Cosmology and science

View 773 Tuesday, May 07, 2013

I’m slowly recovering from whatever it was that bit me.

I am still reading The Static Universe. It states that there are QUASARS with measurable proper motion, but whose red shift distance places them so far away that the motion we see and measure has to be orders of magnitude faster than the speed of light. That seems inconsistent with the General Theory of Relativity on which the whole notion of red shift as the proper measure of distance to the objects is based. There are other observations totally at odds with the Standard Cosmology. I am not so familiar with the literature on Cosmology, but if this book is at all correct, the Standard Theory has been falsified. The Expanding Universe as we were taught it in high school is not correct, and we have not the foggiest notion of how far away a number of cosmological objects are; which means we do not have to accept the Standard Theory with its postulated (but not observed) Dark Matter, Dark Energy, and mega-massive Black Holes. Indeed, we really don’t know a lot about the universe beyond a few hundred lightyears. We have a scientific consensus and a peer review group that accepts the Standard Theory and discourages publications of observations that seem to contradict it, but in fact the consensus is not based on the preponderance of the observed data.

Which sounds a lot like the Consensus Theory of Climate Change.

‘Cosmologists’ are to astronomers as ‘educators’ are to teachers, one finds.

I’m deeply suspicious of anything beyond the most basic, coarse-grained principles of quantum mechanics which we’re fairly sure we sort of understand at a superficial level of detail. As far as I can tell, the rest is pretty much all supposition based on assumptions about an unscientifically-small number of actual data-points.

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Roland Dobbins

Richard Feynman insisted that no one, including him, understood Quantum ElectroDynamics. He could teach you how to do quantum calculations, and to make theories that could be verified by experiment, but he could not tell you how to understand it. What he could do was look carefully at observations. He was careful to point out that Newton never understood gravity, and neither do we, but Newton could generate hypotheses from observations. Now Feynman was addicted to data and observations, and to the best of my knowledge pretty thoroughly accepted the operational philosophy of science,

We have this from The Meaning of Everything:

It was thought in the Middle Ages that people simply make many observations, and the observations themselves suggest laws. But it does not work that way. It takes much more imagination than that. So the next thing we have to talk about is where the new ideas come from. Actually, it does not make any difference, as long as they come. We have a way of checking whether an idea is correct that has nothing to do with where it came from. We simply test it against observation. So in science we are not interested in where an idea comes from.

Richard Feynman

Feynman had little good to say about philosophy, but I find that paragraph more valuable than a semester I spent studying logical positivism under Gustav Bergmann. When I began as an undergraduate I thought I was a logical positivist, until I learned what that meant. Philosophy of Science under Bergmann was an important experience.  I suppose I came away as an adherent of Karl Popper, but that’s a different story.  I did find Bergmann a refreshing antidote to the unrelenting behaviorism of the University of Iowa Psychology Department.

Re: Static Universe

There are a few points to be made on this subject, in my opinion.

The first is that the anomaly in the local area around the Milky Way can be explained by the fact that the Local Group is gravitationally bound. Also, in any system such as this there are bound to be random motions that have nothing to do with the grand scheme; orbital velocities of stars in the Galactic disk are fairly uniform but there are random variations, for example.

The expansion hypothesis is supported at large distances by data from type Ia supernovae (I think that’s right) which are rather uniform standard candles for reasons connected with the basic physics of the supernovae themselves.

The equations of general relativity pretty well demand either a contracting or an expanding universe; the only way to get around this is to introduce a fudge factor (famously known as the cosmological constant) which has to be set to ridiculous precision (120+ significant figures) at an early period of the Universe in order to leave us with the universe we are actually in. Either that, or general relativity is wrong; but there is rather a lot of evidence for relativity and very little against.

Finally, the Hipparcos mission has the primary purpose of determining positions and parallaxes for millions of stars. The precision is high enough that parallax measurements as a yardstick can be pushed out a long way; IIRC the figure is about 500 light years. Useful, because Polaris is closer than that.

Regards,

Ian Campbell

Yes: the extension of parallax methods of determining distance to a Cepheid variable has made it possible to determine accuracies out to to other galaxies in the Local Group by giving a better measure of the distances to a given Cepheid well beyond the limits of parallax measurements. Unfortunately the red shift method of determining distances doesn’t work in that region, as I understand it.

As to the evidence for and against relativity theory, the major ‘against’ is its complexity. Beckmann asserted that his entailed aether could explain all the observations with far simpler math and fewer assumptions. Starting with observed data and generating a new set of theories is of course very difficult, and may never happen.

