Friday, March 23, 2012

The scaling of time: ChronoZoom

One of the conversations that is starting to develop here at the blog relates to the concept of scale. In a recent comment, Michelle wrote about an application that aids with the visualisation of time-scales (although the application's designers see it as more of an interactive teaching tool).

Seeing as "Scale of the Universe" is so popular on the internet, I expect that this application, ChronoZoom, should become equally popular one day soon. Scale of the Universe allows you to zoom in and out of distance scales and it shows you the relevant physics, chemistry or biology at each scale. ChronoZoom kind of does the same for time. However it is quite a bit more detailed and much, much more ambitious as a project. Watch the video above, read a recent article on the project, and play with the application itself.

Michelle wrote in her comment that she finds visualising time-scales through this application more difficult than the equivalent for spatial-scales. This is not surprising. We encounter space with our eyes every day, so visualising space is already second nature. Zooming in and out is also something we do naturally every day. Extending this to a need to zoom in and out on a greater range of scales shouldn't be too hard. However, no matter what happens in life, we always proceed forwards in time at a rate of one second per second and we definitely don't "see" time. Despite all of that I think it is also true that the Scale of the Universe application was specifically designed with the aim to give a sense of perspective. Whereas, ChronoZoom has been designed more as a way of organising information. The sense of perspective it can give seems to be much more of a bonus than a feature.

One interesting observation I can make (and have already to a certain degree in this comment) is how in the early stages of the universe, time scales and length scales were intricately related. This relationship arises from two different mechanisms. The first, and more obvious, is the expansion of space with time. As time progresses, things in the universe get further apart. Therefore the relevant distance scales get larger and larger as well. The second mechanism is the growth of structures in the universe. Structures grow hierarchically. This means small things grow first, then larger, then larger. This is actually a distinct effect from the expansion of the universe, but it's aesthetic implication is the same; earlier times mean smaller scales.

Of course most of the ChronoZoom application is devoted to later times. Something that struck me quite a bit when I first realised it is that the Earth is about a third of the age of the universe. Whether this means that the Earth is very old, or the universe is very young depends on your perspective, but whichever perspective you hold, when it comes to time, the universe and the Earth exist on similar scales. You can see this really clearly in ChronoZoom. What is also quite striking, but already appreciated by many people is just how young humankind is. If you go to ChronoZoom and click on "humanity" right at the top of the page you are given quite a sense of perspective regarding how young we are as you watch it take forever to zoom in on our relevant time.

For both those old dudes, Earth and universe, we humans really are just a flicker.


  1. The Stanford Encyclopedia of Philosophy says that ''ontology' is "the study of what there is." I'd go simpler and even more fundamental than this excellent, open-access intellectual (and peer-reviewed) resource and say that 'ontology' is the study of origins: the origins of things, and the origins of concepts.

    It's always struck me that physics in general, and cosmology in particular, deals with scales of time that exceed the parameters of the philosophical framework by quite a long shot. We don't have an immediate discursive vocabulary for cosmological time that would also be responsive to the discoveries of physics from the late nineteenth-century on - we have to go to twentieth-century philosophers of phenomenology and their inheritors for the starting points of that vocabulary. The reason I find the ChronoZoom challenging and even counter-intuitive to navigate is that it starts to visualize time with a fullness and intensity that, up until now, one has tended to only in encounter in Bergson, Husserl, Heidegger.

    Clearly, we need a guest post from a phenomenological physicist...

    1. I think you're saying in different words what I was trying to express by the "one second per second" remark. The only time scales that I can relate to my own experiences are those between one second and 28 years.

      It isn't just cosmologists in particular, but also particle physicists in particular who deal with radical time-scales. The smallness of the time-scales they are dealing with is equally unimaginable as the longness of ours.

      We do though have many proxies for time (redshift, temperature, relevant distance-scale for structure formation) that do a good job at contextualising these time-scales. I'm also not convinced that the way I would use these proxies is not translatable to a non-physicist. I will give it a shot later in the year with a post about how time is measured in cosmology (and particle physics too actually, why not?).

