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Vanamonde
2008-Apr-05, 07:58 AM
"I never thought there were corners in time, until I was told to stand in one" - Grace Slick from the song, "Hyperdrive".

In the episode about the shape of the universe, Dr. Gay talked about one possiblity is that the 3D universe is bent into the shape of a fourth dimensional hyper-dodecahedron - that way parallel lines remain parallel yet spacetime is still close. This is the first I have hear of this.

The thing that boggles my mind about this is the edges and the vertices. Are we going to have like a some big black holes at each vertex and would it be necessary to hold this shape. What effects would occur when you went around the edge?

This is so dulling my Occam's Razor! But I would like to learn more about the concept. I have to agree - dodecahedrons are cool. Sagan talked about how the Pythagoreans thought it was so weird, they kept it a secret.

Vanamonde
2008-Apr-06, 05:20 AM
Think more about this, it seem the vertices and edges remind me of the warp of space of a gravity field and that is why I thought it may require large black holes at the vertices to keep it stable. Am I off base with that? Maybe the edges would have cosmic strings to hold them in place?

i dunno.

dcl
2008-Apr-20, 03:40 AM
I do not buy into the duodecahedron idea or any other complicated models for the universe. I am a firm advocate of the Occam's Razor approach: simpler ideas are likely to be closer to the truth than elaborate ones. I therefore take a dim view of 3-tori, "doughnut", and dodecahedron models. I urge you to consider the four-dimensional hypersphere model that I described at the beginning of my "The Shape of the Universe" thread.

Vanamonde
2008-Apr-20, 06:06 AM
dcl, you have articulated your position very well in the topic on the size of the universe, as well

Before I reject an idea, I like to at least try to understand it. I started this topic, not to debate the hypothesis but to understand it. I see you are a physicist and I am guessing that you eat Maxell's field equations for breakfast and actually do pure research. If so, that is very cool, very cool indeed.

Can you play devil's advocate and explain why anyone would consider such a crazy idea as the universe as a hyper-dodecahedron? Or maybe provide a link? My search engine skills have failed me on this subject.

But no one has told where I can stand in a corner in spacetime, yet - or even showed me a picture!

dcl
2008-Apr-20, 04:57 PM
Thank you, Vanamonde, for your comments. My responses follows.

I agree that one should not reject an idea before considering its plausibility. Plausibility is the sole ground on the basis of which I reject arcane shapes for the universe when no data are available or can be devised against which to test the ideas experimentally. I feel that the plain 3-torus, Dr. Gay's distorted 3-torus that she describes as a doughnut, and the dodecahedron all fail the plausibility test miserably.

Much as I as a physicist would like to have had the opportunity to do fundamental research, things didn't work out that way for me. Now retired, I am an applied physicist, having taken on projects for which there was need as opposed to based on quests for new scientific knowledge. Even that has given me a very interesting life that I wouldn't have missed for anything: At Los Alamos during World War II, I analyzed frame-by-frame through a micrometer microscope the original negative of the motion picture film of which we've seen prints many times on television showing the explosion of the first atomic bomb in New Mexico to measure the speed of the shock wave. This information, along with other types of data, was used to determine the TNT tonnage equivalent of the explosion. I also determined how much exposure to radium was required to fog x-ray film brought back from a city in Japan other than Hiroshima to the same extent as was film from a hospital in Hiroshima by radiation from the atomic bomb dropped on that city. Incidentally, I was allowed to operate an unlicensed radio station right in Los Alamos itself during this period even though the FBI had detected its carrier in Albuquerque 65 miles away! The station was operated during the day by soldiers, and I operated it during evenings! When I left for Bikini, the army took over operation of the station! The following year, at Bikini, on the day before it was exploded, I and several others wrote our names on the atomic bomb that was exploded underwater. I had designed an electronic instrument two copies of which I attached mechanically to and connected electrically into the bomb itself. I watched the bomb explode from 12.5 miles away, outside the lagoon. A number I determined, 2.2, was written into the FCC transmission standard for color television in 1954. RCA had told the National Television System Committee that was developing the color television system currently in use in the United States and is scheduled for replacement next February by a digital one that the value of the number was 2.,75. My number insured better color fidelity than the RCA one would have. A field manual that I developed was used during the Gulf War in Iraq to guide Air Force personnel in setting up novel point-to-point over-the-horizon microwave radio systems that were instrumental in coordinating Air Force tactical operations during the war and is presusmably still being used now in the current war. The moral: It's not necessary for a physicist to engage in fundamental research in order to have an interesting life! When I read back over this paragraph, I find it hard to believe that I've actually had all of these experiences!

