How I Killed Pluto and Why It Had It Coming

by Mike Brown

  After Quaoar, I learned an important lesson. Names should be pronounceable. In the end, when it was time for a real name for Dutch, I settled on Sedna. Sedna is simple and easily pronounced, and has a serene sound to it.

  The name Sedna comes from Inuit mythology. Since Dutch was so far away from the sun and was the coldest object anyone had ever seen in the solar system, I was looking for a name from an appropriately cold region. I quickly settled on Inuit as the closest polar mythology to my home in Pasadena. Sedna is the goddess of the sea. She lives in an ice cave at the bottom of the ocean, which seemed pretty cold to me. Plus the name has only two vowels—and they are not in a row. She does not, however, have a pleasant backstory.

  In Inuit mythology, Sedna was a young girl who refused to marry any of her many suitors. Her father finally forced her to marry a mysterious stranger who couldn’t be seen beneath his cloak. The stranger was a raven, who took the girl back to his nest. Her father finally heard his daughter’s screams and, filled with remorse, crossed the sea in his kayak to rescue her. As he was paddling her away, the raven appeared and caused a great storm.

  A typical story line in mythology goes as follows: The father sees the error of his ways and saves his daughter; the evil suitor attempts to take her back; the father vanquishes the suitor. In the Inuit myth, however, things go slightly differently.

  The father, fearing for his own life, throws his daughter overboard into the storm and back to the raven. The girl begins to sink. She grabs the side of the boat to hang on to. The father takes out his knife and cuts off her fingers to keep her from climbing aboard. The girl sinks and becomes the goddess of the sea. Her fingers and thumbs become the seals and whales of the ocean. She is angry much of the time—understandably so—and causes storms to thwart the hunters. But she is soothed when a shaman swims to the bottom of the ocean and brushes her hair (having no fingers, she can’t hold a brush), and then she relents and lets hunters safely venture again. I hope Sedna is happier now, at the bottom of the ocean, and, especially, up in the sky, than she was with her creepy father or raven husband.

  Contemporary Inuits make fantastical carvings of their mythological figures. The weekend before the press conference at which I was going to reveal Sedna to an unsuspecting world, I signed on to eBay and found that Sedna carvings could be had for a few hundred to a few thousand dollars. To celebrate the discovery, I bought what to me was a particularly nice—and particularly affordable—carving in which Sedna has the body of a seal, the arms of a woman, hands with no fingers, and a mermaidlike face. The Sedna carving sits in the center of my desk to this day, surrounded by other mementos of planetary discovery. The eBay bidding on the Sedna carving closed on Sunday night. The press conference was on Monday. By the end of the day on Monday, I checked and saw that prices of Sedna carvings had gone up by a factor of two. Yes! Maybe I had a future in Wall Street insider trading when discoveries in the solar system finally came to an end.

  The name was a hit. I was surprised to discover that a good name with an interesting story behind it could lead people to have an emotional connection with an unseen object in space, though perhaps it shouldn’t have been such a revelation to me, given people’s attachment to Pluto. Quaoar never really caught on, but Sedna struck a nerve. Newspaper headlines proclaimed, “Welcome Sedna!” My mailbox began to be flooded with drawings from schoolkids who crayoned in nice red Sedna in the solar system right after Pluto. Astrologers quickly hit on the story of Sedna to declare that Sedna would herald a new feminine influence over environmental stewardship. Or awareness of child abuse. Though none of the astrologers agreed with one another, they certainly found the name and the story compelling.

  The only problem with the name was that I had jumped the gun and broken the astronomical naming rules.

  This was not the first time I had broken the rules. When I announced the discovery and name of Quaoar, it turned out that I had not sought approval through the proper channels in the International Astronomical Union. I didn’t realize that I was supposed to have tracked down the Committee on Small Body Nomenclature of the International Astronomical Union and proposed the name, allowing the august committee to deliberate and declare whether or not my name was appropriate. Luckily, the name Quaoar was perfectly appropriate, so the CSBN of the IAU promptly approved the name without my having gone through the channels, though eventually it did make me fill out the official form.

  No harm done, and it seemed to me that nobody cared much. At least, that’s what I thought.

  Unknown to me there was a group who cared a lot. Somewhere in the far corner of the Internet was a chat group composed of astronomy enthusiasts who had appointed themselves the celestial police. I didn’t know they existed until one day a student of mine pointed me to their chat site with the comment “Wow, they really hate you, don’t they?” And it did seem as if they hated me, or at least felt that antagonistic indignation that can be pulled off particularly well on the Internet.

  They were angry because with Sedna, I had not only broken the rules, I had done so on purpose. At the time of the announcement of Sedna’s existence, we didn’t quite have enough data for Sedna to officially qualify for a name—it would take us another few months to have what we needed. The rules on when an object qualifies for a name are obscure, uninteresting, and designed to keep names from being given to insignificant asteroids that are seen a few times, then never again. Nonetheless, they are the rules, and to the zealous enthusiasts, they must be followed at all cost to prevent astronomical chaos from breaking out.

