Welcome to Science Talk, the weekly podcast of Scientific American, for the week of March 19th, 2009. I'm Steve Mirsky. Time—just what the heck is it anyway? We will talk to journalist and writer Dan Falk, author of the new book In Search of Time. Plus, we'll test your knowledge of some recent science in the news. Dan Falk is a Toronto science journalist who focuses on astronomy, cosmology and physics. He is the author of the award-winning book Universe on a T-Shirt: The Quest for the Theory of Everything. He was recently in New York and dropped by at Scientific American's Manhattan office.
Steve: Dan, is Julius Caesar still alive?
Falk: That's a great question Steve and let me say it's a pleasure to be on the Scientific American podcast. You know, before I started researching this book, I thought Julius Caesar is dead—I think most of us thought Julius Caesar [is dead]—and then I spoke with a physicist named Julian Barbour a[n] independent researcher based near Oxford in England and he states Julius Caesar is alive, and part of the problem is that, you know, we think Julius Caesar's life lies in the past, but Julian Barbara says that there is no past-present-future, he denies the existence of time. He thinks it's all an illusion, kind of a mistake the mind has made.
Steve: Wasn't that his quote, "It's a trick the mind plays"?
Falk: Yeah that's right. He says, let me see, the quote is something like, "I say of time what Laplace said to Napoleon about God: I have no need of that hypothesis." That's right, he says it's a mistake the mind has made, as mind boggling as that seems.
Steve: So the really interesting thing about that is, I think even more than the statement is, that serious people, not science fiction writers—who can also be serious people obviously—but serious physicists, serious philosophers can have this conversation; and this is a legitimate argument about whether Julius Caesar is still alive or not. And, of course, we are not just talking about Caesar, we are talking about anybody, we are talking about whether time has a future and a past and a present or whether it is some other thing entirely.
Falk: Yeah, absolutely, and when I spoke with Julian Barbour you know, he happens, at the time of our interview he was 70, but he states that the version of himself who is 60 is still just as real, just as alive and the version of him who is 50 and 40 and so on. When we are talking about Julius Caesar, you know, I thought may[be]
be he is being sort of metaphorical or maybe using language in a funny way. I said, "You mean he is literally, do you think Julius Caesar is literally alive? That whatever it is that makes me alive, that he possess[es] those same attributes?" And Barbour said, "Yes, absolutely" that's what he means. Now you can say Barbour, well you know, maybe he is a little bit over towards to the fringe. He is an independent researcher and he is not actually based at Oxford, but his view is only, I think, just a little bit further in that direction then what is the mainstream position within physics, which is that, you know, time—sure events are separated in something that we can call time and different clocks give different readouts, but [that] the flow, this alleged flow of time just doesn't seem to be there in physics. So it's almost as if, you know, physics has said, "We've done our part, we've shown how clocks behave under different circumstances and, Einstein knows, special and general relativity," but if you're trying to find this alleged flow of time that carries future to present and present to past, you may have to look in psychology You may have to look at the workings of the human mind; it just doesn't seem to be there in physics.
Steve: But you also in the book, you do talk about the fact that there is clearly some kind of time appreciation, time experience in nonhuman species for example the scrub jay, you talk about this really interesting experiment with scrub jays.
Falk: Yes, and it's interesting, people might intuitively think that the great apes who are our closest cousins in the animal kingdom might have, you know, revealed the most about our [an] awareness of time and past and future; but actually the most compelling results come from this bird which is a little bit like a blue jay called a scrub jay. And in one particular experiment the birds were placed in different compartments and in one compartment they are guaranteed to get a breakfast the next morning, but there's another compartment where there is no breakfast served the next morning. And they are also given sort of supply of extra seeds, and they can do whatever they want with them. Their habit is to [cache them,] they sort of hide them. So in whatever habitat they are in they like to hide seeds. And what they found is when they have access to the different compartments, what they do is they preferentially store seeds in the compartment where breakfast isn't served, which suggests that they have, you know, maybe the word planning is too strong, but there is some sort of a conception of the next morning. You know, some sort of conception of the hunger that they're going to feel the next morning. They're not hungry now. They are well fed. They've been snacking but, you know, it's not just, sort of doing what you have to do because you are hungry, but they seemed to have some degree of awareness, how much, you know, you can save. Right, we don't know what's going on in the mind of these birds, but maybe they've some conception that there is a tomorrow.
