Quarks to Quasars

A total solar eclipse is one of those few natural phenomena that seems to defy description.  It’s been called “awe-inspiring” and “nature’s grandest spectacle” – but the words do little to convey the actual experience of standing in the moon’s shadow.

You'll hear the phrase “once in a lifetime event" – but most people, in fact, never get to see one at all.  (Many have seen partial eclipses – but the difference between a total and a partial eclipse is literally like the difference between night and day.)

The funny thing is, in a global sense, total eclipses aren’t all that rare:  A total solar eclipse can be seen from somewhere in the world roughly once every 18 months.  But in practice, the “path of totality” – the stretch of land from which you can actually see it – is often very far from home.  (And if you stay put, and wait for a total solar eclipse to come to you, you’ll be waiting on average 375 years between each one!)  The last total eclipse visible from the contiguous 48 states of the U.S. (or from any part of Canada below the Arctic Circle) was in the winter of 1979.

And so I’ve been struggling to come up with a good analogy.  Let’s try this:  Everyone knows that sunsets at the Grand Canyon are spectacular.  And they’re pretty quick, too – it only takes the sun a couple of minutes to slip below the horizon – in the same way that the total phase of a solar eclipse lasts only a few minutes.  But now suppose that instead of happening every day, those sunsets only happened every 18 months.  And now suppose that the Grand Canyon kept moving around, so that it was only in North America a handful of times every century… are you getting the picture?  (Perhaps we can take another analogy from from the world of music -- think of the lengths that fans will go to see their favourite band -- espeically if you're worried that each tour might be the last!)

That’s why, as a teenager hooked on astronomy, I eagerly awaited my first chance to see a total solar eclipse -- an opportunity that I would finally get on July 11th, 1991.  The “path of totality” for that eclipse passed through Hawaii and Mexico (and enormous swaths of ocean).  It was also one of the longest eclipses of the century, with a duration of almost seven minutes.

I ended up joining a tour led by a group of Canadian amateur astronomers – members of the Royal Astronomical Society of Canada.  We set up our equipment in a soccer field in the small town of Santiago, near the southern tip of the Baja California peninsula.

The weather ended up presenting a challenge:  The day had started off sunny and clear – but as we got closer to totality, clouds started to build up, overhead.  (This was probably due to condensation, triggered by the temperature drop that inevitably accompanies being in the moon’s shadow.)  In the end, we it became a kind of game of hide-and-seek:  We gawked in the direction of the eclipsed sun – and relished in every second during those gaps between the clouds, when we could actually see the eclipse! 


While conditions may not have been perfect, we had spectacular views of solar “prominences” – giant plumes of gas that shoot up from the surface of the sun. 

I’ve been privileged to have seen three more total solar eclipses since then – from the Caribbean island of Curacao in 1998; from Salzburg, Austria, in 1999; and from Easter Island, in the middle of the Pacific Ocean, in 2010.


For those eclipses, I had better luck with the weather:  In Curacao, for the first time, I got to see the corona – the sun’s tenuous, pearly-while outer atmosphere, in all its glory (see the two photos above). In Salzburg (below), my friend and I climbed a hill on the north side of the Salzach, the river that flows through the heart of the city, to view the eclipse from the grounds of the Kapuzinerkloster, a 16th-century Capuchin monastery.  From this vantage point, the eclipse unfolded above the old city of Salzburg, seen across the river.  We arrived early, but before long we were joined by dozens of enthusiastic locals. 

And then, Easter Island – my last journey into the moon's shadow, before the “Great American Eclipse” of 2017.  It’s hard to think of a more exotic location from which to observe an eclipse.  Located some 3,500 kilometers off the coast of Chile, in the southeastern Pacific Ocean, Easter Island (Isla de Pascua in Spanish, Rapa Nui in the indigenous Polynesian language) is one of the most remote inhabited islands in the world.  About 6,000 people live on the island – a figure that may have almost doubled during the week of July 11, 2010.  Though the weather on Easter Island is always unpredictable, in the end it was mainly clear on the big day – and I viewed the spectacle along with a couple of hundred eclipse enthusiasts from around the world.  We watched from a grassy field beside Ahu Tahai – an ancient ceremonial complex consisting of seven stone figures (moai), on the island’s west coast.  I can’t think of a more incredible experience than watching the sun disappear from the sky, above the moai of Easter Island.

