A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Research
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

WIMPS?



 
 
Thread Tools Display Modes
  #21  
Old June 10th 13, 07:45 AM posted to sci.astro.research
Phillip Helbig---undress to reply
external usenet poster
 
Posts: 629
Default WIMPS?

In article , "Richard D. Saam"
writes:

On 6/9/13 5:55 AM, Phillip Helbig---undress to reply wrote:
No. The new phases involve MOLECULAR hydrogen.

Yes, MOLECULAR hydrogen but possibly in a phase
not presently electromagnetically observable a la 'dark matter'
a portion of which continues to sublimate
into presently electromagnetically observable
gaseous MOLECULAR hydrogen.


Work through big-bang nucleosynthesis, include this new phase, and let
me know what you get.
  #22  
Old June 15th 13, 07:09 AM posted to sci.astro.research
David Staup[_2_]
external usenet poster
 
Posts: 347
Default WIMPS?

On 6/4/2013 1:24 AM, Robert L. Oldershaw wrote:
Beware glib answers. Science requires much more thought and skepticism.


What does the math say, if anything, about black hole mass?

or perhaps a better way to put this is "what is responsible for black
hole mass"?

[Mod. note: quoted text trimmed -- mjh]
  #23  
Old June 17th 13, 08:21 AM posted to sci.astro.research
Nicolaas Vroom
external usenet poster
 
Posts: 216
Default WIMPS?

Op zaterdag 15 juni 2013 08:09:00 UTC+2 schreef David Staup het volgende:

What does the math say, if anything, about black hole mass?

or perhaps a better way to put this is "what is responsible for black
hole mass"?


I think to answer the question "What is responsible for mass"
is impossible.
On the other hand to answer the question: "how do we calculate
the mass of the blackhole" please read this
http://www.eso.org/public/news/eso0846/
Specific follow the first link "More Information"

An other good document is this:
http://en.wikipedia.org/wiki/Sagittarius_A*

Nicolaas Vroom
  #24  
Old June 17th 13, 08:04 PM posted to sci.astro.research
David Staup[_2_]
external usenet poster
 
Posts: 347
Default WIMPS?

On 6/17/2013 2:21 AM, Nicolaas Vroom wrote:
Op zaterdag 15 juni 2013 08:09:00 UTC+2 schreef David Staup het
volgende:

What does the math say, if anything, about black hole mass?

or perhaps a better way to put this is "what is responsible for
black hole mass"?


I think to answer the question "What is responsible for mass" is
impossible.


My question was specific to black hole mass and I meant the question to
point out that "we" cannot describe the source of a black hole's
gravity. Is it matter, dark or otherwise? Is it energy? Or is it
something else?

[Mod. note: not sure what you're getting at here. 'The math' (i.e.
relativity theory) says that black holes are a form of matter, and
therefore of energy. Whether they are 'dark' or not in the
astronomers' sense depends on their environment -- mjh]
  #25  
Old June 18th 13, 07:14 AM posted to sci.astro.research
Steve Willner
external usenet poster
 
Posts: 1,172
Default WIMPS?

In article ,
David Staup writes:
Whether [black holes] are 'dark' or not in the
astronomers' sense depends on their environment -- mjh]


Whether they are radiating or not depends on the environment.

The OP's language was confusing, but I think his "dark or not" might
have been meant as "baryonic or not." That depends on the formation
process. All processes we know of for making black holes involve
baryonic matter, but in principle non-baryonic matter could form
black holes if there were some way to concentrate it enough.
Existing black holes must accrete tiny amounts of non-baryonic matter
regardless of how they formed.

Black holes are, so far as we know, a trivial part of even the
baryonic mass of the Universe, so the data don't support worrying
about a non-baryonic component. Theory could deal with the
consequences of non-baryonic black holes if that turned out to be
important.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
  #26  
Old June 18th 13, 07:15 AM posted to sci.astro.research
jacob navia[_5_]
external usenet poster
 
Posts: 543
Default WIMPS?

Le 17/06/13 21:04, David Staup a écrit :

My question was specific to black hole mass and I meant the question to
point out that "we" cannot describe the source of a black hole's
gravity. Is it matter, dark or otherwise? Is it energy? Or is it
something else?

[Mod. note: not sure what you're getting at here. 'The math' (i.e.
relativity theory) says that black holes are a form of matter, and
therefore of energy. Whether they are 'dark' or not in the
astronomers' sense depends on their environment -- mjh]


Is the ratio dark/visible matter in the galaxy known?

If yes, then we should expect that same ratio in the central black hole
of the galaxy isn't it?

If that mass is "X" kg, a certain percentage of it (the same as the
galaxy as a whole) should be dark matter.

Since nothing gets out of that hole (it is completely invisible), in
principle knowing if that ratio holds is impossible.

Or is 100% of the mass of a black hole "dark" matter?

Black holes are... black!!, the color of darkness :-)

Black hole mass has some characteristics of dark matter. It
only interacts with the rest of matter through gravity.

A "black hole" particle would fit our WIMPY thoughts or not?

Black holes much smaller than the size of an atom *could* exist and
even in big numbers.

Problem is (for my new theory of the universe) that holes tend
to slowly fill with surrounding matter that falls into them.

If atomic black holes interact with atoms by swallowing them, they
should be visible after a certain time has passed since they would get
bigger and bigger. And when swallowing an atom it is difficult to
believe that not a single photon (gamma ray, whatever) would not
be emitted.