Steve: Let me go back to Julius Caesar for a second.
Steve: Only because I want to use Caesar to get into, sort of, the cultural aspects that you spend a great deal at the beginning of the book on. I mean, Caesar was famously assassinated in 44 B.C. We take it for granted, you know, what B.C. means now, but as you point out in your book, a lot of the developments in our time-keeping systems, the calendars we use, some of the changes to our modern calendar didn't happen in England until the middle of the 18th century. I mean, I remember that our first American president[s] would have two birth dates, because the calendar got changed during their lifetime. So we aren't exactly sure when George Washington was born.
Falk: That's right.
Steve: So talk a little bit about these systems of keeping track of the, first it was just the seasons, but then the days and finally you know these miniscule slices of time.
Falk: Yeah. Well the whole history of our ability to keep track of time first, you know, the years and divisions of the year and ultimately divisions of the days is such a long and fascinating business. So I devote three whole chapters to that in In Search of Time, and, you know, beginning with a stone age artifact, this funny bone with some notches in it, that dates from the Paleolithic era about 30,000 years ago, and the notches are in sort of rows of 15; and the anthropologist who studied it, a guy named Marshack looked at and said well you know these two rows of fifteen that's about 30 that's roughly the period of the lunar cycle. So maybe, I mean we can't prove it, but maybe this was a primitive lunar calendar. So here's the beginning of this [story], you know,
story 30,000 years ago. We know when Stonehenge as built, around 3000 B.C., roughly. The main axis, there's an axis of symmetry through this central kind of horseshoe pattern of stones, and it's aligned on this part on the horizon where the sun rises on the summer solstice, the longest day of the year. There are a lot of other purported alignments but they are all sort of controversial but that one is quite unambiguous, so ....
Steve: You report in the book that any structure with [a] sufficient number of items will have all kinds of alignments.
Falk: That's right.
Steve: [A] lot of which of are probably just accidental.
Falk: That's right, a lot of which might be accidental. But this particular one, it's fairly unanimous amongst anthropologists and archeologists that this was intentional and the same for another structure called Newgrange in Ireland. So here we have the earliest human structures and no doubt structure[s] like Stonehenge, I am sure, served more than one purpose, whether religious, ceremonial, a gathering place or meeting place. It could have been all these things, and to use a modern word like "observatory" or "calendar" is probably too strong, but I think we can say it was partly motivated by a desire to keep track of the passing of the seasons.
Steve: Although is it too strong to use the word "observatory", when you are talking about the Mayan systems that you go into in the book?
Falk: Well, I guess, you know, the Mayans had a very sophisticated calendar tracking not just the seasonal cycle and the lunar phases but also the planet Venus which has sort of a complicated cycle of movements being in conjunction with the sun and then is visible in the morning sky, then it's conjunction with the sun again and then it goes into the evening sky and back and forth. And we know the Mayan[s] were keeping track of this; depending on how you measure it, you can actually sort of argue that they had a better calendar than our Gregorian calendar, you know, depending on which criteria you used to measure it. So that they had quite an elaborate system and, you know, so did the Egyptians. All these civilizations had to struggle with reconciling the incongruent motions. I mean, wouldn't it be nice if there was an even number of days in a month, but there isn't; it is roughly 29 and a half, and it's not even exactly that but roughly that. And wouldn't it be nice if there were 12 lunar cycles a year, but there is not, there is between 12 and 13. So, all these cultures had to struggle with getting these cycles to fit into each other. I like the Egyptian solution which was, you know, to have 12 cycles and then just party for that, you know, just to have a celebration for the five days or so that are left over the end of the year.
Steve: Twelve 30-day cycles and then you make up the difference with just some...
Falk: Yeah, some festival, that's right.
Steve: You talk about Omar Khayyam [who] computed the length of the solar year to the fourth decimal place accurately in the early 14th century.
Steve: So there was [a] really sophisticated understanding of what was going on in terms of, you know, the astronomical relationship to time, which is how we really experience time.
