51 replies to this topic

[bgwowk]

Dark Matter has been known since 1933. It affects the rotation rates of glaxies, among many other things.

Dark Matter is totally different from Dark Energy. Dark Energy is the observation that the rate of cosmic expansion is currently increasing. Dark Energy is a relatively recent (1998) observation.

[xanadu]

I read the article and it wasn't too bad. It started out with the usual protestations of faith that bg uses all the time. It stated theories as facts and neglected to explain anything. But, later in the article it got a little bit more detailed and the gaps and assumptions began to appear. The latter part of the article took away much of the certainty trumpeted in the first part.

the redshift describes only the change in the scale of the cosmos, and does not tell us the distance or the age of the universe when the light was actually emitted.

The extension to higher redshifts was poorly determined, but by making assumptions about the energy density and pressure content of the universe, general relativity can be used to connect redshifts with distances.

Yes, assumptions, just what I've been saying. The article end up by rambling through a mish mash of theories that might possibly explain dark energy. Just as I've said all along, the latest theories rest on many assumptions and the belief that red shift can be reliably linked to distance. If my theory is correct, that red shift can be caused by other things over great distances, then a monkey wrench has been tossed into all those delicate theories and they will never recover. Not only the size but the age of the universe would be much different than is currently believed.

The article never did go into any detail about how the universe could be expanding FTL. This seems to relate to the other belief system that space is expanding due to stretching of space itself or the creation of new space. A particle called the "inflaton" is supposed to be responsible for this. Another unicorn for us to believe in. A few decades or centuries from now, people will be reading these current theories and having a good laugh just as we do now over old theories.

[MichaelAnissimov]

Happy 1000th post to Brian Wowk.

[bgwowk]

xanadu wrote:

This seems to relate to the other belief system that space is expanding due to stretching of space itself or the creation of new space. A particle called the "inflaton" is supposed to be responsible for this.

"Belief system"?. Have you ever heard of the Big Bang? That's what expansion and growth of space is. Inflation has nothing to do with the concept.

Thanks for the wishes of happiness, Michael. Unfortunately this discussion has brought little. Accordingly I herewith resign from cosmology discussions at Imminst. While I find the subject fascinating, it's impossible to have a coherent discussion in an environment that is constantly peppered with false statements and snide dismissal of the most basic concepts.

[Lazarus Long]

Unfortunately this discussion has brought little. Accordingly I herewith resign from cosmology discussions at Imminst. While I find the subject fascinating, it's impossible to have a coherent discussion in an environment that is constantly peppered with false statements and snide dismissal of the most basic concepts.

Brian this is not really true. You and Jay, or with me and others have never been anything if not cordial and coherent, even friendly as well. I certainly have not been hostile to your criticism and I feel I have always benefited by our exchanges even when we might disagree.

I really wish you would reconsider and recognize that most of us (the membership) are not the ones you object to whether we are the ones responding or just reading.

I agree that the snide remarks are not helpful and I wish that everyone would refrain from them but it is also possible to just ignore them most of the time as they are at best a destructive distraction. Do not let your dispute with one or two posters escalate into emotional angst or an even more destructive end to communication over these subjects.

If you do then you have ceded the topic to those you least respect and they in turn get to dominate the dialog, which I do not think is either helpful or wise.

[bgwowk]

I do confess amazement at the extent to which this discussion of esoteric matters of no practical relevance has gotten under my skin, even as the Insitute has agonized over issues of much greater importance. I suppose it's because modern cosmology rests upon the greatest and most ingenious accomplishments of physics, inluding General Relativity and the Standard Model of particle physics. Disrespecting this incredible edifice of knowledge and human achievement without knowing anything about it is like a savage soiling a great work of art produced by a thousand geniuses, and then painting a single jagged line and saying, "I think mine is just as good."

