Time
clock | September 21, 2008A clock is supposed to tell time. Furthermore, it is supposed to do it accurately and precisely. These days, it is not too difficult to build a mechanical, quartz, digital or atomic clock that is marvelously accurate and precise. But if a clock is not so good, it will have a systematic error, i.e., it will go slightly too fast OR slightly too slow and will, over time, get seriously inaccurate.
On the other hand, a biological clock is messy - it relies on ineractions between molecules. Thus, it will display occasional fluctuations - getting a little bit ahead at one point, a little bit…
clock | July 19, 2008Carl Zimmer: How Your Brain Can Control Time:
For 40 years, psychologists thought that humans and animals kept time with a biological version of a stopwatch. Somewhere in the brain, a regular series of pulses was being generated. When the brain needed to time some event, a gate opened and the pulses moved into some kind of counting device.
One reason this clock model was so compelling: Psychologists could use it to explain how our perception of time changes. Think about how your feeling of time slows down as you see a car crash on the road ahead, how it speeds up when you're wheeling around a…
developingintelligence | June 13, 2008Children can be notoriously constrained to the present, but a fascinating article in JEP:HPP by Vallesi & Shallice shows exactly how strong that constraint can be: in a study with 4-11 year-olds, they show that only children older than about 5 years will take advantage of additional time provided for them to prepare for a simple task.
Among adults, this finding is part of the literature on "foreperiod phenomena." Classically, this refers to the finding that reaction times are disproportionately faster with longer intervals between a warning stimulus and an "imperative" stimulus (e.g…
clock | June 12, 2008Two of my SciBlings have recently covered papers that my readers should find interesting:
Joseph: Bright Light and Melatonin Treatment Improves Dementia:
A study published in JAMA indicates that treatment with bright light alone (1,000 lux), or bright light combined with melatonin, can improve symptoms in patients with dementia. Melatonin alone appeared to have a slight adverse effect.
Chris Chatham : Time Perception: In the Absence of "Time Sensation?":
In their newly in-press TICS article, Ivry and Schlerf review the state of the art in cognitive modeling of time perception - perhaps the…
esiegel | April 11, 2008So, what's the deal with this one? startswithabang.com reader Scott Stuart asks the following question:
I was reading "The First Three Minutes" last night and came across an
interesting section about blackbody radiation and energy density. The
author states that as the universe expands, the number of photons
running around (in the CMB, for example) is unchanged, but their
wavelengths get stretched. The energy in a photon is, of course,
inversely proportional to its wavelength, so the energy content of a
photon decreases as its wavelength increases. That seems to mean that
the total energy…
esiegel | April 1, 2008There's a graduate student that I'm sort-of mentoring/working with at Arizona, named Xiaoying Xu (hi Xiao!). She's bright and curious, and she asks some very good questions. She asked me one yesterday that's pretty tough to wrap your head around:
How do I explain to someone why light doesn't age?
Well, here on Earth, time progresses at a certain speed. That is, if I measure how many seconds tick by as the Earth revolves once around the Sun, I'll get 31,556,926 seconds. (31,558,150 if I'm measuring a sidereal year.)
But let's say in the course of that year, I put you on a rocket ship, and…
clock | March 13, 2008On this day in 1884 the International Prime Meridian Conference established a system of standard time zones:
In 1884 an International Prime Meridian Conference was held in Washington D.C. to standardize time and select the Prime Meridian. The conference selected the longitude of Greenwich, England as zero degrees longitude and established the 24 time zones based on the Prime Meridian. Although the time zones had been established, not all countries switched immediately. Though most U.S. states began to adhere to the Pacific, Mountain, Central, and Eastern time zones by 1895, Congress didn't…
cevans | June 8, 2007
I never cease to wonder about the vast amount of futures we have in store. While there is only one past, albeit an eternally contested and subjective one, the future is manifold and unfuckwithable. Recent pulpy science fiction binges and forays into blockbuster cinematic media have proven this indubitably; After all, maybe the main reason Science Fiction works as a storytelling medium is because no one can prove it wrong. Who's to say that the Pre-Cogs, soaked in some primordial slime, will not be able to see crimes before they occur or that Rama, hollow and the size of a moon, is not…
clock | May 25, 2007Hey, is he intruding on my territory? ;-)
An excellent article about many aspects of time, how we perceive it and what it means to us.