Falk: Yeah, we often forget that in the early Middle Ages it was the era of astronomers who were really at the forefront of the profession, so to speak, you know, making sophisticated instruments like astrolabes and other devices, sextants and so on, for tracking the motions of heavenly bodies. I devote roughly a chapter to the Gregorian calendar because, of course, this is the one that won out. This is our calendar. It is very good. It is very sophisticated, but of course it wasn't the only one. You know, other cultures had their own calendar systems. But I do think it is remarkable how our calendar evolved, you know, taking first it was the Julian calendar and even that, that didn't start with Julius Caesar, that was his reform of an earlier calendar that had been in use in Egypt and so on. So we think maybe, you know, leap years are new, leap years aren't new; Julius Caesar invented leap years, or his advisors did; so those are already 2,000 years old. And so what was the big thing Pope Gregory did in the 1500s? Of course it wasn't the leap year. Those were already there. It was deciding to omit a leap year one time out of every 100 years. I think I've got that right. So it's quite a refined thing just knowing that, you know, the mathematicians Clavius and others that were part of this commission under Pope Gregory XIII's supervision, you know, had a sophisticated enough picture of what was going on. On a side note, let me just say, you know, we have this impression that science and religion have always been battling each other. We think of Galileo, this year of course being the 400th anniversary of Galileo aiming his telescope at the night sky, which [we're] marking [with] the International Year of Astronomy. But of course the church was more highly motivated than anyone to keep track of the seasons to learn to know when to celebrate Easter, the most important holiday in the Christian calendar. It's a complex process and that was actually, of course, the reason behind the reform of the calendar. Easter which you wanted to be, sort of, in spring time, you wanted to be after the vernal equinox and it was sort of drifting, it was getting to be a summer holiday if they didn't do something about it. So it's really quite interesting that religion was a prime motivator to get us to perfect our calendar system.
Steve: But the other thing that Pope Gregory did was decree that, you know, that we are going to lose 10 or 11 days out of [the] calendar.
Falk: That's right.
Steve: And later on it was the British who had to add to get another day because they waited.
Falk: That's right they waited, there was so much resistance. So it's funny as the Gregorian reform, sort of, swept across Europe so that, you know, the Catholic countries picked it up right away. You see, you can see sort of the politics that was involved here. So Italy first and immediately, you know, Portugal and Spain and so on; eventually the Protestant countries of northern Europe. Britain as you said, I think was 400 years and a bit, a bit more actually before Britain finally adopted it, so by then the difference wasn't 10 days but 11, so [they] had to drop the 11 days from the calendar. And it's funny that there was resistance to that and there were protests in London and I think it was in the city of Bristol where protesters where chanting, "Give us back our 11 days," you know, they thought that they were being cheated out of 11 days' pay.
Steve: Right. There's couple of fascinating groups of humans [around] the globe who have a whole different kind of relationship with time as it relates to work. You talk about these New Guinea tribesmen who, their cultural more is, "We don't work two days in a row". So, you know, they sound like a pretty advanced civilization to me.
Falk: Yeah, I would sign up for that. You know it was quite interesting reading up on some of the cultural variations. I will mention two in particular, and we'll see if there is time for more. The two that really caught my attention, one is the Aymara people of the central Andes region in South America. These are people who gesture in a particular way that's the opposite of what we do. So when we talk about the future metaphorically, we talk about the road ahead. Well one of our political leaders talks about the way forward in Iraq, we know that means, you know, forward in time, like if a politician says that in 2009, you know, they mean they are referring to 10, 11, 12, and so on. They are not referring to a year that has already happened. And when we refer to the past, we say things like water under the bridge, just like that, and when we gesture and humans love to gesture—I am gesturing now, but people can't hear it on audio—but we would point in front of us to talk about the future and we [might] gesture backwards, you know, to the rear to refer to the past. But the Aymara people do it the other way around. They gesture forward when they are talking about the past and backward when they are talking about the future. And that seems [a] little funny to [us]. The anthropologist who studied the Aymara came to the conclusion—I guess this is a little bit speculative, but—he thinks that when they talk about the past these are things they've witnessed, things they've seen with their own eyes, so these are things that are very concrete just like the view in front of you is very concrete; so may[be] that's why they gesture forward. Whereas the future is unknown, mysterious, you can't see it so maybe that's why they gesture behind them you can't see the future. Another really interesting case and so different from our own in Western society is the [Unida] people who live in Central New Guinea. And they seem to track time, in[stead] [of] sort of mentally mapping it out on a line, everything seems to be relative to today. So it's interesting; they do have a seven-day week, but instead of Monday, Tuesday, Wednesday, here are the seven days, and I will read it so I don't stumble. They have the day before the day before yesterday, the day before yesterday, yesterday, today, tomorrow, the day after tomorrow and the day after the day after tomorrow. And the anthropologist who studied these people, his name was Gale, and he wrote [of] the Unida (unclear 16:57) week, so to speak, "Today is always Wednesday."