The problem here has really been with one individual. That's unfortunate, but as long as there is freedom of speech, as there should be, this kind of thing is going to happen. People need to know that in any public forum where science is discussed, loudness is no assurance of veracity, and silence of others who know better does not imply endorsement. But silence it will have to be because I simply cannot keep up with this any longer. The BS just keep coming in relentless torrents. Perhaps I'll confine future comments about physics to discussions in the full member section as time permits.

[xanadu]

Well gee whiz, bgwowk, you do not take kindly to disagreement it seems. Now I'm a savage desecrating the temple of science with my doubts and alternate theories. I thought science was the free flow of ideas and rigorous even harsh criticism of established beliefs? Isn't that how we advanced? Advancement has never come by agreement and avoiding any opposing points of view. Advancement has come by examining our beliefs and finding a better way.

I'm certainly sorry if I hurt anyone's feelings by not showing enough respect towards accepted theory. I've tried to avoid any sort of personal attack and to confine my discussion to matters of science. Perhaps implying or saying that someone is wrong can be taken personally but there is no need to take it that way. I may very well be wrong about everything I've talked about but I'd like to see why I'm wrong instead of being told "Einstien says so" or being called a savage. Not that that bothers me but it's not being scientific. I will try very hard to avoid any referrence to him and to stay out of his discusions by and large, if that will help. Am I still allowed to discuss things with other people or will I finally be kicked out for being such a heretic?

[jaydfox]

Now I'm a savage desecrating the temple of science with my doubts and alternate theories.

No, you're just an ignorant, arrogant skeptic. Desecrating the temple would imply that you understood the science enough to have been admitted to the temple. You can't desecrate what you don't have access to, and I can't grant you that access, nor can Brian, nor can a university. You grant yourself access when you bother to learn the basic math and physics underlying GR and quantum mechanics.

You claim inconsistencies and holes in theories you don't understand in the slightest, and protest when others can't dumb the science down enough for you to understand it. It has been pointed out to you repeatedly where your inadequacies in science and math are, yet you refuse to acknowledge your ignorance and instead criticize the deeper understanding of others as faith.

When you can demonstrate a minimal proficiency in tensor calculus, you will begin to have the tools to have a halfway intelligent conversation about general relativity. Until you have such a proficiency in tensor calculus, you're ramblings are amusing, but not very helpful for those who actually want to learn something. Your ramblings have been useful to the extent that Brian Wowk and I and others have been able to use them as a starting point for teaching others some basic concepts. To the extent that you seem to think that you're making some sort of noble stand, or that you're exposing some grand conspiracy or whatever, you're only exposing yourself as an idiot. It used to frustrate me, but now I find it pretty funny. I've never met anyone so enthusiastic to make himself appear the fool. It's gotten to the point where I can only assume it's all an act, though I'm not quite sure what your intentions are. Piss people off? Make people think you're cool because you're the ardent skeptic? Stroke your own ego? Whatever the reason, it's hilarious. I just wish it didn't get under the skin of people like Brian. But maybe that's all you care about, is getting under people's skin and driving them away, then claiming "victory".

Anyway, best of luck in your future physics career. Like I said, a good place to start is to acquire an understanding of tensor calculus. If you can't do tensor calculus, you're never going to be able to have anything that might be mistaken as an intelligent discussion about general relativity. I've known people who can have intelligent discussions about general relativity without the requisite understanding of tensor calculus, but that was because their intuitions about spacetime and GR seemed to mesh well with what tensor calculus teaches us. Your intuitions seem to be sorely lacking, though not entirely wrong. There is hope for you. Study tensor calculus, and you should gain some of the intuition you seem to be lacking. In the process, you might even answer some of your own questions. If not, you'll be in a position to ask them intelligently, to provide concrete examples, analogies, and equations to provide context for your questions, and to critically analyze the answers.

[biknut]

Even though I don't understand the math, I find the subject matter fascinating. It's great to get to listen in on the conversations of people who do.

The best thing to do is just ignore comments you don't like.

