Anyone Here REALLY Believe In Dark Matter?
Bret Cahill
Bret Cahill
Wordsmith
Bret Cahill wrote:
> Couldn't something else provide a rationalization?
>
>
> Bret Cahill
It's as good a hypothesis as any. Something's got to explain the
"glue" that holds galaxies together, right?
W : )
Immortalist
"Bret Cahill" <BretC...@aol.com> wrote in message
news:1141851968.6...@p10g2000cwp.googlegroups.com...
> Couldn't something else provide a rationalization?
>
Default logic can express facts like "by default, something is true"; by
contrast, standard logic can only express that something is true or that
something is false. This is a problem because reasoning often involves facts
that are true in the majority of cases but not always. A classical example
is: "birds typically fly". This rule can be expressed in standard logic
either by "all birds fly", which is inconsistent with the fact that penguins
do not fly, or by "all birds that are not penguins and not ostriches and ...
fly", which requires all exceptions to the rule to be specified. Default
logic aims at formalizing inference rules like this one without explicitly
mentioning all their exceptions.
http://en.wikipedia.org/wiki/Default_logic
The dark matter hypothesis aims to explain several anomalous astronomical
observations, such as anomalies in the rotational speed of galaxies (the
galaxy rotation problem). Estimates of the amount of matter present in
galaxies, based on gravitational effects, consistently suggest that there is
far more matter than is directly observable. The existence of dark matter
would also resolve a number of inconsistencies in the Big Bang theory, and
is crucial for structure formation.
http://en.wikipedia.org/wiki/Dark_matter
I was watching this interview the third time and E.O. Wilson was talking
about how creationists claim that becasue there are weaknesses in particular
parts of evolutionary theory that this alone makes it follow that god
exists. How much is the dark matter theory like this default theory?
http://meaningoflife.tv/video.php?speaker=wilson&topic=complete
Sounds almost like an An Ad Hominem which is a general category of fallacies
in which a claim or argument is rejected on the basis of some irrelevant
fact about the author of or the person presenting the claim or argument. But
this applies to people not theories, anyone know the correct fallacy to
compare it with?
http://www.nizkor.org/features/fallacies/
>
> Bret Cahill
>
George Dishman
"Bret Cahill" <BretC...@aol.com> wrote in message
news:1141851968.6...@p10g2000cwp.googlegroups.com...
There have been recent papers on VirgoHI 21 suggesting
it is possibly a galaxy made almost entirely of dark
matter with about 0.2% of hydrogen, just enough to make
it detectable. The findings are still tentative though.
http://www.pparc.ac.uk/Nw/d_galaxy2.asp
George
Bret Cahill
shiny?
Chicken gizzards are pretty dark. Why not have fried chicken gizzard
matter?
Bret Cahill
Wordsmith
Cosmic background radiation would probably render the FCGM useless in
performing its cosmological task. It would be a tad, well, overcooked.
W : )
Llanzlan Klazmon
@p10g2000cwp.googlegroups.com:
> Couldn't something else provide a rationalization?
At present dark matter is a useful hypothesis to explain an observed
phenomena. It is very much an open question. Some other ideas have been
tried. Look up MOND. I also heard that a Chinese group have recently come
up with some sort of variation of general relativity that seeks to give an
alternative explanation. All of these ideas have to be measured and tested
against the available evidence. You don't "believe" in scientific
explanations, you ask how well they are supported by the evidence.
Klazmon.
>
>
> Bret Cahill
>
dave
Bret Cahill wrote:
> Couldn't something else provide a rationalization?
Here's something I've wondered about.
The "mass function" tells us the relative density of stars in the
galaxy with a given mass. The function is something like c*M^(-2.35),
where c is some constant. Thus, stars with half the sun's mass are
about 5 times as numerous as stars with the sun's mass, and stars with
a quarter the sun's mass are about 25 times as numerous. The mass
function must break down for very small mass objects, since it predicts
there would be infinite mass in the galaxy if it held all the way down
to zero mass. But if it is valid further down the mass scale than
astronomers currently believe, it seems that it could account for dark
matter.
Comments?
Brian Fletcher
"Wordsmith" <word...@rocketmail.com> wrote in message
news:1141852190.3...@i39g2000cwa.googlegroups.com...
David Deuche's book The Fabric Of The Universe (a quantum physicist) puts
forward an excellent explanation in layman's terms.
BOfL
Brian Fletcher
We do 'have' such matter.Another example of our ambiguous language, our
attempt to label reality beyond our reference capacity is impossible. Like
the wise fish trying to describe to the 'school' :-( ....what lies beyond
the water. He can only compare it with something they can identify, and then
add "its not that".
