Dry Slot

Time Passages IV

Posted by: Bogon, 06:37 PM GMT del 13 Febbraio 2012

The Past

A year ago I posted a series of three loosely affiliated blogs, which shared the same title and which discussed different aspects of the same subject. The first one talked about two trees newly planted in my yard. Both trees are potentially very long-lived, but what is their life expectancy here on this suburban lot? How much time will they be granted? You'll be pleased to hear that those trees survived their first year. They've had a chance to set roots. This (and each subsequent) year's summer heat and drought should pose less difficulty for them. There was a third tree, an Eastern redbud, which did not fare so well. It got struck by lightning. Wife and I had to replace not only the fatally zapped sapling, but also the main circuit board in our television. Ouch!

The second blog presented a personal overview of time. How do we speak about time? How do we experience its passage? The third installment addressed cosmology: time considered on the largest possible scale.

So what brings me back again after all this, uh, time? Well, life goes on. We live and learn. This year I learned of some new developments in physics. I am not a physicist, but I try to understand how the world works. It is the same curiosity about the world that brings me to Weather Underground. I'm not a meteorologist, but I like to learn what I can about the weather.

As long as we're talking about the past, it might help to set the scene by reviewing some history. It has been nearly a century since Albert Einstein announced his theory of relativity. General relativity remains our best tested and most trusted model of the operation of the universe at the large scales observed by astronomers and cosmologists. The theory describes the interactions of space, time and gravity. Einstein's equations treat space-time as a continuum which warps and flexes in response to the presence of mass and energy. The word 'relativity' refers to the way the theory relates moving objects. Each object has its own point of view. According to the theory there is no fixed background or point of reference. If two spaceships pass in the night, the passengers on each one will tell a different tale about what they saw.

At the same time Einstein was developing relativity, other scientists were working on quantum theory. This theory accurately models the universe at the very small scale of subatomic particles. Quantum electrodynamics describes the forces of electricity and magnetism perfectly (insofar as we are able to measure). There are also good working theories for the forces responsible for radioactivity and nuclear power. The word 'quantum' refers to the discrete discontinuous appearance of nature when viewed at the smallest possible scales. It's like when you zoom in on your computer screen you see jaggies and dots, the individual picture elements, that make up the displayed image. According to quantum theory matter is comprised of a small number of elementary particles, each of which has a fixed mass. Energy is exchanged in little packets. Events proceed stepwise. From any point of view those events are likely to look a little blurry, because there are definite limits on how finely you can measure. The act of measurement affects the thing being measured.

Throughout the remainder of the 20th century these two theories were tested and applied. Both work very well within the domain for which they were designed. For any real-world situation, physicists are obliged to choose one theory or the other or compare the predictions of both. Nobody has figured out a way to combine the two. The theory of relativity does not extend to situations involving high energy and small scales, and there is no quantum theory of gravity. The math is too hard. The techniques developed within one theory break down when applied to the other.

The Present

For the last few days my mother has been battling an eye infection. Her doctor prescribed some ointment and an eye patch. Mom complains that, when she goes to pour a beverage, without proper depth perception she's liable to miss the cup and spill her drink on the counter.

Physicists, too, are tired of peering at the universe through one eye or the the other. They think their view would be a lot clearer with full stereoscopic vision. So when I say there is no quantum theory of gravity, I mean there is no complete theory. The last ninety years have not been wasted. People are working on a variety of approaches. Some start with relativity and try to quantize it. Some start with quantum theory and try to develop a background-independent version which includes the graviton.

One approach that gets a lot of press these days is string theory. The basic idea behind string theory is that elementary particles should not be portrayed as dimensionless points. They are granted a finite size, which makes some of the mathematics more tractable. I say 'some' of the math; there is much more to string theory that is very hairy indeed. String theorists propose a group of elementary particles that have not been detected and postulate several extra spatial dimensions beyond the three that we observe. In support of their theories they offer weak circular arguments such as the anthropic principle. Whenever reality threatens to contradict the theory, they spawn a new version. In fact there are a zillion string theories with no obvious way of picking a winner.

