I'm thrilled to have won the 2009 American Institute of Physics Science Communication Award, in the Science Writing category, for my feature article "End of Days – A Universe in Ruins". The article, which was published in COSMOS magazine in 2008, examined the long-term fate of our solar system, the universe, and life itself. (I won the AIP award previously, in the broadcast category, for my radio documentary "From Empedocles to Einstein" in 1999.)

Read the announcement from the AIP, or view the winning article.

To mark the New Year as well as a new decade, I've made this short video on the nature of time. Enjoy!

I'm very pleased to be moderating The Great Time Debate, featuring cosmologist Dick Bond, physicist Lee Smolin, and philosopher James Robert Brown. This lively panel discussion, to be held Jan. 26 in the OISE auditorium in Toronto, will explore one of the most intriguing subjects in all of science: the nature of time. The event is sponsored by the Centre for Inquiry and the University of Toronto Secular Alliance. More information can be found on the CFI's website; it is also a Facebook event.

The shortest day of the year is known as the winter solstice, and it falls on (or very close to) December 21. (For those in the southern hemisphere, the shortest day comes on or near June 21.)

But anyone who keeps a close eye on the time at which the sun rises and sets will notice something a bit perplexing: Neither the earliest sunset nor the latest sunrise falls on the day of the winter solstice. In fact, the earliest sunset can fall more than a week before the solstice, and the latest sunrise can fall more than a week after the solstice.

Of course, astronomers are well aware of this phenomenon, but it remains very difficult to explain in simple terms (and I admit I have some trouble wrapping my head around it myself, in spite of having written a book on “time”!).

The short answer is that the discrepancy is due to the earth’s orbital axis being tilted (this is what gives us the seasons), and also to the earth’s orbit being elliptical rather than circular.

Now for a more detailed analysis: The solstice, by definition, is the day on which the sun reaches its most southerly declination in the sky. If we measured time with a sundial – which gives “local solar time” (or “apparent solar time”) – the day of the solstice would also be the day of the earliest sunset and the latest sunrise. But we don’t -- we set our clocks to “mean solar time.” (Actually, we use UTC – Coordinated Universal Time – but for the purposes of this discussion, we can ignore the difference between this and mean solar time). Mean solar time is an average: Think of it as the time that a sundial would read, if the Earth’s axis wasn’t tilted with respect to the ecliptic (the earth’s orbit around the sun), and if its orbit was a circle rather than an ellipse. But of course it is tilted, and the orbit is an ellipse. The result is that clock time differs from local solar time. The difference varies over the course of a year, and at its maximum it can be quite large – as much as 15 minutes. The difference between local and mean solar time is called the “equation of time,” and it depends on one’s location. As a result of these two effects, the time of sunset as read by a clock (i.e. as measured via mean solar time) is at its earliest more than a week before the solstice, and, similarly, the day with the latest sunrise comes more than a week after solstice.

Although less immediately noticeable, the time at which the sun reaches its greatest altitude in the sky also varies over the course of the year. If we kept to local solar time, of course, “noon” would just be half-way between sunrise and sunset. But, since we keep mean solar time, the sun may reach its high point anywhere from 15 minutes before, or after, 12:00.

Thanks to physicist David Tindall of Dalhousie University for some helpful comments, and to my friend Maria for getting the discussion started.

What a year for science! And a good year to be a science journalist, too, as we marked not only the 150th anniversary of Darwin’s Origin of Species (along with Darwin’s own 200th birthday), but also the 400th anniversary of Galileo’s first use of the telescope. Although I’m a big fan of Darwin, astronomy and physics have long been my bread and butter, so it was Galileo who captured my attention through much of 2009. This spring I toured through Galileo’s Italy, and paid a visit to a world-class observatory on an Arizona mountaintop. (Among the results: A two-hour radio series titled “Looking Up” which aired recently on the CBC program Ideas; an article in The Walrus; and another radio documentary for the program Tapestry, set to air later this fall.)

Just seeing the sites associated with Galileo was a thrill: his birthplace in Pisa; the house in Padua where he first used the telescope; the site of his trial in Rome; the villa near Florence where he lived his final years under house arrest – along with a spectacular exhibit on the history of astronomy at the Palazzo Strozzi, in Florence.

On top of that, I had the privilege of witnessing a re-creation of Galileo’s famous “falling bodies” experiment at the Leaning Tower of Pisa. In fact, historians are skeptical as to whether Galileo actually carried out the experiment at the famous tower – but this spring, physicist Steve Shore definitely did. Amid much fanfare, he dropped water bottles of different sizes from the top of the tower, and you can see the results in my short video of the event. (Without giving too much away, let’s just say that Galileo would have been pleased with the results.)

In Arizona, I visited the Steward Observatory Mirror Laboratory, where some of the word’s best telescope mirrors are made, before heading for the summit of Mount Graham to visit the Vatican Advanced Technology Telescope (the VATT, or, more affectionately, the “Pope scope”), one of two facilities run by the Vatican Observatory.

My host at the VATT was an astronomer named Guy Consolmagno, who also happens to be a Jesuit Brother; he also curates the Vatican’s extensive meteorite collection. We talked about many things that evening, but the issue I was most interested in exploring was the “science and religion” question – after all, Consolmagno works for the Vatican, the very institution that persecuted Galileo, the father of modern astronomy. (Consolmagno admits that when Pope Leo XIII founded the Vatican Observatory back in 1891, it was at least partly to show the world that the Roman Catholic Church was not anti-science – an allegation that had persisted ever since the time of Galileo’s trial.) It was clear that Consolmagno had completely reconciled his science with his faith. Make no mistake: Brother Guy is no fan of creationism, either in its traditional form or in its most recent incarnation as “intelligent design.” But he still believes that the universe is God’s handiwork; indeed, he sees the act of doing science as “a way of playing with the Creator.” (See the Walrus article for more on Consolmagno’s perspective on the relationship between science and faith.)

I certainly respect Consolmagno’s view – but it is not the only way to interpret what we see in the heavens. It certainly stands in sharp contrast to the views of Steven Weinberg, the Nobel Laureate physicist who I spoke with a few months later. Weinberg, of course, is an outspoken atheist, famous for having once written, “The more the universe seems comprehensible, the more it seems pointless.” (More than 30 years later, he still gets letters and e-mails about that line.) Weinberg and Consolmagno are both keenly aware of the vastness of the cosmos, but have drawn very different conclusions about it. The discoveries of science don’t disprove religion, Weinberg says, but he adds that the universe is “clearly not organized for our benefit”; indeed, it is “so vast and, generally speaking, so hostile” that it hardly seems the handiwork of “a benevolent Creator who had us in mind – or, I would say, who had life in mind, let alone us.”

Personally, I tend to sympathize more with Weinberg than Consolmagno; to admit the possibility of miracles, as Consolmagno does, strikes me as being problematic for anyone seeking naturalistic explanations for the world around us. Even so, the two men agree on the most important questions: 400 years after the “Galileo affair,” they both recognize that the Catholic Church made a terrible blunder in the way it treated the scientist, and that dogma should never be allowed to hinder scientific inquiry.