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George Ellis and the Multiverse

George Ellis and the Multiverse

Last Friday’s IAP “blockbuster” seminar speaker was the renowned cosmologist George Ellis. Ellis talked to us about the “multiverse”,  a topic which has gained an enormous amount of coverage in the popular press. Countless books have been written about it: during his talk he gave us a healthy selection of quotes from many of these texts.

The “multiverse” idea is essentially that the the Universe we observe is really only a universe, with a small u, and that outside the bubble of our past “light cone”, those photons which can reach us within the lifetime of the Universe, there are in fact an infinite number of other Universes. And, this is the important part, these Universes many not resemble anything like our own Universe at all: they could be Universes completely different. Radically different, with a different set of physical parameters, leading to them being utterly barren of planets, stars and structures. God does not only play dice, but he does it with the whole Universe, infinite numbers of times. There could be a Universe exactly like the one we are living in with the only difference being that my espresso this morning was slightly stale. The reason this idea is attractive is that helps us to explain why there are complex structures like human beings and stars — we just happen to live in one of these multiverses where everything was tuned just the right way. Otherwise, of course, we wouldn’t be around to observe any of it — the anthropic principle.

Or, does it really explain anything at all? The point is that we can never, ever observe any of this. Since the multiverse are too far away from us, photons from these Universes can never reach our Universe. They are in a region of space which is not casually connected to our own (or maybe — Ellis talked about the mind-bending idea that Multiverses could actually collide — if that happened in our Universe it would lead to the formation of a ‘ring’ on the cosmic microwave background. No rings have been spotted so far ;- ).

And that is really his criticism — multiverse theories aren’t really science. One of the most important aspects of any scientific theory is that it should falsifiable, which is to say that there must be some observation which you can make to exclude the theory. Since there is no casual link between these other universes and our own there is no way we could ever make an observation to rule out the theory.  It’s not testable: these universes don’t ever interact with our own.  But, it is certainly presented as a scientific theory by its practitioners. Fair enough — to me, as someone who spends a lot of time on  galaxy surveys and observations, I appreciated very much his blast of Popperian realism, which is something sometimes you don’t get too much of in the more speculative branches of cosmology (I think all most of my observer colleagues would agree with Ellis).  And, warned Ellis, once you accept the theories of the multiverse as a real scientific theory, the gates are soon opened to all other kinds of questionable theories…

Is this really any different from what has happened before? In the past, there have been lots of crazy theories which either turned out to be consistent with observations and not falsifiable (quantum mechanics is a pretty good example of that — the theory is so counter-inutitive, and people have gone to enormous lengths to try to “catch the universe out”, like Serge Haroche with his single atom traps — but no-one has succeeded so far).  Or,  they have been ruled out by observations, like the “luminiferous aether”, instantly killed by Michelson and Morley and their interferometer experiment. These “bad” theories just fall away, because they don’t help us understand the Universe any more. However, the difference with the ideas around the “multiverse” is that they have a strong philosophical attraction to us — they claim to provide (at least a partial) answer the question, “why are we here?”.  But, for the moment, they’re not science.

Reflecting on this I see one possible course of action for the multiverse practitioners — start a church!

Back to the world-wide-web

Back to the world-wide-web

It was 1993 or 1994, maybe, and I had just seen my first web site –it was the Canadian Astronomy and Data Center’s (CADC) front page. I was in Canada, studying for my Masters’ degree at UVic’s astronomy department. I can even remember the first image I saw on the web – it was a picture of the Hubble Space Telescope, hosted at the CADC. 

Of course, I was already known at the department as an internet hacker, always interested in searching out obscure materials hidden in the deepest corners of internet. But in those days, that meant logging into libraries in Saskatchewan and seeing if they had the latest novel from Kurt Vonnegut or not. And of course everything in those days was text only — although I remember one particularly interesting episode where I found wax cylinder recordings of the World’s Most Evil Man, Alastair Crowley, and played them through the telephone-audio quality loudspeakers we had on our Sun workstations. In the middle of the night, I think? Anyway. But this world-wide-web thing was something else. Right from the start, there was a ton of content. Not only could you look at web sites — but you could also make your own! With a friend in the department, Luc Simard, we downloaded the apache web server and installed it on a server in the basement, and set to work creating the astronomy group web site.

Those were simpler times — no CSS, just plain HTML. We found a picture of the astronomy dome and stuck it on the front page. With another friend,  James Overduin, I went to the library looking for suitable pictures we could use  (remember of course there was really no Web at this time so any pictures you wanted you had better scan them yourself). We found a picture of some cave-men building Stonehenge and put that on the Grad student page, and wrote at the bottom ‘At work on the next generation of telescopes’.

I wrote most of the text. The front page was simply picture of the astro dome, along with three or four paragraphs of text interspersed with links (which, in those days remember, were blue). I resisted innovations. I approached it a bit like telling a story.