From my point of view they are all losers. String theory is a monster that devours talented young mathematicians. It sucks up lifetimes and hefty research budgets and leaves nothing to show for them. It provides a convincing model for how to parley government grants into academic careers, but it has done nothing to shed light on how the physical universe operates. There are no verifiable predictions of string theory.

There are numerous competing theories that seem more promising. There's Roger Penrose with his spin foam and tensors. There's Lee Smolin, who champions a theory called loop quantum gravity. These guys are results-oriented. Unlike string theorists, they manage to refrain from wandering off into fanciful realms of elegant mathematical complication. They'll be content if they can explain known particles in three dimensions.

Loop quantum gravity theory asserts that space-time is quantized, i. e. there is some minimal unit of volume out of which space is constructed. Thus, on a very small scale it would be possible to view space as a kind of fluctuating grid. An elementary particle would have a finite size. It could be no smaller than a block in the grid. The particle would be represented as a set of properties (e. g. quantum numbers) assigned to some region of the grid. Gravity appears as curves and waves in the grid lines.

Here are links to two presentations from Perimeter Institute in Canada. You can watch Renate Loll describe causal dynamical triangulation, and/or view Fay Dowker as she expounds on the theory of causal sets. You may have noticed that the last two theories include the word 'causal' in their titles. That's where time enters the picture: the sequence of cause and effect. In addition to quantizing space, these theories add the notion that all the little grid lines must be aligned timewise. The arrow of time is built in from the start rather than being sought as an emergent property. That turns out to be a significant innovation. Calculations become easier, and believable results follow. If you listen to the videos, you'll hear how several lines of evidence from thermodynamics, information theory, black hole theory, astronomy and cosmology converge to indicate that these people may be on the right track.

The advantage of such theories is that they can reproduce some of the observed properties of three-dimensional space (plus time) with a minimal set of assumptions. A disadvantage is that each theory only provides an incomplete and unwieldy model. It is not an equation. It is an algorithm for simulating space-time. It runs on a computer much like one of the weather models here at WU.

The Future

None of these theories is ready for prime time. Progress is slow, because the problems are hard. Only in hindsight is it clear what questions to ask in order to get the right answers. Will it be easier to work from the top down by quantizing relativity? Or will the bottom up approach, adding the force of gravity to an existing quantum theory, yield the prize? Will it become possible to translate a computer-driven algorithmic model into a concise set of equations? Will string theory ever be good for something practical?

The goal of all this theorizing is perfect binocular vision. Physicists want a Theory of Everything. It doesn't mean that they'll immediately be able to solve all problems and write down all possible knowledge in a book. It means that we humans will finally have a single unified theory that accounts for all known particles and forces. Far from being an end to science, it will make a great beginning for whatever comes next.

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151. masshysteria 04:40 PM GMT del 13 Aprile 2012
Good Morning Bogon ~ Glad you had a safe round trip to your Mother's residence. Hope that she's doing better than her laptop seems to be. I'm curious to know if she still uses it, herself, despite some of its obvious intricacies? If so, I'm duly impressed! I know what you mean about the features of a laptop versus a desktop. I'm more comfortable with the latter and would feel quite annoyed without a scroll-wheeled mouse. I'm definitely an old creature of habit. Similar to the dryness of your area, Massachusetts has been going in and out of a critical red-flagged mode and, therefore, parts have experienced the occasional outbreak of dangerous brushfires. Fortunately, hubby and I have escaped these threats, in spite of living in a wooded area. There's no real sign of any plentiful rainfall in sight despite recent and upcoming periodic sprinklings. When there's time, we're soon going to have to start up the ole power mower, too, as the mixture of overgrown grass and ugly dandelions is overtaking our yard. YUK! At least, better temps of 70's are expected over this weekend with sunny and mid-80's on Monday. That should give us the impetus to get off our duffs to either get mowing or break open a new jar of barbeque sauce. Right now, the last thought seems more appealing. LOL! Have a pleasant and safe Friday the 13th! Member Since: Giugno 21, 2006 Posts: 52 Comments: 7130

