Posts Tagged ‘hidden galaxies’

AT THE BEGINNING OF TIME; what the James Webb telescope might see

July 21, 2022

Congratulations to the whole James Webb team. Against all the odds they have built us a cathedral in Space as awesome as Santa Sofia, and a window through which we can potentially look almost all the way back to the beginning of Time. What might we see? What should we be looking for?

I’m waiting as eagerly as anyone because I have been involved in this stuff going right back to 1977 as a key member of three Hubble Space Telescope teams, including the one that built the camera still going strong up there now. And in this post I want to pass on some words of both encouragement and warning. Be ready for surprises!

Before they design a single lens or circuit Space-camera teams must look deeply into the kinds of science they might be doing 20 years ahead and my team asked me to look into high redshift galaxies. Knowing nothing of that subject at the time  (1977) I naturally went round to ask the real experts. They were unanimous: “Don’t bother with them because you’ll never be able to see them owing to the Tolman effect.”

I looked it all up and found that Richard Chase Tolman was a brilliant American astrophysicist who probably knew more about Relativity than Einstein. The idea that the whole universe was expanding had just been mooted in the 1930’s and Tolman tried to find a test that would prove it. And he did. Extended objects like galaxies would be dramatically dimmed by redshift in an expanding universe, so dimmed in practice as to become invisible in any decent Space camera. Imagine my shock then in 1993 when we got our first really deep Hubble image. It was plastered all over with very distant but quite distinct galaxies not dimmed in the least. That meant the universe couldn’t be expanding – not according to Tolman.

But when I tried to point this out the new self-appointed experts said; “No ; it just means that young galaxies in the distant past were intrinsically much brighter than the galaxies today – after all they were younger in the past and generating more brilliant young stars.”

That sounded vaguely plausible – but not really convincing. Why not? Because all the galaxies: irrespective of their distance had exactly the same surface-brightnesses as each other, and as the galaxies around us here today. For that to be true there just had to be far too many fortuitous coincidences. But by the time I’d measured this and worked it all out a whole

industry consisting of hundreds of newly minted ‘High redshift galaxy astronomers’ had become wedded to their fortuitous hypothesis. The idea that the universe wasn’t expanding was to them completely unthinkable. To my shame I mostly shut up and kept my council. Tolman had presumably screwed up somewhere back in the 1930s.

The Hubble Ultra Deep Field, still the deepest picture ever taken of the Universe. Notice that it is covered all over with galaxies in the far distance, but their surface brightnesses are no dimmer than those that are obviously nearer by. This is a very great puzzle ,because according to the ‘Tolman Effect’ they should be far too dim to see.

But later (2009) we sent an even more sensitive camera (WFC- 3) up to Hubble specifically to look at the higher redshift universe – and guess what – it was plastered with high surface brightness galaxies going out all way to redshift 7 – to a time when the universe was less than 1 billion years old (it’s 13 billion today).

Still the ‘experts’ weren’t shocked – and I realised they could explain everything – and in doing so – nothing. They were too wedded to their trendy hypothesis to ever question it.

But by 2010 I had officially retired which meant I could do something those experts could not. I could spend literally thousands of hours thinking about the problem of high redshifts galaxies and my colleague Huw Lang and

I eventually produced a refereed paper entitled “The Galaxy Ancestor Problem” in a prestigious astrophysical journal (see Note). We argued that the trendy picture simply couldn’t be right, and that something probably far more interesting was afoot.

Nobody read it, apart from the referee. And you can’t blame them. It contains 70 numbered equations and is hideously complex. It was much easier to ignore it than try to understand it. That’s part of a long tradition in astronomy going back 600 years: if you don’t like something, stick with the crowd and ignore it. 15th century astronomers didn’t want to believe the Earth was orbiting the Sun, and invented ridiculous ‘epicycles’ to disguise the truth from themselves – and everybody else. Only when Galileo saw with his first spyglass (1609) that Venus was crescent-shaped did they finally ‘Hesitate’. What they did though was imprison Galileo for life (1632) – because that was much easier than changing their minds.

There is a more general point here though. Explorers rarely comprehend what they have discovered at the time. Columbus never admitted that he’d run into a new continent – so far as he was concerned he’d been to Cipangue (Japan) – because that is where he’d set out to go. It took his successors, notably Amerigo Vespucci, to acknowledge that the previously unknown continent of America actually existed.

I’m not claiming that Huw and I are right, and that everybody else is wrong, I’m merely pointing out that the true interpretation of the high redshift universe, the universe Webb will soon see in unprecedented detail, may be very surprising, very surprising indeed.

Without going into any detail let’s enumerate three key puzzles:

(I) Tolman couldn’t be wrong: his physics is as sound of a bell. So, if the universe really is expanding, which seems likely, why do all the galaxies, irrespective of their redshift, appear to have the same identical surface- brightness? High redshift galaxies are no less than 4000 times brighter than they ought to be. There’s no escaping from that. 4000 times!

(II) That we can see so far means that the cosmos out there is transparent. That’s obvious. But how did it become so? Where did all the energy come from to split all the electrons in extra-Galactic space apart from their natural proton partners ? That is called ‘The Re-ionisation Problem’. There are vastly too few galaxies out back there to produce the ionising starlight needed to bust all those atoms apart and make Space transparent.

(III) Very high redshift objects, notably Quasars, have dozens, sometimes hundreds of dark lines in their spectra(see our Post ‘The Cosmic Rosetta Stone’). Those lines could only be produced by the atoms in galaxies along the lines of sight to such quasars. But there are vastly too few such visible galaxies out there to produce them.

