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THE HUBBLE SPACE TELESCOPE

November 5, 2020

Given that there are roughly ten tons of turbulent murky atmosphere above every square metre of the Earth’s surface it is a wonder that we can see the Cosmos at all. Thus the urge to orbit a big telescope above that atmosphere was irresistible. So in 1976 NASA and ESA put together a joint mission , which was eventually to be christened ‘The Hubble Space Telescope’ (HST) after Edwin Hubble. If, and it was a very big if at the time, all went according to plan, the prospects were breathtaking. The machine would image the Cosmos in a thousand times more detail, and across an eight times greater colour range than its ground based counterparts. Because of its accuity it would begin to see the Universe actually moving for the first time. Furthermore it ought to detect objects a hundred times fainter and thus ten times further away, and because light has a finite speed that meant it would be a Time Machine able to observe the Universe as it was long before the Earth and Sun were born. No wonder some suggested it would become “the most exciting project ever undertaken by mankind”.

This illustration shows the NASA/ESA Hubble Space Telescope in its high orbit 600 kilometres above Earth. It’s about the size of a bus while the ‘wings’ are solar panels

But if it was to succeed there were huge challenges to overcome. How was a mirror of the required precision ever to be made? How could the telescope take pictures up there and then return them to Earth? Given that there would be no crew (too clumsy), how was it first to find its targets and then hold steady on them with unheard of precision? How could it be serviced, or repaired if things went wrong, as they were bound to do on on a spacecraft far more complex than any nuclear-powered aircraft carrier?

Nobody knew the answers. But that was half the point. Like JFK challenging the Apollo Mission to get to the Moon in the 1960s “……not because it is easy, but because it is hard” so NASA and ESA were throwing down the gauntlet to their successors. “Here” they said to their selected teams “Here’s a problem we can’t solve. You go crack it. But you’ve only got so long!” And that of course was the very kind of challenge which inspires scieneers.

Astronauts installing WFC-3 camera on Hubble Space Telescope in 2009

Teams, committees, call them what you will, were the secret, and the Camera Teams were at the very heart of the entire enterprise. Only the cameras on board could exploit the full power of the telescope, and so deliver its most ambitious science. But what was that science to be? Before they designed a single lens it was those instrument teams , and those alone , which had to peer far into the future and try to imagine the most exciting questions that the telescope would be called upon to answer.

I was lucky enough to attend the first meeting of the Faint Object Camera team in 1977, and the last meeting of the Wide-Field-Camera-3 team, in 2010. So I feel well placed to describe our long voyage of discovery, as one of the on-board crew. I have chosen to tell it in novel form because what was to happen had to first germinate in the human heart and mind, the drivers of everything else. It also allowed me to cut many a tedious corner while keeping the true cast of thousands to less than Tolstoyian size. I hope readers, and in particular fellow members of the crew, will forgive me for that, and certainly for omitting episodes and heroes they feel should have been included. But this is meant to be a human story of a very human endeavour, not the synoptic history which will no doubt emerge when we have all gone.

Since The HST story occupies much of my three novels:

The Whispering Sky ( 1976 to 1983)

Crouching Giant (1983 to 1995). and

Beyond the Western Stars (1996 to 2011)

all Amazon Publishing (2020)

I won’t say more here. You can see then all described here under the ‘My Books’ Category.However I intend to add, from time to time , images and scraps which could enrich the reader’s experience of the adventure. and I would be grateful if readers, or ex-comrades, could suggest more.

Here is the recent Ultraviolet Ultra Deep Field image taken with Hubble WFC-3, the deepest picture of the universe ever taken, and illustrating its capability as a Time Machine. Apart from the odd spikey star all the objects are galaxies vast distances away. The tiniest reddest ones have redshifts as large as 7 indicating that we are seeing them as they were over ten billion years ago. The Sun is only 5 billion yeas old. Copyright NASA/ESA/stsci.

