The Best American Science and Nature Writing 2020

by Michio Kaku

  By 4:30, the slew was complete, and the brightness of the galactic plane was out of the way. Brown asked Batygin to read out the numbers.

  “Yep! 7715 is 0.8. 7516 is 1.0. 7515 is 0.7. 7518 is 0.8.” They continued coming in under 1, a relief. Joking in the room resumed. An observer asked Batygin how they process the data after they return to Caltech, to which he replied, “Well, we have these algorithms—”

  Brown interjected: “We have algorithms? Uh, no. I have spent most of my life writing these programs. This is not stuff you can get at the App Store.”

  “You should sell your algorithms on Google Play,” joked Batygin.

  “Ninety-nine cents,” said Brown, with a slight roll of his eyes. “Give me more numbers!”

  At 5:50, we heard another “cuckoo!” The dome began to close and the team packed up the Pop-Tarts and gear. Despite the 1.4s, the night marked the first successful collection of data in more than a year. All anyone could talk about was breakfast. There wasn’t any coffee at the summit, and warm eggs, potatoes, sausage, and enough coffee to fill a bucket was all that anyone wanted.

  The beauty of leaving the summit after 6 a.m. was that it took around twenty-five minutes to get back to base camp: just enough time to watch the sun come up. In just under a minute the dark gray of twilight was swept away. The air was grayish blue, the rocks I had felt under my shoes earlier were a burnt umber, small and light. On Mauna Kea, the sun does not just rise, it cracks the sky open with an almost blinding yellow that is quickly seized and destroyed by an even brighter orange. Every second new colors appeared as banded layers of horizontal clouds. What I once understood to be light blue was slightly more light blue. It met and danced with lavender that bled like watercolor into mauve, then a soft pink. As we left the parking lot and started to drive down the mountain, other telescopes appeared. They were everywhere. Suddenly white and glossy silver, their towering domes stood atop the reddish soil of the peaks. They were massive. As we drove, the car shook from side to side from the road, like being in a paper airplane played with by the wind. We passed the red mounds of ancient volcanic vents that stood there, markers of lost time. The clouds, like the whitish gray of an old cobblestone street, lingered in the valley below, and suddenly the purple sky began to turn.

  Hale Pōhaku. Tuesday, December 4, 2018. 7:30 a.m.

  The living room just outside the cafeteria had a Christmas tree and completed jigsaw puzzle that looked like it had been baking in the sunlight since the dorms opened in 1983. There were three couches and cozy green chairs and a fireplace with red and white stockings, hung mostly with care. Batygin spent the day back at the dorm, first trying to figure out if a passing star could have perturbed Planet Nine, placing it into its weird orbit. Brown sorted through data from other telescopes trying to—​surprise—​find Planet Nine. He has spent nearly every free moment in Hawaii combing through data from the ZTF instrument on Palomar’s Samuel Oschin Telescope, the same telescope he used to find the dwarf planets that made him as famous as an astronomer can reasonably expect to be. So far anyway. Lunch was served at 1 p.m., but it would be our dinner. We would go to sleep at 3:30 p.m. and wake up at 11 p.m. to go back to the telescope.

  The guys had no idea if they would find Planet Nine that week, and Brown’s mood oscillated accordingly. After they got back to Caltech and received the data from the headquarters in Tokyo, they would rely in large part on machine learning to sort through the roughly 160,000 images they’d have. They would take their list of candidates and run it through the computer, and any that came up as possible Planet Nines, as many as 1,000 images, would then be looked at in the old school way: by eye. They would be looking for a tiny speck of moving light. “If ever there were one barely crawling across the screen,” Brown told me, “it would be an ‘Oh shit, that’s it’ moment.”

  This search was different from Brown’s previous endeavors. “For my entire career what I feel like what I have been doing is exploring the solar system,” he told me. “It never occurred to me that there was more primary exploration left to do. So finding Planet Nine is the grandest exploration that can be done of the solar system right now. I wouldn’t want to be doing anything else.”

  “I agree with everything Mike said,” added Batygin.

  “First time today!” Brown replied.

  “Cherish it. It’s not going to happen again.”

  Batygin feels confident that the planet is there. It is not just the evidence of these clustered objects, but after four years of simulations and doing calculations that look like they are in some alien language, he feels that his equations confirm that this is a large mass object that is shepherding these objects into place. Planet Nine is doing this. He wants to know that his math is right, and the detection of Planet Nine would do that: “There’s a different thrill here for me which is actually the thrill of refutation of confirmation. With theory it’s almost like it emerges out of nothing. And really it’s only in our heads, it’s not something that we have seen before. It is a pure outcome of imagination and there’s a thrilling magnetism to that because that imagination might be right. For me that is the most amazing thing, being guided only by mathematics.”

