I got two press releases in my email today — both touting the upcoming solstice as something newsworthy. Oohhhkayyy.... let's look at this a bit deeper. First of all, "what's the solstice?" you might ask. Simply put, it's the day when the Sun reaches its southernmost point in the sky during the year. After that, its zenith point marches steadily northward. This year that special day is Monday, December, 22nd at 2:04 a.m. (for the folks on the East Coast of the U.S. -- folks on the West coast start winter at 11:04 p.m. on the night of the 21st and for folks in England, it's 7:04 a.m. on the 22nd.)

So, you might further ask, what's the big deal here? Will the world tip over? The stock market surge on the news? The planets move into alignment? Will spiritual auras envelop everyone who waves a burning sage bouquet in front of a pyramid-shaped quartz crystal? Naw. The solstice isn't a mysterious or metaphysical occurrence. It's an entirely naturally-occurring twice-a-year event that has more to do with how the Earth moves around the Sun. Here's what the good folks at Sky & Telescope have to say about the solstice:

"The seasons' starting times are governed by the Earth's motion around the Sun — or equivalently, from our point of view, the Sun's annual motion in Earth's sky. The start of winter (for the Northern Hemisphere) is defined as the moment when the Sun hovers over Earth's Tropic of Capricorn (the line of latitude 23.5 degrees south of the equator) before heading north — a moment called, by Northerners, the winter solstice.

The Sun appears to move north and south in our sky during the year because of what some might consider an awkward misalignment of our planet. Earth's axis is tilted with respect to our orbit around the Sun. So when we're on one side of our orbit, the Northern Hemisphere is tipped sunward and gets heated by more direct solar rays, making summer. When we're on the opposite side of our orbit, the Northern Hemisphere is tipped away from the Sun. The solar rays come in at a lower slant to this part of the world and heat the ground less, making winter.

North of the equator, the June and December solstices mark the beginning of summer and winter, respectively. The effect is opposite for inhabitants of the Southern Hemisphere; for them the December solstice signals the beginning of summer, while winter starts at the June solstice.

For a skywatcher on Earth (at north temperate latitudes), the effect is to make the Sun appear to move higher in the midday sky each day from December to June, and back down again from June to December. A solstice comes when the Sun is at the upper or lower end of its journey; an equinox comes when the Sun is halfway through each journey."

So, if the solstice is a by-product of Earth's motion around the Sun, what's the big hoo-hah about? Why the press releases? It's a fancy way of announcing that winter will be coming in on Monday and what clued us into that fact. For those of us north of the equator, it marks the longest night and the shortest day of the year. So, should you do anything to celebrate?

Well, yes, as a matter fact there IS something you can do. Parties, of course, are always in order. It's a partyin' time of year. In fact, solstice celebrations are some of the oldest known get-togethers in human history. But, the festivities don't stop with solstice. Wait until December 25 (Christmas Day for those who celebrate that) and you'll be rewarded with a great celestial sight. Dress up appropriately for the weather in your area, go outside and look toward the western horizon after sunset (in the dusk). If your skies are clear, you should be able to see the planet Venus and the thin crescent Moon low in the southwest. These aren't really an effect of the solstice — they just happen to be visible a few days after solstice. If you're lucky, as the sky grows darker you might be able to see the full moon glowing faintly in reflected Earthlight beyond the edge of the crescent. This is called the "Old moon in the new moon's arms."

The Old Moon in the New Moon's Arms, image by Dennis Mammana, from Memphis Geological Society website.

Have fun with your celebrations this year — and just remember: six months until the next solstice. Plan now!

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12.15.2003

Thought For The Day

I am always on the lookout for astronomy-related sayings. The hunt for references to stars and planets and the cosmos takes you through all sorts of literature. I don't limit myself to wise sayings though — I like to look for poetic references too. So, things like this:

"Many a night I watched the Pleiads, rising thro' the mellow shade, glitter like a swarm of fireflies, tangled in a silver braid" (from Alfred Lord Tennyson's "Locksley Hall")

combine inspiration and observational astronomy all into one. But what other sayings are there? Well, books by popular astronomers have tons of these quotes in them. I use them in my books as a way to invite other writers (some long-gone) be a part of my books. I like seeing their names and wisdom up there with the chapter heads — their pithy sayings sometimes encapsulate an idea quite nicely. Here are a few of my favorites.