After seeing four total solar eclipses, I can understand why people get hooked.  (In fact, I may have “caught the bug” even before totality had ended, during that first eclipse back in ’91!)  And so for years I’ve been looking forward to August 21, 2017 – a date that always seemed so far away…

I’ll be in west central Oregon, near the center-line of the “path of totality,” for the Great American Eclipse.  I hope you’ll be able to see it, too.  And if not – well, there’s always the next one.  The next time the moon’s shadow strikes North America will be on April 8, 2024.  It will be here before you know it…

As many of you know, I’ve been spending the current academic year doing a Knight Science Journalism Fellowship down here at MIT. It’s no exaggeration to call the fellowship a once-in-a-lifetime opportunity, and there’s no way I could talk about all the things I’ve seen and done and learned since settling down in Cambridge, MA, in late summer – but I’ll do my best to pluck out a few items that I think are worth a special mention…

First, the people: I’m thrilled to be one of 12 science journalists from around the world to have been chosen for this year’s batch of “Knights.” (You can read our bios on the Knight website.) Here are our smiling faces on this year’s Knight brochure:

Of the other 11 Knights, five are from the United States, with one each from the U.K., Norway, Poland, Nigeria, China, and Cambodia. The director, Phil Hilts, is a veteran investigative journalist and author who’s been on staff at the New York Times and Washington Post. (And he’s not a bad bowler, too.)

One of the great things about the fellowship is the privilege of taking courses at both MIT and Harvard. Here’s a picture of the MIT campus, or at least the “elegant” part of it:

The Knight offices are also at MIT, so in a sense this has been “home base,” though I ended up living in an apartment closer to Harvard. Of course, Harvard has an even more dignified-looking campus than MIT – but what do you expect, they had quite a head-start. (It’s staggering to think about just how long Harvard has been around. It dates back to 1636, a mere 16 years after the Pilgrims landed at Plymouth Rock, and a solid 140 years before the United States became a country. At least, it’s impressive to anyone who didn’t attend Oxford or Cambridge…)

Choosing courses at the two universities, I felt like a kid in a candy store: Genetics or robotics? Relativity or quantum mechanics? Copernicus or Kuhn? For my first semester, I chose two courses at Harvard and one at MIT (though I dropped in on a few others). At Harvard, I took “Re-thinking the Scientific Revolution” and “Science and Literature.” While the former focused on the period from Copernicus’s De Revolutionibus to Newton’s Principia, the latter covered virtually the entire scope of Western literature, from Lucretius to cyberpunk – focusing, of course, on works that were inspired by, or offer a commentary on, developments in science. In that course, I was introduced to many texts that I ought to have read before, but never quite got around to: Fontenelle’s Conversations on the Plurality of Worlds, Shelley’s Frankenstein, and Stoppard’s Arcadia, to name just a few.

In choosing both of those classes, I was motivated by my passion for the “big picture”: Sure, I could have focused in on some particular branch of contemporary physics, or another branch of science – but instead I chose to step back and look at the larger issues raised by the scientific adventure. As different as these two courses were, there was a significant degree of overlap. Lucretius, for example, came up in both; so did Robert Hooke and his remarkable Micrographia

Just for fun, I also took an Shakespeare class at MIT – well, more or less for fun; Shakespeare was born in the same year as Galileo, and lived just at the same time that our view of the universe was being transformed. It’s interesting to see how Shakespeare and his contemporaries were influenced by the scientific discoveries unfolding around them.

In the Knight Fellowship program, the classes are just the beginning. We’ve had a number of field trips; the big one for our firsts semester being a visit to the Woods Hole Oceanographic Institute, probably the world’s leading lab for marine biology.

On top of our tour of WHOI and affiliated labs, we had a “scientific cruise” on Nantucket Sound, south of Cape Cod, collecting samples and seeing just what goes on beneath he waves. (The man in the red hat was our friendly biologist / first mate.)

And we’ve had other chances to explore New England, or at least this corner of it. One of the Knight staffers had a party at her home in Rockport, MA; here we are out on the rocks by the ocean. (The scenery reminds me of Nova Scotia, where I grew up – sometimes stark, but always beautiful.)

Back at MIT, there was an incredible lineup of seminar speakers – talks held every Tuesday and Thursday afternoon, just for us Knights. For me, highlights included talks by primatologist Richard Wrangham, psychologist Rebecca Saxe, and physicist David Kaiser. On the journalism side, we heard from top-tier professionals such as Carl Zimmer (Discover, The New York Times, and more), Sarah Kramer (The NYT’s multimedia guru), and Robert Krulwich (from NPR’s amazing RadioLab).

