Monthly Archives: May 2013

View 773 Thursday, May 09, 2013

Pledge week continues. This journal operates on the Public Radio model – it is free to all, but it will continue only so long as enough people subscribe. If you have not subscribed, this would be a great time to do it. We encourage you to become a patron of this place of rational discussion. It is also a daybook. If you have subscribed but have not renewed in a while, this would be a good time to do that. Since this is a Public Radio model site, I hold periodic pledge drives. I time them according to the pledge drives of KUSC, the Los Angeles good music station. They’re having their Spring drive now which is why you are seeing this. Normally I don’t pound on you with exhortations.

And thanks to all those who have already responded to this Spring pledge drive, both with new subscriptions and renewal of older ones.

Discussion of the Benghazi Incident in which the American Consulate in Benghazi was left hung out to dry in the face of a major terrorist attack over a period of some ten hours resulted in the deaths of four Americans including the US Ambassador to the newly “liberated” Libya continues without much result. For reasons not yet revealed, the US Ambassador to the United Nations went on national television five times with the story that the Benghazi Incident was a general uprising in reaction to an obscure anti-Prophet video posted on You tube. This supposedly erupted into a spontaneous demonstration which grew into an actual attack by mortars and other heavy weapons. Various US responses including sending in a military reaction team to secure the Benghazi airport and conduct an evacuation of US personnel were contemplated, and at one point a team was ready to depart from Tripoli when it was told to stand down. We do not know who gave the order to stand down – either who was directly responsible for conveying the order, or who originated it. Normally the US military is more clear in defining its chain of command.

The US State Department second in command in Libya (a career Foreign Service Officer who was in Tripoli) was told by the Ambassador on the telephone that the Consulate in Benghazi (and the Ambassador personally) was under armed attack. There was no mention of a video or of any spontaneous demonstration. He has since been demoted from second in command to a desk officer. No explanation of this has been published.

The Congress is the Grand Inquest of the Nation, and it is supposed to determine why extraordinary events happen. Such inquiries can be used as political weapons, but that is not their purpose. One would think that both political parties would be interested in knowing how such a thing could happen and what the US, with the world’s most powerful military establishment, might do for the future. Perhaps a company of airborne troops on ready alert in each major theater? That might be overly expensive. Still we have this greatly powerful military – surely that confers some capabilities? We have carrier groups. We have various air weapons. Has no one given any thought to such matters?

And for the record, the President left the scene at 5 PM with the instruction to the Secretary of Defense and the Secretary of State to “do what you have to do”, which I would have read as a blank check to include anything up to a nuclear weapons response. One can understand that a President with no military experience might turn the matter over to the Department of War (well, we call it defense now). It may be that he simply went back to the domestic quarters of the White House having left the matter in what he thought was good hands with full power to deal with it.

What happened was that nothing happened. No rescue units were sent, no airplanes were sent to buzz the area, no tankers were sent to stand by to refuel any fighters that might be sent; there not only was no single integrated operational plan (although one might think that on the anniversary of 9/11 there might be some reason to have some active forces on ready alert), there don’t seem to have been any plans at all for dealing with major incidents in Northern Africa – an area that is still volatile.

Is that worth discussion? Are operational plans being formed now? Have any units been designated as standby for alert in case of a repeat incident? If so I don’t know of any. It all seems very odd.

In past times here wasn’t a lot of choice. Technology dictated that we would do nothing but react to incidents of this sort although I seem to recall that we had contingency plans on how we could react swiftly – it was the lack of any real operational plan that led to the developments in the early days of the Korean War with the defeat of Task Force Smith and the near disaster when the Pusan Perimeter was threatened. MacArthur and the Marines saved us at Inchon, but with that came a determination that we would be more ready in future. Of course that is a long time ago and few will remember those times.

The Iwo Jima class helicopter carriers with a battalion of Marines aboard were designed to be the ready force available for brush fire wars and general world peace keeping. They came about due to a number of strategic theory papers published in the 1950’s: a way to project a fair amount of force in a reasonable time. They were built and in use in the last part of the 20th Century, and were quite effective. Over time they were sold off and scrapped, supposedly replaced with more effective systems. Perhaps so but has a couple of Iwo Jima class ships been cruising the Mediterranean the Benghazi incident would not have happened. Of course those ships were not cheap and keeping operational level of troops on alert is expensive, but if we have goals requiring the projection of force we need to have forces to project.

Perhaps we need to rethink the need for swift reaction forces for the future with the technologies available to us now. They would be useful for either a Republic or a Competent Empire.