Many people will be surprised that such egregious problems are not shouted from the roof  tops; there is almost a conspiracy to cover them up. The only comment I will make upon that is that ‘experts’ are generally reluctant to admit “We really don’t know”. Take the situation of Continental Drift. For 50 years the experts at all the ‘big’ universities pooh-poohed Alfred Wegener’s radical idea. They were only forced to eat their hats when otherwise inexplicable geomagnetic patterns turned up on the ocean floor. Perhaps the James Webb will force a similarly dramatic rethink.

During its recent briefing about Webb NASA was anxious to emphasise that “The telescope belongs to all of us”. That will only be true if we all dare to think about the new high red shift observations – when they come in. If we don’t, the ‘experts’ might cover up the truth – yet again.

NOTES: The Disney/Lang paper is at Disney M J., and Lang R.H, The galaxy ancestor problem, Mon. Not. R Astron. Soc., 326, 1733-1749 (2012). Other relevant Posts on this site are: ‘The Cosmic Rosetta Stone’; ‘How Dark is the Night?’; ‘Hidden Galaxies, Hidden Universe’.

ADVENTURING WITH A PEN

April 27, 2022

I love writing — spending several hours a day in solitude with pen and paper because it can be the most enchanting activity imaginable. But why is it so? Daniel Boorstin the historian admitted “I write in order to find out what I think.” Writing is a form of exploration which can take one on the most exciting journeys to meet unforgettable characters you never knew existed, until you encounter them emerging, like ink, from your pen. In some magic sense they must have been inside you all along, hiding just out of sight, waiting their chance to have their say and become part of your family. Many storytellers will attest to that. I will never forget finishing my first novel in rather dramatic circumstances. I was camping utterly alone on The Bay of Fires in remote Tasmania. I had taken my stool and writing table to the edge of the surf to commune with Griff, with Salome, with Elephant and Naomi — my main characters, and my only companions at the time, seeing that my flesh and blood family were still busy back in Britain. I uncapped my pen, looked out across the turquoise sea towards the rising sun and let my characters write the end of their story — which had very little to do with me. Three hours later they were done. They had finished with me, rising up into the sky and vanishing back from wherever they had come. I burst into tears, abandoned, desolate, like a tiny child dumped without warning at boarding school.

That was 20 years ago but I have been writing novels ever since as more and more characters come down to join me and my pen on any number of vivid adventures. To my regret I have never had a flesh and blood daughter : no problem; Petrel came down in “Crouching Giant” and she’s been with me ever since, while my fictional step-father Bob Salt badgered, inspired and entertained me every day throughout the 4-volume saga “Written in the Stars”, claiming to have written much of it himself.

But explorers, as I claim to be, ought to make discoveries. But how could one possibly make discoveries with just a pen? That turns out to be a very profound question linked to an even greater mystery — why can we humans think so much more successfully than our primate cousins in the wild who share 98 % of our genes? Natural Evolution is a painfully slow process whereas we have transformed from Cave Man to Space Man in a mere few thousand years. It cannot be biology — it has to be technology — which kicked in not much more than 3000 years ago. And I’m pretty sure of the answer now.

3800 years ago in the Sinai desert not far from Phoenicia , some turquoise -miners invented the ‘phonetic-alphabet’ which could translate language, any language, into written words. It was such a valuable trick that it spread from Asia Minor across the Mediterranean to Greece, Rome and far beyond, literally transforming everything — but why and how? Here comes another private adventure — even further afield than the Bay of Fires. For my living I was an astronomer obsessed with ‘Hidden Galaxies’. The figure below shows a montage of galaxies — colossal islands of stars in Space. They are the basic units of the Cosmos — and we live in in one such spinning island ourselves — The Milky way.

As you can see some are bright whilst others are so dim as to be virtually invisible. Back in 1975 I collected some pretty convincing evidence suggesting that the Cosmos was probably packed with with completely invisible, that is to say ‘Hidden Galaxies’ (‘HG’s). If that sounds implausible you must remember that, because we live right next to a bright star called the Sun, even the darkest sites on Earth are still 5,000 times brighter than they would be from a typical point of cosmic Space. My suggestion sparked off several large-scale campaigns to either find, or rule out this hypothetical “Hidden Universe”. Strong pieces of evidence both for and against the proposition turned up — but conflicted. That led to furious debates within the profession. To reconcile the two sides I decided to consult “The Scientific Method”, the underlying philosophy to which all of us scientists subscribe. Easier said than done. The harder I looked for the Scientific Method the faster it danced away. Almost none of the people who wrote about it endlessly were scientists themselves, but philosophers or statisticians, while we scientists were suspiciously mum about the whole topic. Einstein had said that: “Science is no more than a refinement of everyday thinking.” but admitted: “The physicist cannot proceed without considering critically a much more difficult problem (than physics), the problem of analysing the nature of everyday thinking.

It eventually dawned on me that no one on Earth qualified to know had any idea what the Scientific Method was or is, or whether it existed at all. So, when I retired I decided to track down dozens of historical scientific discoveries to find out how exactly they had been made. They clearly revealed that Common Sense Thinking (CST) was at its core, and that implied weighing different clues against one another and against the hypothesis under debate. Now here comes the point: to do that effectively and reliably ONE MUST BE ABLE TO WRITE. Neither animal nor human memory is large enough or reliable enough to do that job. So now we recognise the source of our sudden and spectacular ascendancy above our fellow creatures. Because we can write we can think millions of times more effectively than they can. And when I say ‘millions’ I am not exaggerating . You can actually calculate the height of our leap — far above the clouds — out among the tumbling stars. My favourite fairy story as a child was Jack and the Beanstalk. Now we don’t need his magic beans. We can vault far above the clouds with pen alone. At first I couldn’t believe these new found powers to explore and to think. It felt more like a fantasy dream than sober reality. I never expected it, but when you think of human-kind’s miraculous ascendancy there has to be a rational explanation. On the ceiling of the Sistine Chapel Michelangelo painted God reaching out to inspire Man with celestial fire. But notice , their fingers don’t quite touch — as if the artist wasn’t quite sure.

