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deSitter
Still in Old School


Reged: 12/09/04

Re: Are Globular Clusters White Holes? new [Re: GlennLeDrew]
      #5620233 - 01/13/13 07:14 AM

Did I just say this to hear myself talking??

"If you could return to the 50s and tell someone - what's the most amazing thing about modern life - what would it be?"

"I have a device in my pocket that can reach most of human knowledge. I use it to look at cat pictures and get into arguments with strangers."

http://arxiv.org/abs/0707.2459

Now where's my cat picture site?

-drl


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llanitedave
Humble Megalomaniac
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Are Globular Clusters White Holes? new [Re: deSitter]
      #5620431 - 01/13/13 10:14 AM

Where do they get the assertion that globular clusters don't contain dark matter?

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GlennLeDrew
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Are Globular Clusters White Holes? new [Re: llanitedave]
      #5621595 - 01/13/13 08:28 PM

I don't know... That paper appears in the ESO Messenger; is that a peer review Journal? Nonetheless, that globulars for the most part exist *within* the larger potential of the Galaxy and hence are subject to tidal stripping, can we confidently ascribe an apparent flattening of the velocity profile to some departure of gravitation in the weak acceleration regime?

If only we could study a system in at least near to isolation, and not well enveloped in the potential of a system having a mass many orders of magnitude larger.


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deSitter
Still in Old School


Reged: 12/09/04

Re: Are Globular Clusters White Holes? new [Re: llanitedave]
      #5622393 - 01/14/13 10:12 AM

Quote:

Where do they get the assertion that globular clusters don't contain dark matter?




They are not gravitationally bound (e.g. Palomar 5 tidal stripping).

-drl


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GlennLeDrew
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Are Globular Clusters White Holes? new [Re: deSitter]
      #5622729 - 01/14/13 01:52 PM

Tidal stripping is not indicative of a stellar system being not gravitationally bound. These two states are not incompatible. Such clusters have existed for 10+ Gyr, which is a great many crossing times for a star residing in the system. If not gravitationally bound, they would have dispersed quite thoroughly after less than 10% of their current age.

Tidal stripping is an ongoing process, commencing immediately upon cluster formation. Individual stars, which through encounters with others have their orbits 'pumped up' with sufficient energy, can have their orbit apocenter pushed out to and beyond the tidal radius, leading to the star being 'stolen away' by the Galaxy.

Many if not most globulars must be shadows of their earlier selves, having lost a considerable fraction of their member stars to the Galactic halo. Yet what remains today is still well bound gravitationally, including the least concentrated and less populous examples.


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NorthWolf
Carpal Tunnel
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Reged: 02/23/09

Loc: Eastern Canada
Re: Are Globular Clusters White Holes? new [Re: NorthWolf]
      #5626975 - 01/16/13 08:37 PM

I'm watching Inside the Milky Way right now on the Discovery channel and even Nebulas look like white holes.

Why? We don't know where the gas is coming from. What if all that gas and matter is all the spaghettified and compressed energy and matter that's coming out of a blackhole? We can't even see the source of these nebulas. I'm sure these white holes will be understood in a century from now. Maybe different shaped and types of blackholes/whiteholes produce different shapes (Globular clusters, Nebulae, Galaxies) because of the way the matter and energy is spat out?


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GlennLeDrew
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Are Globular Clusters White Holes? new [Re: NorthWolf]
      #5627404 - 01/17/13 03:25 AM

The nebulae in that program look like white holes? So I guess we can now say that white holes look like nebulae. And globular clusters. And what other objects?

Has anyone yet identified, with any reasonable degree of certainty, a white hole? In all my readings I have yet to encounter anything like a firm claim supported by *some* evidence. To my knowledge, the concept of the white hole is currently just that; a concept.


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Jarad
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Reged: 04/28/03

Loc: Atlanta, GA
Re: Are Globular Clusters White Holes? new [Re: NorthWolf]
      #5627669 - 01/17/13 09:18 AM

Quote:

I'm watching Inside the Milky Way right now on the Discovery channel and even Nebulas look like white holes.

Why? We don't know where the gas is coming from.




I don't think that's true. For planetary nebulas, the gas is being ejected from the central star. For some like the Veil, the nebula is the shockwave from a supernova. For emission nebulas like M42, it is the remains of the gas clouds that were condensing in to form stars being heated by those stars after they ignite fusion.

Remember, "empty" space isn't really empty - it has gas spread out through it. The density is very low, but the volumes are huge, so the total mass is still quite significant.

Jarad


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NorthWolf
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Reged: 02/23/09

Loc: Eastern Canada
Re: Are Globular Clusters White Holes? new [Re: Jarad]
      #5628105 - 01/17/13 01:36 PM

Where are all the gases coming from?

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Jarad
Postmaster
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Reged: 04/28/03

Loc: Atlanta, GA
Re: Are Globular Clusters White Holes? new [Re: NorthWolf]
      #5628138 - 01/17/13 01:54 PM

According to current theory, all the normal matter in the universe was created at the Big Bang, and was mostly hydrogen with a small amount of helium. Small variations in density caused sections to collapse under gravity into stars. The first stars fused the hydrogen into heavier elements, then went supernova, spraying heavier elements into the interstellar gas, and also creating shockwaves that help start other gas clouds collapsing into more stars. Some also left behind black holes that accreted more gas, but in the process sent out jets creating shockwaves, etc.