"For my part I know nothing with any certainty but the sight of the stars makes me dream." Vincent van Gogh

"It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small." Neil Armstrong


"The sky is the ultimate art gallery just above us." Ralph Waldo Emerson
Ralph Waldo Emerson

posted by CCP on 12/15/2003 04:28:00 PM | * |



12.14.2003

Ringworld in Gemini

Saturn's position in late December/early January 2003/2004.
Star chart by C.C. Petersen using Cartes du Ciel and Adobe Photoshop software.

Every year we send out a star map with our holiday cards and letters. This year's map is a sneak preview of Saturn, which is dancing through the constellation Gemini throughout 2004. It's visible now around 9 p.m. about halfway up the eastern sky; by January it will be up all night long, appearing high overhead in the late evenings. It's worth a shot to observe Saturn over the next few months before it disappears into the glare of the Sun June through mid-August and gets too difficult to observe. Just bundle up warmly if you live in a cold climate, and bring along a small telescope or a powerful pair of binos so you can make out the rings.

Sometimes our friends or family members mention the star chart in letters or conversations. My aunt Cecile told me that they always look forward to getting it so they can do a little stargazing with their daughter. They live in Wyoming in a pretty dark sky site, so I imagine they get a big charge out of the stars. One of my cousins lives in Alaska, and I often think of them going out stargazing for a few minutes and being greeted by auroral displays. Some family members live in the desert southwest or in Florida, which gives them a nice thing to do on a balmy December night, and we even have a few cards going to friends in Europe and one or two in southern hemisphere locales. This far-flung empire of recipients puts a few constraints on what I can illustrate in the charts. Obviously extreme southern or northern sky sights aren't suitable, so that leaves us the "middle" of the sky (as I like to think of it). The good news is that the constellations of winter (for northern hemisphere types — they're summer sights for our southern-hemi friends) are really quite pretty, no matter what the temperatures are under which we observe them. So, if you're looking for a sight to see after your December holiday dinner, here's this year's chart. Happy observing!

posted by CCP on 12/14/2003 12:45:00 PM | * |



12.10.2003

Back to the Ringed Planet

Image courtesy of Astronomy Picture of the Day

Way back when I was a kid I saw a picture of Saturn in a Time-Life book. That image embodied all the ideas I had about space travel at that time (which I admit were inflamed by the astronauts going up in the Gemini capsules and orbiting the Earth). Saturn was cool and remote and just about the most fascinating place I could think of. I remember wondering about those rings — what were they made of? Could we fly through them?

Some years later as a newspaper writer I covered the Voyager 2/Saturn encounter and learned more about this wonderful planet than I ever thought possible. So, it's with a great deal of interest I watch out for Cassini mission images as this last of the grand explorers makes its way closer to the ringed planet. Early last month, Cassini delivered this image back to waiting mission scientists. You can make out ring features, the cloud-tops, and one of the planet's moons. Cassini will arrive at its destination next July (2004) and settle into a circular orbit ideal for study and mapping. Later, it will send the Huygens probe to the surface of Titan, giving us a great look (we hope) at what's hiding beneath the clouds that shroud the moon from our view. It's been long time since we've had a probe out at Saturn (since 1981, actually). I can't wait to see what we find this time!

posted by CCP on 12/10/2003 08:58:00 PM | * |



12.08.2003

Is the Universe Like A Box of Chocolates?

A while back I got an email from a student who wanted to make a career in science writing. Among the questions she asked, she wanted to know how I decided what topics to write about. Science writing is sort of like getting a huge box of candy (no, I'm not going to make a Forrest Gump comparison here). The cosmos presents a lot of things to us that are like chocolate-covered lumps. You just have bite into them to find out what they are. I never know what flavor I've got in a given topic until I bite into it.

Some topics grab my attention because they're hot and happenin' — for example, a press release about a discovery in another galaxy comes my way and it spurs a story. Sometimes I get a commission to write about a specific topic, like an article I did for Sky & Telescope about gravitational lensing. The same thing happens with planetarium shows, although the last one I did for a client outside of Loch Ness Productions was actually about the universe itself. As you can imagine, it was pretty broad. The producer basically presented me with 20 minutes of science visualization and said, "Here, write us a story about the cosmos." So, I did.