Last night I was listening to a discussion on the radio about quantum physics. They said Einstein hated the concept of quantum physics because of the random nature of it. The example they gave that he hated a lot was that if proton goes up, another one goes down. It apparently doesn't matter how far apart they are. One could be on one side of the universe and the other one here, and they both move at the same time. Is that right? They said it implies something has to happen faster than the speed of light and Einstein didn't like the idea of it. They said understanding this may lead to time travel.

[xanadu]

I see jay made some sort of attack/reply to me but I didnt read it beyond the first sentence or two. I've already heard everything he has to say along that vein. Nothing but personal attacks, that's why I do not discuss anything with him anymore.

biknut, that's interesting about Einstein. People lay all this stuff on him like he is supposed to never be wrong. He never claimed such a thing but imagine having a rep like that to live up to. He was a human being like anyone else. Whenever he made a small mistake people made a big deal out of it like he wasn't supposed to ever be fallable. Many of the predictions made from quantum mechanics have not been observed and can be called theory. We aren't going to get any farther in this discussion because no one here knows any more about it beyond repeating what they've been told. After that it just gets repetitious especially the name calling.

[DJS]

Jay's post, distilled:

learn tensor calculus ASAP

Capice?

[jaydfox]

http://www.imminst.o.../guidelines.php

If you have problems with this, you can post 'em in the Free Speech Forum.

People lay all this stuff on him like he is supposed to never be wrong. He never claimed such a thing but imagine having a rep like that to live up to. He was a human being like anyone else. Whenever he made a small mistake people made a big deal out of it like he wasn't supposed to ever be fallable.

Yes, even the most respected of physicists have made mistakes, though made on a level that none of us here could relate to. It's like taking a chess comentator's word for it that Kasparov made a less-than-ideal move, when I myself can't appreciate the strengths and weaknesses of either the move he made or the "more ideal" move he should have made. I'm not in a position to critique, but that doesn't mean that it's not fascinating to see the mistake pointed out.

And it is interesting to see such mistakes in action, and where they've slowed progress in various fields. Of course, the many other positive contributions more than make up for any roadblock to progress such mistakes have caused.

I just got done re-reading* Kip Thorne's 1994 book, Black Holes & Time Warps (subtitled "Einstein's Outrageous Legacy"), and it's fascinating seeing the history of this one particular and narrow branch of GR studies. As much as he shows where new insights helped innovate and often revolutionize fields of physics, astronomy, etc., he also shows where influential physicists have made mistakes and delayed progress because the scientific community took the opinion of such esteemed experts as the final word.

However, such mistakes can never stop, only slow progress, and once the mistakes came to light, progress was rapid because of the exciting implications of such a mistake: our intuition was wrong and needs to be adjusted. In some ways, such mistakes are good for overall progress, because they force paradigm shifts in thinking.

As for this particular example with Einstein, one important thing to point out is that his opinion of QM depends in large part on the exact model/interpretation of QM. His remarks weren't quite as applicable to consistent histories and many worlds interpretations, but they were quite damning for the Copenhagen interpretation. The thing to learn from this is that, if we are to be swayed by the intution/opinion of someone so highly regarded as Einstein, then we should be swayed into having doubts about the Copenhagen interpretation, and not QM as a whole. I myself used to prefer the Copenhagen interpretation, but in the last few months have found a new interest/preference for MWI. This in no small part due to studying some of the paradoxes and intuitively bass ackward things that Einstein pointed out, which lead others to develop alternative views on QM to reconcile Einstein's objections.

* During my re-reading, it became clear to me that the first time I read the book, I only read the prologue and chapters 10-14. Apparently, during that first reading, I read those chapters because I thought myself smart enough to skip the first section of the book. In hindsight (i.e., now that I understand the basics of tensor calculus, etc.), I see that I missed some good material. More importantly, I missed a fascinating historical background to the modern (up to 1993) understanding of black holes.