Repeat for several generations of stars and supermassive black holes, and you get what we have now. The interstellar gas is generally less dense than in the beginning due to the combination of expansion of the universe (more volume), and much of the gas being condensed into stars, planets, etc. The remaining gas is now seeded with a significant proportion of heavier elements from supernovae. Various clouds of gas still collapse to form new stars or clusters of stars (depending on the size of the cloud). Such collapses can be triggered by supernova shockwaves, density waves in spiral galaxy arms, galaxy collisions or close passes, etc.

But the bottom line is the gas has been hanging around out there since the beginning, as far as we can tell. Nebula and clusters don't form due to new gas appearing, they form due to existing gas collapsing.

Jarad


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NorthWolf
Carpal Tunnel
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Reged: 02/23/09

Loc: Eastern Canada
Re: Are Globular Clusters White Holes? new [Re: Jarad]
      #5628205 - 01/17/13 02:34 PM

I never bought into that whole Big Bang theory... To me it looks more logical that all these nebulae, (Not the planetary ones), Globular Clusters, some Galaxies are all appearing through blackholes/whiteholes/bent space/time/wormholes from other universes and just keep spreading and spreading...

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GlennLeDrew
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Loc: Ottawa, Ontario, Canada
Re: Are Globular Clusters White Holes? [Re: NorthWolf]
      #5629227 - 01/18/13 01:00 AM

It might 'look' more logical to the layperson, but science, as we currently understand it by considering all available *evidence*, suggests otherwise.

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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Are Globular Clusters White Holes? new [Re: NorthWolf]
      #5629840 - 01/18/13 12:08 PM

Quote:

I never bought into that whole Big Bang theory... To me it looks more logical that all these nebulae, (Not the planetary ones), Globular Clusters, some Galaxies are all appearing through blackholes/whiteholes/bent space/time/wormholes from other universes and just keep spreading and spreading...




It's not a question of buy-in. We don't choose our theories based on what "looks more logical to me". At least not since Galileo decided to test Aristotle's logical pronouncements and found them mistaken.

It's a matter of understanding the processes and the math, and causation. Logic is involved, but it's a much more rigorous logic than somebody's gut intuition, and it has to be tested to see if it conforms with predicted observations.


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TL2101
professor emeritus


Reged: 09/17/10

Loc: Concord, CA
Re: Are Globular Clusters White Holes? new [Re: llanitedave]
      #5630382 - 01/18/13 06:41 PM

Aren't there at least three competing theories of the universe?

The Big Bang
The Big Bounce
M Theory - the collision of two branes


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llanitedave
Humble Megalomaniac
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Are Globular Clusters White Holes? new [Re: TL2101]
      #5630748 - 01/18/13 10:45 PM

I think the next two incorporate the Big Bang into their hypotheses, so they aren't really in competition with it.

Plus, I hesitate to call them "theories" in the sense of being predictive and explanatory, although others are free to disagree. I don't think they've made it past the hypothesis stage yet.

Edited by llanitedave (01/18/13 10:46 PM)


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Carl Coker
member


Reged: 07/30/12

Loc: Ohio
Re: Are Globular Clusters White Holes? new [Re: llanitedave]
      #5634174 - 01/20/13 11:47 PM

That's right; all the Big Bang really says is that the universe was once in a hot, dense state and expanded. It says nothing about how it got to that hot, dense state, or anything about the universe's creation.

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llanitedave
Humble Megalomaniac
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Are Globular Clusters White Holes? new [Re: Carl Coker]
      #5634903 - 01/21/13 12:48 PM

And it can't. Not without an extension to the laws of physics that can make predictions beyond the event horizon.

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deSitter
Still in Old School


Reged: 12/09/04

Re: Are Globular Clusters White Holes? new [Re: Carl Coker]
      #5635378 - 01/21/13 05:14 PM

Quote:

That's right; all the Big Bang really says is that the universe was once in a hot, dense state and expanded. It says nothing about how it got to that hot, dense state, or anything about the universe's creation.




This is an overlooked point. Even if you adopt the most optimistically naive point of view about what the observations imply, you can only really conclude that the Universe was once much hotter and denser. The rest is wishful thinking. And so the real question is one of level of naivete.

-drl


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Pess
(Title)
*****

Reged: 09/12/07

Loc: Toledo, Ohio
Re: Are Globular Clusters White Holes? new [Re: NorthWolf]
      #5635549 - 01/21/13 07:03 PM

Quote:

I never bought into that whole Big Bang theory... To me it looks more logical that all these nebulae, (Not the planetary ones), Globular Clusters, some Galaxies are all appearing through blackholes/whiteholes/bent space/time/wormholes from other universes and just keep spreading and spreading...




If that were the case wouldn't the Universe grow in mass to the point where it would eventually collapse in on itself?

Also you are violating conservation of mass law if you don't postulate a source for all this gas. Are we deflating another Universe somewhere?

Pesse (Isn't that what happened to Beverly Crusher?) Mist


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