Steve: Isn't it horrible to be stuck in Wednesday forever?
Falk: It's so hard for me even to conceive of this system, but there is nothing wrong with it. You know, it's all right. I think it just makes planning, I can imagine it would make planning things more than three days in advance into a real nightmare, but I suspect that there aren't that many things they do that are planned more than three days in advance.
Steve: That reminds me the story, I will tell it because I heard Patrick Stewart, you know, Captain Pickard, [tell it], he was in a production of Macbeth doing a Sunday matinee and he got to the famous speech, "Tomorrow, and tomorrow and tomorrow, creeps in this petty pace" and after he said "tomorrow and tomorrow and tomorrow", he heard a little old lady in the first row say to a friend next to her, "Well, that would make it Wednesday then." Let's get back to the hard physics again.
Steve: What did Einstein do to time in our conception of it compared to where Newton had left it?
Falk: It's a good question, and I think it is really, this is what I get asked about the most when I am giving lectures, as I am doing these days in promoting the book. People want to know, first of all, they want to know what Einstein did, and then they start getting kind of cranky and asking questions and then they can't quite believe it. So let's start with Newton. So just over 300 years ago, Newton was writing his famous book the Principia and he starts the Principia with some definitions and it's kind of funny. He states, "Well, I don't have to define space and time because these are well known to all," but then he goes ahead and defines it anyway, and I think tries to justify it. So this is a famous definition where he says time, pure mathematical time flows uniformly— [and] that's one of the key words, "flows", without reference to anything external‚Äëand that sounds like, kind of, common sense thing. He wanted to distinguish—the reason he says that, even bothers with the definitions—he wanted to distinguish this pure mathematical time from what he called the common time, what you might read off the sundial or from a clock in [Newton's] day, of course, the medieval clocks were not very good, but they were getting better, they gain or lose 10 to 15 minutes a day. And, of course, even that the celestial bodies themselves are imperfect in the sense that if you're just tracking, you know, the motion of the sun across the sky, it's not uniform for a lot of reasons, the Earth's orbit is elliptical, so when we are near Perihelion the sun moves a little faster and the tilt of the Earth's axis causes, the motion of the sun is nonuniform for [that reason as well.] So Newton understood this quite well. So that's why he postulated this pure mathematical time, which he said must, kind of, loom in the background, as I say in the book, you know, [it's] this kind of metaphysical, you know, backdrop that Newton is imagining. So I think for some reason, our common sense welcomes that description. I don't know why that is. I wouldn't be surprised if it has something to do with our clocks. You know, now that we have spent 400 or 500 years staring at clocks, and especially the last couple of centuries where the clocks had second hand, and you see the second hand sweeping around and around kind of relentlessly, you know, reminding you that, you know, that you're not getting any younger and that sort of thing, maybe it's only a short step from that to just imagining that time is a steady progression for everyone, everywhere in the universe, which seems to be what Newton is getting at. So that's three centuries ago. What did Einstein do? Einstein worked out a new set of laws of motion of how things behave that apply at high speeds for special relativity and in strong gravitational fields for general relativity, his theory of gravity. But what I concentrate on in the book is the implications of that: What does it mean for time? And the biggest implication is that it takes away this backdrop of time as a steady progression. And, in fact, when I talked to Roger Penrose, he put it a kind of bluntly; he said,
he said you know, "If there is one thing we know for sure [it's] that time isn't is this uniform steady progression." So I understand why people get kind of cranky about that. You know I explained to them that in modern physics, of course, it depends, you know, there are some doubters, but the general position in mainstream physics is that time is just what you get from reading the clock. It is not something else. You know, the clocks aren't struggling to mimic some kind of a pure metaphysical time in the background. That's what Newton thought but there is just no reason, in Einstein['s] world, there's no reason to think that that has any merit. So we're left with saying that time is what clocks measure, and I think that is the biggest change that Einstein brought about.
Steve: And you can see this if you put a clock on the space shuttle. It measures time differently from how [it] would have if you left it on Earth.
