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Author Topic:   Starlight
Percy
Member
Posts: 22490
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.0


Message 5 of 84 (508929)
05-17-2009 9:38 AM
Reply to: Message 4 by NosyNed
05-17-2009 9:16 AM


Re: Trig?
NosyNed writes:
Impossible!
I thought so, too, but while seeking evidence of how daft the claim of a trigonometric measurement was I found this at the Munich Atronomical Archive (http://www.maa.clell.de/Messier/E/m106.html):
The dense disk around this object works as a maser (Microwave Amplifier by Stimulated Emission of Radiation, i.e. a microwave laser). Thus nuclear maser ring allows a geometric distance measurement, independent of other distance indicators such as Cepheid variables, given by James Herrnstein in his PhD thesis (Herrnstein 1997, and NRAO Press Release). He obtained a distance value of 7.3 +/- 0.4 Mpc (23.8 +/- 1.3 Mly), stated to fit with available Cepheid data.
Pretty neat!
--Percy

This message is a reply to:
 Message 4 by NosyNed, posted 05-17-2009 9:16 AM NosyNed has replied

Replies to this message:
 Message 8 by NosyNed, posted 05-17-2009 11:49 AM Percy has not replied

  
Percy
Member
Posts: 22490
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.0


Message 15 of 84 (509039)
05-18-2009 8:24 AM
Reply to: Message 13 by slevesque
05-18-2009 5:33 AM


Hi Slevesque,
I'm a moderator, too, and we moderators tend to be a grumpy lot. I agree with Adminnemooseus that your lols often seem misplaced, but on the flip side I do think I sense a sincere desire to follow the evidence where it leads, an important quality rarely seen in creationists.
--Percy

This message is a reply to:
 Message 13 by slevesque, posted 05-18-2009 5:33 AM slevesque has not replied

  
Percy
Member
Posts: 22490
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.0


Message 35 of 84 (509413)
05-21-2009 10:56 AM
Reply to: Message 32 by riVeRraT
05-21-2009 10:34 AM


Re: Duck! It's M31
Hi riVeRraT,
Some of what you said was expressed in a way where I can't tell if it represents misunderstandings or is just ambiguous, so here's my interpretation of either what you meant, or at least should have meant.
riVeRraT writes:
I had said the expansion as a result of the big bang of objects in our own galaxy cannot be measured because they are moving with us.
The expansion of the universe is not a result of any impetus provided by the Big Bang. Rather, expansion appears to be an inherent property of the universe. And the expansion is not caused by objects moving away from each other within space. Rather, it is caused by the expansion of space itself.
Then I was talking about our local group, and not being able to measure their expansion relative to the universe, not to us.
Space within the local group is expanding, but the galaxies of the local group are sufficiently near one another that gravity is strong enough to keep them from moving along with the expanding space. The force of gravity is not strong enough to keep more distant galaxies from retreating along with the expansion of space, and so they recede from us with increasing velocity with increasing distance.
Onfire: I was taught a long time ago by the administrators to try and combine posts, cause it can get out of hand, and that 300 limit can come up fast. Anyone who is involved in the thread should be reading all posts, otherwise things get repeated.
Combining replies into a single message is usually only suggested by moderators to those who have a tendency to post a bunch of consecutive short replies to many messages.
--Percy

This message is a reply to:
 Message 32 by riVeRraT, posted 05-21-2009 10:34 AM riVeRraT has replied

Replies to this message:
 Message 38 by riVeRraT, posted 05-22-2009 10:37 AM Percy has replied
 Message 39 by riVeRraT, posted 05-22-2009 10:39 AM Percy has not replied

  
Percy
Member
Posts: 22490
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.0


Message 40 of 84 (509567)
05-22-2009 1:29 PM
Reply to: Message 38 by riVeRraT
05-22-2009 10:37 AM


Re: Duck! It's M31
riVeRraT writes:
Also the name Big Bang does not lend itself to be considered anything but impetus.
Fred Hoyle coined the term Big Bang as an attempt at derision and the name stuck. The term was never meant to be descriptive. The Big Bang was merely the rapid expansion of the universe from an extremely hot dense state.
Just at the moment of the Big Bang the universe was incredibly tiny, hot and dense. All matter and energy of the universe was contained in a space tinier than an atom. And it was contained in that space not by any container, but simply because that's how big space was. There was nowhere else for matter to be but within that tiny, tiny space.
The Big Bang was actually a very rapid expansion of the size of universe. From a size tinier than an atom the universe rapidly expanded, and the contents of the universe expanded with it. There was never any explosive impetus.
I would think it to be logical to assume that there is some force behind the expansion of space,...
There is, just as you say here, a force behind the expansion of space. We call it dark energy, but we don't really know what it is. But the ongoing expansion of space is not the result of space, or of matter either, being blown outward by the Big Bang.
Especially since objects are attracted to each other, something must be driving them apart.
Nothing is driving them apart in the sense of any repulsive force. Again, it is space itself that is expanding, and it is carrying away with it the matter contained therein, except in cases where the matter is sufficiently dense to hold itself together despite the expanding space.
Either way there should be some kind of leading edge (microwave background)...
There is no "leading edge" to the expansion of space. Space is expanding everywhere. The microwave background radiation arrives from all directions simultaneously everywhere throughout the universe.
If all the stars within our dot are moving with us, we can't measure their expansion relative to the rest of the universe.
That's because they're not expanding, but we can measure the speed with which our local group of galaxies is receding from other local groups. We can't directly measure the expansion of space within the local group, but we infer that it is the same here as it is for everywhere else throughout the universe.
--Percy

This message is a reply to:
 Message 38 by riVeRraT, posted 05-22-2009 10:37 AM riVeRraT has not replied

Replies to this message:
 Message 42 by cavediver, posted 05-22-2009 5:27 PM Percy has replied

  
Percy
Member
Posts: 22490
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.0


Message 43 of 84 (509607)
05-22-2009 7:06 PM
Reply to: Message 42 by cavediver
05-22-2009 5:27 PM


Re: Duck! It's M31
Yeah, I meant the acceleration of the expansion.
--Percy

This message is a reply to:
 Message 42 by cavediver, posted 05-22-2009 5:27 PM cavediver has not replied

  
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