How I Killed Pluto and Why It Had It Coming

by Mike Brown

  I remained adamant.

  She pressed: “Didn’t you used to joke that your definition of a planet was ‘Pluto is not a planet, but anything that I find that’s bigger is’?”

  Yes. I had made that joke. But it was a joke.

  Diane was in her energetic superwoman second trimester. If I was working late trying to figure out something about Xena or Santa, she would stay awake even later looking at baby magazines. If I woke up early to try to look at a few pictures of the sky just as they were coming off the telescope, she would already be awake looking at pregnancy books. As long as she was fed, she was unstoppable.

  “But really, you are going to have people arguing that it is a planet, and you’re going to stand up and say, ‘No no no no’? If Petunia is a really cute child, will you go around and point out that, really, she is not so cute because, well, her nose is a bit big?”

  Well, only if it is big.

  “Don’t you think it would overall be better for astronomy to have new planets discovered rather than have old planets killed?”

  I think it’s better to get it right.

  “But don’t you think the public would be more excited and engaged in astronomy and in science if there were new planets being discovered?”

  Enough, woman who needs no sleep! It is past my bedtime! But I will ponder your suggestions in the morning when I wake up, which will be long after you’ve already risen.

  As winter waned to spring, three independent trains of thought ran through my mind. If I ever got to spend more than a few hours in a row thinking about one of them, I would suddenly sit up with a start and remember one of the others and start thinking about that one, before I suddenly remembered the third, and then the process would start all over again.

  The first ticking calendar was strictly biological. Petunia was getting bigger. Her bones were hardening. Her eyebrows were growing. She had a July 11 due date, and though there was not much I could do to influence anything, I could nonetheless obsess about what, precisely, a due date means. I asked anyone who I thought might have some insight. I know, for example, that due dates are simply calculated by adding forty weeks to the start of the mother’s last menstrual cycle. But how effective is that? How many babies are born on their due dates?

  Our child-birthing class teacher: “Oh, only five percent of babies are actually born on their due dates.”

  Me: “So are half born before, half after?”

  Teacher: “Oh, you can’t know when the baby is going to come.”

  Me: “I get it. I just want to know the statistics.”

  Teacher: “The baby will come when it is ready.”

  I asked an obstetrician.

  Doctor: “The due date is just an estimate. There is no way of knowing when the baby will come.”

  Me: “But of your patients, what fraction delivers before, and what fraction delivers after the due date?”

  Doctor: “I try not to think of it that way.”

  I propose a simple experiment for anyone who works in the field of childbirth. Here’s all you have to do. Spend a month in a hospital. Every time a child is born, ask the mother what the original due date was. Determine how many days early or late each child is. Plot these dates on a piece of graph paper. Draw a straight line for the bottom horizontal axis. Label the middle of the axis zero. Each grid point to the left is then the number of days early. Each grid point to the right is the number of days late. Count how many children were born on their precise due dates. Count up that number of points on the vertical axis of your graph and mark the spot at zero. Do the same with the number of children born one day late. Two days late. Three. Four. Keep going. Now do the early kids. When you have finished plotting all of the due dates, label the top of the plot “The distribution of baby delivery dates compared to their due date.” Make a copy. Send it to me in the mail. My guess is that you will have something that looks like a standard bell curve. I would hope that the bell would be more or less centered at zero. It would either be tall and skinny (if most kids are born within a few days of their due dates) or short and fat (if there is quite a wide range around the due dates). One thing I know, though, is that the bell would have a dent on the right side. At least around here, no kids are born more than a week or two after their due dates. Everyone is induced by then.

  I am usually capable of allowing myself to give up on trying to get the world to see things in my scientific, statistical, mathematical way. But this mattered to me. If I was at a dinner party with Diane and the subject of due dates was broached, Diane would turn to me with a slightly mortified look in her eyes and whisper, “Please?” I would rant about doctors. About teachers. About lack of curiosity and dearth of scientific insight and fear of math. I would speculate on the bell curve and about how fat or skinny it would be and how much it might be modified by inductions and C-sections, and whether different hospitals had different distributions. Inevitably the people at the dinner party would be friends from Caltech. Most had kids. Most of the fathers were scientists. Most of the mothers were not. (Even today things remain frighteningly skewed, though interestingly, most of my graduate students in recent years have been female. Times have no choice but to change.) As soon as I started my rant, the fathers would all join in: “Yeah! I could never get that question answered, either,” and they would bring up obscure statistical points of their own. The mothers would all roll their eyes, lean in toward Diane, and whisper, “I am so sorry. I know just how you feel,” and inquire as to how she was feeling and sleeping and how Petunia kicked and squirmed. (As an aside, my female graduate students wanted to know the answer to my question, too, and were prepared to rant alongside me. Times have no choice but to change.)

