Posted on 01/07/2003 6:23:34 PM PST by forsnax5
You gave me that link before, and here's what I said:
It's from a Texas chapter of an Objectivist study group, not from the Ayn Rand Institute. Anyway, I read only the introduction, and I encountered this:When I have finished, I think you will be convinced (especially those advanced enough to follow the math) that the theory of relativity is not consistent with Objectivism, while the Lorentz ether theory is, and you will understand what the theory of relativity actually means.
I don't have the time to study the entire thing. I consider myself an Objectivist, and I'm familiar with special relativity (although I've never studied the general theory). I've never been aware of any contradictions between Objectivism and special relativity. Indeed, Einstein demonstrated that the universe is objectively real, and verifiably so, notwithstanding the various observations of different observers in different frames of reference.
I read just a bit more. In the first chapter (after the intro) the author says: At current levels of understanding in physics there is no known way to construct immutable clocks or rulers, but their existence, at least in principle, must be assumed if the concepts of length or time are to have any meaning. Here the author betrays his lack of understanding of special relativity. Perhaps if I read further he would clear things up, but at this point I'm giving up on the guy. Relativity isn't for everyone.
Neither. Objectivism is perfectly compatible with SR and QM, and if an Objectivist claims otherwise, it proves only his own failure to adhere to the epistemology.
The universe is the way it is, and not how we might wish it to be.
I'd love to see any of the "Objectivist scientists" on this forum refute the claims made on the said website by either logical or scientific method.
He doesn't dispute the formalism, just the interpretation. I think his interpretation is lame, however. He simply postulates by fiat that rulers shrink and clocks slow down, and then insists that rulers and clocks don't "really" measure space and time, anyway. Nowhere does he say why, philosophically, I should expect the stub-your-toe physical reality of differently-aged twins. Nowhere does he describe a physical mechanism for atomic decays to occur at a slower rate. You can handwave away time dilation as a mere problem of perception all you want, but at the end of the day you are left with the reality these stone cold phenomena.
I haven't read the Ayn Rand Lexicon, but Peikoff's statements about physics in Objectivism: The Philosophy of Ayn Rand are pure comedy.
How do you reconcile the violation of conservation of energy in general relativity? One of the tests for "junk science" is to see if it violates conservation of energy by this metric GR is "junk science".
Energy conservation is not violated in general relativity. But I'm curious: why are you and Lenny so wedded to energy conservation? Do you know why energy is conserved? Can you state the necessary and sufficient conditions for energy non-conservation?
How much of physics have you accepted on faith - someone else's expertise because you cannot understand it yourself?
I take less of physics on faith than at least 99.999% of humanity, I estimate (placing myself for reasons of modesty at the bottom of my profession).
LOL, I guess I can tell where you stand on the "Fact and Value" debate.
Dr. Leonard Peikoff states: "...The universe is everything. 'Outside the universe' stands for 'that which is where everything isn't.' There is no such place. There isn't even nothing 'out there'; there is no out there.'"
Did it occur to Peikoff that the term "universe" is used in two different ways ("everything that exists" and "everything that you can geometrically travel to or see") and that these two senses aren't necessarily congruent? When we say, "the universe is expanding," we are clearly referring to the latter sense.
"If the universe is everything and it is expanding, what is it expanding in to?"
This is difficult to visualize, but an expanding universe doesn't necessarily imply that there is any external space. It's a geometrical question you're asking, and there are geometrical solutions that expand into themselves without postulating any boundaries or extra dimensions (for example, a de Sitter space).
Based on Dr. Peikoff's statement the very concept of the big bang is a contradiction - it cannot have happened. So is the big bang a bust, is the Big Bang theory incompatible with Objectivism or is Dr. Peikoff not an Objectivist?
Peikoff is an Objectivist whose failure to adhere properly to Objectivism has led him astray on the topic of physics. I don't think that makes him a bad person. And now you know where I stand on "Fact and Value". :-)
Physicist, I apologize for addressing you in #152 and #153 ... I won't trouble you with any further requests for clarity.
Not exactly... It bitches about a particular application of an equation, but it doesn't really go into details about the "experimenter's methods".
Without more discussion of those actual methods, it's impossible to say whether Van Flandern has a valid objection or not.
However... Looking over Van Flandern's website, other works, and his specific piece on the gravity experiment, I can't say that I'm impressed.