  I admit that in the week before the announcement, even I worried a bit about breaking the rules. I am, by nature, a rule follower. But I really wanted Dutch to be Sedna in time for the announcement. I thought it mattered—and, it turned out, based on those crayon drawings, it did. Finally I decided I would buck the rules, though politely. I called Brian Marsden, an astronomer at Harvard University who was, in my opinion, the gatekeeper of the solar system. He was the person to whom you sent the very first announcements of discoveries. He checked that your calculations were right. He put your discovery on the official list. And he was always the first to be amazed and say, “Wow! What a great discovery.” Brian was also the secretary of the Committee on Small Body Nomenclature. I told him what I was planning to do. He asked if he could tell the chair of the committee ahead of time. Of course, I said. Everyone agreed that a name was a good thing and that Sedna was a good name.

  To the chat group, though, I was a rule breaker in need of punishment. One particularly agitated enthusiast tried very hard to prevent me from officially naming Sedna Sedna. Before Sedna was quite eligible for an official name, he proposed, through the official channels, that an unremarkable, hitherto anonymous asteroid—which was nonetheless eligible for a name—be named Sedna, after the Inuit goddess of the sea. No two things in the solar system can have the same name, so my Sedna would have had to get a different name.

  “Rejected,” declared Brian Marsden. Names of important mythological figures would be used only for important astronomical objects.

  The enthusiast next proposed to name the unremarkable asteroid after Kathy Sedna, a Canadian singer.

  “Clever,” responded Brian Marsden, who, being in charge also of when things are eligible for names, quickly realized that my Sedna was now eligible and made sure the name became official.

  I found all of this pretty amusing at the time. It was proof to me that names do, in fact, matter, and I even found it moving that there were people who cared so much about the details of scientific naming. I didn’t know that in just eighteen months some of these very people would have a hand in almost stealing the most important discovery I had ever made.

  Sedna remained Sedna. And with all of the crayon drawings showing Sedna’s rightful place in the solar system, Sedna was surely a planet, right? It’s true that I had argued against Quaoar and Pluto being planets on the basis of their being in the middle of swarms of similar objects. To me, it made no se
nse to pull one or even a few objects out of the swarm and call them something other than part of the swarm. But Sedna was, as far as we knew, all by itself. There was no swarm of objects out in the region of space where nothing was supposed to be found. Couldn’t it be called a planet? That, too, made no sense. Sedna would eventually be found to be part of a swarm, too. If we called Sedna a planet now, when that swarm was finally found, we would have to go through the process of planetary argument all over again. It seemed better to put Sedna in the right place to begin with.

  Besides, Sedna was smaller than Pluto. In the beginning, we had been certain that Sedna would be bigger than Pluto. It was so bright! But when we finally got a chance to look at it with the Hubble Space Telescope, thinking we would get to see a little disk of a planet, all we saw was a tiny point of light, and that tiny point of light told us that Sedna was no more than about three-quarters the size of Pluto. How could that be? The answer is always the same: albedo. Sedna has an even more reflective surface than Quaoar, so part of the reason it is so bright is simply that reflectivity. Still, three-quarters the size of Pluto is big! No one else alive had ever found anything bigger in the solar system. But finding bright things that are almost certainly bigger than Pluto only to realize that, well, no, they aren’t actually bigger after all, gets old.

  I hadn’t thought about it for a while, but it had been four years since my bet that someone would find something bright enough to be called a planet within five years. Much had happened since that bet. We had found Quaoar, at half the size of Pluto; Sedna out where the solar system was supposed to end; and dozens of other smaller objects that were nonetheless among the biggest things anyone else had ever seen. But we hadn’t found anything yet that would qualify for the bet to be won.

  We announced the discovery of Sedna in February 2004. My bet ended on December 31. I had a little more than ten months to find something truly large, or I was going to lose.

  I hate to lose.

  And even worse than losing, I hate being stupid.

  One thing nagged at me. I had almost missed Sedna. Sedna is so far away and therefore moves so slowly that the computer program I had written had almost ignored it. If Sedna had been just a little farther away and therefore moving just a little more slowly, we would never have found it. My computer program would have declared it to be a stationary star and kept searching. If Sedna was there and had been almost ignored, couldn’t there be something far out there that had been ignored? Finding such distant things would be crucial for testing my hypothesis about the birth of the sun and the odd population of distant objects that would have been created. But also, if we can see things that far away, they have to be big. It occurred to me that one of the best places to look for planets might not be in the remaining unexplored parts of the sky but in the many, many pictures I had already taken. If there was a planet already there that I had missed the first time around, I would, indeed, feel I had been stupid. But as I had learned earlier, the trick was not to figure out how not to be stupid, the trick was to be smart instead.

  I spent most of that summer in my office slouched in front of my computer screen, writing, testing, and rewriting software. About halfway through the summer, one of the other professors on my hallway started commenting.

  “You never move,” he said.

  “My fingers move.”

  In fact, my fingers moved a lot. I had thoroughly rewritten all of the computer software. Chad had written the first version without the benefit of having any of the data at the time. With the luxury of data, I could rewrite it to work better, run faster, search farther, and see fainter objects. I was ready. I started spending my days not just looking at the new pictures coming from the telescope the night before but also scanning the thousands of pictures that I had stored on the disk drives of my computer.