God, off screen right, is seen here powering up Adam in Michelangelo’s famous fresco on the ceiling of the Sistine Chapel. But as you can see their fingers didn’t quite touch, as if Michelangelo wasn’t quite convinced. I don’t blame him. Courtesy of Wikipedia Commons.

Now we know it wasn’t God but some ingenious turquoise miners in the Sinai desert trying to leave decipherable messages for their successors scratched on rock walls, 3,800 years ago. The history of Science turns up other stories of momentous but unintended developments like that — though none quite so dramatic: Johannes Kepler understanding that the darkness of the night sky implied the finiteness of the Universe; Darwin in the Galapagos Islands realising that the diversity of finches beaks from island to island implied the Evolution of species; Alfred Wegener recognising that identical fossil-beds on opposite sides of the Atlantic meant that continents must drift. The problem though with such serendipitous discoveries is that they are so improbable and therefore so hard to believe. .Who is going to believe that Common Sense Thinking (CST) is millions of times more effective than any other scheme simply because of writing — though Einstein did remark “My pencil and I are are smarter than I am”. But think of puzzles like crosswords and Sudoku — they would be impossible without writing. So it is with CST and the Scientific Method. Which brings me full circle to Hidden Galaxies. It took over 20 conflicting clues, 40 years and a great deal of writing to settle that issue. Hidden Galaxies certainly do exist and Fig 3 shows one of the first — pinned down using the Westerbork Radio telescope in Holland.

Fig 3.The first convincing Hidden Galaxy, Virgo HI21 . It was found by Dr. Jon Davies and his team from Cardiff University back in 2007. The banana shaped radio source in the Left hand image is a massive edge-on spinning disc of Hydrogen first found with the Jodrell Bank radio dish in Cheshire, and here seen projected upon a negative optical image of the famous Virgo Cluster of galaxies of which NGC 4254 is the brightest, most massive spiral. As you you can see, something has dragged out a bridge of Hydrogen gas from it towards the banana. To have done so VirgoHi21 must be very massive itself although it appears to be totally dark. The right hand image is a velocity-map of the Hydrogen observed with the Westerbork radio telescope in Holland. The twitch in the banana signifies that it is spinning rapidly like a plate seen edge on, and indeed must be very massive to prevent itself spinning to bits. All the evidence was published in the prestigious Astrophysical Journal in 2007, and although several sceptics have tried to undermine the arguments none has remotely succeeded. Hidden, even totally dark galaxies exist. And , thanks to writing, we know they do.

The more one thinks about Thinking the more fascinating puzzles the subject raises. If, as I am suggesting, Common Sense is the way even scientists like Einstein use, then why didn’t they teach us about the subject at school? I believe I know the answer — but I leave it as a fascinating puzzle for you. IF either of us can solve it we might, like those turquoise miners 3,800 years ago, take humankind on another journey far beyond the visible stars.

NOTES: 1 The Tasmanian novel is ‘Pterodactyl’s Blood‘ ,see ‘My Books’ Category. 2 For Hidden Galaxies see several Posts this Blog in ‘Astronomy ‘Category . 3 For Virgo HI21 see Minchin et al,2007, The Astrophysical Journal, 670, pp 1056-1064. 4 For CST see many Posts this blog under ‘Thinking’ Category. 5 For history of writing see “The Secret History of Writing‘ a series of 3 wonderful films made by Henry Sington and shown on BBC ch. 4 in 2021.

PARTICLE THEORISTS POISON COSMOLOGY

November 4, 2021

Despite three decades of effort and tens of millions of dollars spent on accelerators and their like, it looks as if Particle Physics is coming to a sad end. No new particles beyond those such as the Higgs Boson proposed 50 years ago, and in particular none of those Supersymmetric particles which theorists had hoped would explain that greatest of all scientific mysteries — Dark Matter. Of course there will now be cries for more money and even larger machines, after all the Large Hadron Collider at CERN in Geneva is a mere 27 kilometres in circumference. But wait! Perhaps there is something far more interesting and fundamental at work: Perhaps Particle theorists have misled themselves, and everybody else , through neglecting a philosophical principle at least a thousand years old called ‘Ockham’s Razor’ (OR), named after a mediaeval monk called Friar Ockham.

At the heart of the Scientific Method is the business of Hypothesis Testing, which is where OR comes in. It states “Always prefer the simplest hypothesis first” and that, I suggest, is where Particle Theorists went so horribly wrong. Their “Standard Model” — as they call it, is fiendishly complex — what with its Quarks, Gluons, ‘Asymptotic Freedom’ and so on and so on. How do we measure complexity in Science? By the number of ‘Free Parameters’ (FPs) needed to describe a theory. One way you can think of them is to say they are arbitrary numbers brought into a theory to force it to fit the experimental data. A ‘good theory’ doesn’t need many FPs because it fits the experimental world naturally(for instance Newton’s very successful Theory of Gravitation has only 2 FP s) The so called Standard Model of Particle Physics needs no less than 18 FP s which has always suggested that it is an ugly and unnatural construct. It should be no surprise then to find now that it actually looks to be wrong.

So why did theorists construct such an ugly model in the first place, mostly back in the 1960’s and 70’s? Probably because they didn’t understand just how fundamental OR is. And there’s some excuse for them — because the Philosophers of Science, the self-appointed arbiters of the Scientific Method, didn’t understand OR themselves. Even Einstein, who relied on it extensively, waffled about some plastic ‘God’.