  There was another calendar ticking, too. At the moment, the sun was almost directly between the earth and Xena. We knew Xena was out there, but we couldn’t see it. When Chad had looked at the surface of Xena and realized it looked similar to Pluto, he had done so at almost the last possible moment. Xena had been low in the western sky just at sunset. A few weeks later Xena set with the sun, and we couldn’t see it anymore. But slowly, the earth was moving around the sun, and Xena was eventually going to reappear on the other side, this time in the early-morning sky. As desperate as we were to learn more about Xena, we had no choice but to wait. Our first chance to get a good look would not be until September. I made sure that we were scheduled to be at the Keck telescope then. Other than that, there was little we could do except try to keep from telling people. I was looking forward to springing my news on an unsuspecting world.

  But another calendar was ticking, too, this one involving two different moons. One of the people I had told about Santa was Antonin Bouchez, the former graduate student of mine who had convinced me not to quit two years earlier. He now worked at the Keck telescope helping to develop a fancy new technologically intensive way to make extra-sharp pictures with the telescope. Usually, when you take a picture of a star or planet or anything else with a telescope, the earth’s atmosphere blurs that object a little bit, preventing you from seeing the smallest details. This blurring was the reason that we were never certain at first how big the things we kept finding were; their little disks were blurred out enough that they all looked the same. Antonin had been hired to work on a project to fix this problem. The trick is to take a powerful laser and shoot it out the front of the telescope into space. The light from this laser traverses the earth’s atmosphere, and then, right when it is about to shoot out the top, it encounters a thin layer of gas that has been burned off from asteroids as they enter the earth’s atmosphere. The laser light is precisely tuned to bounce off the asteroid gas and return back to the earth. If you then take your telescope and point it right at the location of the laser, you see a little spot of light—an artificial star!—in the sky. The real trick then happens. You take that picture of the laser beam, which has been distorted by the earth’s atmosphere, and you bounce it off a fun-house mirror that is warped precisely so that the picture of the
laser is as sharp as you know it is supposed to be. And then you do it all over again one-hundredth of a second later, using a different fun-house mirror shape, as the roiling of the earth’s atmosphere distorts the laser beam differently. If you can get all of the laser light going in the right place and the computers calculating fast enough and the fun-house mirrors warping accurately at your command, you can then take a nice long picture of the sky, and you will see a beautiful pinpoint of a laser beam, just as you shot it. That would be a lot of work just to see a laser beam; but if you pointed the laser beam directly at something else in the sky that you really cared to look at, you would also be perfectly correcting the light coming from that object, too.

  One of the very first times that Antonin and the rest of the team hard at work at the Keck Observatory got all of the pieces in place and pointed up to the sky to test things out, they looked at Santa—and they found that Santa has a moon. We named it Rudolph.

  Discovery of moons is extremely helpful, since it means that you can weigh the object using simple high school physics. Once you know how far away the moon is from the object and how fast it goes around the object, you’ve got all the information you need. Now that we knew that Santa had a moon, we only had to observe it a few more times and we would know how fast it was moving and how far away it was.

  For me, all this meant was a lot of waiting. The first ticking clock was, strangely enough, that of our own moon. Because the laser system that Antonin was working on was still experimental, no one wanted to potentially waste the most valuable observing time. The laser was allowed to experiment on the telescope only when the moon was full—when it was bright time and many of the astronomer’s favorite targets in the sky were washed out by the glare of the moon. So though we knew about the moon of Santa quickly, we didn’t get our second look until twenty-nine days later, when the earth’s moon came around full again.

  After twenty-nine days Rudolph had moved, but we now had no idea if it had gone around several times and come back or if this was still its first revolution. We had to wait twenty-nine more days to get our next look. At this point it was close to where we had seen it the first time. This would all make sense if the moon took about fifty days to go around Santa, but I couldn’t be certain for twenty-nine more days. The fourth time we saw it, we knew for sure: Rudolph goes around Santa every forty-nine days. It took one final measurement for confirmation to make sure we had the distance down, too. Combining the time period of the orbit with the distance from Rudolph to Santa allowed us to know that Santa weighs only one-third as much as Pluto. It was a relief, almost. We had finally been careful not to get our hopes up too much.

  Just because there was Santa’s moon to track and due dates to fret about and Xena to anticipate, it didn’t mean that new pictures weren’t rolling in every night.

  The universe speaks to me in strange ways. One day when I was in graduate school, two of my best friends who didn’t know each other separately told me that they were each expecting their first child. Strange, I thought, when the second friend told me. What could this mean? What is the universe telling me? I thought about it for a while and came to the conclusion that, clearly, this meant that my sister, who had been married for several years by this point, must be pregnant. What else could the universe be trying to say? I talked to my mother that very night.

  “I think Cammy is pregnant.”

  “What?” my mother replied. “Have you just talked to her?”

  “No, the universe told me.”

  My mother never quite knows how seriously to take me.

  When my sister called my mother the very next day and said, “Mom, guess what?” my mother said, “You’re pregnant.” My sister was extra flabbergasted when the answer to “How did you know that?” was “Mike told me.”

  When my sister called me, she asked, “Are you studying astronomy or astrology?”