BOfL
Brian Fletcher
"Llanzlan Klazmon" <Kla...@llurdiaxorb.govt> wrote in message
news:Xns978179E7C7C95Kl...@203.97.37.6...
Its not as simple as that these days.
Watching the random course of a single photon, defying the 'belief ' that
light travels in a straight line (difficult when space is
curved)...demonstrates "something is going on".
In that sense , not much has changed.
Ironically, many metaphysicians are watching their (for want of a better
word,) 'philosophical' views being confirmed. Some are traditional
scientists, some not.
They still "see" what is happening.
BOfL
Bret Cahill
It will require some night time rock climbing but we need to sneak up
on some observatories to make sure they aren't just partying all night.
They probably think they are pretty safe doing LSD, mushrooms, peyote,
etc. on top of a mountain with only one 26' wide access road.
Bret Cahill
Spaceman
"Bret Cahill" <BretC...@aol.com> wrote in message
news:1141851968.6...@p10g2000cwp.googlegroups.com...
> Couldn't something else provide a rationalization?
Sure,
Try this thought.
Space is full of the same stuff electrons and protons etc..
are made of and that stuff is spread out so far
it is only detectable when compressed.
Electrons and protons etc.) are like clouds of extremely tiny matter
Place a cloud into a lesser pressure area
and it will expand to the point that you can no longer "see" it anymore.
and it will not "act like a cloud either".
This "dark matter" is simply matter that would normally make up electrons,
protons ,etc but expanded beyond detection by simple electron..etc detection
methods.
:)
Too simple huh?
It also explains gravity.
Simple yet complicated differentials in pressure with no limit to the
"smallest" pressure or smallest "size" of matter.
:)
--
James M Driscoll Jr
Spaceman
Bret Cahill
to Safford right now for my expose.
Bret Cahill
George Dishman
Bret Cahill wrote:
> Why just have ordinary and dark?
Ordinary matter interacts with EM, "dark matter" is so
called because almost the only thing we know about it
is that it doesn't interact with EM but does have a
gravitational influence.
> Why not also have red, clear and shiny?
>
> Chicken gizzards are pretty dark.
Those are optical properties so imply an EM interaction.
> Why not have fried chicken gizzard matter?
Why ask a question if you don't want to know the answer?
George
Brian Fletcher
"George Dishman" <geo...@briar.demon.co.uk> wrote in message
news:1141902918.5...@i40g2000cwc.googlegroups.com...
I spent half my life trying to work that one out :-)
Some people in certain circumstances, act as an unconscious catalyst for the
person who is being asked, stimulating that person to find answers.
I know some smart people who have absolutely no recall of their questions to
me, but triggered my finding exactly what I was looking for.
BOfL
SleepyHeed
Bret Cahill wrote:
> Couldn't something else provide a rationalization?
>
>
> Bret Cahill
It's the best explanation at the moment, given that the current
scientific-cosmological model is that galaxies have a certain
coherence, but that galaxies themselves seem to be moving away from
each other at an ever-increasing rate.
Given those facts pretty much any explanation's going to seem bizarre,
because the facts are themselves bizarre. It's like finding that
earth-bound rocks are stable in and of themselves, but that the spatial
distance between them is ever-increasing. However you look at it
something weird's going on. (Of course it might be that certain
assumptions used in cosmology are incorrect - perhaps red/blue shift
isn't as pronounced as it looks and something else is affecting light
reaching the earth - but then you'd have to provide an explanation of
/that/ weird fact. Fact is that the universe is a bizarre place from a
human point of view.)
Sean
"SleepyHeed" <simonh...@hotmail.co.uk> wrote in message
news:1141910800.3...@j52g2000cwj.googlegroups.com...
Actually it may be more accurate to say humans are more bizarre, from a
universal point of view.
;-)
Spaceman
> That does it! This nonsense has gone on long enough. I'm driving over
> to Safford right now for my expose.
Good luck,
Walk away if you get any mean thoughts..
:)
SleepyHeed
Good point - from the evidence we've got so far we are alone.
*sigh*.
Oh well. Never mind!
Bill Sheppard
>Ordinary matter interacts with EM, "dark
>matter" is so called because almost the
>only thing we know about it is that it
>doesn't interact with EM but does have a >gravitational influence.
So it's invisible to any form of EM, nonreflective and non-refractive.
Yet it does have gravitational influence. Thus, one would assume it must
contribute to gravitational lensing.
So here's a question: In observed examples of
gravitational lensing, is the lensing consistent with just *visible*
mass, or is it consistent with *implied* mass inclusive of 'dark
matter'?
This question was discussed before and commented on by Odysseus. But
IIRC no clear consensus was reached.
In light of the great paucity of astronomy-related postings, maybe the
subject could be discussed again.
oc
Jonathan Silverlight
<david_lawr...@yahoo.com> writes
Isn't that roughly the problem? (and the answer !)