      What is a phenomenological physicist? Or what do you mean by it?

    2. The most common particle physics proxy for time would be energy. In fact there are a number of quite profound links between time and energy in fundamental physics. That might be another interesting topic for me to try and tackle one day.

    3. I don't know very much about phenomenological physics, and thus the question: I would like to have a sense of what this field does, as a starting point to wondering if there are real parallels to phenomenological philosophy, or orientations to phenomenology in art. I suspect there are a whole field of potential subtle connections.

    4. What is phenomenological physics? Or what do you mean by it?

    5. Well, I assume particle physics is a big part of it. But, you should skool me. I have a lot of associations for the word that might not matter to physics, and don't want to project.

    6. Um, I'm confused now... I didn't first use the word phenomenology... there was a specific type of person you wanted to guest-blog I'm not sure I understand what that type of person is. That's why I'm asking.

      What the word phenomenology means to me is kind of irrelevant. The relevant question is what word would I use to describe what you're calling phenomenology.

    7. Ok, an attempt at banishing mystification! Is there a stripe of physicist that would self-identify with the word 'phenomenology'? Who are they, and what do they do?

    8. Alright, I'll blink first.

      There is such a thing as a "particle phenomenologist". They basically take all the crazy theories that physicists come up with and calculate what the observational consequences of these theories would be in things like colliders.

      It is a relatively new "phenomenon" and is a symptom of the ever growing amount of knowledge humanity has. Many theorists are too busy trying to solve internal problems with the theory to have time to calculate the observable consequences... hence the phenomenologists come to fill the vacuum.

      But I think it is just a coincidence that they happen to be called phenomenologists. I don't think they're thinking any more about what you call phenomenology than you or I are. In fact (by the particle physics definition of phenomenology) I could probably quite justifiably call myself a cosmology phenomenologist.

    9. This kind of thing is why I love language and the yawning chiasms that can erupt inside the etymology of a single word. Will think about this and write some more about it later.

    10. I had intended to write this on your original post about scale, but in discussions I have with colleagues, "scale" would be by far one of the most used words. Scale is a very important concept for both cosmology and high energy physics, the two things I play with for money.

      Length scale, time scale, energy scale.

      And, in this case, I think physics' use of the word and your use of the word actually match definitions.

    11. Just one example...

      One of the most interesting discoveries of the last few decades is that the primordial fluctuations in the universe were *very nearly* "scale-invariant", meaning that they had almost the same amplitude at both large distance scales and small distance scales. That they were ever so slightly not scale-invariant is a puzzle that has many candidate solutions.

      The concept of scale seems like a very genuine point of connection.

    12. Clearly - and a rich one because it is so nuanced. We have lots to explore on this point I think.

  2. Some bonus thoughts for the people who read the comments:

    There is a nice symmetry to the way humans engage with time. As I wrote above, at earlier times, smaller length-scales become relevant. But, smaller length scales do things more quickly too. Therefore, at earlier times, stuff happens more quickly. In the first three minutes of the universe all of the primordial nuclear elements had already been made. It took billions of years until secondary elements started to get made in supernovae.

    As a result, the earlier you go in time, the more narrow your time-scales need to be to properly appreciate what is happening. If it was just the universe watching, then this would be the end of the story and the later in time one went, the slower that interesting stuff would happen. However, it isn't just the universe watching, it's us too. And human history is doing the opposite. The further we go in time, the more we master physics, the more and more those very small time-scales become relevant again (to us). Until life began a minute had long been a ridiculously and boringly small length of time, but now a minute is enough for an entertaining physics youtube video. And the time-scales being probed at the LHC make a minute seem like the age of the universe. All of this is mirrored by the exponential growth of technology.

    What made me think about all of this was seeing how on both the left and right of the ChronoZoom application there are small boxes. Unfortunately the one on the left (early universe) isn't filled out much yet, but it is still there. I like that symmetry.

    1. I like this extrapolation of symmetry - and the relative nature of 'brief' time. And it certainly helps me make sense of the conceptual logic of the ChronoZoom.