Space: Infinite? Not so much.

For a variety of reasons I’m allied with the notion that space is finite and discrete. Both of you that follow my blog know that we’ve already discovered that there are “holes” in the CMB; now they’ve got an alternative to the “flat” space geometry that has held sway to date, namely the Poincare Dodecahedral Space Model. The part of the article I like is:

the data delivered between 2003 and 2006 by the NASA satellite WMAP, which produced a full-sky, high resolution map of the Cosmic Microwave Background Radiation (CMB), yield a very poor fit to the concordance model at large angular scales. They rather tend to favour a finite, positively curved space, and provide hints about a multiply-connected topology. [full story]  

My rune for 2008

wunjo.pngWunjo, pronounced vun-yoh, is the rune of joy, peaceful winning, and wishes fulfilled. I drew this rune after a rebirth at a solstice ritual. It is one of the few unambiguously “good” runes in the Elder Futhark, and it surprised and delighted me as portents are seldom so clear and kind. Here’s hoping it holds true.

The biggest absence of all

Being something of a Void devotee, I’m always on the lookout for new nothing, or bigger nothing. Heck, I can even get pretty exited by a big hole in the ground. I try to remain aware of the little nothings, but after a while all those absences just lack that certain je ne sais rien.

So of course I’ve been following the news of the great big hole in the sky with some excitement. In a paper coming out nowish, they advance the theory that the void is evidence for a phase transition in the early universe. I like that one, if only because it hearkens back to Void’s sweet cousin, Noise.

Personally I still side in favor of the argument that the great big hole is a reflection of the fact that the universe is not infinite and thus you don’t see symmetry in the CMB ‘all the way up’. Why would I be in favor of a finite universe, you might ask; and well you might, because besides solving Zeno’s paradox and being an essential precondition for living in a simulable universe, there’s an even niftier thing that a finite universe implies:

More nothing.

Solstice: what is it?

The solstice is upon us, and in discussing it with some folks online I realized people have a fairly fuzzy concept as to what it actually is. As someone who has come to feel that reflecting upon the cycles of nature is somewhere between important and holy, I’ve given the matter much thought.

Many ancient peoples thought about the matter a great deal, and constructed a wide variety of stone instruments to measure when the solstice occured. There is general consensus that a number of these cultures engaged in some sort of practice when the instrument was active, and observation indicates they were only active twice a year, though some of the artifacts respond to other times as well. Precisely what practices they engaged in, and which of those are germane to our present context, is left as an exercise for the reader.

The modern take, exemplified by the archaeoastronomy site, suggests that the solstice is a precise moment, calculable to within one minute of resolution. This implies that the solstice is an orbital relationship between the sun and the earth. This sounds nice and scientific, but unlike the ancient version, there’s no way to directly measure when this moment would be (from earth) and if you make precise enough measurements to actually predict when the earth will be in the same relationship to the sun, you find out that it doesn’t really happen. A bright fellow named Malenkovich came up with an amazing way to date old ice cores by taking advantage of the fact that the earth’s orbit is irregular.

So the number you see on the archaeoastronomy site isn’t based on observation; it’s extrapolation from an average earth orbit computed as if the earth and the sun were the only two bodies in the solar system.

So what’s the solstice about? To me, it’s about a relationship between the sun and the earth, as exemplified by the two days each year when the sun is in a particular relationship to a patch of ground on the earth. I don’t think the modern, abstract and inferential (but pleasingly ‘objective’) notion of orbital relationships has concrete meaning, and for a variety of reasons I think direct encounters with the lived world are superior to mere ideas as a foundation for my relationship with all-there-is.

Ancient solar observatories like stonehenge were basically giant immobile sextants that ‘activated’ when the sun at the highest point in the sky at different times of the year. If we’ve agreed that observing the sun is better than Keplerian projection for fixing the moment of the solstice, the question becomes: how accurately can the sun be measured?

Interestingly, the answer is that most ancient monuments do a better job than just about anybody bothers to do with the solstice these days. The US Naval Observatory has a page where you can get sunrise/sunset dates for your area; if you look to around today, you’ll notice that there are likely 2-3 days with the same rise/set times. The difference in position of the sun at apogee varies by an astonishingly small amount in 2-3 days- a small fraction of the apparent width of the sun itself. Unless you build yourself a remarkably precise solar observatory, you can’t differentiate between those days.

I would argue that it is this 2-3 day interval that is the genuine “solstice”. So feel free to party today, tomorrow, or perhaps even Saturday and feel safe that you’re observing the solstice as it is happening.

Three Roads to Quantum Gravity

A few observations on Three Roads to Quantum Gravity. Unfortunately this post has been wating to be published for over a year and so I can’t expand on the quotes and be confident I’m reflecting accuratewhat the book says, but these blurbs are too good to pass up, so here they are with my current reflections:

On the many worlds hypothesis (Smolin doesn’t buy it, while I do): “one universe, seen by many observers, rather than many universes, seen by one mythical observer outside the universe.” I think it’s the conceptual framework that’s at issue here – ‘seeing’ is just a particular class of relationship between some processes in the universe, and so many observers implies a multiverse.

“Universe is made of processes, not things.” – I more or less take this as read, but I like to hear a theoretical physicist say it.

“The universe of events is a relational universe.” This one has been kicking me about for quite a bit; I find myself constantly layering phenomena by their causal prerequisites; combustion occurs when there is enough deoxygenated carbon and free oxygen, enzymatic activity occurs at a given temp & pressure, earth-like planets couldn’t form before the megastars/quasars made enough heavy atoms. Related to the notion of time as an emergent property of the distance of difference.

Deoxygenated water

My lovely and talented wife made an off-hand comment on the playa suggesting that we bring dehydrated water next time. I had the thought that perhaps taking deoxygenated water would achieve the same end. Here’s my thoughts to that effect.

Methane (CH4) has a molecular mass of 16 amu and H2O is about 18 amu. Liquid CH4 is thus less dense than H2O. However, each molecule of CH4 can be exchanged for two molecules of H2O through the miracle of combustion.

Still, it would be a tremendous amount of methane, which requires a rediculously low temperature to remain liquid. My searching was able to uncover a few places that make LNG tanks for commercial vehicles. However, their insulation is only sufficient to keep the LNG liquid for about three days, which is insufficient for our needs.

Propane seems to be the best bet, although the C/H ratio is nearly half that of methane: it is widely available and liquifies at a reasonable pressure. The 0.5ppm of ethyl mercaptan seems to not be considered any sort of health risk, though it appears that SO2 is a combustion byproduct.

scale free networks

In a lovely paper, Geoffrey Grinstein and Ralph Linsker write about synchronous activity in scale-free networks. Scale-free (also known as “small world”) networks have the property that no node is greater than N hops from any other. These gents show that this topology can persist over a node-set of arbitrary size. This handily mitigates a concern of mine regarding the scalability of various Distributed Hash Table algorithms I’ve been pondering.

Another upshot is that I need to think of some kind of experimental protocol that would allow me to assess the topology of biofilms’ chemical networks.

In other topology news, the evolutionary tree is looking bushier every day.

Drumbeats alone can carry emotion

An interesting article from Cognitive Daily, one of my favourite blogs, on how drumbeats alone can carry emotion. One of the things I’m curious about is whether these emotions could be conveyed to animals; in my last class on audio illusions, I made the argument that since we have specialized neural apparati for tying together auditory stimuli, only we (and other animals with complex vocalization like some birds, whales, and dolphins) could appreciate music. Unfortunately the distribution in perception shown in the article doesn’t seem to be sharp enough to get reliable neurological traces out of, say, mice.