What is not detected.

And there it goes, my new theory of the Universe...
  #27  
Old June 20th 13, 07:36 AM posted to sci.astro.research
Steve Willner
external usenet poster
 
Posts: 1,172
Default WIMPS?

In article ,
jacob navia writes:
Is the ratio dark/visible matter in the galaxy known?


Not as well as we might like. It's hard to measure either one from
our location within the Galaxy. Values for external galaxies thought
to be similar to the Milky are better known.

If yes, then we should expect that same ratio in the central black hole
of the galaxy isn't it?


Why would you expect the average ratio for the whole galaxy to apply
to any specific region? An average is even less likely to apply to a
region that has special conditions.

If that mass is "X" kg, a certain percentage of it (the same as the
galaxy as a whole) should be dark matter.


Are you using "dark matter" as a synonym for "non-baryonic matter?"
They aren't the same. For obvious physical reasons, a black hole is
far more likely to accrete baryonic matter than non-baryonic matter.

Or is 100% of the mass of a black hole "dark" matter?


This is a question of terminology. Isolated black holes are "dark
matter" (but within the baryonic mass budget), but accreting black
holes are not dark. However, they contribute a trivial fraction of
the overall mass budget of a galaxy. Nevertheless, a black hole's
mass can dominate its immediate surroundings.

Black hole mass has some characteristics of dark matter. It
only interacts with the rest of matter through gravity.


Black holes can be charged, though there's no evidence that real ones
are.

A "black hole" particle would fit our WIMPY thoughts or not?


Absence of lensing rules out stellar-mass and larger black holes as
significant components of dark matter. And anyway black holes would
be baryonic and would not contribute to the non-baryonic dark matter.

Black holes much smaller than the size of an atom *could* exist and
even in big numbers.


You might want to calculate the lifetime of such a black hole.
That's aside from the lack of any obvious creation mechanism.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
  #28  
Old June 21st 13, 06:34 AM posted to sci.astro.research
jacob navia[_5_]
external usenet poster
 
Posts: 543
Default WIMPS?

Le 20/06/13 08:36, Steve Willner a écrit :
Why would you expect the average ratio for the whole galaxy to apply
to any specific region? An average is even less likely to apply to a
region that has special conditions.


I suppose that this "dark" matter interacts with matter through gravity.
A black hole is quite a beast in gravity terms. It is a very strong
gravity field isn't it?

Then it should attract as much "dark" matter as normal matter and should
feed with BOTH kinds of matter.

Interestingly, does that "dark" matter emit any kind of radiation when
leaving this world into the black hole?

Observing the black hole at the center of our galaxy if we detect some
radiation with no obvious normal matter to explain it, it could give
us (yet another) test for that "dark" matter, unless it emits "dark"
photons :-)

jacob
  #29  
Old June 21st 13, 06:35 AM posted to sci.astro.research
Robert L. Oldershaw
external usenet poster
 
Posts: 617
Default WIMPS?

On Thursday, June 20, 2013 2:36:31 AM UTC-4, Steve Willner wrote:
In article ,
This is a question of terminology. Isolated black holes are "dark
matter" (but within the baryonic mass budget), but accreting black
holes are not dark. However, they contribute a trivial fraction of


--------------------------------------------------------

An important correction here is that primordial black holes, i.e.,
black holes that are not formed in supernovae, are non-baryonic and do
not come "within the baryonic mass budget".
  #30  
Old June 22nd 13, 07:02 AM posted to sci.astro.research
jacob navia[_5_]
external usenet poster
 
Posts: 543
Default WIMPS?

Le 31/05/13 08:03, Richard D. Saam a écrit :
There are no (within 95% CL)
WIMP annihilation cross sections and decay lifetimes
as measured by FERMI LAT
that could contribute to dark matter.
http://arxiv.org/abs/1305.5597


Frustrated by dark matter?
Can't figure it out?

Do not worry. YOU ARE NOT ALONE.

Read this article written by the famous scientist "Lord Kelvin"
(Sir William Thomson ) in

Macmillan's Magazine, vol. 5 (March 5, 1862), pp. 388-393.

In this article Lord Kelvin tries to figure out how old the
sun is.

His only conceptual framework to explain the heat of the
sun was that this heat was "generated by the falling in of meteors"

But that provokes OTHER problems since in their way to the sun
those meteors should pass through the earth orbit...

The url for that document is:

http://zapatopi.net/kelvin/papers/on...suns_heat.html

It makes for a fascinating reading, hopefully the same kind of
fascination that astronomers in year 2163 will have when reading the
discussions here or the papers about that mysterious dark matter.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
DarkAttack2012 Conference: NO "WIMPs"! Robert L. Oldershaw Research 1 July 20th 12 07:04 AM
Generic WIMPs Ruled Out Robert L. Oldershaw Research 10 November 27th 11 10:09 AM
WIMPs AWOL Again? Robert L. Oldershaw Research 91 November 16th 11 10:28 AM
Constraints on WIMPs as Dark Matter. dlzc Astronomy Misc 4 August 24th 11 03:21 PM
Xenon100: No "WIMPs" Robert L. Oldershaw Research 0 April 14th 11 09:39 AM


All times are GMT +1. The time now is 10:14 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.