT= use "asteroids" --- you would use dust. And you would not
want it in a "belt," which would only obscure light if the narrow plane
of the belt happened to accidentally also be aligned with your line of
sight to the star (which would be highly unlikely): You would want the dust
to be dispered fairly uniformly througout all of space.

However, I assure you that the problem is =NOT= merely that some of the
starlight is "obscured" by something. The amount of mass out there
is _TEN TIMES LARGER_ than what can be accounted for in stars and gas.
Furthermore, we have independent methods of measuring the masses of stars,
particularly the ones that have planets. Finally, as I mentioned earlier,
whatever that mass out there is, I can't be "normal" matter, because
that much "normal" matter would screw up the observed abundances of the
lightest chemical elements and isotopes created during the Big Bang.


-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'

On 26 Apr 2004 00:24:09 -0500,
(Gordon D. Pusch) wrote:

The total mass of the Oort cloud is indeed small compared even to a large planet,
let alone a small star, and could not possibly account for the "Dark Matter,"
which exceeds the amount of "ordinary" matter by nearly ten to one.

Furthermore, there are very strong reasons to believe that _whatever_ the
"Dark Matter" is, one thing it _CANNOT_ possibly be is any form of "normal"
matter, because that much "normal" matter would screw up the observed
abundances of the lightest chemical elements and isotopes that were created
during the Big Bang, such as helium, lithium, and deuterium.

Chuckle...we don't know what `dark _matter_ ' is but we conclude it
cannot be ordinary or normal because that would screw up our
observations even though we can not observe it ...chuckle

Modern astronomy is getting to be a real pain with uncertainty,
strings, 11 dimentions, an strange `matter' that is not observed. Now
we can move to a consideration of dark energy and anti-matter of
which we occasionally get a fleeting glimpse . Oh for the happy days
in pursuit of the bashful nutrenos. I believe I will hid in a
singularity or a worm hole - both elusive in their own right.

vonroach wrote:

Chuckle...we don't know what `dark _matter_ ' is but we conclude it
cannot be ordinary or normal because that would screw up our
observations even though we can not observe it ...chuckle

It would have affected the isotopic composition of the matter
that we *can* see.

There's a similarly motivated cosmological upper bound on
the number of neutrino generations (since superceded by
tighter bounds from the decay rate of the Z boson.)

Paul

vonroach writes:

On 26 Apr 2004 00:24:09 -0500,
(Gordon D. Pusch) wrote:

The total mass of the Oort cloud is indeed small compared even to a large planet,
let alone a small star, and could not possibly account for the "Dark Matter,"
which exceeds the amount of "ordinary" matter by nearly ten to one.

Furthermore, there are very strong reasons to believe that _whatever_ the
"Dark Matter" is, one thing it _CANNOT_ possibly be is any form of "normal"
matter, because that much "normal" matter would screw up the observed
abundances of the lightest chemical elements and isotopes that were created
during the Big Bang, such as helium, lithium, and deuterium.

Chuckle...we don't know what `dark _matter_ ' is but we conclude it
cannot be ordinary or normal because that would screw up our
observations even though we can not observe it ...chuckle

You confuse "cannot _see_ dark matter because it does not emit light"
with the completely different statement "we cannot observe dark matter
_AT ALL_, by _ANY_ method;" the former statemnet is true, however the
latter statement is false. While we cannot _see_ "Dark Matter" optically,
we can still detect it indirectly by the gravitational forces it exerts,
and by the other influences it has on processes that we _can_ observe.
Indirect observations are hardly a new thing in science; in fact,
very little that science now routinely deals with, from radiation
outside the visible spectrum to subatomic particles and forces
can be _directly_ perceived as primary sense impressions. If science were
limited only to what we could see, hear, smell, touch, and taste directly,
then like Ernst Mach we would still be denying the existence of atoms,
like early alchemists we would still be routinely poisoning ourselves
tasting chemicals in an attempt to identify them, and we would be unable
to make an _quantitative_ measurement at all, because human senses are
simply =NOT= sufficiently sensitive to do more than the most trivial sorts
of scientific experiments with!

Whether you like it or not, modern science _necessarily_ rests on an
elaborate multi-layered structure of deductive and inductive inference;
otherwise it would not be able to deal with phenomena so many many times
removed from that which we can directly see, hear, smell, touch, or taste
using our unaided senses.


-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'

"vonroach" wrote in message
...
On 26 Apr 2004 00:24:09 -0500,
(Gordon D. Pusch) wrote:

The total mass of the Oort cloud is indeed small compared even to a large
planet,
let alone a small star, and could not possibly account for the "Dark
Matter,"
which exceeds the amount of "ordinary" matter by nearly ten to one.

Furthermore, there are very strong reasons to believe that _whatever_ the
"Dark Matter" is, one thing it _CANNOT_ possibly be is any form of
"normal"
matter, because that much "normal" matter would screw up the observed
abundances of the lightest chemical elements and isotopes that were
created
during the Big Bang, such as helium, lithium, and deuterium.

Chuckle...we don't know what `dark _matter_ ' is but we conclude it
cannot be ordinary or normal because that would screw up our
observations even though we can not observe it ...chuckle

Dark matter is observed via gravitational lensing on a regular basis.

Modern astronomy is getting to be a real pain with uncertainty,
strings, 11 dimentions, an strange `matter' that is not observed. Now
we can move to a consideration of dark energy and anti-matter of
which we occasionally get a fleeting glimpse . Oh for the happy days
in pursuit of the bashful nutrenos. I believe I will hid in a
singularity or a worm hole - both elusive in their own right.

Anti-matter is quite easily created in particle accelerators. Astronomy
isn't the field where people are talking about strings and 11 dimensions.

Jason