We also have a pair of first-rate multimedia instructors here, and we’re been diving head-first into the world of video and audio editing and production. (I learned many of the basics back in journalism school – but the technology keeps changing, so it’s good to keep up!)

There’s a lot to love about Cambridge, but for science enthusiasts like me, much of the appeal comes from the city’s sheer brain power: There are endless opportunities to give the ol’ gray matter a workout around here. Every week at either MIT or Harvard, there’s something amazing going on (and almost always for free). For example, a riveting panel discussion neutrinos, and why they (allegedly) were measured to be travelling faster than light…

…and Adam Riess’s mesmerizing talk on “the accelerating universe,” just two weeks after he was informed that he’d won the Nobel Prize for that very discovery:

And then there was the panel discussion on “Life in the Universe” that I caught at the MIT Museum. And the symposium on “art and science” that I popped across the river to see at Boston University. And I can hardly describe what a privilege it was to take a class in which we’d been reading Lucretius – and then to walk across campus to hear a talk by Stephen Greenblatt, who’s just written a book on, yup, Lucretius. Not to mention getting an expert guided tour of the recent exhibition, Prints and the Pursuit of Knowledge in Early Modern Europe at Harvard’s Sackler Museum. Twice.

It’s hard to believe the Fellowship is already half over… it’s all happened much too fast!

(And just a reminder: You can follow me on Twitter and “like” my Facebook Page.)

Happy Holidays!

This entry – the first in my “Quarks to Quasars” blog – is adapted from an essay I originally wrote for the website of Pages Books in Toronto earlier this month.