The front page is still there, actually, linked to from the Astronomy department’s front page.  Some of the words that I wrote almost twenty years ago are still on that page. Looking at the source file I was amused to see the date of modification/creation was 16 November, 1994, and the user was one “Howard W. Cambell”: assiduous students of American literature will know just who he was (answers on a postcard…) Those pages lasted a long time because they loaded so fast and contained most of the information you needed. Today, of course, they look terribly dated. 

But it was funny — in those early days, I was the only Henry Joy McCracken on the internet searches (people interested in the other Henry Joy hadn’t yet heard about the world wide web) and I even got a few emails about my little personal web-page telling me that such-and-such a link was broken, etc. I never made another web page again, for various different reasons. But …. now, here in the 21st century, I’m obliged for other (professional) reasons to make one again. And I am obliged to write this blog post, because if the link is not out there, Google will never index it (and the best chance of them indexing it is if it’s on one of Google’s own pages, i.e., here). So, here it is:

http://www.iap.fr/users/hjmcc/

So yes, I admit that this blog post was an advertisement. But, at least there was at least a small story in there somewhere.

At the great wall

At the great wall

I am back again in my room at the campus of Peking University. It’s Sunday morning and I can hear the birds in the trees outside — and what I now recognise as the sound of distant construction works. Construction never stops here. In China, work like that doesn’t stop for the night or the weekend. In Xinlong, at the observatory, in the forest, we often passed a derrick drilling a well to bring fresh water from deep underground. Drilling continued all day and all night, making a clanking, grinding noise which could be heard all around the observatory. In the morning, returning from our observations, lights still burned on the drilling platform and through the trees we could see three or four workmen wrestling with heavy machinery or leaning against the derrick and watching the drill bit slowly spiralling downwards. In the corner of the clearing I could see a small green tent, and nearby, clothes were strung out on a line. Did they sleep here? If they slept here, how did they sleep with the unending noise of the drilling?

Yesterday we did not return directly to Beijing – instead, we went first a little further to the north and south, taking us to Great Wall – note the capital letters. Over the past ten days, during my arrival in Xinlong and last Monday during our excursion to the Qing tombs, we could often see sections of the wall around us on distant hilltops, some of it restored, some of it crumbling and showing the passage of time. But on Saturday, we drove (or rather we were driven, by once again our gracious host, who had never yet visited that section of the wall) to Jinshaleng, where there is a very large section one can walk — more than four or five kilometres of total length I think, although we only walked a fraction of this. It is quite remote, around two hours from Beijing and consequently there are far fewer people than on the more heavily frequented sections like Badaling, where most buses from the capital arrive. So it was a real privilege to visit there.

We arrive at the parking lot at the foot of the mountain at around midday. Despite the supposed remoteness of the location, we find that the parking lot is already full. A cable car takes us to the wall; the cars advance with maddening slowness, swaying slowly in the breeze, trees below scraping the cabin. A trapped fly buzzes angrily in our cabin for perhaps fifteen minutes, but there is no way to open the window. We can hear people talking on their mobile phones in cars passing in the other direction.

Then we arrive, and jump from the cabin. Leaving the platform, I see the wall from close at hand for the first time: not only is the nearest section only a few hundred meters away, I can see both to my left and right sections disappearing down into valleys only to rise up again on more distant hilltops even further along. The wall continues across the mountains until it merges with the distant misty horizon, always tracing the crest of the hills, following the steepest path imaginable, continuing on. At each hilltop there is a guard tower of perhaps two or three stories in height, and it is one one of these guard towers which is our first direct contact with the wall.

Through the northern windows of the tower we see the rugged hills disappearing into the distance. To the south, the same hills, and near the southern horizon sunlight through the clouds picks out a shimmering distant lake — this, I am told, is the main water reservoir of Beijing. Here at the wall, the sky is overcast although an occasional patch of sunshine slides across the hills. There are a fair amount of people at this part of the wall, so we continue to walk. We don’t have enough time to walk the entire four kilometre length of this section so we will turn around after one hour and head back and retrace our steps.

After walking for perhaps ten or fifteen minutes, there are already far fewer people. Here there are long, straight sections of the wall where we are almost alone with the exception of or two locals trying halfheartedly to sell us “tea coffee beer”. Standing there on the wall I am reminded of Angelopoulous’ film “The hanging foot of the stork”, a film about frontiers and borders. Imagine, says a character in the film, I stand here on this bridge, a bridge on a river dividing two countries, and I raise my leg on the border line, in the middle of the river, the centre of the bridge: where am I? Where am I indeed. We walk further along the wall, up the steepest steps I have ever climbed in my life, and I think the same thing as Angelopoulous’ character, here on this wall separating civilisation from the outer darkness. At the highest point, a kilometre from where we arrived, I can see the wall extending far into the eastern distance, merging with the horizon. I wonder how it must have been to be here in the darkness of night six hundred years ago, surrounded by this desolate and empty countryside. I see the soldiers eating their noodles, drinking tea and straining to hear sounds or distinguish shapes of against the darkened treeless hills. Fearing the arrival of intruders.