Generally, while Van Flandern clearly has a lot of knowledge of the field of astronomy (he ought to, he has a PhD in it), and is capable of making some good points, he also is clearly more than a bit of a crank. For example he's an evangelist for the proposition that there are artificial structures on Mars, which he presents with unshakable belief based on the slimmest of evidence and yet calls "proof".
He follows the crank pattern of having a naysayer's argument against nearly every established theory (the Big Bang, origin of the asteroid belt, cometary formation, the possibility of a tenth planet, etc. etc.). Most scientists are lucky if they ever manage to revolutionize even a *single* bit of conventional wisdom -- Van Flandern has the crank's arrogance of thinking he can overturn *all* of it. And has built a personal website to preach it.
He also has the crank's paranoid mantra down pat: In his own words, he writes that his website's "[...] goal is to do astronomy research wherever promising avenues of advancement are blocked by funding authorities solely because the research results might conflict with an accepted paradigm." Yeah, sure, you can't get your theories published because of the *conspiracy*, and not because they appear to be crackpot ideas.
But let's get specific...
In his argument against the results of the recent gravity experiment, he gets some *basic* astronomical concepts astoundingly wrong, which does not bode well.
In his overview of alleged previous findings in the field, he claims:
The propagation speed of gravitational force is bounded by six experiments to be much faster than the speed of light [5]The work cited in footnote five was written by... Van Flandern himself (didja ever notice how often cranks cite their *OWN* works for supporting evidence?).
That work can be found here.
In it, while describing his claim that "Laplace determined that the minimum speed of gravity consistent with observations was at least 10 million times the speed of light", he writes:
As viewed from the Earth's frame, light from the Sun has aberration. Light requires about 8.3 minutes to arrive from the Sun, during which time the Sun seems to move through an angle of 20 arc seconds. The arriving sunlight shows us where the Sun was 8.3 minutes ago. The true, instantaneous position of the Sun is about 20 arcs seconds east of its visible position, and we will see the Sun in its true present position about 8.3 minutes into the future. In the same way, star positions are displaced from their average position by up to 20 arcs seconds, depending on the relative direction of the Earth's motion around the Sun. This well-known phenomenon is classical aberration, and was discovered by the astronomer Bradley in 1728.This is just... wrong. (Although it's clearly where Aruanan's earlier post came from.)
While it's true that light from the sun exhibits an apparent aberration (i.e., false visual displacement) of 20 arc seconds of angle, and while it's true that Bradley discovered this in 1728, just about everything in between is nonsensical twaddle.
Note how much Van Flandern harps on "8.3 minutes" (the time it takes light to travel from the Sun to the Earth). One has to wonder why, because the aberration has *NOTHING* to do with how long it took the light to get from the Sun to the Earth. If the Sun were half as far away (and its light took 4.25 minutes to get here), the amount of aberration would *STILL* be 20 arc seconds. Furthermore, light from distant stars shows the same 20-arc-second aberration (when the Earth's orbit is traveling perpendicular to the Earth-star line), even though the light from those stars took *years* (some, thousands/millions of years) to arrive here. "8.3 minutes" is *entirely* irrelevant to the issue of aberration.
Even worse, he constantly misrepresents aberration as having something to do with 8.3 minutes in the "past" or "future", when aberration has NOTHING to do with where anything was or will be, timewise. It's simply an optical illusion caused by the fact that the orbiting Earth is traveling "crosswise" (at 29.79 Km/s) to the path of the incoming photons (streaming in at the speed of light). It's similar how rain appears to be angling downward at you as you drive your car through a straight-down sprinkle. There's a good discussion of this phenomenon (as opposed to Van Flandern's mangled version) at: http://www.newtonphysics.on.ca/Aberration/Aberration.html.
Keep in mind that light aberration from a star/Sun depends *only* on the speed which the Earth is cruising along in its orbit. Now let's take Van Flandern's errors and nonsense line by line:
Light requires about 8.3 minutes to arrive from the Sun, during which time the Sun seems to move through an angle of 20 arc seconds.No, sorry. Here Van Flandern confuses parallax with aberration. "Seeming to move" is caused by parallax, and by coincidence the apparent motion of the Sun "around the Earth" due to the Earth's orbit is 20.45 arc-seconds per 8.3 minutes, which is reasonably close to the 20.49 arc-seconds of stellar aberration. BUT THEY ARE IN NO WAY RELATED (and if the Sun's gravity were greater/lesser, they wouldn't be even approximately the same size).