It's a good book, and I recommend it. I should warn that, while the analogies and diagrams are good, they still don't quite fully convey the intuitive "feel" for curved spacetime that you need to understand black holes. But that's mainly the fault of the medium. I think a book is somewhat inadequate for conveying the mental imagery necessary to have an intuitive feel for GR. I'm still developing that intuition, guided mainly by mathematics, and many of my mental images would require a 3-D medium and/or animation to get the imagery as intuitive as possible.

[eternaltraveler]

Kip Thorne's 1994 book, Black Holes & Time Warps

great book. Haven't read it since 1994ish. My middle school library had a copy (I read every physics book in that libary). It was great for getting my interest piqued enough to get into some harder stuff.

[jaydfox]

Middle school? How old are you? I was in high school in 1994, though I don't think I bought this particular book until I was at Chico State, so sometime in 1997 or maybe 1998. I didn't start studying tensor calculus until 1999.

[eternaltraveler]

high school, middle school, it was the same school for me anyway

In 94 I was 15.

[jaydfox]

My middle school library had a copy (I read every physics book in that libary).

By the way, you sound like me. When I was in the sixth grade, I was good at arithmetic, but didn't really understand higher mathematical concepts. My dad was taking algebra in college at the time (trying to finish up a bachelor's in business, but he had taken so much time off when I was born that he had to basically start over: he was 7 classes--not units, classes--short of his degree, with over 180 semester--not quarter!--units under his belt!), and when he got done with the semester, and I was done with school, I started reading his books.

I started with the "Elementary Algebra" book, and read from the beginning. Sections 1.1 and 1.2 weren't too bad, but by 1.3, things started to get a little confusing. By the time I finished chapter 1, sections 1.3 and 1.4 made sense. By the time I finished chapter 2, chapter 1 made sense in its entirety. By the time I finished chapter 3 (which I didn't really understand), chapter 2 made sense. And so on, until I finished the book. This spanned a couple days. Then I picked up the "Intermediate Algebra" book, and read from the beginning. It went so far as to introduce the topic of limits and give the derivation of a derivative (no pun intended), and ended with the concept of the exponent rule for derivatives, or whatever you call that rule, where Dx[x^n] = nx^(n-1).

That took another week almost. I then got a bus pass and library card and spent the entire summer at the library, five days a week, 6-10 hours a day, reading books on trigonometry (which was damn hard for some reason), calculus (which was relatively simple for some reason), basic physics (well, mechanics, not electromagnetism), and by the end of the summer, relativity, cosmology, and particle physics. I learned more in that one summer than most undergraduate physics majors learn in a year. But it was mostly conceptual; my mathematical rigor was still lacking. My intuitions and conceptual understanding hasn't changed much since that summer, though my mathematical rigor and understanding has vastly improved, allowing me to derive concepts I once had to take for granted. With the mathematical rigor, one also sees where analogies are only that: analogies. There are always subtleties that you have to understand the underlying math to fully grasp, but many of those subtleties don't get in the way of the types of high-level discussions we have here.

Between quantum mechanics and general relativity, my conceptual understanding has changed far more with respect to QM, as my mathematical understanding has increased over the least 17.5 years. My intuitions about GR were mostly accurate, with a few notable exceptions. My intuitions about QM were mostly incorrect, other than the basic ideas every physics student knows about, such as in the case of the double slit experiment.

[MichaelAnissimov]

Smartfolk like Brian should understand that when you think you're arguing against only one person, you're actually communicating with the hundreds or thousands of people that read this thread silently. You can fail to convince the one stubborn person, but still teach something to thousands. Most individuals don't really matter in the memetic scheme of things. I barely even participate in online forums or mailing lists anymore, because I see myself doing a lot more good on my blog where 1) my voice is inherently given more currency, 2) much wider exposure than would be possible buried within registration-barred sites, 3) a better stepping stone to widespread recognition and pushing forward the cause.

