Re: Have huge stars powered by Dark Matter been discovered?

[LizR]

I don't suppose this could be one of them?

https://www.nasa.gov/feature/goddard/2023/webb-reveals-colors-of-earendel-most-distant-star-ever-detected


On Sun, 16 Jul 2023, 23:58 John Clark,  wrote:

> As early as 2012 scientists predicted that the Hubble telescope would see
> something they called a "Dark Star".
>
> Observing supermassive dark stars with James Webb Space Telescope
> 
>
> They theorized in the early universe Dark Matter, whatever it is, must've
> been much more densely concentrated than it is today, and if Dark Matter
> particles are their own antiparticles as many think then their annihilation
> could provide a heat source, they could keeping star in thermal and
> hydrodynamic equilibrium and prevent it from collapsing. They hypothesized
> something they called a "Dark Star '', it would be a star with a million
> times the mass of the sun and would be composed almost entirely of hydrogen
> and helium but with 0.1% Dark Matter.  A Dark Star would not be dark but
> would be 10 billion times as bright as the sun and be powered by dark
> matter not nuclear fusion.
>
> Astronomers were puzzled by pictures taken with the James Webb telescope
> that they interpreted to be bright galaxies just 320 million years after
> the Big Bang that were much brighter than most expected them to be that
> early in the universe, a recent paper by the same people that theorized
> existence of Dark Stars claim they could solve this puzzle. They claim 3
> of the most distant objects that the Webb telescope has seen are point
> sources, as you'd expect from a Dark Star, and their spectrum is consistent
> with what they predicted a Dark Star should look like. With a longer
> exposure and a more detailed spectrum, Webb should be able to tell for sure
> if it's a single Dark Star or an early galaxy made up of tens of millions
> of population 3 stars.
>
> Supermassive Dark Star candidates seen by JWST
> 
>
> John K ClarkSee what's on my new list at  Extropolis
> 
>
> 3vy
>
> --
> You received this message because you are subscribed to the Google Groups
> "Everything List" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to everything-list+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/everything-list/CAJPayv02R9uavpw5wXxn_gepp7X_tx%3DQR-RR6KqgiJpebikbpA%40mail.gmail.com
> 
> .
>

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/everything-list/CAKzbsNeo4xvZXszAi-ehKHY4%2BdQtNmg8pMMLGN%3Dyxcv9BpJvKw%40mail.gmail.com.

Re: Have huge stars powered by Dark Matter been discovered?

[smitra]

See page 11 section A: "Cold Thermal Relic" of this paper: 
https://arxiv.org/abs/0709.3102


As pointed out there, the mass of the particle then drops out of the 
estimate of the cross section. And as pointed out in section C: 
"Supermassive relics", if the mass is more than 240 TeV then it cannot 
be a thermal relic.


Saibal






On 10-08-2023 23:42, Jesse Mazer wrote:

Any links on this argument? If we do assume that dark matter is made
of WIMPs and that they *were* approximately in thermal equilibrium not
long after the Big Bang, does the argument imply an upper limit on the
collider energy needed to observe them, because WIMPs at higher
energies than this limit would be inconsistent with cosmological
observations about dark matter?

On Thu, Aug 10, 2023 at 7:58 AM smitra  wrote:


A more model independent argument (which does have loopholes) goes
as
follows. The weaker WIMPS interact with themselves and with baryons,
the
sooner after the Big Bang they decouple, leading to a higher
present-day
abundance. Then with the present-day abundance fixed, this implies
limits on the parameters describing WIMPS. And it becomes more and
more
difficult to accommodate for WIMS with smaller and smaller small
cross-sections. But dark matter that has extremely weak interactions
and
self-interactions would never have been in thermal equilibrium,
which is
a possible loophole out of this no-go argument.