For more than a hundred years – ever since H.G. Wells penned his groundbreaking novel The Time Machine – people have speculated on the possibilities and paradoxes of time travel. There are, presumably, two ways in which such travel could be realized: Human beings could eventually build a time machine, or we could stumble across a pre-existing machine built by a more advanced civilization. Both possibilities have received much attention – indeed, I focus on such questions in Chapter 7 of my latest book, In Search of Time: Journeys along a Curious Dimension (McClelland & Stewart, October 2008). But the question of whether time travel may eventually be possible is almost beside the point. Merely considering such travel raises a host of mind-bending philosophical problems, enough to challenge the most careful thinkers. So this essay will not be about wormholes or rotating cosmic strings or any of the other exotic physical structures that may one day be exploited to bring about time travel. Instead, I want to focus on one particular philosophical objection time travel – the famous “grandfather paradox.” I will examine one proposed resolution of the paradox, and some difficulties with that purported solution that have perhaps been overlooked. If you’re even an occasional reader of science fiction, you’re probably familiar with the grandfather paradox. The basic idea is this: suppose you travel back to the time when your grandfather was a young man, and kill him (either by accident or by a willful act; the logical conundrum is the same). He never meets his future wife, never has children, and so you are never born – so how could you have traveled through time? One solution – if that’s what it is – is the idea that history must be “consistent.” The idea is that you can do as you please when you travel back in time, so long as those events correspond to what actually happened. This rules out killing your grandfather in a rather straightforward way: You can’t kill him, because you didn’t. But if grandpa has always told stories about a crazed young man who took pot shots at him with a rifle back in the1930s, then you could indeed be that crazed man; history would be consistent. You can try to kill him; you just can’t succeed. In a nutshell: You may have some degree of freedom on your jaunt through time, but you can’t change history. As physicist Brian Greene puts it: “If you time-travel to the past, you can’t change it any more than you can change the value of pi.” But there are problems here. Does it matter how well we know the relevant history? That is, is our knowledge of past events somehow relevant? Would someone who failed History 101 be free to run amok at the Battle of Hastings, while an A-student would have to tread carefully so as to not interfere with the death of Harold and the victory of William? The answer, presumably, is: “No, because the rest of us know what happened there.” But what about a visitor to the Jurassic era? Could our time traveler do as she pleases, simply because so few records from that era survive? And then there’s the flip-side, in which we have too much knowledge of a particular time and place. This brings us to what I call the “Downing Street dilemma.” Suppose you travel back in time just a few years, to 2005, and tried to visit Downing Street in London. Home to the British Prime Minister and many top government offices, the street must surely be one of the most intensely-monitored thoroughfares in the world: No doubt there are dozens of closed-circuit TV cameras on every block, and this must already have been the case by 2005. Suppose you have a time machine at your disposal, but, before you begin your journey, you scan the videotapes that show Downing Street circa 2005. And suppose, as you can the tapes for some particular day, you see no sign of yourself: You did not, it seems, walk along Downing Street on the selected day in 2005. Already thing are getting complicated: We have to consider not only “2005 you,” but “time-traveling you” as well. Let’s say you’re 33 now (in 2008), which means you were 30 in 2005. If 30-year-old you walked along Downing Street in 2005, you would surely remember it in 2008 – but that’s not the point. Time-traveling you has no option of “becoming” that person. Rather, what you can “become” – if that is the right word – is the 33-year-old traveler who may appear on the videotape at some point. Let’s consider the first case: the scenario in which the tape for some particular day doesn’t show you at all. How does that impact your proposed journey? Does it mean you simply cannot visit Downing Street on that day in 2005 with your time machine? Is such a trip ruled out before it can even begin? Now imagine the alternative scenario: Suppose the tapes reveal that time-traveling you did in fact take a stroll along Downing Street on some particular day back in 2005. This is hardly more appealing: Now, not only can you take the trip, but, presumably, you must; and when you get there, every step, every muscle twitch, must accord precisely with what was recorded by the cameras! Free will would seem to be greatly compromised, if not utterly extinguished. (Actually, Downing Street has been closed off by a gate, and guarded by police, for some time. But we could simply replace Downing Street with some other un-gated but heavily-monitored area – Trafalgar Square, for example.) The “consistent history” argument says, roughly, that if you travel back in time, you can only do things that are consistent with the overall history of the universe. Or, put more simply: If you travel into the past, you will only be able to what you actually did. This rules out many kinds of trips, or at least curtails the activities a time traveler can engage in while visiting the past. So what, exactly, are we left with? Must our time traveler experience an endless series of puzzling coincidences, peculiar constraints, and a bizarre absence of free will? (Must every rifle aimed at grandpa misfire? Must every attempt to stroll along Downing Street go awry?) Perhaps, as a number of scholars have suggested, such questions put the cart before the horse. As philosopher Nicholas Smith has argued: “If a time traveler is going to travel to some past time, then she has already been there. If she is going to save a life or prevent a birth when she gets there, then she has already done so.” From this perspective, the abundance or accuracy of the “records” of the period we travel back to (the amount of video surveillance, etc.) is simply irrelevant. The question isn’t what the historical record can show us; it’s what actually happened, recorded or not. Presumaby Smith would counter my Downing Street dilemma as easily as any of the other standard scenarios: If the time traveler took a stroll along Downing Street in 2005, then he surely had free will at that time. And – crucially – it is a mistake to think that he walked along the street again a few years later with the help of the time machine: That trip simply was the original 2005 trip. Smith refers to this mix-up as the second-time-around fallacy. It is a mistake, he argues, to think that some particular event happens, and then “happens again” when experienced by a time traveler. It simply happens, period. If a time traveler is on hand, so be it; but that means he was there all along. Smith’s argument is simple and powerful, but it still leaves a great deal to ponder. What does it mean to say that a time traveler had free will when he visited X, if he has yet to jump into the time machine to carry out his visit to X? As you climb into the time machine for a visit to Downing Street circa 2005, your intuition says that you ought to be able to do as you please throughout your journey – yet history demands that you are restricted to doing what you actually did. The problem arises because, in this bizarre scenario, your future lies in my past (or simply, “the past”). To you, these are future events which can unfold in one way or another depending on your actions; to the rest of us, they lie in the past and are fixed, unchangeable facts about the world. And then there is the awkward problem of having two “yous” in the world at the same time. What if the time traveler encounters himself? Surely in that case the moment is indeed “experienced” twice – once by the young version of the traveler and again (or should we say “simultaneously”?) by the older version. (Based on an e-mail I received from Professor Smith, I think he would concede this point.) Mind you, if you did walk along Downing Street in 2005, at age 30, and met another you who was three years older – that is something you would surely remember! At the very least, having two entities both claiming to be “you” does seem to raise some perplexing philosophical problems. What happens to our notion of “self”? Rather than having solved the grandfather paradox, we may have compounded it. Of course, I have not exhausted the proposed “solutions” to the grandfather paradox here; I haven’t even mentioned, for example, the much-discussed “parallel universes” scenario. (I do try to go through all of them fairly thoroughly in Chapter 7 of my book.) But I think this series of simple thought experiments shows that even when we think we have a straightforward “solution” to the paradoxes of time travel – “don’t worry, the time traveler can do as he pleases so long as history is consistent” – the solution may not be quite as satisfying as we had hoped.