Books are kind of a different story, if only because I figure out what I want to cover in a book, think about how it will be illustrated, and then I propose it to a publisher. If they like it, they bite on the proposal. Visions of the Cosmos grew out of my interest in sharing the universe with readers and showing it in as many wavelengths as astronomers study it in. Jack shared that interest with me, and so we went to work sifting through great pics that would either illustrate what we wanted to say or give us a new and interesting way to write about hot topics in astronomy. There are millions of great images out there, taken in every part of the electromagnetic spectrum, and each one has a story to tell about how the universe works, how it came into being and where it's evolving to. Unfortunately, as Jack and I point out in our preface, we can't possibly publish all the pictures, and choosing from the many excellent science images that came our way was a delightful, if frustrating task. We ultimately settled on 187 or so images that would help tell the story, and off we went.

There are more stories out there in science than you can possibly imagine. Which is great — they're wonderful fodder for me, for my planetarium shows and books, and for all the future science writers who follow the stories of the cosmos.

posted by CCP on 12/08/2003 02:09:00 PM | * |



12.06.2003

Co-Author and Friend

In the previous entry for December 4, I talked some about my latest book, Visions of the Cosmos, but actually it's not just MY book. It's a project that my co-author, Jack Brandt, and I undertook starting about two or three years ago. I get the question a lot about how I ended up partnering with Jack Brandt on books. It's a long story, but here's the executive summary. Way back when I decided to go back to school to study astronomy and suchlike stuff, I needed to find a job that was a bit less demanding than lecturing at the planetarium. So I applied for a job with a group called the International Halley Watch, involving measuring plasma tail characteristics captured in images of Comet Halley. The head of the group at CU was a guy named John Brandt, whom I'd never heard of, but I was told he was a good fellow.

The day of the interview we talked for a few minutes about the work and then another hour about mutual acquaintances and experiences. A couple of days later, he wrote me an email inviting me to join his team. Little did I know at the time that I'd just lucked into a major friendship and partnership that continues to this day. Jack is pretty amazing — he's one of those people who has been there and done that and has amusing stories to tell about all of it. Among his varied academic and work experiences, he studied under Subramanian Chandrasekhar at the University of Chicago, was a grad student along with Carl Sagan, spent some time teaching at Berkeley, Columbia University, and the University of Maryland, was a lab chief at Goddard, led the Hubble Space Telescope's Goddard High Resolution Spectrograph team, and many other career moves that I found out about as I worked for him from 1988 through the end of 1996. It was a rewarding eight years and a period of my life that I enjoyed very much (and that I found challenging and stimulating).

Jack Brandt's faculty listing

at the University of New Mexico. (No, I don't know why he looks so surprised in this picture. Ask him sometime... )

In the early 1990s, just as I began my graduate work at CU (with much encouragement from Jack), I started working on Hubble Vision. At first Jack was my science advisor and fact-checker, but as time went by I realized he was offering much more than an advisor would do, so I asked him to be my co-author. He agreed so quickly I knew it was the right move. Ultimately, we went through two editions of that book and ended up authoring and editing several other papers and a conference proceedings together, too. While we wrote Hubble Vision during our tenure at the University of Colorado, our latest partnership, on Visions of the Cosmos, required us to communicate through email and telephone between Massachusetts (where I moved in 1997) and New Mexico (where he retired a couple of years later) — rather than by the almost daily contact we had during the time I worked for him at CU. Now, after several years of this strange long-distance partnership, we've managed to crank out another book (see my previous entry), we're still talking to each other, and I'd like to think we've turned out a good book together. Or at least, that great minds think alike!

Jack taught me a great many things, not always in the classroom or during our bouts of research. For instance, before I met him I had never drunk Watney's Cream Stout. I didn't know much about red wine. I hadn't been to too many baseball games. And, before he had me working for him, I doubt Jack had been too cognizant of such things as planetarium shows, space music, and good Mexican food. Of such things are friendships made — and they continue. Jack and his lovely wife Dorothy have hosted us in their New Mexico home several times (and before that in their Colorado home), and they've come to visit us in Massachusetts a few times. This past October, Mark and I met up with them in Miami for a Jazz Cruise through the Caribbean. It was a wonderful way to celebrate the completion of our latest book project, Dorothy's birthday, and the occasion of Mark and my 25th wedding anniversary.

So, the next question is, will Jack and I do another book together soon? Anything could happen... ;) We'll keep everybody posted!

posted by CCP on 12/06/2003 09:30:00 PM | * |



12.04.2003

A Book Is Born!