clock | May 17, 2007A must-read by Sara Robinson. You can use it to understand the persistence of Creationism. Or the lack of Internal Locus of Moral Authority in people belonging to Moral Majority.
cevans | March 27, 2007
Welcome to the second in an ongoing series of Interviews with authors of Science Fiction. I'm lucky to have had a chance, recently, to review Portland local Thomas A. Day's A Grey Moon Over China, a totally postapocalyptic epic that takes the ongoing cultural fear of an energy crisis to a particularly dark and alienating place in the cosmos. He's an interesting writer for his sense of grand scope -- in the complexity of the narrative and the breadth of time it represents -- but also because of his background: he's worked in the aerospace industry, flown night-cargo planes, and developed…
clock | March 26, 2007This is, after all, A Blog Around The Clock, so, I guess I should be a strong and vocal proponent of the Clock Theory aka Specified clockplexity. After all, nobody's ever seen a clock move! So, I should start fighting against vile, rabid, Atheistic Blindtimekeepingism:
Atheists often level a strawman at Intelligent Timekeepingist (hereafter referred to as IT) views. They force you to stare at a clock for 5 minutes or so and claim vindication when the big hand of the clock moves. But DTists all agree that the big hand moves! This is simply microtimekeeping, and it does not go against ITist…
clock | March 23, 2007Apparently, in Denmark, the 'larks' (early-risers) are called 'A-people' while 'owls' (late-risers) are 'B-people'. We all know how important language is for eliciting frames, so it must feel doubly insulting for the Danish night owls.
Today, in the age of the internets, telecommuting and fast-increasing knowledge about our rhythms and sleep, retaining the feudal/early capitalism work schedules really does not make sense.
And owls are by no means minority. Among kids and adults, they comprise about 25% of the population (another 25% are larks and the rest are in between). But among the…
clock | March 12, 2007This is the time when everyone is talking about the Daylight Saving Time and I always feel pressure to blog about it from a chronobiological perspective. And I always resist. As I will this year. So, here are a couple of related links instead:
Larry provides a brief history of time zones and the Dalyight Saving Time (and a cool map that goes with it).
Dave finds some data that the DST does not actually save any energy.
Among numerous newspaper articles, I thought this Boston Globe one gives the most accurate summary of what DST does to our circadian rhythms and sleep. It explains why it…
clock | February 14, 2007Considering the name of this blog, you may not be surprised that I am a sucker for clocks and watches. If I had more walls and more money, I'd collect them by dozens (hundreds?). Grow-a-Brain has been collecting links to sites showing all kinds of clocks.
I wish I could have something like this, this or this for the house and this for the pocket.
clock | October 30, 2006In my part of the world, and most of the US and Europe as well, there was a general agreement that all clocks would be set an hour off back in April. This may have made sense in a world in which most people worked on a single shift, and most factories were lit via skylights for that single shift, but it's absurd in the 24/7 world of this millennium. Fortunately, as of 2:30 this morning we've allowed to set our clocks back to the correct time. The computers switch automatically, I think I know how to set my wristwatch back (well, ahead 23 hours actually, it's digital), but millions will be…
clock | July 19, 2006Sometimes a metaphor used in science is useful for research but not so useful when it comes to popular perceptions. And sometimes even scientists come under the spell of the metaphor. One of those unfortunate two-faced metaphors is the metaphor of the Biological Clock.
First of all, there are at least three common meanings of the term - it is used to describe circadian rhythms, to describe the rate of sequence change in the DNA over geological time, and to describe the reaching of a certain age at which human fertility drops off ("my clock is ticking").
I prefer the Rube-Goldberg Machine…