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dark matter hypothesis



 
 
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  #11  
Old December 8th 18, 07:38 PM posted to sci.astro.research
Steve Willner
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Default dark matter hypothesis

In article ,
jacobnavia writes:
IF the halo is spherical THEN the study is right.

If the halo is NOT spherical but follows the plane of the milky way,
i.e. most dead stars are in the galaxy plane and WITHIN the galaxy, that
study proves nothing.


Aren't there also microlensing studies towards the Galactic bulge?

Now, most stars that go supernovae have non-symmetrical explosions that
could propel their "dead" corpses in random directions, but the galaxy's
gravity should hold most of them back and keep them within the galaxy
plane.


How would motion perpendicular to the plane be damped out?

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  #12  
Old December 8th 18, 07:38 PM posted to sci.astro.research
Steve Willner
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Default dark matter hypothesis

In article ,
Martin Brown writes:
A Unifying Theory of Dark Energy and Dark Matter: Negative Masses and
Matter Creation within a Modified =CE=9B CDM Framework

https://arxiv.org/abs/1712.07962

Arxiv link but now also in A&A'. It makes some testable predictions.


Paper link is at
https://www.aanda.org/articles/aa/fu...a32898-18.html

A&A site was flaky the last day or two, but eventually it served the
paper.

As I wrote on sci.astro, the paper seems highly unconventional but
mathematically consistent. It requires _two_ unconventional
hypotheses -- existence of negative mass and continuous creation of
it -- so skepticism on that basis is warranted.

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  #13  
Old December 8th 18, 07:45 PM posted to sci.astro.research
brad
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Default dark matter hypothesis

[[Mod. note -- This article arived in my moderation mailbox with a
number of garbled non-ASCII characters, and many excessively-long
lines. I have "tidied up" and reformatted the text; my apologies
to all if I've garbled the author's intended meanings.

Memo to all newsgroup participants: Usenet isn't fully 8-bit-clean,
so it's much safer to restrict your postings to plain ASCII. Notably,
avoid "smart quotes" -- they are almost always garbled somewhere before
the moderators ever see your submission.
-- jt]]

1:13 AMMartin Brown

At the risk of opening up a new can of worms what do people think of the
new paper from Jamie Farnes at Oxford which seeks to unite dark energy
and dark matter as a negative mass fluid filling all of empty space (if
I have understood his paper correctly). It seems to work... title:


A Unifying Theory of Dark Energy and Dark Matter: Negative Masses and
Matter Creation within a Modified =CE=9B CDM Framework


https://arxiv.org/abs/1712.07962


Arxiv link but now also in A&A'. It makes some testable predictions.

--
Regards,
Martin Brown.


For what my opinion is worth, I'm glad to see it. I've long been
of the opinion that looking for exotic matter or applying modifications
to GR were futile. They both ignore published work by W. Israel,
H. Sato, K. Maeda among others whose work could potentially be
generalized to explain Dark Matter.

If we consider that gravity is actually a configuration of space
time we must wonder what types of relevant physics we can expect
from other types of configurations. And most especially when two
different types abut one another, as when expanding Voids interact
with stationary matter structures and their associated gravitational
fields. In other words when two different metrics are involved.

I'm particularly encouraged by this:
"It seems that the proposed negative mass fluid can be modelled
as either matter or vacuum energy. It has previously been proposed
that space-time arises as a form of large-scale condensate of more
fundamental objects, that are typically of an unknown nature
(e.g. Liberati & Maccione 2014). One could therefore speculate
that the negative masses could be interpretable as a quantised
form of energy associated with space-time itself".

That, _that energy_, is natural to spacetime in the absence of
matter. That matter inhibits this energy by its presence.

Furthermore,

H.Sato and K. Maeda (here)
Humitaka Sato Kei-ichi Maeda
Progress of Theoretical Physics, Volume 70, Issue 1, 1 July 1983,
Pages 119--127, https://doi.org/10.1143/PTP.70.119

offer an idea whereby expansion of a Void causes matter to cluster
along the void perimeter and ultimately to form structures via
gravitational collapse.

With these ideas and Israel's formalism (snowplow effect of expanding
space time metric during a supernova) we could ask if: matter
structures are, in effect, 'confined' to the filaments because of
expanding Voids and cannot escape that confinement? can enough
centrifugal acceleration be imparted to disrupt structure? that
is : can stars in the outer galaxy even leave bound structure without
giving up their energy and "falling back" ? if voids are constraints
and they didn't exist would galaxies be larger in breadth? And would
their outer components then follow Newtonian mechanics? are DM and
DE two sides of the same phenomenon? (To me that seems most plausible,
especially when the expansion is accelerating.)

Ultimately I don't like the idea of negative mass unless it is in
the idea of Dirac's anti electron. That is, more like a "hole" in
a sea of normal mass. Also I wonder if negative mass is electromagnetically
responsive. I'm more inclined towards any theory explaining the
Dark phenomena that invokes, or at least recognizes "metric
confinement".

Brad
  #14  
Old Yesterday, 10:19 PM posted to sci.astro.research
Eric Flesch
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Posts: 299
Default dark matter hypothesis

On Thu, 06 Dec 2018, Martin Brown wrote:
new paper from Jamie Farnes at Oxford which seeks to unite dark energy
and dark matter as a negative mass fluid filling all of empty space


Unimaginative. Dark energy & dark matter are just quantifications of
the discrepancy between physical law and our models of it. I prefer a
dimensional interpretation where additional dimensions have as-yet
unmodelled qualities like "scale" or "Mach's Law". Try explaining
colors to a totally color-blind person to get a glimpse of this task.

 




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