Visions of the Cosmos

My latest book has arrived! After more than two years of work, Visions of the Cosmos is finally a reality. My advance copy arrived a couple of days ago and I've been paging through it to see how everything turned out. Mind you, I'd seen the whole thing in layout when the publisher sent me PDF copies for final approval a couple of months ago, but holding the real thing in my hand seems like the culmination of a long birth process. Now, I just hope it sells! It's starting to trickle into the bookstores here in the U.S., although it's been on the shelves in the UK for a few weeks now. Amazon has it listed as arriving after Dec. 24, but they constantly update their stock, so I wouldn't be surprised if it showed up as "available now" any time. And, it appears likely the book will spread worldwide. The publisher (Cambridge University Press) wrote this morning to tell me that there's a good possibility that it will go into six translations very soon.

So, we started out wanting to write about the cosmos — and we did. But, after that part's done, the mundane, down-to-earth tasks were left. Those were the work of a cast of dozens of people, starting with Jack and me, to the editors, layout artists, graphics people, printer folk, bindery people, shipping and warehousing personnel, the Post Office, the bookstore buyers and sellers. Now is the fun part for the reader — sitting back and exploring the universe — assimilating the ideas we wrote about in the book.

So, how does a book get published in the digital age? The whole thing was pretty much done digitally. All of the images were sent as TIF or EPS files (a few had to be scanned into TIF format) and the text went as WORD2000 files. Proofs were done digitally as PDFs, except for the final image proofs, which I still insisted be sent to me in hard copy. The strangest things happen when you move from digital back to print — some of which are out of the author's control and are left to the printer gods to handle. When I got the cromalin proofs (sort of like very fine, heavy-paper photographic prints) one of the images I sent came back with what looked like a screen-door crosshatch pattern on it. I figure it was due to the screening process, but obviously that would have been unacceptable in a print book. So, I drew it to the publisher's attention and it was fixed in the final version. Multiply that sort of problem by a hundred or a thousand-fold in terms of error-correction, fact-checking, layout correction, and queries about why the typesetter did a page a certain way, and you begin to understand that the act of writing a book doesn't end when the writer types the final words in the last chapter. Detail, detail, detail. It's a lesson the writer has to learn, and in reality, I've found that I have to be a very proactive partner with the publisher to make sure the book turns out the way I (and my co-author) envisioned it.

Would I do it all again? Sure. This is the sixth time I've been through the book publishing process. It's the most involved I've been in production of my own work, although when I worked at Sky Publishing I edited two books and was very involved in those as well. No matter whose work is being published, it's never routine — each project has its similarities, and each one has had its glitches and obnoxious points. But in the end, all that mattered was that the reader got a quality product.

posted by CCP on 12/04/2003 12:10:00 PM | * |



12.03.2003

Guidance

I just got back from a family reunion over Thanksgiving. Among other things, I had a chance to sit down with my dad and talk about astronomy. He was the one who got me interested back when I was a little girl and he has always taken pride in my astronomy writing and career. He's a sunspot watcher and has been for a long time. I didn't know that until he showed me 11 years worth of drawings he had done at the telescope, tracking sunspots for nearly a whole solar min-max cycle. Pretty amazing and it took a lot of dedication for him to do that.

Not too many others in our family are interested in astronomy, although I have a couple of nieces who show some promise. I do my best to stoke what glimmerings of interest do show up, by answering their questions, telling them about upcoming celestial events, and so on. It's my little bit to keep the love of the skies alive. Well, that and the planetarium stuff! And the books...

posted by CCP on 12/03/2003 11:35:00 AM | * |



12.02.2003

Winter Stargazing

Anybody living north of, oh, say, Florida or Southern California in the United States and the Riviera and the Mediterranean shores in Europe can't help but notice that the nights are getting longer and the days shorter and the air temperatures for stargazing just a whole lot colder! It's more tempting to stay inside with a warm drink than it is to venture outside on a chilly night and do a little stargazing. I know it is for me. Yet, some of the most beautiful sights of the late autumn and winter skies are out there to be had if you can put aside the toasty comfort for a few minutes and step outside.

One night when I was in Phoenix visiting family I stepped out and looked up and there was Orion! THAT constellation always says "winter" to me (although for southern hemisphere readers, the big guy is a harbinger of summer). It was a little strange to see it on a balmy desert evening, and kind of funny how our minds associate things like temperature and season with a particular set of stars in the sky at a certain time. I always imagine that if we were on a starship or an L5 colony, things like seasons and even day-and-night distinctions wouldn't apply. Do you suppose we'd even be interested in stargazing?

posted by CCP on 12/02/2003 10:50:00 AM | * |