Falk: That's absolutely right. Even before, that in the 1970s, they put very accurate atomic clocks on jetliners, commercial jetliners, and they put more than one just to be sure, and they had a couple of identical clocks on the ground, sent the clocks around the world. And sure enough the ones that went around the world say we're traveling at not, of course, not anywhere near the speed of light but just enough that these clocks can measure it; and the mismatch, the disparity, was not just some random error but exactly what was predicted by Einstein's theory. But, you know, I tell people this when I give lectures and they still can't quite believe it, you know. They think there's something funny about it. Let me just add, and for any one else [out] there who uses a GPS device—and by now almost all of [us] have one— the GPS devices, they know your location by sending signals back and forth to a network of satellites, and the signals have to be sort of exquisitely timed out and the people who write the software that allows the GPS systems to work have to actually put in this correction both for special relativity and for general relativity. And if they didn't do it, you know the signals will be off, and you would get a location that would be off by dozens or, you know more, meters.
Steve: And if you're trying to land the jetliner at few hundred miles an hour, that can be a really a big problem.
Falk: Quite possibly. You really want to land on the runway, and GPS devices are huge part of helping our pilots do that. So relativity has passed test after test after test, so you know, there are no doubts that relativity works, but the only questions are sort of, you know, how you interpret it like and what does it mean and so you end up with philosophical debates about the implications of it.
Steve: And we do in the book get into some time travel material, and I will let readers deal with that because this is in a nutshell, it is, not only is it quite possible to travel into the future, but people have done it, and if, as you say, even on the jetliner, if you're going 500 miles an hour for few hours, you have traveled into the future, a minuscule portion of a second.
Falk: If you come back, if you are reunited.
Falk: That's right, yeah.
Steve: And you talk about the Russian astronaut who's been whizzed around the Earth for over...
Falk: 800 days.
Steve: ... 800 days almost three years out there and he's a fiftieth of a second ahead of where he would have been.
Falk: That's absolutely right.
Steve: ... than he stayed on Earth.
Falk: That's right. If he had had a twin brother, I don't think he does, but if he had had a twin brother this man Krikalev would be one-fiftieth of a second younger than his twin. But again I will tell you, I give my little Power Point presentation when I give lectures on this sort of thing, and people just can't quite believe it. You know, first of all they say, "Well tell me a fiftieth of a second, maybe you know, you can't prove it." But then they say things like "Well, okay, maybe your clock would be off by that" but, you know, I had a gentleman at one of my talks saying "Yes, but how would the cells in his body [know to] age less, and I have never quite figured out how to give a good answer to that. But, you know, of course cells are just like little clocks; I mean it's all, these are all just mechanical systems and I am afraid, they all slow down, you know, when time slows down. So I know it sounds strange but it is research limited by technology; you could travel arbitrarily far into the future if we had, you know, sophisticated rockets that would; I mean the example I have given in the book is what I actually got from another writer named Michael Lockwood. You know, you go around the galaxy, that's a very long trip: 150,000 light years; but you do it at a very mild rate of acceleration, 1G, and then sort of decelerate it 1G for the other half and when you get back to planet Earth you will think that 23 years would have gone by, that's how much your body would have aged and so on, but your family won't be around to greet you because 150,000 years approximately will have passed on Earth. And so if that's not time travel into the future I don't know what it is. I mean that is time travel in the future and we could do it; we could it right now if we had the suitable technology.
Steve: So [time travel] into the past, however, [a whole other] thing; although again some serious people think that it might not be completely impossible with the provision that you can only go back into the past. Everything I have seen from serious thinkers on this is, you can only go back into the past to the point where the machine was created. You couldn't just go back in to the past to see Julius Caesar actually breathing.
Falk: Unless of course the machine was already there.
Falk: Right and, you know, the ways [some] science fiction writers get around that, and I know at least the movie version of Carl Sagan's Contact, you know, very helpfully an alien civilization had already built the wormhole. So you know, it was already in position, and I guess if one end of [a] wormhole was anchored to, you know, 100 BC then on Earth you could visit Julius Caesar. I'll tell you, the whole business of time travel, first of all I knew like there is a sort of an appetite for these people, especially fans of the TV series Lost and the[se] sort[s] of things; they are all very interested in time travel. So I knew I had to get my facts right, and as I was researching, as I was just beginning to research [In Search of Time], I actually wrote that chapter first because I knew people would read it with a critical eye. And it was so interesting because, of course, general relativity, you see it doesn't prohibit time travel, it actually allows these funny curved paths through space time. I mean every path through space-time is curved a little bit, but the question that's very much up in the air is, could your path be so highly curved that to get to you back to where you started? And then you get into the whole business of the paradoxes and changing the past and well, you know, accidentally running over your grandfather in your delirium before you slow down from  miles an hour. So I do explore that in some detail in that chapter.