As I see it Hypothesis Testing works like this. You have some data-points, with error bars of course, and you have your hypothesis which generates a smooth curve which you must try to fit through those points. If there are lot of points the Odds on your hypothetical curve fitting them all by chance must be small. So if it does so fit then the Odds are that the hypothesis is probably right. If it doesn’t fit then you can always complexify your hypothesis ,so twisting your hypothetical curve until it does fit. But you can see that’s not a very convincing way to proceed, because eventually you are always going to force a fit. In that case the Odds in favour of it being actually right vanish. And that, I would suggest is what happened to Particle Theory, starting half a century a century ago.

There’s nothing fundamentally wrong with modifying a theory to fit the facts, after all that’s how science progresses. But you have to be very frugal in doing so. Only introduce a new concept (FP) into your theory if it fits at the very least two more data points than its simpler predecessor. And that’s hard to do, but it won’t degrade the Odds on it being right. But if it only fits one more data point the Odds will generally degrade dramatically. And that’s what Particle Physicists were tempted to do; making names for themselves at the expense of undermining the Odds on their so called ‘Standard Model’ theory. And that’s why almost nobody believes in their theory anymore. It’s as if they’d undermined their currency by printing too many notes. It works for a while — then collapses!

I am not a Particle Physicist, thank God, I am an Astrophysicist. And what worries me is that those same Particle theorists have dragged their own dodgy practices into our subject, with predictably unhealthy consequences. Take “Dark Energy”, an entirely artificial concept dragged into Cosmology by a particle theorist called Ed Turner from the Fermi Lab (and the University of Chicago). Now astronomers are raising hundreds of millions of dollars to chase this fantasy around the cosmos when there’s no justification for doing so, none at all. It was a thoughtless quick-fix extra Free Parameter to fit the apparent acceleration of Cosmic Expansion inferred from Supernova measurements in 1998. Had its introduction explained TWO or more discrepancies between theory and observation we might have welcomed it in. But it didn’t. So it should never have been introduced in the first place. Never!

PS Actually the situation is far worse than I am implying because the bloody particle theorists who have undermined their own subject actually introduced two more unnecessary FPs into Cosmology before Dark Energy: ‘Inflation’ to cure Isotropy and nothing else, and ‘Dark Matter’ to fix the Cosmic chemical abundances. We need to throw them out too.

So where do we go from here? Cosmology should chuck out Dark Energy, Inflation and Dark Matter and start again without them. As for Particle Physics I suspect that they may have to go back 50 years and try to reconstruct a more parsimonious theory of particle interactions than the ‘Standard Model based on quarks and gluons. In his wonderful book ‘Constructing Quarks’ Andrew Pickering (Univ. Chicago Press 1981) suggested that that theory was a social construct anyway, the product of trendy acclamation, rather than sober assessment.

More generally all of us need to understand the process of Hypothesis Testing on which the modern world of ideas is entirely built. Because if that isn’t sound ,God help us all.

For much more on Ockham’s Razor see our post “Fuzzy Thinking and Ockham’s Razor’ under the ‘Thinking’ category here on our blog. For a detailed explanation of Ockham’s Razor and why it works go to the url:

https://mjdisney.org/wp-content/uploads/2021/11/AMSCI4-copy-1.pdf

But if you want to go into the whole business of Common Sense Thinking (CST) , of which Hypothesis Testing is only a part, try my book “Thinking for Ourselves” publ Amazon (2020) which is described in the ‘My Books ‘ Category on this site.

‘t

THE COSMIC ROSETTA STONE

March 6, 2021

Archaeologists use tree-rings to date events several thousand years ago, climate scientists use ice-cores to decipher the state of the atmosphere as it was several hundred thousand years ago and astronomers bore holes in the Cosmos that potentially tell us of the Universe as it was billions of years in the past. But all these signals need some ingenious deciphering to get at the truth.

Look at the spectrum below, taken with the VLT, the world’s. most powerful optical telescope, sited high in the Chilean Andes. What is so remarkable about the spectrum, which stretches from the violet to the deep red, are all the dark lines imprinted upon it as the light from a very distant quasar has traversed Space on its immense journey to reach us. They probably have a fascinating tale to tell, far more momentous than the Rosetta Stone. But what is that tale? Why not have a go at cracking it?

This image, originally entitled “Fingerprints of the early Universe” can be dowloaded from The European Southern Observatory’s spectacular website eso.org under /images/ ‘Quasars and Black Holes’. It is an extremely deep spectrum of the Quasar (or ‘QSO’ standing for ‘Quasi-Stellar Object’) HE 0945-1050 (at redshift 3) taken with the UVES instrument on their Very Large Telescope (VLT) . What is remarkable about it is the presence of so many dark lines imposed on the spectrum, each the result of an absorbing cloud of gas lying along the line of sight to the quasar, which is several billion light years away from us. ( Acknowledge V. D’Odoricco, Osservatorio Astronomico di Trieste, Italy)

Experts have been staring at such QSO Absorption Line Systems (QSOALS for short, or ‘Spectral Ghosts’ as I prefer to call them) for over 50 years years now, and have come up with some intriguing clues. The lines, which have nothing to do with the quasar itself, are caused by atoms in distant clouds of gas lying at different redshifts ( or distances, because of the expansion of the Universe) along the line of sight. They know that from measuring the ratios of the wavelengths of those lines, ratios which in many cases are identical to to the ratios of spectral lines from ordinary atoms in the laboratory such as Hydrogen, Magnesium, Carbon, Oxygen, and so on. Since most of those atoms can only be made inside stars we infer that the mysterious clouds must also contain stars. But the only gas-clouds we know of containing stars are Galaxies, huge whirlpools of gas and stars , structures like the Andromeda Nebula and our own home The Milky Way ( See our post “Galaxy Gallery” for images). So what we must be seeing are the atoms in galaxies at different redshifts (distances away) intercepting and scattering out discreet wavelengths as the light-beam passes through them. Hence the spectrum is the log of an immense journey, and of all the encounters with galaxies which the light beam has made on its way from the Quasar to the Earth. Right? Well no.