Saibal

On 10-08-2023 01:42, Jesse Mazer wrote:

Does the idea that colliders should have already found WIMPs

depend on

the "naturalness" idea at
https://en.wikipedia.org/wiki/Naturalness_(physics) which requires
supersymmetric particles at those energies in order to solve the
"hierarchy problem", or are there independent reasons to think

that if

WIMPs existed they should already have been found? I've read that
those who endorse the string theory "landscape" idea see anthropic
fine-tuning as an alternative to naturalness and thus didn't

predict

that supersymmetric particles would likely be found at LHC

energies,

for example Leonard Susskind's 2004 paper at
https://arxiv.org/abs/hep-ph/0406197v1 said the following on pages
1-2:

'If the Landscape and the Discretuum are real, the idea of

naturalness

must be replaced with something more appropriate. I will adopt the
following tentative replacement: First eliminate all vacua which

do

not allow intelligent life to evolve. Here we need to make some
guesses. I’ll guess that life cannot exist in the cores of

stars,

cold interstellar dust clouds or on planets rich in silicon but

poor

in carbon. I’ll also guess that black holes, red giants and

pulsars

are not intelligent.

'Next scan the remaining fraction of vacua for various properties.

If

the property in question is common among these “anthropically
acceptable” vacua then the property is natural. By common I mean
that some non-negligible fraction of the vacua have the required
property. If however, the property is very rare, even among this
restricted class, then it should be deemed unnatural. Of course

there

is no guarantee that we are not exceptional, even among the small
fraction of anthropically acceptable environments. It is in the

nature

of statistical arguments that rare exceptions can and do occur.

Michael Douglas has advocated essentially the same definition

although

he prefers to avoid the use of the word anthropic wherever

possible,

and substitute “phenomenologically acceptable”. We have both
attempted to address the following question: Are the vacua with
anthropically small enough cosmological constants and Higgs

masses,

numerically dominated by low energy supersymmetry or by

supersymmetry

breaking at very high energy scales [8][7]? In other words is low
energy supersymmetry breaking natural? My conclusion–I won’t
attempt to speak for Douglas–is that the most numerous

“acceptable

vacua” do not have low energy supersymmetry. Phenomenological
supersymmetry appears to be unnatural.'

On Sat, Aug 5, 2023 at 5:26 PM Lawrence Crowell
 wrote:


One weakness with this idea is it depends upon WIMP theory. This

is

where the DM particles are weak interacting and Majorana. They

are

their own anti-particle as a result annihilate themselves. The
problem is that detectors means to find WIMPS have come up with
nothing. DM appears to exist, but it may not be a weakly

interacting

particle or WIMP.

LC

On Sunday, July 16, 2023 at 6:58:19 AM UTC-5 John Clark wrote:


As early as 2012 scientists predicted that the Hubble telescope
would see something they called a "Dark Star".

Observing supermassive dark stars with James Webb Space

Telescope

[1]

They theorized in the early universe Dark Matter, whatever it

is,

must've been much more densely concentrated than it is today,

and

if Dark Matter particles are their own antiparticles as many

think

then their annihilation could provide a heat source, they could
keeping star in thermal and hydrodynamic equilibrium and prevent
it from 

Re: Amoeba's Secret openly available under CC-BY license

[Brent Meeker]

That's great!  Many thanks to you, Russell.

Brent

On 8/12/2023 3:15 AM, Russell Standish wrote:

Hi guys,

I finally got around to doing something I meant to do years ago - I
have released the English translation of "Amoeba's Secret" as a freely
downloadable PDF under the Creative Commons CC-BY license at
https://www.hpcoders.com.au/docs/amoebassecret.pdf .

Bruno Marchal was a long time contributer to this list, and this
semi-autobiography is also one of the clearest explanations of his
ideas.

Enjoy,



--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/everything-list/02b409fd-beb7-fc98-47ce-0757c44baa67%40gmail.com.

Amoeba's Secret openly available under CC-BY license

[Russell Standish]

Hi guys,

I finally got around to doing something I meant to do years ago - I
have released the English translation of "Amoeba's Secret" as a freely
downloadable PDF under the Creative Commons CC-BY license at
https://www.hpcoders.com.au/docs/amoebassecret.pdf .

Bruno Marchal was a long time contributer to this list, and this
semi-autobiography is also one of the clearest explanations of his
ideas.

Enjoy,

-- 


Dr Russell StandishPhone 0425 253119 (mobile)
Principal, High Performance Coders hpco...@hpcoders.com.au
  http://www.hpcoders.com.au


-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/everything-list/20230812101516.GF17399%40zen.