152. Bogon 08:29 PM GMT del 13 Aprile 2012
Mom tried hard, but at age 94 she has given up on mastering the computer. She keeps it around for people like me, who are hopelessly addicted. The laptop is Mom's second computer. The first was a conventional desktop machine, which ran Windows 98 and connected to the internet via dialup modem. Mom never really got the hang of it. I installed Typing Tutor software on it, and she fixated on that. Her typing improved, but she never figured out the mouse. Mom is not handy around machinery of any sort. All those nested visual metaphors — the windows, buttons and toolbars — were too much for her. She came to computing too late in life. Dad didn't use the computer much, either. He never came to view his interaction with the console as a form of self-empowerment. It was merely a chore, one that he preferred to delegate. He was always the boss, and he thought typing was secretaries' work. It's a generational thing. I can attribute my own success with personal computing to getting an early start. I received an introduction to computing in college. At that time it was all about mainframes and keypunch machines, but it gave me the foundation I needed to understand words like 'digital' and 'file'. For a while I worked as an electronics technician, a fixit guy. That acquainted me with logic circuits, so I can say I understand computers from the inside out. I bought my first PC twenty-five years ago. Later I went back to school for a computer science degree. I got a job as a software engineer. There I discovered how to design a program around a message processing loop. I learned the nomenclature and properties of common controls and dialogs. Windows and buttons were the tools of my trade. What knowledge I possess was accumulated over a lifetime. There's no way I could absorb all that starting now, at age 60. Indeed, at this point I'm thoroughly tired of trying to keep up with the latest tech trends. So now I've reached a point of being able to understand some of my dad's attitude. Smart phones? Pretty nifty, but I have decades of experience living without the darn things. Why would I want one now? What would I do with it (except annoy people)? How would I pay for the hardware, the software and the services? Maybe I could write an applet. So what? I don't care. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

153. BriarCraft 09:37 PM GMT del 13 Aprile 2012
You had me wondering for a minute, about what Uma Thurman had to do with the topic at hand, but your link to the photo explained it all. And of course there's a fun side to blogging and to wandering the interwebs, but be careful -- you could get lost out there ;-) Member Since: Giugno 21, 2004 Posts: 49 Comments: 2418

154. Bogon 08:45 PM GMT del 14 Aprile 2012
Hi, BriarCraft. I do get lost out there. The good news is that it's pretty easy to find my way home. All I have to do is let go the mouse, stand up and walk out of the computer room. Home is there waiting. Cats, wife, teevee, all that stuff. Ran the lawn mower today. That was my big chore. The weather was cool, dry and breezy, which made the job go a lot easier. I could bask in a feeling of accomplishment, but I have mixed feelings. Had to whack a lot of wild flowers, which weren't really hurting anything, as far as I could see. So I could also bask in the feeling of being an axe murderer. I'm trying to focus on the positive aspects of the job. Chief among those is that I should be good to go for another week vis-à-vis the dang grass. Last night Wife and I drove to Durham to see comedian Lewis Black at the Performing Arts Center. I left the show wondering why the man is cast as jester rather than king. There are no politicians who speak as he does. If there were, I would feel a lot better about casting my vote. If you don't know Lewis Black, here is a sample at YouTube. I'm posting a link rather than embedding the flash player, because most of Black's monologues come with an adult language advisory. To me that means that he tells it like it is. Your mileage may vary. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

155. Bogon 03:28 AM GMT del 18 Aprile 2012
Rain chances tonight and tomorrow. The weather has been magnificent lately, which means the rain would be welcome, if it materializes. So far it looks like the Dry Slot is working. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

156. ycd0108 04:42 AM GMT del 18 Aprile 2012
Evening Bogon: Dat Lewis can rant,eh. I'm wondering if he is not already one of the jokers posting on Dr Masters' blog. Member Since: Gennaio 1, 2008 Posts: 142 Comments: 3444