I started out hoping to become an astronomer, so my interest in cosmology goes way back, in fact, to my freshman year in high school in 1935 when my general science teacher challenged the class to find proofs that the world is not flat that he could not refute!. In spite of my having been sidetracked from that ambition by World War II, I've nevertheless had a number of fairly rare astronomical experiences. I've been in the dome with both the Yerkes 40-inch and Lick 36-inch telescopes, the two largest refracting telescopes in the world. In fact, I even moved the Yerkes telescope by hand -- only about six feet at the eyepiece end, but that was at least something! I pushed on a wooden pole like a broom stick but about twice as stick extending back about six feet from the tube. I had to push for about 15 seconds to get it moving, and another 15 seconds against its inertiaq to stop it while it was moving freely about its declination axis. I've also been in the dome of the Mt. Wilson 100-inch alone with an astronomer, and I've been in the dome with the Mt. Palomar 200-inch telescope, until a few years ago the two largest reflecting telescopes in the world. I've also visited Kitt Peak National Observatoy near Tucson, AZ. I saw the solare "Green Flash" there projected onto a screen from a solar tower telescope.

Now you know more about me than I thought I knew about me myself!.

Vanamonde
2008-Apr-21, 04:44 AM
Whoa. Why cool, dcl. Your bio makes me want to go back and delete the word "pure" from my earlier post - but that would be wrong, I have rung that bell and it should not be unrung.

But, again, I do understand the implausiblity of the hyper-dodecahedron model. It blows my mind to think of any shape for spacetime with edges or vertices.

So, anyone, why would anyone consider such a model? What was the evidence or problem this strange shape solved?

Steve Limpus
2008-Apr-21, 07:01 AM
If one follows (I have a little) the papers of Neil Cornish et al. - which seem to be those most often quoted in popular reports - one gets the impression the motivation was to prove that the universe was not so small as to allow the 'cosmic hall of mirrors" effect attending the donut and soccer ball universes.

It's as if someone said, "Hey you know what, the universe might be small, smaller than the light horizon." Then someone else says "Cool! That would mean we could see around it to the back of our heads." And someone else "Whoa, space is nearly flat so it could be like a soccer ball... someone pass the donuts." Then the scientists are like "Great, I suppose we'll have to debunk this lot next." And they have to a large degree.

I wonder if this quote catches the tone:


"Has this search ruled out the possibility that we live in
a finite universe? No, it has only ruled out a broad class of
finite universe models smaller than a characteristic size.
By extending the search to all possible orientations, we
will be able to exclude all topologies out to 24 Gpc."
Neil Cornish

I might be reading too much into this but I think it's revealing that he chose to use the phrase 'we will be able to exclude all topologies out to..." rather than, say "We expect to/want to/hope to find topologies larger than 24 Gpc", at a time when they still have 4 Gpc to go before they reach the boundary of the observeable universe.

Just my take on it though.

dcl
2008-Apr-21, 04:49 PM
Thanks, Vanamonde and Steve Limpus, for your comments. Following are my responses:

Vanamonde, since you find my bio so fascinating, I'll add some more entertaining tidbits in the form of a list of famous people I've met:

George Gamow: Instrumental in creation of the Expanding Universe concept. While working at Sylvania Research Center in Bayside, New York, in the 1955 - 1965 time frame, Robert M. Bowie, Director of Research, asked me to suggest a guest speaker for an upcoming Sigma Xi (physics honor society) dinner meeting at which staff and spouses would be present. I suggested George Gamow. Bowie told me to write to Gamow and persuade him to come. He wrote back in longhand, accepting my request. I met him at the Long Island Railroad station, drove him to my home in my car, and introduced him to my wife. He showed us a silly parlor trick: He cut a horus (that word keeps cropping up in the darndest places) and stood it on end on top of an empty milk bottle and asked me for a coin. I gave him a nickel, which he placed on top of the torus (there's that word again!) and asked my wife if she could remove the torus !!) in a way that would cause the coin to end up in the bottle. I don't remember what our responses were, but he then used one finger to flick the torus (that word really does keep coming up, doesn't it!) horizontally from the inside. It flew off to the side, and the coin dropped neatly directly into the bottle! We then drove to the Sylvania laboratories, and Bowie and I gave him a tour of the laboratories. That evening, in an elegant restaurant in Manhasset, Long Island, Gamow, Bowie, my wife, and I had dinner at the head table. Then I introduced Gamow to the audience, comprising laboratory staff and spouses. I mentioned his popular Mr. Tompkins books and his latest publication, something about gravitational collapse of dying stars the size of the sun into white dwarfs. I thought it appropriate to explain to this non-astronomically oriented audience that a white dwarf is not a Caucasian human being with a pituitary deficiency. After the dinner, I drove Gamow back into Manhattan and dropped him off at the Pennsylvania Railroad station. Gamow was noted for his sense of humor. When he and graduate student Ralph Alpher were about to publish a paper on nucleosynthesis in the Big Bang, he thought it would be clever to bring Hans Bethe (see next item) into the picture by publishing the article under the collective auther list Alpher, Bethe, Gamow (first three Greek letters, alpha, beta, gamma), which they did. Bethe had nothing to do with it except to allow them to add his name to the list!

Incidentally, Dr. Bowie had an experience I was glad to forego: He was a passenger on the American Airlines Boeing 707 that collided in midair=e with an Eastern Airlines Lockheed Super Constellation over the Bronx. The 707 lost 17 feet off one wing but managed to limp into at-that-time Idlewild Airport, now JFK, airport on Long Island. The Super Constellation crashed and burned.

