As an astronomer, I have long had a professional aversion to waking up before dawn, preferring instead to see sunrises not as an early morning treat, but as the signal that the end of a long night of work has come, and it is finally time for overdue sleep. But in the pre-dawn of August 25th, 2005, I awoke early and was up sneaking out the door, trying not to wake my wife Diane or our one-year-old daughter Lilah. I wasn’t quite quiet enough. As I was closing the front door behind me, Diane called out, “Good luck sweetie!”
I made the short drive downhill through the dark empty streets of Pasadena to the Caltech campus, where I found myself at 4:30 AM, freshly showered, partially awake, and uncharacteristically nicely dressed, unlocking my office building to let in news crews that had been waiting outside. All of the local news affiliates were there, as well as representatives of most of the national networks. Outside, a Japanese-speaking crew was pointing their TV camera up at the sky, their flood lamps disappearing into space. A glance at their TV monitors showed nothing but flood lamps disappearing into space.
The news crews would probably have preferred to be asleep, too, but today was the last day of the International Astronomical Union meeting in Prague, and the final item on the agenda at the end of two weeks' worth of discussion was a vote on what to do with Pluto. Everyone’s favorite ice ball was in eminent danger of being cast out of the pantheon of planets by the vote of astronomers assembled half a world away, and whatever happened would be big news around the whole globe.
I like planets. But I didn't care enough about Pluto to get up at 4:30am. A year earlier, it is true, I was waking up at 4:30am or 1am or 3:15am or whenever the then-newborn Lilah happened to need a late night bottle, but, after a year, I was pretty happy that these days Lilah almost never woke up in the middle of the night. I liked my sleep.
But this Pluto vote half a globe away mattered enough to me to drag me out of bed that morning. To me that vote had nothing to do with the ninth planet; it was all about the tenth. And I cared a lot about that tenth planet, because eighteen months earlier I had discovered it, a ball of ice and rock slightly larger than Pluto circling the sun every 580 years. I had been scanning the skies night after night looking for such a thing for most of a decade, and then, one morning, there it finally was.
At the time of the Pluto vote, my discovery was still officially called only by its license plate number of 2003 UB313, but to many it was known by the tongue-in-cheek nickname of Xena, and to even more it was known simply as the tenth planet. Or maybe, after today, not the tenth planet. Xena had precipitated the past year of intensive arguments about Pluto, but it was clear that Xena would also share whatever fate was dealt to Pluto. If Pluto was to be a planet, then so too Xena. If Pluto was to be kicked out, Xena would get the same boot. It was worth waking up early to find out the answer.
The previous two weeks in Prague had been perhaps the most contentious gathering in modern astronomical history. Usually the International Astronomical Union meeting is nothing but a once-every-three year's chance for astronomers to advertise their latest discovery or newest idea while spending some time in a nice international destination, having dinners with old friends and catching up on their celestial gossip. On the final day of each meeting, in a session attended by almost no one, resolutions are passed, usually all but unanimously, on such pressing topics as the precise definition, to the millisecond, of Barycentric Dynamical Time (I have no idea what this actually even means, but, presumably, it matters critically to someone).
This year was different. The usually placid astronomers had spent their time in Prague arguing and bickering day and night about Pluto and about planets and about how to reconcile the two. While several of the typically unintelligible resolutions were indeed to be voted on this last day, the final two resolutions would be all about Pluto. The usually sparsely attended final session was likely to be full of surly astronomers itching for a fight.
While the astronomers were gathering for their vote in Prague, the news crews and I were arriving in the early morning on the Caltech campus in Pasadena so that we could watch the excitement via a webcast from the other side of the world. My job was to provide commentary and analysis for the press and moral support and scientific cover for the astronomers who were – rightly, I thought – trying to take the bold move of ridding the solar system of the baggage of planet Pluto. I found the webcast, projected it on the large screen, and we all sat back to watch.
Three mostly esoteric and tedious hours later it was all over. On the final vote, the air was filled with yellow cards with which the astronomers in Prague were voting “no” for Pluto planethood. There was no need to count; the vote was not even close. After hours of detailed explanation and analysis and discussion of the subtleties of all of different possible outcomes, I could finally just say: “Pluto is dead.”
The cameras whirred; correspondents talked into their microphones, and, on a screen on the other side of the room, I could see myself on some local television station repeating, like an echo, “Pluto is dead.”
Before anyone else could ask a question I quickly picked up the phone and called my wife Diane, who was now at work. I had made a similar phone call 18 months earlier, only minutes after I had discovered Xena. Back then, the moment she picked up the phone I said "I found a planet!"
Back then, her voice had risen, “Really?”
This time, instead, the moment she picked up the phone, I said, “Pluto is no longer a planet!”
Her voice dropped, “Really?”
Yeah! Really! I was still excited from the vote and had not quite grasped her mood.
She paused for a long time. “And Xena?” she finally asked quietly.
But Diane already knew the answer. Xena had indeed gotten the same boot as Pluto, and Diane was already mourning the little planet that we had gotten to know so well.
In the days that followed I would hear from many people sad about Pluto. And I understood. Pluto was part of their mental landscape, the one they had constructed to organize their thinking about the solar system and their own place within it. Pluto seemed like the edge of existence. Ripping Pluto out of that landscape caused what felt to be an inconceivably empty hole.
That first morning, though, Diane was having the same reaction, but for Xena instead of Pluto. For her Xena was more than just that thing that used to be called “the tenth planet.” She had listened to me enough over the previous 18 months that she had gotten to know all about the onetime 10th planet. She knew about the tiny moon, the incredibly shiny surface, and the atmosphere frozen in a thin layer all around the globe. Diane and I had discussed the excitement of the search, what to name the 10th planet, and how many more like it might be out there. Xena had become as much a part of our own mental landscapes as Pluto might have been for anyone else. And Xena would be forever tied in our minds to our daughter Lilah, who was only 3 weeks old when Xena was announced to the world. All of those memories of the first months of our Lilah's life -- the lack of sleep, the dazed confusion, the questions about what life would be like after this sudden change-- are tied up with all of those memories of what became10th planet mania -- the rush to learn more, the push to discover others, the questions about what life would be like after this sudden change. And now, just a little after Lilah’s first birthday, Xena was gone.
I had to tell Diane: The astronomers did the right thing. Xena is not really gone, of course. It is now actually the largest of the dwarf planets, where it rightfully deserves to be.