Why not? Because there are about a hundred times too many black absorption lines to be accounted for by ordinary galaxies. A hundred times! That’s going to take some explaining. The experts of course have such an explanation: they say galaxies must simply be a hundred times bigger than we thought; they must have a vast invisible halo of gas around them which intercepts quasar light and etches all those lines we can see.

But don’t you think that explanation sounds just too glib, too ad hoc, rather too much like a child’s lie or the fairy tale about The Emperor’s New Clothes? I do. I think it’s a blatant attempt to brush a fascinating mystery under the carpet. Experts, especially those who make their living out of their expertise, don’t like to admit to mysteries, because they might undermine their claims to expertise. How often have you heard your doctor admit; “To be honest Mr. Jones I have no bloody idea what’s wrong with you.”

Of course the QSOALS experts claim to have at least some evidence in support of their Giant Halo Hypothesis. But if you look at that evidence very carefully, it’s not convincing at all; at least that’s what I think. I’ve got an alternative explanation for the dark lines, even more dramatic than Halos, but I won’t go into that here, because it too has its detractors.

Instead, the purpose of this post, is simply to point out that there is a great mystery out there and to encourage curious outsiders to have a go at solving it. After all The Rosetta Stone itself was solved by a young self-taught outsider, Jean-Francois Champollion who had taught himself Coptic Greek, which turned out to be the key … but that’s another fascinating story.

If it seems ridiculous to suggest that any but a professional astrophysicist (as I am myself) could make a serious contribution to this problem, that ignores how profoundly the Internet has changed Science. Here the germane facts are few. The relevant data is available for all to download from public archives, as are the existing scientific papers on the subject. And just remember that modern academics have become far too busy to really think any more. So you won’t have much serious competition from them.

So why not have a go? Deciphering the Cosmic Rosetta Stone will be far more exciting, and momentous, than cracking Egyptian history. But don’t expect it to come without effort. A couple of thousand hours of focussed reading should get one up to speed however. And here’s a useful tip to start: find out what the ‘ADS’ is ( it’s got something to do with NASA) and start using it.

Good luck. If nothing else you could have a hell of a lot of fun.

HOW DARK IS THE NIGHT?

November 10, 2020

My trade as an astronomer , involves travelling to the very darkest spots on Earth, peering up to see what is there, and returning to report to you, my fellow humans. You poor devils can’t see much of the splendour because you have blinded yourselves with artificial lighting.

These expeditions into the dark started in the Arizona desert, then on to the Warumbungles in the Australian bush, to the island peaks of Hawaii and La Palma, and finally to La Silla up in the Chilean Andes where I measured the darkness in between the stars at 22.5 Blue magnitudes per square arc second. In my ignorance I was impressed though I was disappointed to see little more from up up there with the naked eye than I could espy from a moonless beach in Wales. ‘Why not?’ I wondered.

It turns out that the rod cells in the eye, which enable us to see in the dark — if we treat them properly, are critically dependent on Oxygen. Climb a mountain, where of course all our telescopes are constructed, and you’ve lost it. I discovered that by accident when I woke up in the bottom of my little sailing boat up a remote creek in West Wales to find a colossal glow several moon-widths across, peering down at me from on high. Yes I’d had a few pints but….surely…. It took minutes to realize that I was being watched by the Andromeda Nebula, our fellow Spiral galaxy, which I’d never seen before, even from those remote mountain peaks. [Try it for yourself on a moonless night in summer. Get as far away as you can from city lights, and go to sleep in the open (that ‘dark-adapts’ ones eyes), then wake and look up — and with any luck you might see a marvel you will never forget.]

This is a composite image showing just how big The Andromeda galaxy is compared to the Moon. It’s really worth looking for. Copyright Adam Block and Steve Puckett.

Why hadn’t the big telescopes I’d been using make much difference? First because their fields of view are far too small. Second because the light you want to see is accompanied by much more background sky-light that you don’t. The big mirror amplifies both, only weakly improving the contrast. And that is what one needs to discern the dimmest structures in the universe — more contrast!

When I joined the Hubble Space Telescope Team it was natural to suppose that seen from up there in Space the sky would be really dark. But no. In between the planets drift tiny motes of dust which reflect sunlight back down into our dark — the so called Zodiacal Light — which you can actually see , if you know where to look. So disappointment once again.

Perhaps, if we could escape from the Solar System? But no again; there will still be faint starlight out there from the Milky Way and scattered starlight too. What a disappointment. Is there nowhere in the cosmos from where we could see the Universe as it really is? What about out there between the galaxies out in Intergalactic Space? You and I will never be able to go out there, but perhaps our distant descendants?

If I couldn’t go at least I could calculate how dark it ought to be out in that farthest, remotest, darkest immensity, an unimaginable distance away from any luminous star. It wouldn’t be absolutely black of course because some light would still be leaking from the nearest galaxies several million light years away.

What a shock I was to get from my calculation when I finally made it in my eighties. Out there the sky would have a brightnesss, or rather a dimness of 31.5 Blue magnitudes per square arc second, 9 magnitudes darker than the darkest site on Earth (Remember? 22.5 of the same magnitudes in the Andes). Now 5 magnitudes is one hundred by definition, so 9 magnitudes is one hundred times forty, or four thousand. Turn the calculation around and you can see why I was stunned. We live on a planet where the darkest night sky we will ever see is four thousand times brighter than it has to be if we are ever to see the Universe properly . We’re dazzled, blinded, blind. It is far more likely than not that we are blinded to most of the structures out there, and that all we will ever see, for all our technology, is a tiny fraction of the true Universe. Think on that. Knowing what we cannot know is sometimes more informative than knowing what we can.

