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Cosmology
Posted: 09 July 2006 02:15 PM   [ Ignore ]   [ # 16 ]
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jim,
There is no link that I know of. Most likely there isn’t one because they want people to subscribe to the magazine.
Bob

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Posted: 09 July 2006 09:12 PM   [ Ignore ]   [ # 17 ]
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Jim,
The article was adapted from “Many Worlds in One: The Other Universes” a book by Alex Vilenkin. The author is a professor of physics at Tufts University.
Bob

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Posted: 09 July 2006 11:42 PM   [ Ignore ]   [ # 18 ]
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Perhaps he’s just explaining the ‘many worlds’ interpretation of quantum mechanics, whereby there are parallel universes with humans in them, etc. That is in a sense uncontroversial—the interpretation exists, and it has these characteristics.

But as we have discussed in other places, the interpretation itself is controversial. As I recall hearing, very few physicists buy into it. It’s more a sop for philosophy classes and popular literature.

I’d guess one day we’ll get these interpretations all sorted out, perhaps with the grand unified theory, whenever that is discovered ...

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Posted: 10 July 2006 12:35 AM   [ Ignore ]   [ # 19 ]
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[quote author=“dougsmith”]Perhaps he’s just explaining the ‘many worlds’ interpretation of quantum mechanics, whereby there are parallel universes with humans in them, etc. That is in a sense uncontroversial—the interpretation exists, and it has these characteristics.
But as we have discussed in other places, the interpretation itself is controversial. As I recall hearing, very few physicists buy into it. It’s more a sop for philosophy classes and popular literature.

I’d guess one day we’ll get these interpretations all sorted out, perhaps with the grand unified theory, whenever that is discovered ...

———

doug,
I do believe that he is explaining the many worlds interpretation of quantum mechanics. It would be good to have the interpretations “all sorted out”. Let’s hope it’s soon.
Bob

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Posted: 10 July 2006 06:35 AM   [ Ignore ]   [ # 20 ]
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Scientific American sent me a request to return to their fold. with it if I choose to do so would come the essay “Parallel Universes” A Scientific American Special report. Separately bound and promoted with the following statement

Is there a copy of you in another universe reading this sentence? The most popular cosmological model today suggest the answer is yes. And while it’s about 10 to the 10 raised to the power of 28, meters away, its very existence is supported by astronomical observations.

The existences of many universes was once the stuff of science fiction. But, like a round earth, curved space and black holes, it has recently joined the ranks of ideas now experimentally testable.

Testable? I can’t see how. but I have the little sheet that was included in the envelope that says exactly that.

Jim

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Our lives begin to end the day we become silent about things that matter. (MLK Jr.)

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Posted: 10 July 2006 07:15 AM   [ Ignore ]   [ # 21 ]
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Wow… If I had a copy in another dimension, I’d want it to be doing something more productive than simply mirroring my actions here.  Perhaps “BizarroMe” could be running some errands while I’m at class, or out looking for a potential mate or something.  I’d hate to think all these copies are going to waste.

...But what if I AM the copy???  AHHHHHHHH!!!

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Posted: 10 July 2006 02:25 PM   [ Ignore ]   [ # 22 ]
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[quote author=“jimmiekeyes”]Scientific American sent me a request to return to their fold. with it if I choose to do so would come the essay “Parallel Universes” A Scientific American Special report. Separately bound and promoted with the following statement

Is there a copy of you in another universe reading this sentence? The most popular cosmological model today suggest the answer is yes. And while it’s about 10 to the 10 raised to the power of 28, meters away, its very existence is supported by astronomical observations.

The existences of many universes was once the stuff of science fiction. But, like a round earth, curved space and black holes, it has recently joined the ranks of ideas now experimentally testable.

Testable? I can’t see how. but I have the little sheet that was included in the envelope that says exactly that.

Jim

——-

jim,
That’s very interesting. Supported by astronomical observations? I never heard that before. Testable? I can’t see how either. Maybe doug knows something about that.
Bob

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Posted: 11 July 2006 01:26 AM   [ Ignore ]   [ # 23 ]
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Whoops, I thought the whole essay was at this link
 

I googled the following -“Parallel Universes” Scientific American - and hit “Feeling Lucky”

I hadn’t read it yet. Wanted to get the link up here before I did and of course only a part is there, the reader must subscribe to get the whole issue. I was thinking about the paper version for a little less money now I think this might be better…. but 40 bucks is 40 bucks. Anyone want to share? LOL

It looks good and is available for 8.00 so I guess I’ll get it. Hang on for future updates FOTFLOL
Jim

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http://secularhumanism.meetup.com/1/
Our lives begin to end the day we become silent about things that matter. (MLK Jr.)

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Posted: 11 July 2006 03:11 AM   [ Ignore ]   [ # 24 ]
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I can’t think of any way this would be testable, but I’m certainly no cosmologist. Sounds like marketing-speak to me. But I’d love it if this could be tested!