It has been a while since I gave serious thought to these matters; but it is time someone did.

Subject: space shuttle main computers

http://en.wikipedia.org/wiki/IBM_AP-101

They required a cold plate to keep from burning up. Brute force, the flower of 1970’s tech. 24 layer printed circuit boards etc.

Phil

Even more primitive than I remembered.

IBM_AP-101

You missed this ( or at least didn’t point it out ) in the link about the space shuttle’s computer.

"The shuttle software was written in HAL/S, a special-purpose high-level language."

Arthur C. Clarke, where are you?

"Open the pod bay doors, HAL."

Pete

Peter Wityk

View 773 Wednesday, May 08, 2013

I posted a mixed bag mailbag earlier today. It has some interesting items and comments.

I’m trying to catch up. In theory this ought to be pledge week – KUSC is having their Spring Pledge Drive, which means that I sort of do the same. This site operates on the Public Radio model: it’s free to all but if not enough subscribe to support it, then it will go away. I don’t spend much time bugging you about this, but whenever KUSC, the Los Angeles classical music station, does a pledge week I do the same. But since I didn’t have much going in the first part of the week, I decided not to inflict the pledge drive on you. If you haven’t subscribed, this would be a good time to do it. If you haven’t renewed your subscription in a while this would be a good time to do that.

The news today is dominated by the recovery of the three young women kidnapped a decade ago and kept in slavery in a house in Cleveland. I expect we’ll have to comment on that at some point, but mostly I am reminded of the conclusions Possony and I reached many years ago: societies deep in decadence and subject to revolutions tend to have a massive increase in bizarre crimes as harbinger.  Of course as the population grows the absolute number of all crimes increases, but still, we do seem to have a lot of the bizarre…

The other story of the day is that the Congress is acting as The Grand Inquest of the Nation in looking at the Benghazi Affair. This is a necessary and proper power of the Congress and has been known from the earliest days. It should not be a simple political witch hunt. And it is important to understand just who ordered the C-130 with the rescue teams about to take off from Tripoli to stand down. Who issued the order, and why? And there may be very legitimate reasons for that: it’s one reason I don’t want to play with breaking news. But I am glad to see Congress acting properly here.

Continuing the discussion of The Static Universe by South African astronomer Hilton Ratcliffe. Radcliffe’s style can be irritating, and one definitely has to read his book twice because he assumes you know things he won’t get to until two chapters later; but he does a fair job of raising doubts about the Standard Cosmology Theory with its Expanding Universe, Big Bang, Dark Matter, Dark Energy, massive Black Holes, and other constructs necessary for the Theory but which have not been observed, and in some cases can’t be observed from here. The Standard Theory seemed rather simple when I learned it in high school, and seemed confirmed by the discovery of the 3◦ microwave background radiation by a pair of Bell Labs radio engineers. True, it was about 20 times smaller than the background radiation Gamow had calculated, (and was very similar to the background temperature expected by the static universe theorists well before the Big Bang was postulated); but there it was, a universal background, the temperature left over from the Big Bang. I remember the headlines. I was involved in missiles and space analysis at the time and didn’t have much time to appreciate it, but I remember being impressed.

Ratcliffe devotes the largest chapter of his book to this radiation and possible causes of it, and if you ignore the snarky language, he does make a pretty good point: it’s predicted by many theories, and it’s smaller than the Expanding Universe Standard Theory expected it to be.

: Did you C that? —

OK, I’m definitely out of my league in this group on this subject, but someone here surely knows something about this.

As Mr. Beaufils pointed out, much of cosmology is based on assumptions. Assumptions should be re-examined from time to time to see if they still hold water (or whatever it is they are supposed to hold). You will be familiar with this notion since you have been exposed to Korzybski.

So, what about the speed of light? We assume that it is constant not only in space but in time. That is, it was the same yesterday as it is today, on back through the eons. But is it? Googling reveals that there are those who don’t think so and they can point to the fact (which I am not equipped to check) that every time we measure C, it gets smaller. Not by a lot, but one would expect that errors in accuracy would be random – some smaller and some greater. But with C, it’s always smaller, apparently.

The implications are non-trivial. If C were significantly larger in the past, then objects are not nearly as far away as we think.

As you are wont to say, “it may well be that the universe is not only queerer than you imagine, but queerer than you can imagine.”

Richard White

Austin, Texas

I am convinced that it is queerer than we can imagine; QED convinces me of that. But that doesn’t mean it has to be so complicated that it takes tensors to explain it. I am prepared to believe that the speed of light is different in different media – few dispute that – and that there is no vacuum: space is never empty. As to what medium light waves in (if any) I consider that still an open question. One thing is certain. If we don’t know how far away things are it’s hard to tell how long light took to get here from there, and what objects or media pools it had to go through to get here.

