Cassandra has moved. Ugo Bardi publishes now on a new site called "The Seneca Effect."

Thursday, January 19, 2012

Breaking the walls of Diaspar: the revolution of planetary science

The title of this post derives from the 1956 novel by Arthur C. Clarke "The City and the Stars" which starts with the description of the ancient city of Diaspar - one billion years in our future.  Just as the protagonist of the novel breaks one barrier after the other in his quest for truth, so we are breaking one scientific barrier after another in a series of scientific revolutions. A recent one has started with the discovery of a large number of extra-solar planets coupled with the new understanding we have of the mechanisms that keeps our Earth "alive".

If I go back to my teenage years, I can identify some of the reasons that led me to follow a scientific career. One is a novel by Arthur C. Clarke: "The City and the Stars," published in 1956 and that I read when I was, maybe, 15 years old. The name of the city of the novel "Diaspar" has remained riveted in my mind ever since. 

"The city and the stars" is "hard" science fiction; it deals with planets, stars and spaceships. You can read it as an adventure novel, but also as an allegory of the human search for truth and enlightenment. It starts with the protagonist locked inside the walls of Diaspar. A jewel of a city of a billion years in our future, but also a small world from which the protagonist tries to escape. And he succeeds; breaking one wall after another, exploring what is left of the ancient planet Earth, and then moving to space to find all sorts of wonders. The novel leaves you breathless with its width and depth. It is pure magic: the magic of scientific discovery.

It is said that science is 1% inspiration and 99% perspiration. I can confirm from my experience that it is true. Of course, science fiction makes things easier: it removes the 99% of perspiration. But even in real science, the 1% of inspiration is well worth the 99% of hard work. Good science brings to you the same sensation of wonder that good science fiction produces - the sensation of breaking down one knowledge barrier after another, with the advantage that it is for real!

So, during the past few years, we have had so much good science that it has been almost overwhelming to keep track of it. Every morning, I give a look to the web to see what is new in science and, almost every morning, I am struck by something new and unexpected to be read and understood. It is hard to absorb so much, but I try and it is always fascinating.

The latest scientific revolution is in planetary science. It seems almost unbelievable that just some decades ago people were still debating on whether extrasolar planets actually existed. Today, we are discovering so many of them that it is now believed that almost every star in the galaxy has planets. It all reminds us of the times of Galileo Galilei. Think about that: before Galileo, planets were just specks of light fixed to crystal spheres. Then, after Galileo looked at the night sky with his telescope, - bang! - planet became big balls floating in space. And and not just that: there were small planets orbiting big planets; miniature solar systems. A sudden expansion of the horizon - the breakdown of a knowledge barrier. From Galileo to us, it has been breaking one wall after another: science is enlarging our horizons at a breathless pace. The universe keeps becoming bigger. Now, everytime you raise your eyes to look at the Milky Way, you know that you are looking at a galaxy full of planets. (image below from ESO, showing a comparison of the planets of the Solar System and those of Gliese 581, a star located at about 20 light years away from the Sun. )

But the thrill of new discoveries doesn't just come from knowing that extrasolar planets exist. It comes also from what we know about these planets. A revolution in planetary sciences has been going on at a breathless pace. It is a synthesis that puts together geology, biology, astronomy and physics to give us a picture of the life and the evolution of planets. Life on an Earth-like planet is not just a question of being at the right distance from a star. It is a delicate balance of factors that involve plate tectonics, the core temperature, the carbon cycle, solar irradiation; all interacting with each other to keep a planet "alive". The right combination of these factors can make a planet suitable for organic life and, probably, for the development of intelligent life. So, looking at the sky at night, we what we are seeing is not just a galaxy full planets, but also full of life and - probably - of intelligent life.

At the same time, the new science of planetary systems gives us a pretty clear view of how we can destroy our civilization by upsetting the delicate balance of the factors that keep our planet alive and friendly to us. We can do it in more than one way, but the most effective one is to continue to emit greenhouse gases in the atmosphere. So, once you have looked at the stars, come back to Earth and start doing something because we are all in trouble. If we manage to destroy ourselves it will little consolation to know that others in the Galaxy may do better than us.


About extrasolar planets, you may look at "Centauri Dreams" for updates.

A good synthesis of the interlocking factors that keep planets alive can be found in an article by Milan Cerkovic.

A previous post of mine on galactic civilizations is "The Hubbert hurdle: revisiting the Fermi paradox"


  1. Hi Ugo,

    are you aware of atmospheric physicist Tim Garrett's website?

    and there:

    •If the global economy is able to achieve gains in energy efficiency or energy productivity, it will accelerate energy consumption by accelerating healthy civilization growth into new energy reserves. Efficiency gains create a “super-exponential” acceleration of energy consumption and carbon dioxide emissions while growing the GDP. Expressed in terms of economic demand, this effect has been termed “backfire” or “Jevons’ Paradox”.

    •Growing global wealth requires increasing global emissions of carbon dioxide because both are linked to energy consumption rates. The two go hand in hand ... unless we change civilization’s fuel mix. If we are to simply stabilize CO2 emissions at current growth rates, this would require building the equivalent of about one new nuclear power plant per day.

    •If we are no longer able to grow our rate of consumption from our energy reservoirs, then civilization wealth will enter a phase of collapse. A collapsing civilization will emit less CO2 because it is consuming less energy.
    •If global warming becomes so severe that it causes civilization collapse despite our best efforts to avoid it, it will manifest itself economically through hyper-inflation.