Steve: What was it about time that got you so interested that you decided to spend however many years that [it] took you to write this book?
Falk: Well, so you know, I have a long-standing interest in both physics and astronomy. Well physics is what I studied back at university. Astronomy has just been a hobby of mine from, well forever. I don't know if some journalists might know H. A. Rey and some books aimed at children that he wrote. One of them is called Know the Stars and I think there is another one called Know the Constellations. And if that name sounds [at] all familiar, H. A. Rey is better known as half of the writing team of Curious George and the illustrator of the Curious George books. And so with [these] very cute little books got me started and then I got my parents to buy me a telescope—well if I say that it would give away my age, but it was after, let's say, it was actually before Halley's comet; it was before the last time that Halley's comet came around.
Steve: Your age is in the book.
Falk: That's right, [that's] right. They can just look it up. Well anyway, so astronomy and then by extension cosmology and, you know, these big questions of how did the universe began? How is the universe going to end? And these over[arching]things: What is space? What is time? And as fascinating as space is, I think time is even more interesting than space.
Steve: Our time is up. Dan Falk's website is www.danfalk.ca that's F-A-L-K.C-A for Canada. One quick correction—which Dan knows well, but you can pass it under the radar in [our free flowing] conversation—[there] is no leap year every century year like the year 1800 and 1900. But the years divisible by 400 are leap years. The year 2000 was a leap year. For more [arcane] leap year rules consult Wikipedia or Cliff Clavin.
Now it's time to play TOTALL....... Y BOGUS. Here are four science stories; only three are true. See if you know which story is TOTALL....... Y BOGUS.
Story number 1: [A] prototype of a production model of a flying car at a successful first flight.
Story number 2: Researchers are trying to fight malaria by helping the mosquitoes that carry it.
Story number 3: Despite our desperate need for more engineers in this global economy, college enrollment in computer science and engineering in the US and Canada dropped for the eleventh year in a row.
And story number 4: A centuries-old female corpse unearthed in Venice was found with a brick in her mouth meaning that she was thought to be a vampire.
Story number 1 is true, although the flying car called the Terrafugia Transition is really more of a small plane that can be driven from airport to your home and parked in the garage. Its maiden flight lasted 37 seconds and featured the all-important successful landing.
Story number 2 is true. The mosquitoes that [transmit] malaria are themselves infected with the plasmodium bacteria. So strengthening the insect's immunity might fight the disease before it can reach humans. For more, check out the March 17th episode of the daily SciAm podcast, 60-Second Science.
And story number 4 is true. The woman who probably died in the plague of 1576 was indeed found with a brick in her mouth, evidence of a post mortem exorcism presumably to stop her from feeding. Similar finds have been made in New England when bodies were exhumed often to add new bodies to a mass grave during a plague. Some of the recently buried corpses might actually look better then when they were alive because bloating from internal gas build up after death could make it look like the dead person was still feeding, so the skeletons of the dead were sometime ritually exorcised, which in the European variation meant a brick in the mouth.
All [of] which means that the story [number] 3 about engineering enrollment dropping in colleges is fortunately TOTALL....... Y BOGUS, because enrollment in engineering and computer science programs in the US and Canada grew by 8 percent last year. We haven't had any increase in enrollment since 2002. The engineering degree is a tough cl[imb] but there are jobs in [them thar hills].
Well that's it for this edition of Scientific American's Science Talk. Check out www.SciAm.com for the latest science news and our In-Depth Report on how to green your office; not putting in a putting surface, making it environmentally friendly. For Science Talk, I am Steve Mirsky, thanks for clicking on us.
Journalist and writer Dan Falk talks about his new book In Search of Time, about the cultural, physical and psychological aspects of the mysterious ticking clocks all around us. Plus, we'll test your knowledge of some recent science in the news. Web sites related to this episode include www.danfalk.ca