Hubble would have been a disaster without the Space Shuttle, which not only launched it back in 1990 but visited it 5 times thereafter, to adjust for the flawed mirror, make innumerable repairs, and install new instruments like WFC-3, the camera which is still up there working perfectly after 11 years in orbit. Man seldom gets things right first time; we do our best by tinkering, by Evolution. Without Shuttle that would not have been possible, and I fear that HST’s successor, the James Webb Space Telescope, whose launch has been postponed at least a dozen times already, could be a disaster because it has no such means for repair. Anyway below you will see a panoramic view of the Cape Canaveral launch-site in 2009 with Shuttle Atlantis on Pad 39-A about to go up on its final mission STS 125 to the telescope, carrying WFC-3, along with its brave crew. In the background is Shuttle Endeavour on Pad 39-B, standing by to act as a Lifeboat to bring the crew back should Atlantis experience a serious failure, as happened with Columbia. In the background is Merritt Island nature reserve. If you zoom in enough, you might spot Morgan swimming up one of the alligator infested creeks to get as near to Atlantis as he could.

Those interested in following up the treasury of wonderful Hubble images and what they signify, can go to websites such as stsci.edu, nasa.gov, eso.org , http://www.cosmos.esa.int, and http://www.spacetelescope.org.

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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.

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THE SCEPTICAL COSMOLOGIST

October 13, 2020

 

Somebody said, Einstein I believe: “The most beautiful thing we can experience is the mysterious. It is the source of all true art and science .” And no subject is so imbued with profound mysteries as Cosmology – despite what some glib professionals would have us believe

Think of Cosmology’s Big Questions:

1) Why is the sky dark at night – if the universe is infinite?

2)  Why do distant galaxies have highly red-shifted Spectra?

3) Is the universe changing, and did it have a beginning?

4) What is the source of the powerful cosmic background radiation which glows in all directions?

(5) How can that radiation be so uniform (To one part in a hundred thousand) if the speed of light is finite – which it definitely is?

(6) If the universe is expanding in a hot Big Bang – which so many professionals maintain – then how did flimsy structures like galaxies form out of it? Nascent galaxies should have been torn to bits by radiation pressure.

(7) When you slam the brakes on  in your car, why does your head jerk forwards ? It is being violently decelerated, but decelerated relative to what? It turns out that it is being decelerated  with respect, not to the Earth,  but to the distant stars. But how does it know that? ( ‘The Problem of Inertia’ ). In other words what is the physical mechanism that  must connect your head to the stars?

These are all profound and mysterious questions to which science has so far been able to offer only fumbling answers  –   despite what some cosmology-priests would like us to believe: “The universe is expanding,”  they say, “There was a Big Bang, Space – Time is curved, and we’ve got answers to all, or nearly all those other awkward questions too – Cold Dark Matter, Inflation, Dark Energy……”

Don’t believe them. Cosmology is an extraordinary difficult subject if only because it lies at the nexus of so many others: Astronomy, Physics, Mathematics, Philosophy, Sociology, Instrumentation, Computer -simulation…… Of the sixty different civilisations we know of, every single one has come up with a cosmology of sorts – it seems to be a necessity for the human psyche. And that leaves room for a priesthood only too eager to supply one.

To keep a sense of proportion it is worth recalling some recent cosmological follies:

Thinking of Time as linear: “We’re already back to within three minutes of the Big Bang” they say  – when, in the cosmological  context, Time is surely logarithmic. In logarithmic Time the Cosmos was completely opaque throughout the first 43 decades of its 60 decades of existence. Its origins will therefore be veiled  beyond our sight – probably for ever.

If galaxy redshifts are not the Doppler effect in action – which apparently they are not – then what causes them? Yes, they come out of the mathematics (the ‘Robertson – Walker – Metric’), but that is hardly Physics.

Once the impossibility of forming galaxies in a Big Bang cosmology was recognised, an ingenious new substance christened ‘Cold Dark Matter’(CDM) was conjured up to solve it. Elaborate computer  simulations were offered as proof that CDM works. But it doesn’t. Observed galaxies look nothing like the CDM variety; nothing like1. Yet the cognoscenti refuse to admit it.