Mike Flynn, sometime collaborator and statistical inference expert who dabbles in philosophy says

Medieval science and logical positivism

Jerry,

You quote Feynman as saying "It was thought in the Middle Ages that people simply make many observations, and the observations themselves suggest laws." This is only partly correct. The whole process as described by Grosseteste was a loop. The Aristotelians held that all knowledge begins in the senses (which may be why mathematics has always flirted with Plato!) But they would have been puzzled by the suggestion that inanimate "observations" could ever "suggest" anything. From the quia, or particulars, the natural philosopher derived a propter quid, or rationale, by inductive reasoning, a la the Posterior Analytics. Then using this propter quid and deductive reasoning, a la the Prior Analytics, conclude to the quia. But Grosseteste emphasized two things.

1. The deductive phase ought to conclude to quia that were not part of the formation of the propter quid. Otherwise the reasoning would be circular. In modern terms, the theory ought to predict facts that were not included in the original reasoning.

2. Between the inductive and deductive phases, the philosopher must perform the "work of the intellect" (negotiatio intellectus). That is, he must consider all the various explanations of the phenomena under examination and determine which of them is truer to the facts. For example, in concluding from the phases of the Moon that the Moon <i>must</i> be a sphere, the philosopher would consider all sorts of other geometric shapes: a plate seen flat-on, a cylinder seen base-on, etc., and show how each of them fails in some manner. This is a work that many Late Moderns, even scientists, now neglect. Publish-or-perish does not permit measured reflection, and one usually goes with some bright notion, never considering other possible explanations. Feynman was being very Feyerabendian because he recognized that facts do not explain themselves. There is always more than one theory that can explain the same set of facts.

But it is also the case, as Einstein told Heisenberg, that theory determines what can be observed. That is, our prior beliefs will not only condition how we see the observations, but also determine what observations we consider important to make. Keep in mind that all astronomical observations for more than two millennia were adequately explained by Ptolemaic models. Right up to the discovery of the phases of Venus. The Ptolemaic model predicted Venerian phases, too; but not the same phases as were seen. Whereupon, astronomers abandoned Ptolemy for… (wait for it) … the Tychonic and Ursine models. Tycho’s system was mathematically equivalent to the Copernican and matched it, prediction for prediction. It was up to physics, not astronomy, to cast the deciding ballot: ca. 1800, with the measurement of actual Coriolis effects and parallax in the fixed stars. (And somewhat earlier, but less surely, of stellar aberration.)

In all this it is well to keep in mind something Aristotle said:

We are far away from the things we are trying to inquire into, not only in place but more so in that we have sensation of exceedingly few of their accidents.” – De Caelo, 2.3.286a5-7

and further:

It is good to inquire about these things and so to deepen our understanding, although we have little to go on and we are situated at such a great distance from the attributes of these things. Nevertheless, from contemplating such things nothing [we infer] should seem to be unreasonable, holding them now as fraught with difficulties.
– De Caelo, 2.12.292a14-18

Thomas Aquinas also appreciated the work of the intellect. He noted on his Commentary on the Physics as well as en passant in:

“The theory of eccentrics and epicycles is considered as established because thereby the sensible appearances of the heavenly movements can be explained; not, however, as if this proof were sufficient, forasmuch as some other theory might explain them.”

– Summa theologica, I, q.32, a.1, ad. 2

Which led Pope Urban to comment to Cardinal Zollern (who then wrote Galileo in a personal letter) that “the Church had not condemned nor was about to condemn Copernicanism as heretical but that the theory was rash and that, furthermore, astronomical theories were of such a kind that they could never be shown to be necessarily true.” So Pope beat Popper by 300 years. (This BTW was the comment that Galileo mocked in the Dialogue and got himself into deep kimchee.)

Anyhow, the medieval method can be found explained from a modern perspective here:

http://home.comcast.net/~icuweb/c02001.htm#10

and continuing through #11

MikeF

Superluminal motion

Hi Jerry.

The phenomenon of certain astronomical objects travelling faster than the speed of light is known as Superluminal motion:

http://en.wikipedia.org/wiki/Superluminal_motion

and can often be easily described as an optical illusion from material travelling at relativistic speeds. Of course, whether that describes everything that is observed is another question. I’ve done some work on one of these objects (M87), and for this particular object I’d be surprised if another explanation came to light. I don’t know about other objects.