If you want to see how the calculation was done go to:

https://mjdisney.org/wp-content/uploads/2020/11/hgreview7sept-1.pdf

GALAXY GALLERY

October 26, 2020

Morgan, the protagonist in the Written in the Stars quartet, and I, have spent our working lives studying Galaxies. This is the first one he saw when he was looking through the 36-inch telescope at Steward Observatory atop Kitt Peak in Arizona, back in 1969.

Spiral Galaxy NGC 7331 in the constellation of Pegasus, at top. Courtesy, Vicent Peris, University of Valencia.

This particular image was taken much later with a huge telescope 3.5 meters in diameter fitted with an ultra-sensitive electronic camera integrating the light for two whole hours. So imagine how little if anything Morgan would see with the naked eye which integrates for all of a tenth of a second, through his much smaller telescope: virtually nothing at all. That’s why he struggled for half an hour to even convince himself that it must be there, and why he felt that studying galaxies could become the lifetime challenge he was looking for. And so it came to be.

NGC 7331 just happened to be the nearest Spiral overhead his telescope at the time. All the spiky stars are stars in our own galaxy the Milky Way, just hundreds of light-years away, while the spiral lies 45 Million light years beyond them, yet is one of the closest such giant spirals to us.It is about a hundred thousand light-years across! The smaller galaxies lower down are even farther off. Morgan was to spend most of his astronomical life studying galaxies whose light had set out towards him when dinosaurs still ruled the Earth, and some so far away that the Sun and Earth didn’t even exist when their light was emitted.

Even now we know little about these beasts; they are full of mysteries. For instance they spin so fast that they ought to fly to bits. So what holds them together; certainly not the stars we can see in them — their gravitational force would be far too weak. Some astronomers mutter about “Dark Matter”, but what is that, and why have we detected no sign of it after 50 years of searching with every ingenious means we can think of? Then we have no idea how galaxies formed, not if the Universe is really expanding, for their infant stages would have been far too fragile to survive the Big Bang. Galaxies remain a challenge for any young person who would like to spend their lives trying to understand what is out there.

Hard as it was to see, it turns out that NGC 7331 is one of the most visible galaxies there are. Over the course of 50 years Morgan and his colleagues were to find much much dimmer specimens using radio waves instead of light. The next montage shows some typical specimens first located with the Parkes Radio Telescope, then imaged in visible colours with the Sloan optical Telescope in New Mexico, both absolutely state of the art instruments. Its worth studying this montage:

Galaxies first found independently of their light signal in the radio, then imaged optically in several colours (Courtesy Julianne Dalcanton, University if Washington, Seattle).

Believe it or not every postage-stamp contains a galaxy, some so dim one can barely spot them. This illustrates the “Visibility of Galaxies” problem which Morgan discovered in that caravan on the Teifi estuary back in 1975 [See my book Against The Fall of Night]. The problem is that, dark as it appears, the night sky is not absolutely dark so that any galaxy dimmer than our sky would be invisible. And why not? Could most of the structure of the Universe be hidden from sight? Morgan, Cotteridge, Cockle and other astronomers spent their careers wrangling over that question. There’s a great deal to think about here.

Broadly speaking there are two types of giant galaxy, Spirals as above, and Ellipticals. As we can see next, Ellipticals look like giant swarms of bees ( actually very old stars).

The Coma Cluster of Galaxies centred on the supergiant Elliptical NGC 4889 taken with the Hubble Space Telescope, courtesy ESA/NASA.

Ellipticals are just as mysterious as Spirals but in somewhat different ways. For instance NGC 4889 seen here fades imperceptibly into the sky; so where does it end and therefore how big and how massive is it? And why are Giant Ellipticals only found in Clusters? And where have the cold gas and the young blue stars gone that light up Spirals? And why do some of them, like this one, have colossal Black Holes in their cores? And how do these giant Clusters hold together when the gravitational forces required are hundreds of times too weak , if only visible material is responsible. Once again we run into speculations about “Dark Matter” which sound a bit like The Emperor’s New Clothes to me. In other words we are mired in mysteries which challenge anyone with Curiosity. By the way, this colossus is about 300 Million light years away, its light having set out towards us even before Dinosaurs evolved and 50 million years before the great Permian-Triassic extinction, which wiped out 90 percent of the the species on Earth. Yet in astronomical terms it’s almost next door, only seven times as far away as our Spiral friend NGC 7331.

We said most galaxies dwell in Clusters containing anything between a few and tens of thousands. Here is a very large Cluster Abell 1689, 2 Billion, not Million, light years away:

Galaxy Cluster Abell 1689 imaged with the Hubble Space Telescope (Courtesy ESA/NASA)

The further away we search , the further back in time, the greater cosmic mysteries become. For instance what you can actually see here is about one per cent of the Mass actually present. We know that because the galaxies in the cluster are whizzing about so fast that the cluster would have dispersed unless there are overwhelming amounts of “Dark Matter” holding it together [Or else there’s something even more mysterious going on.] This dramatic tendency of galaxies to cluster made it very difficult indeed for Tom Morgan and his friends to find “Hidden Galaxies” because the hidden ones would tend to get lost amid a crowd of ‘Visibles’, requiring great precision to get at the truth.