    •Stabilizing atmospheric CO2 concentrations below a level of 450 ppmv that might be considered dangerous requires civilization to begin a collapse of its wealth almost immediately.

    1. You kidding, Alex? I am an avid reader of Tim Garrett's papers. Yesterday I was giving a presentation if Florence, and I was showing slides from his papers!

    2. Hi Ugo,

      I will present on tuesday and will use his graphs too! ;-)

      What was the reaction of people?

      I do not think we are able almost double the global nuclear power generation capacity in one year only to stabilize carbon footprint... sometimes even the economic collapse seems to me a bit slow...


  2. Why not the message "let's just collapse and the sooner the better"
    However I'm still on the line where "jevon's paradox" is really a bit of a false excuse, as volume based taxes should be the primary "tool" if we try to manage a transition.
    And for sure all the "US experts witty discourses" will never point to the current US almost zero volume based gas tax, nor the fact that moving one body with 1,5 or 2 tons of steels and plastic isn't a "human right" in itself.

  3. By the way, regarding "hard science", I don't know if the picture on the book cover is a faithful reflection of a a description in the book, but did you know that one of the current myth or "received idea", is that skyscrapers would be a "good generic shape" to increase density (in the sense FAR floor area ratio) at the level of a city, when this is simply plainly false !
    (under same natural light constraints in comparing different urbanisms made of generic shapes for the buildings)

    This was formalized by Lionel March and Leslie Martin in the sixties in Cambridge, even though in a too simplified manner at the time, basic results sill hold. Ask myself the question, founding almost nothing about it, more or less redid basic claculus before finding their works.

    You can check two papers linked below about it (pdf in English) :

    1. Well, the description of Diaspar in the book is of something like a hyper-technological village. It sort of reminds me the inside of an air terminal. For sure, Diaspar doesn't have the aggressive aspect of a modern city - full of skyscrapers. But it is very difficult to manage to express the concept in a graphic form. The image I chose is the best I found; not too aggressive, it gives the impression of a closed space. Other images show Diaspar as a sort of a giant apple pie; not so good.

      About skyscrapers, it is a complex story and personally I am both fascinated and repelled by skyscrapers. I have an especially emotional relation with the "Ville Radieuse" built by Le Corbusier in Marseille. Sometimes I love it, sometimes I hate it. I wrote a post on it in Italian

      Probably it is worth translating it into English. Right now, anyway, more than in a skyscraper, I feel at home when I stay with my Roma (aka gypsy) friends in a hut heated by wood fire.

    2. I also have a kind of "love hate" relationship with the "cité radieuse" of Lecorbusier in Marseille (and a few others builded), one nice thing about it being the concept of "tête-bêche"(don't now a term in English for that, head on foot or something) duplexes, making each flat traversing the building and a central corridor every three floor :
      Btw, played around sometimes ago making a kind of "enumeration" of possible buildings type (more housing oriented) in below thread :

      But I wouldn't call the "cité radieuse" a skyscraper or tower type, it being more a "slab type", and the point on density is really that even a bit "counter intuitive", towers are simply not efficient at all to increase density whatever the number of floors, except as a singularity of course (and especially true for housing, a bit less for offices as you can make the buildings "thicker", that is bigger surface area for a single floor, except making huge flats for housing)
      This density thing is really strange, for instance when Lecorbusier writes about his Paris plan (replacing almost everything) and increasing density in the process(I think he quotes 7x), he is simply lying !!
      Even though he was right in slabs being more effcient for housing than towers (and in fact he didn't like NYC for instance, calling it "gothic" or something)

      Otherwise can understand the "feeling at home when I stay with my Roma (aka gypsy) friends in a hut heated by wood fire."
      Which somehow could also be seen as a metaphor for the whole world situation except the camp fire running on fossile..(and us being able to say the smoke is bad, which of course is true, but almost unable to show the state of the fuel stock ...)

      On another subject have you seen this (leaked PO report in Australia) :

    3. By the way, also read your article using google translate and think I got most of it, good point on the "vide ordure" and the kind of relationship to waste it implies (putting the thing in a black hole and just forgetting about it).
      On Le Corbusier he was quite a complex case (and associating all the seventies buildings to him isn't really fair), and in fact him was spending more time especially end of his life in a small "cabanon" of 16 square meters he builded on côte d'azur :

  4. Garret's papers are interesting.
    I liked his quote about needing a new nuclear power station each and every day just to stabilize CO2 emissions at current rates.

    I liked doing science, in my small way, because it was open to universal inspection and needed transparency. There was plenty of rivalry, but essentially science could not proceed properly without collaboration. The results were a Public Good. I found that reassuring for my peace of mind. I hoped it brought out the best in me. I was greatly saddened when science in my area of work became increasingly proprietary. Genetic engineering used for patenting became a big issue when ownership of the majority of the world's crop inventory was at stake . Don't let them kid you it was about feeding the world.

  5. I read The City and the Stars recently and I just loved the technology shown and used by the inhabitants of Diaspar. This 1956 (!) novel successfully evoked a sense of wonder that I rarely found in other SF books.

    I completely understand why this book had such an impact on you when you were still a teenager because it really expanded my mind and my horizon as to what to expect and hope for in terms of scientific and technological progress. Obviously, the society in the novel is conservative and stagnant but I mostly focus on how life become materially incredibly better.

    If I read this book earlier in my life, I would have become a scientist like you!



Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)