The mass function does break down, because we don't see enormous numbers
of small objects occulting stars and we don't see the amount of dust you
would need.
But either the mass is there, in some form we can't see, or something
else is messing up the calculations. Something we can't see is currently
preferred to rewriting the laws of physics.
Twittering One
~ Twittering
John Zinni
news:1030-441...@storefull-3172.bay.webtv.net...
> From George D.:
>
>>Ordinary matter interacts with EM, "dark
>>matter" is so called because almost the
>>only thing we know about it is that it
>>doesn't interact with EM but does have a >gravitational influence.
>
> So it's invisible to any form of EM, nonreflective and non-refractive.
> Yet it does have gravitational influence. Thus, one would assume it must
> contribute to gravitational lensing.
> So here's a question: In observed examples of
> gravitational lensing, is the lensing consistent with just *visible*
> mass, or is it consistent with *implied* mass inclusive of 'dark
> matter'?
Google: mapping dark matter gravitational lensing
"The mass that astronomers infer for galaxies including our own is roughly
ten times larger than the mass that can be associated with stars, gas and
dust in a Galaxy. This mass discrepancy has been confirmed by observations
of gravitational lensing, the bending of light predicted by Einstein's
theory of general relativity."
http://map.gsfc.nasa.gov/m_uni/uni_101matter.html
"Map of Dark Matter Developed
Thu, 06 Jan 2005 - Astronomers from Yale have used data from the Hubble
Space Telescope to develop a map of dark matter clumped inside clusters of
galaxies. These clusters contain hundreds of galaxies bound together by
gravity; about 90% of their mass is dark matter. The team used a technique
called gravitation lensing to see how the light from distant galaxies was
bent by the gravity of closer galactic clusters. Even though dark matter is
invisible, its mass will still bend light like regular matter."
http://www.universetoday.com/am/publish/dark_matter_map.html?612005
MAPPING THE INVISIBLE
"Over 90% of the matter in our universe is dark matter. We can't see it. We
can't touch it. But thanks to the recent work of Johns Hopkins
University亡pace Telescope Science Institute researchers, we know where we
can find it.Using the new and powerful Advanced Camera for Surveys,
installed on the Hubble Space Telescope, the scientists created a detailed
map of dark matter distribution in two young galaxy clusters. Their findings
are published in the December issue of Astrophysical Journal."
http://www.seedmagazine.com/news/2005/12/mapping_the_invisible.php
>
> This question was discussed before and commented on by Odysseus. But
> IIRC no clear consensus was reached.
Does "no clear consensus" mean that you dismissed it out of hand???
Art Deco
I'll go out on a limb here and guess that gravitational lensing doesn't
fit the flowing-space "model".
>
>
>> In light of the great paucity of astronomy-related postings, maybe the
>> subject could be discussed again.
>>
>> oc
>>
>
>
--
Official Associate AFA-B Vote Rustler
Official Overseer of Kooks and Saucerheads in alt.astronomy
Official Agent of Deception
Co-Winner, alt.(f)lame Worst Flame War, December 2005
"Causation of gravity is missing frame field always attempting
renormalization back to base memory of equalized uniform momentum."
-- nightbat the saucerhead-in-chief
Bret Cahill
cliff. The temperature has dropped to 15 degrees and I lost my
glasses.
If you could just call those guys in the observatory to drop a rope . .
.
Bret Cahill
Spaceman
I don't have any phone numbers.. sorry.
But you should have just taken the road, and held up a sign that
reads:
"Observatories Don't Exist"
Some people might try and run your over but a true
scientist may pick you up and show you to the observatory
to prove to you that it does in fact exist.
:)
Steve Willner
Jonathan Silverlight <jsilve...@spam.merseia.fsnet.co.uk.invalid> writes:
> The mass function does break down, because we don't see enormous numbers
> of small objects occulting stars and we don't see the amount of dust you
> would need.
The stellar mass function turns over around 0.1 solar masses. (There
are stars and brown dwarfs smaller than that but not as many as the
power law mass function would predict.) In any case, stars are
_baryonic_ matter. If you believe the WMAP results, baryonic matter
is only 4% of the mass-energy in the Universe. Mind you, we still
can't even account for all the baryons, and there might be a fair bit
of matter in dim stars or stellar remnants, but even the whole 4% is
still nowhere near enough to account for galaxy rotation curves and
cluster velocity dispersions, let alone the WMAP and distant
supernova results.
I personally loathe the idea of dark matter and especially
non-baryonic dark matter, but the evidence seems awfully strong.
--
Steve Willner Phone 617-495-7123 swil...@cfa.harvard.edu
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)
Brian Fletcher
However, 'we' are each infinite. Never mind, but soul. :-)
BOfL