157. sp34n119w 05:38 AM GMT del 18 Aprile 2012
Hi Bogon. I've been lurking but missing my chances to comment so thought I'd at least say hi. Jealous you got to see Lewis Black. He is hilarious and, I agree, tells it like it is. I have a nephew who would put him and John Stewart on the presidential ticket. Or, make them gods. Either would do for him. Going back a ways ... I miss Dogwood in the Spring, beach pics are great, happy you avoided the poison ivy this time around, sounds like a nice Easter visit with mom, and I can't keep up with tech, either. Doesn't quite cover it but I wanted to indicate I'd been paying some attention, lol Hope you get your overnight rain and more magnificent weather to follow. Member Since: Gennaio 27, 2007 Posts: 77 Comments: 4049

158. Bogon 12:08 PM GMT del 18 Aprile 2012
It's raining this morning. Just woke up, so I'm not sure how much has fallen or how much is yet to come. Be back later. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

159. Bogon 03:47 PM GMT del 18 Aprile 2012
The sky remains cloudy, but the rain has stopped. It's noticeably cooler outside. This morning I reflexively donned shorts and t-shirt that worked well for the last several days. Now I'm thinking jeans and even long sleeves might be a better bet. Is the rain over? All the meteorologists are waffling. The local NWS forecast gives a 60% chance of rain today and tonight. Radar says it's raining farther west. Our morning rain was on the eastern fringe of the storm. That suggests that the bulk of the rain has yet to arrive. The upper level impulse is taking its time, making slow progress against the oceanic high to the east. It may fizzle out before it gets here. If this storm can't deliver the goods, there's one coming this weekend that probably will. Meanwhile, anything we get today will be a step in the right direction. ycd - As a form of communication Black takes the rant to a high level. I don't know how well his talent would translate into a blog comment. A lossy process, most likely. sp - Thanks for taking the time to make your presence known. I don't operate a visitor counter, so it's hard for me to know whether anyone is reading, unless someone leaves a comment. And unless I have something to say, I let the blog languish on days when there are no comments to acknowledge. I hope it does rain today; we need it. Alas, rain will make the danged grass grow. With nought but sunshine to incite it, the lawn has remained obediently flat since the last time I oppressed, uh, I mean mowed it. I fear that now the downtrodden masses will arise and resume their struggle to take over the world. A rainy day provides a good opportunity to update the ol' blog. There's been quite a bit of Time Passage, since I posted this one. Yesterday I opened a file where I have listed a few possible blog topics that occurred to me in the past. Trouble is, I've done most of the easy ones. The ones that remain will take research and/or deep thought to bring to fruition. None of them really grabs me, not enough to make the effort required. On a couple of occasions I have been tempted to simply put up a new header entitled "NEW BLOG HEADER", which contains nothing but a stupid picture and a randomly chosen quote. Maybe I'll do that. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

160. ycd0108 04:02 PM GMT del 18 Aprile 2012
Here's a link to another Ranter: http://en.wikipedia.org/wiki/Michael_Bywater Member Since: Gennaio 1, 2008 Posts: 142 Comments: 3444

161. Bogon 06:15 PM GMT del 18 Aprile 2012
Thanks for the hookup, ycd. That leads directly to a free sample. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

162. Bogon 12:12 PM GMT del 19 Aprile 2012
Still cloudy. There's moisture in the grass, like dew. There's a fresh smell in the air. Overall, though, I would say that yesterday's storm was proof of the power of the Dry Slot. According to the storm history recorded at the local airport we got about a quarter inch. Most of that was in the morning shower. The main event missed. It rained everywhere except here. :o( The airport is 3½ miles (six kilometers) south of where I'm sitting. That's far enough for some variability in rainfall amounts, but generally I think its figures are representative of what falls in my back yard. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

163. Bogon 03:27 PM GMT del 20 Aprile 2012
...and now for something completely different! This track obviously stands on its own merits, but I would be doing you a disservice if I left you with the impression that this is what the Carolina Chocolate Drops are all about. You would be better served by thinking of this as an exception that proves the rule. I encourage you to click through to YouTube to see more. For instance, Dom Flemons can explain to you how a pair of spareribs can change your life. Attend a revival on Sourwood Mountain. Or listen while Rhiannon Giddens laments the predicament of the bottom 99%. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