  Someone watching over my shoulder that summer would have seen an incredibly monotonous sight: Mike presses a button; a new series of images begins blinking on his screen; he stares for three seconds; he presses a button marked “no”; new images appear.

  I did this for hours a day. My posture got even worse. My back ached. But I was discovering things in the old pictures. The first time around, we had missed a lot. This time, I didn’t want to miss anything.

  I think of this period in the fall of 2004 as one of the most fertile in my life. Still, though, there were no planets, and I was losing my bet. I was working longer hours, sleeping less, all in the hope of getting through all of the data before the end of the year. I really did not want to lose the bet. If there was something to be found in the old pictures, there was nothing, absolutely nothing, that would stop me from finding it. Well, almost nothing.

  At the beginning of December, taking a rare break from looking at my old pictures, someone else showed me a picture of something I had never seen before. The moment I saw it, my mind flashed back to images I remembered having seen in high school. In 1982, a Russian Venera spacecraft sent back the first—and still only—color pictures from the surface of Venus. Venus is a tough place to take pictures from. The surface has an atmospheric pressure ninety times higher than the earth’s and a temperature of more than eight hundred degrees, which would melt the lens of any camera. The Russians therefore built the camera inside a giant can to keep the extreme pressures and heat out as long as they could. To see Venus, a periscope popped out of the can and scanned around. Even so, the whole contraption lasted only two hours before it died.

  The pictures that the Russians sent back from Venus have a peculiar characteristic to them. Because of the periscope, they are oddly distorted, as if they had been taken by a fish-eye lens. Because of the thick clouds of sulfuric acid that cover Venus, among other things, the color pictures have an oddish orange glow and appear almost to be black and white. They are hard to mistake for almost anything else.

  I had been spending most of my time those past few months staring at a huge computer screen hoping to be the first person ever to see a new big thing moving through the distant regions of space. That morning, I stared at a smaller screen and examined a black-and-white image with an orange tint to it and an oddly distorted view like that through a fish-eye lens. It wasn’t Venus. In the middle of the oddly distorted view was a little bean-sized object. Looking at the sonogram, Diane and I, along with our doctor, were the first people to see the tiny movements of a little heart beating.

  “Hey!” I said. “It looks like the Venera lander pictures of the surface of Venus.”

  “You’re insane,” Diane said.

  We told our families on New Year’s Eve. Mine were visiting from Alabama. Diane’s lived in town. Everyone sat down to dinner.

  I began: “Before dinner, I’d like to make an announcement.”

  I had been saying this at every family dinner since Diane and I had been married. I usually then proceeded to say, “It’s time to eat.” People who are regulars at our dinners barely look up while awaiting the now-tedious punch line.

  My family, however, had never heard the joke. They gasped slightly. Diane’s father quickly interjected, “He says this every time, just ignore him.”

  Everyone calmed down and ignored me, until I said, “We’re expecting a baby girl in July. Her real name will come later, but her current code name is Petunia.”

  That night, as the clock struck twelve, my five-year bet came to an end. I lost the bet, but I didn’t feel so bad. Instead of seeing the end of the solar system, I saw that everything was just beginning.

  Chapter Seven

  RAINING = POURING

  The next morning, January 1, 2005, my whole household woke up early to walk down to the Rose Parade, which winds its way through Pasadena every New Year’s Day. In the still-dark early morning I was awake in time to find Jupiter bright in the sky before the sun came up. Jupiter, Saturn, Uranus, Neptune, Pluto. That was it: the end of the planets.

  Maybe.

  Unbeknownst to anyone—well, except for Diane, to whom I told everything, and my parents, w
ho were visiting, and all of my students, and a few friends here and there—two days after Christmas I had discovered the brightest thing I had yet seen. I didn’t know for sure how big it was, so I was not in time to win my bet, but something that bright might well be a planet. In honor of the season when it was discovered, I called it Santa.

  A few years earlier, my first reaction to the discovery of Santa would have been: I bet it’s bigger than Pluto! I’ve finally found the tenth planet! By now, though, I was a bit more skeptical. Quaoar and Sedna had both fooled me with their anomalously frosty surfaces, which made them appear much brighter than I expected. But even if Santa’s surface was as anomalously frosty as Sedna’s, it would still mean that Santa was the size of Pluto. But what if Santa were even frostier? What if Santa was covered in, say, pure ice, which would make it even shinier and brighter than Sedna? I wasn’t going to get my hopes up too much.

  I sent e-mails to Chad and David telling them what we had found. I was careful not to definitively declare the discovery as bigger than Pluto, but I did mention that if it had a dark surface—as we had long assumed most objects in the Kuiper belt did—it would have to be almost as big as Mercury.

  Over the next week, Chad, David, and I raced to see who could find old pictures of Santa to figure out what kind of orbit around the sun it had. Chad won and declared the orbit thoroughly normal. “Normal” in the case of the Kuiper belt means elliptical and tilted, but still within the swarm of all of the other Kuiper belt objects. After the oddness of Sedna, this normal orbit was almost a relief. At least something about the Kuiper belt was making sense.