Suddenly, it seems, it is time to return, although we have no particular desire to leave the summit of the mountain where it is quiet and peaceful. We retrace our steps, leaving the further western reaches of the wall unexplored. It will have to wait for a future trip. The return to Beijing is uneventful, although almost half of our journey seems to be spent crossing the endless sprawling expanse of this vast city, roads thick with traffic, people returning from vacation and weekends. Far in space and time from the frontier lands we visited only hours previously.

In Xinlong

In Xinlong

Last night on the mountain. I am at Xinlong Observatory (or “Xinlong observing station” as it’s called in English around here), about two hundred kilometres to the north east of Beijing. I have been here for over a week now, teaching at a school of observational astronomy. The fact that there are around thirty or forty students here with myself and the other tutors, as well as an internet connection (no matter how slow or unreliable it is) makes one forget the remoteness of the location. But remote it is. Xinlong is the site of numerous small telescopes, as well as one much larger telescope constructed recently, LAMOST, an ambitious instrument designed to carry out large spectroscopic surveys of the nearby Universe. The nearest city to here, half an hour down the mountain, is Xinlong itself, a small village only ten years ago but now bursting with the concrete shells of immense half-completed sky-scrapers, full of brightly lit broad avenues (which is of course bad for the observatory).

My daily routine here this past week has consisted of getting up, pulling back the curtains and gazing out over the valley, a beautiful forested valley — and filling up my Bialetti “moka electrika” (the same one that I took on the train to Tibet in 2007) with water and Illy coffee. That way, once I come out of the shower, there is strong coffee ready. Each morning I scrutinise the contents of the coffee tin, but I am reasonably sure I have enough to last to me until I return to France on Wednesday morning. Lunch and Dinner are at the unusually early (for me) and highly precise times of 12:00 and 18:00. We arrive at the canteen to find small metal trays full of several different kinds of meat and vegetables, usually quite good but — arrive at 12.05 and it’s cold. One thing we have remarked is that windows and doors are left open everywhere, and there is no heating — and it’s almost winter. Warm clothing essential. Everyone eats rapidly, in less than half an hour, and it is always the French who are the last to leave. In between those times — helping the students, or trying to get some work done in my office.

My week here was interrupted by a trip given by one of our gracious hosts to the eastern Qing tombs, which lie perhaps fifty or so kilometres from here, but the trip was longer than this distance would suggest. We took a shortcut through the mountain, back roads which were in very bad condition– in some places nothing more than dirt tracks. The journey started well enough, a new paved road, but soon after that the going became progressively slower. Throughout the countryside there are many small mines, coal amongst other ores, and the constant passage of heavy lorries has destroyed the surfaces. On the way we passed through countless small villages. Around here it is rural and remote, and agricultural, and the roads were often laid out with crops left to dry in sun — posing a considerable hazard for the unwary driver. We passed many people shelling corn, the empty husks filling the streets. A thought flitted through my mind, I thought about passing within inches of people who live very different lives from mine, but then Ireland too has countryside and agriculture. The difference here is of course that everything is still heavily labour intensive and the industrial revolution is only just reaching the countryside.

The eastern Qing tombs themselves rest in the shadow of the misty green mountains, red temple roofs lie against a background of thickly forested hills. The grounds of the many tombs are enormous — one cannot simply walk from one to the next, a car is essential. One arrives along a long, broad avenue lined with many stone animals — this was the route that the funeral processions would make. Each tomb lies in a mouldy, underground cavern. The facades of many of the buildings — some of which are more than three hundred years old — were somewhat the worse for the passage of time. Out here in the depths of the countryside, hundreds of miles from Beijing, time has been allowed to take its course, and nothing has been restored, no new coats of paint had been given. Remember too that just on the other side of the mountains, once was the outer darkness, the invaders: the line of the Wall once snaked unbroken across those mountains over there.

The day of our visit was not just any day — it was in fact one hundred years to the day that the emperor was deposed and modern-day china began its slow and painful birth. But on the day of our visit, nothing seemed to be out of the ordinary. We noticed no western tourists other than ourselves — these eastern tombs are much further away from Beijing than the western ones, which, I understand from my guidebook, are usually on the circuit of tour-buses visiting the great wall. In any case, the emperors, although deposed, their palaces and tombs do not seem to have suffered too much from revolution revolution: living in France, where there is a long tradition of purifying fire, one expects perhaps otherwise.

Tomorrow: a descent from the mountain, and a return to the capital — and on the way, at last, a visit to the great wall, to one of the more remote, less travelled sections.