Hans Bethe: Originator of the Carbon Cycle, which explains the source of energy in some types of stars, altghough not the sun. While at Los Alamos, I started to take a course in electromagnetic theory under him, although I had to drop it when it was time to leave for Bikini. Once, I met him in his office to explore the possibility of moving into his department, the Theoretical Division. I was in the Gadget Division. "Gadget" was the code word used to Los Alamos to refer to the bomb itself. The word "bomb" was a no-no at Los Alamos before the "Little Boy" bomb was dropped on Hiroshima. I told Bethe that I was not a theoretical physicist, so that I might not qualify for his division, but he told me something to the effect that theoreticians aren't all that different from other physicists. As it turned out, I transferred to the Electronics Division when Gadget Division disbanded, and it was in that position that I was selected to go to Bikini as a member of the Los Alamos Field Group for the 1946 atomic bomb tests at Bikiini,.,. But that's another story.

Edward Teller: Developer of the hydrogen bomb: I started to take a course in quantum mechanics at the same time that I started the course in electromagnetic theory under Bethe. I had to drop it when I went to Bikiini. I occasionally asked him questions just after classes adjourned.

Enrico Fermi: I met him in a corridor talking to someone else whom I knew. I joined and became a third memer of the group holding the conversation. No big deal.

Major General Leslie R. Groves: Military director of the Manhattan Project for development of an atomic bomb. He came to Bikini to inspect operations leading up to Operation Crossroads atomic bomb tests in which I participated. I explained to him what the electronic instruments that I had developed were supposed to do. I had the distinct impression that he didn't really understand what the cathode ray oscilloscope, part of my instrumentation, was all about. At Los Alamos, I heard that he once raised a ruckus at Oak Ridge about someone having had a funnel made from brass when he could have bought one at a local hardware store made of tin.

Commander Norris E. Bradbury, successor to J. Robert Oppenheimer as Director of the Los Alamos NationalLaborories. I met him, of all places, when we were standing side by side at urinals in a men's rest room on the laboratory ship on the way to Bikiini. We had a brief inconsequential conversation, but for me it was a monumental occasion!

At the Metallurgical Laboratory at the University of Chicago, another part of the Manhattan Project, I met a a Swedish physics graduate studen also on the project. It was she whom I found talking to Fermi at Los Alamos. After the war, she defected to China to assist in development of the Chinese atomic bomb. Last I'd heard, she'd dropped out of all activity to do with bombs and had settled down in China as a farmer on a small farm. I'm surprised that I don't remember her name.

Unfortunately, I never met Galileo, Brahe, Kepler, Copernicus, Newton, or even Einstein. I guess I was underprivileged.

Steve Limpus: I'm impressed by all of the heavy reading you've evidently done on cosmology. It makes miue pale in comparison. It appears to me that these writers don't want to eliminate any possibilities for fear od inadvertantly discarding the one that fits the actual universe. I prefer the Occam's Razor approach because we'll presumably never know the true shape of the unierse.

Steve Limpus
2008-Apr-21, 07:44 PM
dcl, I'm only a little bit jealous! :lol:


Unfortunately, I never met Galileo, Brahe, Kepler, Copernicus, Newton, or even Einstein. I guess I was underprivileged.

Now, that would be a night at the pub!

I'd hope Le Maitre would be able to make it too, and Hoyle, just to get the debate really rocking... :)

dcl
2008-Apr-21, 08:40 PM
Steve Limpus, I'm sure you can appreciate how totally broken-heared I am at never haviing had an opportunity to meet Le Maitre and Hoyle...

By the way, there's a bit more to the Alpher, Bethe, and Gamow story that I forgot to mention: There was another graduate student named Herman involved in a slightly later paper on the same subject. Gamow was quoted as having regretted that Herman "stubbornly refused to change his name to Delter" so that the authors for that paper could be listed as "Alpher, Bethe, Gamow, and Delter" (alpha, beta, gamma, delta).

Steve Limpus
2008-Apr-22, 12:58 AM
Those years must have been just great to be a physicist.

Einstein, in particular, must have been just an incredible human being. And not just the science. Some of the things he wrote and said just blow me away. I don't think the world will ever quite be like that again.

dcl
2008-Apr-22, 01:22 AM
No question about it. Those years were certainly memorable for me.

By the way, I forgot to mention another noteworthy person whom I met: Stanislaus Ulum. He was a mathematician at Los Alamos. Teller got as far as he presumably could in developing the theory necessary for production of the hydrogen bomb, then ran into a problem that he could not handle: How to eliminate the need for a huge refrigeration system as part of the bomb to enable it to work, too heavy to carry in an airplane. Ulum worked out the theory that finally enabled Teller to make the hydrogen bomb so that it would achieve a fusion reaction.

I took differential equations under Ulum during my senior year at the University of Wisconsin in the 1942-1943 school year. He was a Hungarian and I remember him for his weird accent and his sort of a wild-eyed look, but mostly I rember him as being a remarkably good teacher.