Furthermore, while it makes some sense to talk about apparent motion due to parallax and how "fast" things seem to move, stellar aberration DOES NOT SHOW ANY APPARENT MOTION. It's a fixed displacement. For example, distant stars show no apparent motion relative to the Earth (due to their enormous distances), and yet *still* appear displaced due to stellar aberration. Objects that are entirely at rest even show aberration. It's as wrong to try to pin aberration on movement so many minutes ahead/ago as it is to claim that the angled glass of the side of an acquarium visually displaces the rocks in the acquarium because of where the rocks were "a minute ago".
It's a very bad sign that Van Flandern starts out a discussion of stellar aberration by discussing orbital parallax -- they're unrelated.
The arriving sunlight shows us where the Sun was 8.3 minutes ago.No, since the Sun *hasn't moved* in the past 8.3 minutes. It's right where it always was. The Sun would appear at the same apparent spot in the sky no matter how long it took its light to reach us.
The true, instantaneous position of the Sun is about 20 arcs seconds east of its visible position, and we will see the Sun in its true present position about 8.3 minutes into the future.Again he confuses apparent position in the sky (due to the changing position of the Earth) with "true position" (actual physical coordinates), and parallax with aberration.
The "true position" *doesn't change*. The Sun doesn't go zooming around the solar system. It sits right there in the middle, century after century. Therefore it's nonsense to talk about its "true position 8.3 minutes in the future", as if that's any different from its "true position" right now. And again, the *apparent* displacement due to stellar aberration has nothing to do with movement "8.3 minutes" in the future or past.
In the same way, star positions are displaced from their average position by up to 20 arcs seconds, depending on the relative direction of the Earth's motion around the Sun.Suddenly, Van Flandern admits that distant stars show the *same* visual displacement, without drawing attention to the fact that his fixation on 8.3-minute-old light (which he presented as being key to the Sun's visual displacement) can't possibly be the case for the years-old light arriving from the stars.
Sigh.
But on to his point, even if he has done an amateur's job of confusing the crap out of his audience (and maybe himself) about stellar aberration...
His main point is that although the Sun does indeed appear 20.49 arc-seconds away from where it really is, gravity doesn't. And from this he concludes that gravity propagation must therefore be faster than that of light.
But the mistake is that while the sun's apparent (visual) position is indeed offset due to an optical illusion caused by the Earth's motion, the Sun was never really "there" in the first place. It's not moving, his confused paragraph above notwithstanding. Thus, no matter how long it may take the gravitational force (or field gradient) to propagate, the Sun's "gravity well" is unmoving and unchanging, it's like a standing wave. Thus it's no surprise that the Earth will always find itself gravitationally pulled towards the "true" position of the Sun. This tells us nothing about how fast the gravitational force "adjusts" to changes, since the Sun ain't changing appreciably.
And it's no surprise (and thus not significant) that the gravitational force doesn't demonstrate a 20.49 arc-second aberration like light does, because gravity is presumably a result of space-time curvature, and thus its effects are independent of the lateral motion of an affected body, *unlike* the manner in which incoming photons are encountered as they stream in.
Ah, c'mon, Dan, no response to this? PLEASE PLEASE I enjoy reading your responses. And if ever there were a highly inflexible, NON-bended straight line, Southhack's given you one. Now, some will say it's a cruel sport. It's too easy. It's like hunting elephant in a zoo. But I say: Go for it!
A while back I decided that Southack is a "science troll", purposely throwing monkeywrenches into scientific discussions. No one could be as obtuse as he seems to be, especially since he throws just enough science into a post to show that he *does* know some (like his allusion to diffraction above), and ought to know better than he pretends. Furthermore, he has a track record of being able to recognize when he's fighting a losing battle on one point and he chooses that moment to fling another spitball into the discussion, drawing the discussion in another direction.
He also has the troll's habit of declaring victory after getting nailed, which he knows just infuriates/frustrates most of his sparring partners.
He enjoys rankling us science-types, no more, no less, and he does it by making preposterous statements that cause people to scramble to correct him.
So rather than argue with him ad infinitum, I find it useful to just hammer a few of his posts into the ground in each thread to ensure that people see that they needn't take him seriously -- after that it's a waste of time to bother with his every subsequent attempt to keep trolling, his credibility is already gone, and his followup posts thus speak for themselves.