Expanding Universe

Jerry,

The reason the Hubble shift was assumed to be a Doppler shift is that nobody had a plausible alternative explanation. This assumption was based on the theory that space was a perfect vacuum. It isn’t. Quantum Mechanics predicts "virtual" particles appearing and being annihilated almost instantly. This is experimentally demonstrated by the Casimir effect. Light slows down in a dense (non-vacuum) medium. This implies an energy loss – the red shift. Note also that there is no known way to measure the velocity of light from a distant object.

Regards,

Roy

Roy Lofquist

Ratcliffe’s The Static Universe makes that point: there is no such thing as a vacuum. I don’t think he questions the absolute invariance of the speed of light in a vacuum, but since there is no vacuum… Some Quasars have enormous red shift yet they have detectable proper motion. If we have no real idea of the size of the visible universe… Well, it’s something to think about. But all observed red shifts cannot be a simple Doppler effect of expansion.

re: cosmology

Despite it’s name, astrophysics is barely a science, or more accurately, very little of it has the same reliability as physics.

The core problem is the dearth of direct observation and the small size of the observation database.

Therefore Astrophysicists have to:

1) rely on a lot of second-hand data

2) assume that conditions which apply in the Solar system also apply everywhere else.

2) is further compounded by the scarcity of direct observation even within the Solar system.

So most of what’s presented as knowledge about the universe is actually but speculation, not groundless speculation but speculation still.

Almost every time we send a probe to a new part of the Solar system, we discover that things there are different, sometimes dramatically, from what was until then the accepted truth.

If Earth-based observation gives such unreliable results for objects that are only a few AU’s away from us, how can we assume that our hypotheses about objects that are even a few parsecs away actually describe what’s there?

My favorite example is the Sun: it’s supposed to be fueled by H-H fusion, yet it doesn’t seem to be hot enough for it to happen. The cold, hard truth is that astrophysicists are telling us it works on handwavium. It’s just 1AU away but we have no idea of what really happens inside.

Similarly, if dark matter had been invented in an sf book, there’d be flame wars about whether it’s handwavium or unobtainium.

It’s not very important as actual discoveries are made, like extrasolar planets, and faulty theories about galaxies millions of light-years away won’t kill anybody – not before someone invents a really good warp drive anyway!

What really irks me is this acceptance of speculation as solid science blurs the general public’s understanding of what constitutes a proven scientific theory, something you can base important decisions on, and what is mere opinion – climate is what comes to mind here…

Best Regards,

Jean-Louis Beaufils,

Paris

Some random thoughts:

As I recollect, Fr. Lemaitre derived the expanding universe from the field equations for general relativity. DeSitter space was unstable, but Einstein cooked the books with the Cosmological Constant simply in order to maintain a steady state universe. Nevertheless, it still moved, and Einstein was eventually convinced. In any case, Lemaitre predicted the redshift and the cosmic background radiation. Hubble discovered the former before Lemaitre’s paper had been translated into English (and the English translation was edited to omit the prediction). News of the discovery of the latter was delivered to Lemaitre on his deathbed.

Somewhere along the line, at a conference in California – it may have been one of the Solvay conferences – Fred Hoyle noticed Fr. Lemaitre enter the auditorium, nudged the man next to him and said, "Here comes the big bang man." A legend was born. He meant the term as a put-down, because the idea of the universe having a beginning offended his beliefs; but he and Lemaitre became friends during a road trip to meet Hubble and other American astronomers.

There is a strange parallel between using apparent redshift to estimate galactic distances and the way the medievals used brightness to estimate stellar distances. The dimmer and smaller the star, they farther off they were. But it turned out that some stars were just dimmer than others, and the apparent diameters were artifacts of atmospheric aberration. It’s quite possible redshift is likewise due in part to expansion and in part to other factors.

It’s not too strange that locally we find both red and blue shifts. Locally, stars are whirling around the galactic center, and it seems likely that the Local Group is likewise moving locally due to gravitational attraction among galaxies. So the general motion will be more evident farther away, much as the flow of a river will be more evident looking at the river as a whole rather than the whorls and eddies in the immediate vicinity.

I also wonder because the more distant objects are as they were millions of years ago, not as they are now. So might they be moving faster simply because the universe was expanding faster in the distant past? But surely this is known and corrected for.

Of course, I’m no big fat expert.

Mike Flynn

All of which gives us quite enough to think about. I suppose I need to come out of the Cosmic realm and back to the society we live in.

I would be astonished if there were one single explanation for redshift. But if redshift is our best way to determine distance to an observed very distant object, we need to know when and how to rely on it.

Light from a million lighyears distance travels through a lot of space. How much of that is empty? Sir Fred Hoyle had his ideas on that. And he certainly didn’t believe in the Big Bang. From what I recall of Feynman he would have been delighted to find that everything we knew about Cosmology was wrong…

If you’re looking for a good book to recommend to a young reader, try Starswarm. Adults like it too…