  Apparently my communication with the universe is not always so reliable—I just missed the signs this time. Petunia was growing. Rudolph was revolving around Santa. Xena—mighty Xena!—was swinging toward the night sky. The universe was presumably trying to warn me what I didn’t learn until April 3. While sorting through pictures from a few nights earlier I saw the brightest thing on my screen ever. Brighter than Xena. Brighter than Santa.

  “Here we go again,” I thought.

  The subject line of the e-mail that I sent to Chad and Dave was:

  raining = pouring

  It was raining so hard that I was in danger of drowning.

  We named this new object, found two days after Easter, Easterbunny.

  Easterbunny was so bright that it was probably bigger than Pluto, too, or maybe the same size. We quickly took a look at it with the Keck telescope and realized that, like Xena, Easterbunny had a surface that looked like Pluto’s. The solar system had gone from one to two to three Pluto-like objects in just three months.

  I almost felt bad. This was too much! How was I going to give everything the attention that it deserved? I needed a plan, now.

  Our goal was to follow good scientific practice and announce the existence of these objects to the world with a full scientific account in a scientific journal. But full scientific accounts take time. We had done well with our previous discoveries. Quaoar had taken about four months from discovery to scientific paper. Sedna had taken about the same. We were pretty proud of our speed. But even if we could keep up the fast rate, we suddenly had Santa and Xena and now even Easterbunny to write papers about.

  David and Chad and I made a plan. Santa had been discovered first, and we knew the most about it already. We would each write papers on different aspects of it. Whenever the first paper was finished, we would have a low-fanfare announcement. We knew that Santa was smaller than Pluto, and we didn’t yet know all of the details of Santa’s massive collision and debris field, so we thought there would not be too much interest in it for the public. My goal was to get a paper on Santa finished before the birth of Petunia, since I still had a little free time. Her due date was now only three months away.

  We would then save the big excitement for Xena and Easterbunny, which were sure to cause a stir. We were scheduled to be at the Keck telescope in September to get a first really good look at Xena. With some intense work we could have a scientific paper ready a month after that (the delusions of first-time parents astound me to this day) and make the announcement around the beginning of October. I liked this back-to-school timing, as I thought having the announcement of one or two new objects bigger than Pluto would be the sort of thing that schoolkids would think was cool to talk about in class.

  The plan required writing perhaps the three most important scientific papers of my life in under six months while having my first child. No problem, I thought.

  Diane was having that last spurt of energy that comes in the weeks before delivery. The spare bedroom, which for years I had dubbed the “bike and computer room,” was suddenly transformed, with a crib and pale green walls and a collection of infant clothes waiting for an owner. I acquired a bit of sympathetic energy and redoubled my writing efforts so I, too, would be ready for Petunia. We were going to pull it off, as long as everything went as planned.

  Chapter Eight

  LILAH, AN INTERMISSION

  On Thursday, July 7, 2005, I decided to do something that I almost never did—stay home to get work done without the distractions of the people who kept stopping by my office to check on plans for Santa or Easterbunny or Xena, or to chat about nothing in particular. I had about one more day of work to go before I was finished with the first scientific paper about Santa. According to my calculations, Petunia was due within the next few weeks, so I wanted to get the paper out in the next day or two, just to be safe.

  Rumors were already starting to circulate within the astronomical community that we were onto something big, and publishing the announcement about Santa quietly seemed like a safe way to deflect attention from the real big announcement that was soon to come.r />
  The Thursday that I stayed home, Diane was at work in what was to be Petunia’s room, putting some last touches on the decorations and furnishings, but I noticed little, since I was deep into the analysis and the explanations in my head. Still, at some point I noticed an unusual groan/sigh from the other room.

  “What was that?” I called out to Diane.

  “I’m just having a little cramping today. The doctor said I was supposed to expect something like this,” said the ever-cool Diane.

  “Are you sure? I’ve never heard you make sounds like that before.”

  “Nah. Just what the doctor warned.”

  I suggested that, for fun, we do a labor dress rehearsal. I would write down when Diane had little cramps and time them just as we would the real thing.

  “Fine,” Diane said, humoring my usual need to assign concrete numbers to everything going on around me.

  I went back to work, a little more distracted now.

  Fourteen minutes later, I heard the sound again. I remembered my birthing classes. Fourteen minutes was a pretty long interval. There was nothing to worry about. I was not even supposed to really begin timing things until the contractions were less than ten minutes apart. Even then, if contractions are more than five minutes apart you probably have many hours to go. The best thing to do is go on with whatever you should be doing instead. Like finishing a paper.

  Diane nonchalantly replied, “Well, you missed the one in between.”

  What? That would make the contractions six minutes apart. And six minutes later, there was another.

  “Umm, Diane? Could this be for real?”

  Diane didn’t think so but suggested that we pack our bags just in case if it would make me happy.

  By the fourth contraction, I decided that I needed to be keeping track down to the second and I also needed to count the length of each contraction. Five minutes and twenty seconds, lasting fifty-one seconds. I started writing down the strength: stronger, really mild, strong, supermild.