The problem is that people won't read the literature if they aren't personally interested. There are dozens of people who I have argued with about AI for years whose opinions would probably be changed overnight if they actually read a couple hundred pages, but they never will, so who cares. Biknut is right, just ignore people that don't want to have an educated conversation, because their opinion on these matters is worse than worthless. It's sad to see someone like Brian, who is so well-educated, get all emotional because of one of the many millions of amateurs who like to make up their own theories of physics.

A wise man once wondered why people don't make up their own theories of chemistry or biology the same way they do theories of physics. It's not like physics is more contentious - the most precisely predictive theory in science is the Standard Model.

I really hope that threads like this don't cause more of the leading lights of ImmInst to take off for lame reasons. Aubrey left because of some silly argument about SENS with prometheus, for example. If you guys get worked up like this over physics, I hate to see how you'd react to disagreements in social science or politics.

By the way, this thread boosts my hypothesis that people who use the word "assumption" in discussions, in the context of "you're making an assumption", always seem to be the clueless ones themselves. Not that the informed people don't say the same thing, they just don't seem to use that particular phrasing.

Well, that makes sense. If a black hole is an imploded star from our own universe, then there ain't any way for information to go through to some other universe. I guess those sci-fi freaks had better stop reading Michael Moorcock's 'multiverse' junk.
I believe that the 'information' that he is talking about is the stuff that makes matter into the shape of YO' AZZ. That's information. Anything that ain't pure matter is information. Heck, even the makeup of a proton, atom, electron, quark or whatever is information.

--------------------
http://www.thefighting44s.com

Asian Pride=Asian Honor

This post is particularly awful. It also supports my hypothesis that English-speakers who demonstrate racial pride have lower average IQ than English-speakers who have little to no racial pride.

lol@Chico State, btw.

[jaydfox]

lol@Chico State, btw. 

[thumb]

[MichaelAnissimov]

Relevant to this thread.

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[jaydfox]

I dedicate this link to xanadu:
http://space.newscie...article/dn11180

[tinala]

Does a black hole continue to be to infinity? Not being funny, I am quite interested in the topic but know very little. Plus my young son has been asking me many questions and I would like to feed his enthusiasm and hopefully not kill it. Ok the reason I asked this was, (and bear with me here, I'm dreadful at explaining myself):
Nature seems based on cycles...waves, from ones easily measured, to cycles that have yet to be completed in the time frame of mans existence. e.g Ice ages, ozone hole, etc.

If a black hole exists through a collapsed sun and has this vast gravitational pull, which sucks all in. Is it a possibility that this is a suns cycle?, hence when its pulled in enough stuff it does a big bang thing?
Sorry if this seems an ignorant question, I have a very limited background in science.

[rwoodin]

As far as black holes go, my understanding is that gravity warps or slows time for an object in a very strong gravitational field in the same fashion as velocities that are an appreciable fraction of the speed of light warp or slow time relative to a stationary observer. A stationary observer, observing a fast moving object, sees that objects time moving slower than their own and equivalently, an observer in the absence of a gravitational field sees an object in a strong gravitational field's time moving slower than their own. They will also observe distances as being contracted relative to their own distance scale. This is because space and time are inextricably bound to each other so that distances and the rate of flow of time are variable according to an objects velocity and also, the magnitude of the gravitational field present. Possibly, in a rotating black hole, the mass is not evenly distributed so that the magnitude of the gravitational field (at a fixed point) changes as the black hole goes around. This would cause greater or lesser degrees of time dilation and length contraction at a fixed point. As the black hole rotates, the variable space time and distance rotate around with it, dragging as it were, space and time around.

PS. If I'm way off base here I'd welcome any critique. It's my basic, nonmathmatical understanding of the effects predicted in the theory of relativity. I remember reading Kip Thorne's book on black holes and time warps as well and being very intrigued by it.

Edited by rwoodin, 12 May 2007 - 11:18 PM.