But since you insist...
Light distorts slightly going past the edge of something (like a thumb held out, although the effect is very slight and hard to see unless you artificially enhance it) not because of gravity (it's easy to prove that the amount of gravity generated by your thumb is so tiny that it can't possibly explain the phenomenon) but because of diffraction, which is an effect caused by the wave nature of light. The "waves of light" curve slightly as they pass near an "obstacle" in the same way that ocean waves curve a bit around the edge of a jetty, although given the speed and wavelength of light, the amount of "spread" is slight (but noticeable).
So again, Southack is playing the fool when he implies that diffraction is caused by "gravity" and "gravitons" and that there's any connection to the "speed" of gravity.
GB:
"If the universe is everything and it is expanding, what is it expanding in to?"Physicist:
"This is difficult to visualize, but an expanding universe doesn't necessarily imply that there is any external space. It's a geometrical question you're asking, and there are geometrical solutions that expand into themselves without postulating any boundaries or extra dimensions (for example, a de Sitter space)."GB:
"You're [Physicist] quite skillful at avoiding my little traps. So there's parts of the universe one can't travel geometrically to or see? Then how does one know it exists? (And what is geometrical travel?) So the big bang wasn't the entire universe, just a chunk of it or that which we can observe?"
GB started this dialogue as an attempt to show contradictions between Objectivism and physics. If GB had been successful in showing that Piekoff has an imperfect understanding of cosmology, what would that prove? It's necessary to show more than one man's failure to grasp some complicated material. GB would need to show that some principle of Objectivism is, literally, in conflict with some principle of physics. GB hasn't done that. Physicists who have been exposed to the material have no problem with Objectivism, nor should they.
Anyway, to me the question of "Into what is the universe expanding" isn't all that different from asking "In what direction is the universe moving?" Being everything, the universe isn't "moving" anywhere. Same thing for its size. Being everything, the universe isn't expanding "into" anything. Such questions are inapplicable to the universe. But I'll let Physicist have the final word on this. He's a lot better at this stuff than I am. I mean, a lot better.
Me:
Being everything, the universe isn't expanding "into" anything. Such questions are inapplicable to the universe.
You:
Then is the concept of an "expanding universe" valid? What is it compared to to determine that it is expanding? Is the "Big Bang" theory based on a non valid concept? To me a good deal of cosmology and modern physics is no different than religion. It's based on contradictions such as the above and requires faith (violation of the law of identity).
I think you're leaping to unwarranted conclusions. If it helps you to conceptualize the big bang as expanding into some kind of "meta-space" that's fine with me. Anything that can aid in our ability to grasp the concepts is fine, as long as we don't then reify such things. I don't think meta-space is a necessary concept. The universe is expanding. All the evidence points to that conclusion. It isn't expanding "into" anything, the way I see it, but that's not an opinion which you need to accept.
You can put your faith in Physicist if you like. For me, I rely on my own understanding ...
No "faith" is involved. I know his academic background, and I've seen his postings here. I have "confidence" (not faith) that he knows what he's talking about. His explanations of data seem to be sound, and I value his opinions. You have your own way of looking at things, and that's fine. I'm not aware of any defensiveness, as he's quite able to defend what he says. He's a big boy and I'll let him speak for himself on such matters, if he cares to.
Oops, that should be 4.15, of course.
Most of my group's funding comes from IBM, but I do accept government largesse. Ayn Rand herself sanctioned that explicitly (FWIW, not that I buy into the Rand Cult of Personality). It's value in exchange for value.
He's against big government, but yet works on large scale computer programs that intrude into people's lives.
?
He's an Objectivist, but anyone else who also claims to be an Objectivist and disagrees with his world view is not an Objectivist.
I have no clue what gave you that idea.
He believes in the Big Bang as the starting point for the universe today, but only that part of the universe you can only travel to or see.
How could I believe otherwise? If I can't see it or travel to it, how would I know whether it's expanding or not?
He is intolerant of views differing from his,
Physics is not a matter of one's "views". Some statements are in accord with known data, and some are demonstrably wrong. If you think I'm unforgiving on that score, you should try nature.
as he claims his views are objective reality.
Well, sure. Isn't that part and parcel of being an Objectivist? If I thought my opinions did not reflect reality, I'd change them.
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