Yeah, I already used this title once before. It’s a good title, okay? Cut me a little holiday slack here.
By way of slightly-warmed-over blogging, I present to you the slides from a talk I gave a few weeks ago at Villanova, my undergrad alma mater. The original mandate was to talk about scientific literacy to a collection of undergrads, but I didn’t know how to make that fascinating. So I took it to the next level and went a bit meta, talking about the way science works. It was at a fairly abstract level — I didn’t go into building detectors, and error bars, or anything like that — but not too highbrow philosophy-of-sciencey — I didn’t get into Kuhn vs. Popper, much less Feyerabend or the Strong Programme, although you’ll find touches here and there.
To bring things down to earth (relatively speaking), most of the talk consisted of an extended look at the battle between “dark matter” and “modified gravity.” It goes all the way back to Leverrier and the discovery of Neptune, whose existence was inferred via its gravitational tug on the orbit of Uranus. Neptune was the first successful prediction of dark matter — some unseen substance whose existence is revealed by its gravitational influence. Leverrier tried again with the similarly-discrepant orbit of Mercury, positing a planet called Vulcan; but this time it turned out that gravity itself was the culprit, after Einstein showed that general relativity correctly accounted for the precession of Mercury’s orbit. So the lesson from history is — different ideas work in different circumstances. Keep an open mind until the data come down on one side or another. (And once they do, admit it.)
Today, of course, we’re dealing with an analogous problem, given that 25% of the universe is apparently some kind of dark matter that doesn’t fit into the Standard Model of particle physics, and 70% is some kind of dark energy that is even more mysterious. Modified gravity might be at work here as well, and I talked about the prospects.
Along the way, I drew out some of the lessons about how science works that these various investigations have taught us. I intentionally did not try to wrap it all up with a neat bow into a catch-all philosophy of science, as I think the reality is kind of messy, and it’s worth admitting that. The closest I came was the famous quote from Professor Rumsfeld, previously shared. This led to a series of cautionary homilies warning against misuse of the hypothesis-testing nature of scientific inquiry. The truth is, scientific knowledge is inevitably tentative, not metaphysically certain. But that doesn’t mean that anything goes — some things we really do understand! So I cautioned against various mistakes, using perpetual-motion machines, Intelligent Design, and What the Bleep Do We Know as good examples of what not to do.
Charon,
1) I have read Rob knops’s definition of a perpetual motion machine: when somebody says “perpetual motion machine,” what they really mean is some machine that puts out more energy than is put into it.
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2) Charon you claim: the universe doesn’t give the energy that creates stars, etc. (violating one condition to be a “perpetual motion machine”).
The Universe produces all the energy within it. If there is more energy in the Universe today than yesterday, or say 13.7 billion years ago +/- 0.03% what does that say in relation to Rob knop’s definition of perpetual motion machine.
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3) You and Rob knop claim: The Universe is not local?
Are you speaking from another ‘pocket’ universe somewhere else?
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Though it may appear clear to you both inside your heads, neither you or Rob knop have shown that the Universe is not a perpetual motion machine.
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Charon said: the universe doesn’t give the energy that creates stars, etc. (violating one condition to be a “perpetual motion machine”).
Priceless – The Universe does not produce the stars inside it?
Where did the energy of the first cause of motion come from?
From a power source (or big foot) kicking the universe into motion?
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Comments from “the educators” are always appreciated regardless of the thinking, that our intelligence less then adequate. Hopefully, their “own fires of motivation” will continue to fuel our imaginations by “their choice” to comment. 🙂
There is a relativistic version of MOND–it’s called TeVeS and it was formulated by another Israeli Prof named Bekenstein. I think it’s a recent innovation.