This, believe it or not, is the identical galaxy NGC 7331 to the one at the top of this post, though the image is flipped left to right..I have put it in for several reasons. First it is in colour because it was made up from several images taken through different colour filters with camera WFC- 3 ( Morgan & co.) on Hubble . This colour information paints a very different picture of the galaxy, which is evidently choked in smoke, so that much of it is hidden. Using the old photographic plates little of this was evident and astronomers were convinced galaxies were transparent. Morgan was practically the first astronomer to realise they were not, largely because he had early access to one of the first electronic cameras. Then there is the atmosphere which blocks off all the ultraviolet, and most of the infra-red radiation included in this picture taken from Space. The general point is that our understanding of the universe is very much constrained by the instruments we have to study it. Space astronomy has widened our spectrum by more than a billion and it may take generations to understand the implications. It’s all too easy to rush to judgement, and to see only what we want to see. Copyright ESA/NASA

When we professional astronomers talk to the public we tend, for sociological reasons, to emphasise what we do know, as against what we do not. Now that I’m retired I can admit that most of the time, at least in extragalactic astronomy, we have little idea of what is really going on. Yes there are fools only too ready to rush in with half-baked explanations such as “Dark Matter” or “Dark Energy”, but I doubt that many will stand the test of time because they ignore Ockham’s Razor, a very profound and vital principle of Common Sense [See my book Thinking For Ourselves or a post on this site entitled Fuzzy Thinking and Ockham’s Razor]. In the mean time they not only rob us of mystery and wonder but they can hold up the search for deeper truths. For instance the invention of fictional “Land Bridges” held back the discovery of Continental Drift by a century.

I hope this post encourages readers, especially the young at heart, to retain their sense of mystery because, as Einstein put it : ” The most beautiful thing we can experience is the mysterious. It is the source of all true art and science”.

You can look up hundreds of more wondrous images of galaxies by going either to stsci.edu, NASA’s Space Telescope institute, or eso.org the European Southern Observatory which runs the world’s largest optical telescope (The ‘VLT’) in the Chilean Andes. But beware of beautiful coloured images which look like pizza advertisements; real galaxies don’t look anything like that, they’re far more subtle and infinitely more difficult to decode.

THE PARKES RADIO TELESCOPE

October 8, 2020

Parkes Radio Telescope New South Wales

The Parkes Radio Telescope in New South Wales Australia after it had been fitted with the new Multi-beam receiver system designed to pick up the Hydrogen signals from galaxies with about a thousand times the speed of any previous instrument. It has 13 separate dual-beams and 26 receivers cooled down close to absolute zero (minus 273 degrees C) up in the receiver cabin which is the size of a small house. Up there the very weak signals are mixed with a maser and the lower frequency output signals are sent down to the tower where they are processed by specially designed and very powerful digital correlators to look for the characteristic 21- centimetre wavelength signal of Cosmic Hydrogen. With it Morgan and his Australian colleagues surveyed two thirds of the sky and found over 5,000 such sources among which they hoped to find Dark Galaxies.[See Written in the Stars quartet of novels under ‘My Books’ Category]

The Dish has a romantic background. It was built by Taffy Bowen who, together with Hanbury-Brown, devised the night-fighter radar system which put an end to the Nazi blitzes in 1942. Starting at Bawdsey Manor in 1936 they devised means to cram radar systems into aircraft — which was fiendishly difficult to do in those days when radar waves were 10 metres long. But somehow, supported by Air Marshall Dowding, the head of RAF Fighter Command, they eventually did so.

In 1941 Bowen was sent to the US with his notorious ‘Suitcase Full of Secrets’ to teach the Americans how to build effective radars [See my book ‘History of the Brits‘ for that story ]. Later Bowen came to Sydney to direct the CSIRO Radiophysics Lab and the grateful Americans gave him half the money to build the Parkes dish which was completed in 1961. In 1962 Cyril Hazard from the University of Sydney used it to locate the first Quasar when the radio source 3C-273 passed behind the Moon. The disappearance and re-appearance of the radio-signal enabled Hazard to get a very precise position for it — which corresponded to that of a moderately bright star. An optical spectrum of that star showed it to have a high redshift and so to be an enormous distance away. The first Quasar Stellar Radio Source, or ‘Quasar’ had been discovered — starting off a whole new branch of Astrophysics — leading eventually to the discovery that they are Super Massive Black Holes.

Hanbury-Brown — after whom the term “Boffin” was coined, also made his name later as an astronomer in Australia. He it was who completed the night-fighter radar system which did for the Blitz and saved Britain [He features extensively in my Second World War scientific novel ‘Strangle‘ described in ‘My Books’ Category] .

The main weakness of radio telescopes is the non-existence of a ‘radio-camera’ which can look in more than one direction at once. The big box you can see at the focus was the first successful attempt at one. It has got 26 receivers looking in 13 adjacent but different directions at once — which allowed us to survey two thirds of the entire sky for Hydrogen gas in deep space — in the hope of locating Hidden Galaxies (see our Post ‘Hidden Galaxies‘). Unfortunately we then totally cocked things up by mis-identifying all the 5000 such sources we found with conspicuous optical galaxies , which is all too easy to do when galaxies are so highly clustered together in Space. Actually many of the Parkes sources are indeed dim or dark galaxies or gas clouds. Astronomy is hard….but very exciting!

ABOUT MY BOOK ‘BEYOND THE WESTERN STARS’.

September 29, 2020

A novel about astronomical research

The last of the 4 novels of a saga set amidst Space exploration and astronomical research between 1965 and 2015 when the extragalactic universe truly hove into sight for the first time. Voyaging to a new continent is hard enough, understanding it when you first arrive is harder still. Columbus imagined he was in Japan; in Cochin Vasco da Gama saw little beyond sandalwood and spices; Pissaro couldn’t tear his greedy eyes off Inca gold. What will the first voyagers make of the extragalactic universe as seen from Space? What delusions will comfort them, what preconceptions will blind them to the truth? Morgan and his colleagues, friends and enemies struggle to make sense of a vast new firmament none could have foreseen. Starting at the great radio telescope in Australia Morgan confidently expects to find his own obsession, his Hidden Galaxies. But the results will come as a shock. Or could there be some deep misunderstanding? Meanwhile the race is on to repair and refurbish the Hubble Space Telescope following the Columbia tragedy. Back in Wales Curly and Petrel struggle to make sense of the Sea Empress disaster which chokes their Pembrokeshire coast in oil. Love comes to Morgan from far far away as his university decides to sack him. Old Salt is on his last legs but is not too weak to take on the Establishment, while Frank has persuaded Europe to build the world’s largest telescope. The closest family relationships are poisoned by jealousy; Petrel changes tack; Morgan goes to Venice and ‘hears the horns of elfland faintly blowing’. But has he become unbalanced, as many of his colleagues believe? A great oak falls; Jack Cockle departs. Whose dreams will come true, whose hopes will be dashed`?