As for the determination of distances, this is known as the Distance Ladder, of which a reasonable description is given here:

http://en.wikipedia.org/wiki/Distance_ladder

And Cepheid variables *are* bright enough to determine distances to the nearest galaxies that are subject to cosmological redshift (max distance about 29 Mpc), and thus callibrate that rung of the distance ladder

– that’s how Hubble originally made his discoveries in the first place.

The initial callibration by Hubble at the time was wrong, but it’s drastically improved over the years, although not without many bumps along the way. It was also one of the key missions of the Hubble Space Telescope. The HST observations are given here:

http://adsabs.harvard.edu/abs/2001ApJ…553…47F

I hope this helps!

Cheers,

Mike Casey

A fair statement of the Standard Theory. Ratcliffe picks holes in that by pointing out that not much of that ladder is based on primary observations, and many observations are cast out as ‘anomalies.’ Of course most Cosmologists believe in the Standard Theory. I tend to glitch at postulating Dark Matter and Dark Energy as the major components of the universe. Why would God play such a trick on us? But of course such questions are way outside science.

The distance ladder depends on accurate measurement of distance to the nearest galaxy, M31, better known as the Andromeda Galaxy. Hubble estimated that it was 900,000 lightyears away. He underestimated the luminosity of the Cepheids and thus greatly underestimated the distance., which we now believe to be nearly 3 million lightyears. Incorrect distances lead to incorrect estimates of the sizes of the galaxies. And triangulation only works out to about a hundred parsecs, and that with a 10% error. We are probably getting better and better at that, and one hopes that we will be able to use some form of triangulation out to a thousand parsecs at some point; but that puts us a very long way from finding the distance to M31 or even to the Magellanic Clouds. The ladder is built heavily on theory, and the theory must make a number of assumptions about light and the media it moves in.

I have no expertise in the accuracy of estimating the absolute magnitude of Cepheid Variables, but I note that Hubble himself was off by a factor of four – and this on fairly close objects in which we can see something of what’s between us and M31. Which doesn’t mean the Standard Theory is wrong, but it does indicate that it’s legitimate to question it, particularly when distance estimates depend on accepting the Standard Expansion Theory, thus making it rather circular after a few hundred million parsecs…

Quasars with a proper motion

I am minded of an article (possibly tongue-in-cheek) by Ben Bova and published in Analog many years back, in which he suggested that quasars might not be the fantastically distant, fantastically huge energy sources they seem, but the flare of Bussard ramjets blasting their way around this neck of the galaxy. Presumably we would see both blue-shifted as well as red-shifted signatures and, depending on distance, proper motion

I do not recall ever seeing any kind of follow-up, whether in fiction or speculative fact. However, the hypothesis should be easily testable, although long-term observation would probably be needed: Do any of the objects display acceleration over time? Do any vanish or appear? Whatever the answer, what will we do with it?

Thanks for all you do. Be well.

Ralph A. Moss

Good story. I vaguely recall it. Niven and I briefly thought about a story with that premise.

Hydrogren Fusion in the Sun

Jerry,

The fusion process in the sun is known as the PPI cycle. It runs like this:

p + p -> 2D + (e+) + v

2D + p -> 3He + (gama ray photon)

3He + 3He -> 4He + 2p

where the numbers to the left of the letters are to be superscripted, the "p" is a proton, the "D" is dueterium, the "(e+)" is a positron, and the "v" is an electron neutrino. You can see that the second step must happen twice in order to supply the required inputs for the third step. What you cannot see is that the predictions that the core of the Sun was too cool to allow this reaction were based upon classical calculations. When quantum effects are taken into account, it is seen that at the temperatures and pressures at the core of the sun, the protons can readily tunnel past the Coulomb barrier your reader from Paris was alluding to. Even with quantum effects taken into considerations, however, this first step is the most difficult to accomplish and drives the rate of the entire reaction and is responsible for the fact that the Sun will take roughly 10 billion years to exhaust its supply of hydrogen.

Kevin L Keegan

There are some other inconsistencies in solar observations. Our Sun’s corona is hotter than the surface under it. That wasn’t expected. Does this change what people on a planet orbiting Tau Ceti see as the temperature and luminosity of our Sun? I confess I don’t know, but then I don’t know a lot about astrophysics of the Sun. I doubt I ever will understand all of it.

subject: "Consensus Theory of Climate Change"

Hi, Doc.

I prefer the term "Climate Creation Science".

Matthew Joseph Harrington

"What occurreth in Gomorrah, stayeth in Gomorrah."

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.

—-

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…