Everyone agreed that gravity ought to slow expansion down but when the slowing was looked for it wasn’t there. On the contrary. Expansion had apparently accelerated – and in recent times too. This called for another improbable miracle: Dark Energy – whatever that is.

If expansion of the entire universe does seem  a mite implausible – we do have an acid test for it – the Tolman Test devised in the 1930’s [distant galaxies should dim as the fourth power of their redshifts]. But one glance at the Hubble Deep Field (below) demonstrates that there is no such dimming – it falls short of the required  amount by  a factor of no less than 10,000! But professional astronomers  won’t talk about that. Why not?

           In short Cosmology appears to have been regressing of late because some of its  most vocal proponents appear not to appreciate  a truly  fundamental principle of Philosophy – Ockham’s Razor. Every time you complexify a theory by introducing a new Free Parameter (such as Dark Energy) to solve one problematical feature of it, you fundamentally weaken that theory. So one is only justified in doing so if at the same time that Free Parameter illuminates other entirely new and favourable evidence which more than compensates for the weakening inevitably involved. CDM, Inflation and Dark Energy do not meet that criterion  – and so should be rejected.

           I have been an enthusiastic follower of Cosmology since I was a boy. I even taught  myself Tensor Calculus at age fifteen in order to read Einstein’s original papers. I’ve been a professional extragalactic astronomer for much of my life and have been to some of the big cosmology conferences – including one in the Vatican ( see my book Crouching Giant),  even taught it at university when nobody else would  – but have  become gradually more and more sceptical of the subject as the years roll by. Yes there are some strong arguments in favour of  Big Bang Cosmology – but there are even more against. To come to a measured  view of the whole subject one  needs to weigh them against one another  using Common Sense. When I do so the Odds come out at over hundred to one against Big Bang Cosmology being  broadly right( See another post here entitled  The Scientific Method.) Some aspects of it are probably sound, but which ones?

I’m not suggesting we should abandon  Cosmology as a subject  –  on the contrary. We should study its mysteries with ever more ingenious techniques and instruments. Equally though we need to be  alert  to the crippling weaknesses of the current paradigm. If we close our ears to them, as so many professionals at present do, we could miss some subtle but tremendous secret the real universe is trying to whisper in our ear. As Daniel  Boorstin wrote in The Discoverers: “The greatest obstacle to discovery is not ignorance – it is the illusion  of knowledge.” I believe we all need to become sceptical cosmologists now; most especially professionals.

Hubble Ultra Deep Field. Courtesy ESA/NASA

If you examine this extremely deep image taken with the Hubble Space Telescope almost every object on it is a galaxy . The small images are much further away and have high redshifts. But if those redshifts were due to expansion of the universe then those small images should be so dim as to be invisible. But as you can see they are nothing of the kind. This is a complete shock. On the face of it at least Cosmic Expansion has failed the classical test set for it — ‘The Tolman Effect’ by a factor of 10,000!

On the face of it then the Universe cannot be expanding! After all such dimming was the classic test for expansion proposed by Richard Tolman back in the 1930s when we didn’t have the means to apply it. But now we have, and the universe has spectacularly failed it. But nobody, at least no professional, wants to talk about it, Umm.

There is another more recent post on this site entitled “Big Bang Cosmology is Wrong” under the “Astronomy” Category

I go into the stories behind the Hubble deep pictures in the last 2 books in my quartet ‘Written in the Stars entitled’ : Crouching Giant and Beyond the Western Stars. [See under ‘my books’ Category on this site.

NB You can see hundreds of HST images at stsci.edu, nasa.gov. or eso.org.

Ref 1: Disney M J et al: 2008, Nature, 455, 1082-4, Galaxies appear simpler than expected.

If you want to see the author talking about Cosmology and galaxies there is a 45 minute Youtube video of him being interviewed by the Physicist and Author Alexander Unzicker about 3 years ago at:

https://www.youtube.com/watch?v=KskJrJmfr34

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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!

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