The deepest image ever taken of the Universe. It was taken with the WFC_3 camera which Morgan helped to design and exploit towards the end of his career. Does it prove that the Universe isn’t expanding? Looks like it. Morgan thought there was something very strange going on here. It can see back 12 billion years, to before the Sun was formed. The study is called “the Ultraviolet Coverage of the Hubble Ultra Deep Field (UVUDF) project.” Courtesy ESA/NASA

Paperback available from Amazon £12.50, 400 pages, e-version £3.99

ABOUT MY BOOK ‘CROUCHING GIANT’

September 29, 2020

A novel about astronomical research

The third novel in the saga of Space exploration is a mix of triumph, disaster and surprise. The Space Shuttle Challenger blows up killing all the astronauts. A colossal Hidden Galaxy turns up crouching beneath the sky. Morgan unexpectedly acquires a daughter and discovers, to general surprise, that spiral galaxies are heavily veiled in smoke. The Hubble Space Telescope gets launched, but with a crippled mirror; ways must be found to put it right. Finally the first very deep images come back from Space; but what do they mean? Rows break out between the teams. Frank builds an observatory on a remote Atlantic isle. Bob Salt intervenes in the Cold War while, deep behind the Iron Curtain Morgan has two encounters which will change his life. But then he almost loses it all. The action shuttles back and forth between Wales, Cape Canaveral, The Caucasus, Castel Gandolfo, the Arabian mountains, Baltimore, the Canary Islands, India, Australia, Paris….. See ‘Against the Fall of Night‘ and ‘The Whispering Sky’ for the two previous novels, with same main characters and ‘Beyond the Western Stars’ its successor and the finale to the saga.

A montage of galaxies found by Morgan and his team solely based on their radio signals, thus it shouldn’t be influenced by their optical characteristics. Indeed such a search could in principle find entirely dark galaxies. As you can see some of the galaxies are almost invisible, but not quite. Perhaps most interesting are the six specimens bottom right, because they are all colossal Giants containing more Hydrogen (which emits the radio signal) than our Milky way. But as you can see some are very dim even so. Image courtesy of Prof. Julianne Dalcanton, University of. Washington Seattle, and the Sloan Digital Sky Survey.

Published Amazon paperback, 400 + pages £12.99 and as an e-book on Kindle 2021 £3.99 with equivalent prices elsewhere.

ABOUT MY BOOK ‘THE WHISPERING SKY’

September 29, 2020

A novel about astronomical research

The Whispering Sky is the second of a quartet of self-contained novels relating the saga of two astronomers, originally boyhood friends, caught up in humankind’s endeavour to explore the Universe from Space. Thanks to his feud with Bellfounder – the machiavellian Astronomer-Royal [See ‘Against the Fall of Night’, first in the quartet], Tom Morgan has been thrown out of British Astronomy. Cheated out of the post he had been promised he struggles precariously in Europe to try and prove that his theory of Hidden Galaxies is right. That takes him to far flung observatories from the peaks of the Andes to the Cape of South Africa. Meanwhile the US is building the Shuttle to launch a large telescope into orbit but demands European participation in the venture. Frank Cotteridge, by now Bellfounder’s protégé, is tasked with lighting the European fuse. At conferences and in laboratories across the Continent the struggle begins to try and build the first electronic camera, to act as the great telescope’s eyes. In the 1970’s that looked impossible. And yet without such eyes the telescope will be blind. The race against the clock, and with rivals in California, begins. Personal and professional tensions drive wedges between the two friends while the race for Space forces them to rely ever more closely upon one another. Morgan rashly plans his revenge on Bellfounder, a battle only one of them can possibly survive.

This illustration shows the NASA/ESA Hubble Space Telescope in its high orbit 600 kilometres above Earth. Morgan and Cotteridge began working on its design back in 1977, 13 years before launch. Courtesy ESA/NASA.

At the same time Morgan is struggling, as a single parent, to bring up his son Curly and hold on to him in a bitter custody battle. When he loses, Curly is whisked away to Australia but then escapes and gets hopelessly lost in the bush.

The author was himself a professional astronomer, and a single parent, throughout this epoch. From 1976 until 2010 he was a key member of the Hubble Space Telescope team. Hubble’s story, our story, which he has been preparing to write for 20 years, is packed with dreams, heroes, shocks, villains, and the odd rare triumph. Like one of Magellan’s crew he saw great wonders and has tall tales to tell; the fight to get born, the Challenger disaster, the crippled mirror, the astronaut repair-missions, cancellation following the Columbia tragedy, renaissance, the race to prevent the space-craft dying, the huge discoveries… he was there; he was there; he was there. He knew the people, felt the pain, drank the wine. ENTIRE QUARTET ‘ called ‘Written in the Stars’ comprises: ‘Against the Fall of Night’ (1964 – 1974), ‘The Whispering Sky’ (1976 – 1983) , ‘Crouching Giant’ (1985 – 1995), ‘Beyond the Western Stars’ (1997 – 2012). All four paperbacks – each about 400 pages long – are out on Amazon, (2020), £12.99 or e-version £3.99.