164. ycd0108 03:44 PM GMT del 20 Aprile 2012
Morning Bogon: I've always been susceptible to fiddle music. Gonna come back here and hear more. Thanks. Member Since: Gennaio 1, 2008 Posts: 142 Comments: 3444

165. sp34n119w 07:53 PM GMT del 20 Aprile 2012
I learned a new word today, Bogon. It is "bogan" and it is an Australian slang word. It isn't nice and I would not apply it to you. Also, it is pronounced bow-gun, so it isn't the same. Even so, it caught me by surprise as I first read it as "bogon", of course, so thought I'd share. I just watched the bones. That's way cool. Love how he has to put his hat on, lol You do come up with some interesting music :) Member Since: Gennaio 27, 2007 Posts: 77 Comments: 4049

166. BriarCraft 12:01 AM GMT del 21 Aprile 2012
Thanks for the intro to the Carolina Chocolate Drops. I just returned from a 37-minute detour to YouTube where I enjoyed several of their videos. And "liked" several, so I can find them in the future. I don't really know what to call their style -- folk-blues-funk maybe. Whatever. That's my kind of music. Member Since: Giugno 21, 2004 Posts: 49 Comments: 2418

167. Bogon 04:45 AM GMT del 21 Aprile 2012
Well, I'm happy you all enjoyed the music. BriarCraft, I had much the same experience this morning, because I just discovered Carolina Chocolate Drops for myself. The group was listed in the back of a newsletter to which my wife subscribes. The nature of the publication is such that I regarded the listing as a recommendation. This morning I looked them up on YouTube, and I'm glad I did. sp, the origin of my handle is in computer jargon, not Australia. The word 'bogon' is not particularly complementary when applied to a human, either. I guess I'm stuck with it now. If I change it, no one will know who I am. Ah, I suppose I could adopt a rune as my sigil and style myself as The Blogger Formerly Known As... ycd, one thing that impressed me about this group is how the members were able to pass their instruments around, one to another. Fiddle, banjo, guitar, pipes, bones and beatbox. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

168. BriarCraft 07:44 PM GMT del 21 Aprile 2012
I just enjoyed (or wasted, depending on POV) another half hour with the Carolina Chocolate Drops. Very talented and versatile musicians. Member Since: Giugno 21, 2004 Posts: 49 Comments: 2418

169. sandiquiz 10:44 AM GMT del 22 Aprile 2012
Happy Earth Day from the middle of England:) Member Since: Ottobre 29, 2005 Posts: 252 Comments: 22418

170. Bogon 03:38 AM GMT del 23 Aprile 2012
Thanks, Sandi. That's a great message any day. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

171. Bogon 02:00 PM GMT del 23 Aprile 2012
At 15:54 on Saturday it was 79°. Since then we've had about an inch of rain, and now there's snow rotating into West Virginia. National Weather Service has posted a Hazardous Weather Outlook tonight for "UNSEASONABLY CHILLY TEMPERATURES". Looks like I'll have to drag my potted plants inside the garage one more time. Spring returns Thursday. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

172. sp34n119w 09:18 PM GMT del 24 Aprile 2012
Oh, I want a rune! Where can we get some? LOL It's pretty chilly here, too, and I am not happy about it. Don't have to bring in any plants or anything, though, so I suppose I ought to keep my complaints in the SoCal blogs ;) Member Since: Gennaio 27, 2007 Posts: 77 Comments: 4049

173. Bogon 10:25 PM GMT del 25 Aprile 2012
sp, When the band Led Zeppelin designed the cover of their fourth album, two of the band members chose symbols from Rudolf Koch's Book of Signs. In general, runes are symbols from pre-Roman alphabets. So you can look to ancient Germanic, Slavic, Hungarian or Turkic texts in search of inspiration. The Cirth symbols made up by J. R. R. Tolkien are sometimes called runes as well. Historically runes (either factual or fictional) have been used for magic and divination. Why runes would work better than any other alphabet I cannot say. Unicode supports runic character sets. You can download runic fonts for your computer. Member Since: Giugno 26, 2008 Posts: 72 Comments: 2763

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