MOND proponants claim that TeVeS changes the way gravitaitonal lensing works, so the bullet cluster results may not seal the deal (they did convince me, although I was rooting for MOND)
Along the lines of what George was saying, the freakonomics people wrote an article in the NYTimes about correlations between birth-month and success in life–it was societal, of course, no astrology. But still…
http://www.nytimes.com/2006/05/07/magazine/07wwln_freak.html?ex=1166763600&en=abb6f6ba07d89cf3&ei=5070
Thank you folks for such excellent brainfood once again…
The nonlocality question is important and I found this book quite elucidating>>
‘The NonLocal Universe: The new physics and matters ofthe mind’
-Robert Nadeau & Menas Kafatos; Oxford UP 1999!
Re:astrology v. “science” see: ‘Cosmos and Psyche: Intimations of a new world view’
-Richard Tarnas; Viking 2006.
There is quite a difference between Rob Brezhny and Dane Rudhyar, but i’ve heard that those born with grand crosses in Aries in the fifth house are geniuses or serial killers…
No-one’s looked at the bullet cluster with TeVeS properly yet, but I think it may already be excluded by solar system etc.. anyhow.
The idea that 70% is dark energy and 25% dark matter is the best mainstream model, the lambda-CDM model.
However, the lack of slowing down of supernovae recession wasn’t predicted by the cosmological constant, but it was predicted and published two years ahead by a dynamics for gravity which is entirely factual. There is 100% bias in favour of mainstream and 0% objectivity towards new work, especially where it’s based entirely on facts which are well established (spacetime, Hubble recession, Newton’s 3rd law etc.).
Any statement of the constructive facts get ignored, any criticism of the mainstream gets responded to with a request for constructive facts, which then get ignored. What you never get is any interest in fact based science.
The creation-annihilation loops in the vacuum are limited to the range of the IR cutoff (~1 fm) so they don’t justify “dark energy” which is a hoax due to a faulty use of general relativity uncorrected for redshift of quantum gravity mediating gauge bosons, which get redshifted when exchanged between receding masses (gravitational charges), weaking gravity and preventing the big bang expansion from slowing down due to gravity as Friedmann’s [N*O*T E*V*E*N W*R*O*N*G solution to general relativity] suggested.
(I respect the fact that a comment here is not the best place, but with Jacques Distler and others on arXiv deleting my papers in 2002 within 45 seconds, without reading them, it isn’t possible to put information where it should be. Red tape gets in the way, not to mention elitism, hatred of so-called “pet theories”, etc. Even if you use entirely established facts, you’re still censored because they don’t have the time to read anything not in their carefully censored journals, which are biased in favour of M-theory and related speculations. To publish facts that actually predict gravity with that stuff would be embarrassing and thus impossible not only to them, but to me. I published in Electronics World.)
nc, you’ve said all this before. More along the same lines will be deleted — we’re insufferably mainstream around these parts.
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OK I always thought a perpetual motion machine is a machine which is capable of doing an infinite amount of net work without any new input of energy. This does not necessarily mean that it outputs more energy than is put into it as said by Rob Knopp.
There are two basic kinds of PMMs (perpetual motion machines): those that violate the first and second laws of thermo (which are Rob Knopp type machines that output more than they put in) and those that only violate the second law (machines that are 100 percent efficient). A PPM requries that work be done since a machine is some device that does work. What is work? The physics definition is that work is the dot product of force and displacement. Essentially this means that work = forcexdistance but also that the force and the distance have to be in the same direction (they should be parallel and not perpendicular). A block sliding on ice or better still a body moving through space is not an example of a PPM because there is no force being exerted. A planetary body does have a force being exerted on it over a distance but the displacement and the force are always perpendicular (not in the same direction) so the work done is zero. I am not sure about the expanding universe but my feeling is that there is not force involved in expanding the universe and therefore there is no work. However I don’t really understand GR and I am not sure how things work when you are talking about space itself expanding.
The reason why PPM don’t work is heat. Whenever any machine does work it produces heat. So in order for the machine to keep going it must somehow recover the heat energy it loses. However you basically end up producing even more heat if you try to recover the heat energy you lose and so you can never have a machine with 100 percent efficiency.