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Posted: 20 September 2007 02:49 AM   [ Ignore ]   [ # 25 ]
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Goshies!  I’ve been reading the forums looking for a nice gooey topic into which I might dip my metaphorical left big toe…

First, I gotta express some sympathy for theatheistheretic and his skepticism of some parts of modern cosmology.  In days of yore when I was an undergrad physics student, I was fascinated by notions similar to those akin to Sakharov’s investigations of the origins of Inertia.  Long afterwards (I reckon it was five or so years ago) I came across a nice web-sitewith links to articles about zero-point energy (a nifty scientific phenomena that has spawned legions of zany psuedoscience ideas), and other inquiries into fundamental explanations for the behaviors and inter-relations of space/time and matter.  As most of you folks probably know, good ol’ Albert’s ideas about gravity (specifically the reliance on infinitesimals, or continuously integrable functions) don’t smoosh together with discreetly calculated quantum mechanical dohickies.  Eventually, I was led to trying to bend my poor old noggin around MOND, then string theory, then the hullabaloo about a non-zero cosmological constant and dark energy…

Anyway, I’ve always been curious about potential tie-in between quantum mechanics, (general) relativity and cosmology.  Along the way, I devloped a couple of (OK, maybe more than two, but I’ll only list two here)  “gut feelings”:
1) The Universe is closed - In order to gaurantee matter falling toward an event horizon (i.e. a “black hole”) will not cross that boundary (according to a co-moving reference frame) before the Universe itself re-collapses, thus ensuring everything in the universe (or rather, the universe itself) crosses a singularity at exactly the same moment.
2) Dark Matter doesn’t exist - it’s our theories of gravity that are inaccurate (hence MOND)

Well, I thought my gut feelings were based on sound logic, even though they were contrary to the majority main-stream opinions of professional cosmologists.  As it turns out, I’ve been proven wrong on both counts.  It was pretty astonishing to me when very clear proof of dark matter was put forward. 

At least I’m in good company being wrong:  Einstien was wrong (actually he was meta-wrong) about the cosmological constant, and about Mach’s principle.  Newton was wrong about absolute time.  Euclid was wrong about parallel lines.  Hilbert was wrong about mathematics being a closed formal system. Hawking was wrong about black holes destroying information, etc.  All these brainy fellers had gut-feelings or intuitions which were found to be wrong - sometimes in their own lifetimes, sometimes not.

My point is twofold:  First, it’s ok to disagree with mainstream ideas and even the most popular unproven theories.  If your disagreement is based on rational, deductive, rigorous and (if relevant) mathematical principles, that’s even better - for it puts you in a position of being able to argue your case toe-to-toe with other erudite investigators.  Rigor notwithstanding though, being skeptical of unsubstantiated ideas, even popular ones, is generally not a terrible thing.  However, when evidence obtains which contradicts one’s gut feelings, biases, or pet theories, it takes a certain amount of both self-confidence and humility to resolve the cognitive dissonance in favor of the notion contrary to one’s preconceptions. 

My second point is that nobody is immune from forming biases unsupported by evidence.  I suspect that we humans always want to understand more than our science tells us; which is likely the reason we keep asking new questions and looking for new evidence to learn more truths.  Between what we know and what we don’t know, we have only guesswork to smoosh into the gaps.  Occam’s razor would encourage us to keep our guesses and imaginings exactly as limited as possible.

OK, I hope I ain’t stubbed my metaphorical toe. smile

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Posted: 04 October 2007 04:00 PM   [ Ignore ]   [ # 26 ]
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Bob - 05 April 2006 12:53 PM

Data from WMAP indicate that the universe grew from the size of a marble to nearly its present size in less than a trillionth of a second.
Bob

There is a problem the way you stated this - Edwin Hubble discovered the universe is expanding.  It appears to have been explanding since it came into being with the big bang. 

It is entirely possible that I have missed something but if something has been expanding since inception 13 billion years ago, it would apparently be of a significant size greater than it was one trillionth of a second after it became.

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Posted: 04 October 2007 04:07 PM   [ Ignore ]   [ # 27 ]
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Z - 04 October 2007 04:00 PM

There is a problem the way you stated this - Edwin Hubble discovered the universe is expanding.  It appears to have been explanding since it came into being with the big bang. 

It is entirely possible that I have missed something but if something has been expanding since inception 13 billion years ago, it would apparently be of a significant size greater than it was one trillionth of a second after it became.

Well, I suppose “nearly” is a bit too much, but the point is that during this tiny period of inflation, the universe expanded much faster than it has done afterwards.

To see more about this, I suggest checking out the wiki page on cosmic inflation.

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Posted: 04 October 2007 04:08 PM   [ Ignore ]   [ # 28 ]
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How much greater do you think it should be, Z? Maybe the expansion slowed down right after the “explosion”.

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Posted: 15 October 2007 03:22 AM   [ Ignore ]   [ # 29 ]
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All of this makes me want to go read The First Three Minutes again.

There are so many things in cosmology that don’t make sense to me.  I’m still waiting for the LHC to come online.  Anyone know offhand what kind of insights we’ll get into some of our current theories when that thing gets turned on?  Brane theory for instance?

And what about this business about time becoming another space dimension somewhere down the line?  Anyone heard anything about that?

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Posted: 15 October 2007 07:11 AM   [ Ignore ]   [ # 30 ]
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godblessgeorgecarlin - 15 October 2007 03:22 AM

And what about this business about time becoming another space dimension somewhere down the line?  Anyone heard anything about that?

Time is another dimension like the three of space. In Einsteinian terms, all there is is four-dimensional spacetime. The difference between time and space is of no particular importance to physics, except that entropy increases in the “time” direction in any closed system.

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