  “I’ve never worked on a problem that’s taken this long,” Brown told me. “It is really difficult to sustain this effort for one singular purpose. It’s hard. Sometimes I think, let’s just find it so I can do something else, I’m tired of this stupid planet. That’s the hardest part for me other than the frustration of not knowing where to find it.” Batygin agreed. “There have been a few times in the last few years that I actually stopped working on Planet Nine,” he said. “I had moments where I felt like I was getting over-obsessed with this and kind of going in circles so I would make the conscious effort, for the next two months I’m not going to think about Planet Nine, how about magnetic fields of young giant planets or the Schrödinger equation? I took my mind off of things so I could come back with renewed enthusiasm.”

  “There is only one way to win this survey, and that is to actually find it,” Brown continued. “The correct analogy is that there’s this singular somewhere in the ocean and you don’t know where—​there is only one giant white whale and you need to go kill it because it bit your leg off. Sadly, I think that’s the right analogy.”

  Hale Pōhaku. Tuesday, December 4, 2018. 11:15 p.m.

  Every morning Brown selects a playlist for the drive to the summit. It is usually five songs long, which is about how long it takes to get to the telescope. Brown connected his phone as Batygin, who was driving, switched the car into four-wheel drive and Cake’s 1996 hit “The Distance” began playing. We climbed the rest of the way up the mountain listening to Eminem, Kanye West, Lynyrd Skynyrd (Brown is from Alabama), and Jon Bon Jovi (they attempted the high notes).

  When we arrived at the summit it was windy, much more than the day before. These were fifty-mile-an-hour gusts, close to the maximum the telescope could take. The upper atmosphere was turbulent too. The first batch of numbers came in all over 2.0, which was very, very bad. While they waited to see if the winds calmed down, Batygin sketched out a graph and an equation in Greek. He kneeled on the floor next to Brown and asked for his help. Despite the fact that when we arrived at the summit we were warned that the altitude would make it harder to do calculations, what Batygin had in his notebook was black-belt-level math, he solved it without seeming to break a sweat. Brown checked the numbers: “We’re getting these 2.6s and 2.9s, and these I declare to be shit.”

  “Hold on, I’m still not oxygened up,” said Batygin.

  “What is 4319?” Brown asked, referring to one of the fields they had just imaged. “You’re showing 1.7, I’m showing 2.2. Can you check?”

  “Yeah,” Batygin replied. “It’s 2.2. Sorry, got that wrong.”

  “Please put on your oxygen.”

  Batygin placed the plastic tubes into his nose and, like putting on a cool pair of life-saving sunglasses, slipped the rest of the plastic tubing over his
ears, and took a deep breath of that “sweet, sweet oxygen.” The control room computers had readout charts on the screens that showed wind speed and upper atmosphere turbulence as a red spiky graph, literally off the charts. Because of Planet Nine’s slow pace across the cosmos, these 2.0s and higher were useless data. They were looking for a barely visible point of light; if the stars were blurring out all over the place, Planet Nine would remain hiding. “We are not collecting data that is worthwhile,” Brown said as he began putting together a backup plan for his backup plan. In their three years of using Subaru they’ve had, as Batygin puts it, “pretty shitty luck.” Not only has the weather been unpredictable and rainy, but, in May 2018, the nearby volcano Kilauea erupted, destroying more than 700 houses and displacing roughly 3,000 residents. There was concern that sustained seismic activity also meant that Subaru and its camera might be rendered useless for a good portion of the year, leaving the team without an opportunity to observe. Plus, sometimes the weather is so bad on the summit, they can’t even go up. “Last December we were sequestered in astronomers’ headquarters and hoped that it would stop hailing.” Batygin said. “We didn’t collect one image that whole run. It was really disappointing.”

  The team checked on the numbers again, which were climbing beyond 2.5, nearly killing Brown every time. Just short of defeated he said, “Three arc seconds and I’m going to the beach,” then requested more numbers.

  “Okay, this is a record-breaker, are you ready?” asked Batygin.

  Brown, resigned: “Yeah.”

  “3.3.”

  The entire room shouted: “3.3!”

  “In all my twenty-five years of observing on Mauna Kea I have never had three arc seconds,” Brown said. Numbers this bad were like turning this gigantic 8.2-meter telescope into a one-meter telescope; it would be impossible to find Planet Nine like this. Brown sat at his computer, arms crossed, and said, “The seeing is crappy, but the good news is clouds are coming in!” Indeed a ghostlike cloud was creeping over the valley and heading straight toward the summit. They waited another twenty minutes or so before Brown asked how it was looking.

  Batygin: “Okay, now this is a record. Are you ready? 4919 is 3.8.”

  Entire room: “3.8!”

  Brown: “3.8!? 3.8! I think . . . I officially declare failure, which will significantly influence the music mix on the way down.”

  At 4:10 a.m., Brown and Batygin decided to try the other side of the galactic plane, in the hope that the seeing would be better, and indeed the numbers improved—​back down to 1.3s and 1.5s. One of the tricky and interesting things about if this planet exists is that if they find it, they will have absolutely no idea how it got there. While snacks were consumed and the room filled with a symphony of yawns, Batygin stared into space. He was doing the opposite of what one should do at 14,000 feet—​thinking, writing code, and doing some complex math to try to figure out how the movement of our galaxy and passing stars could have affected Planet Nine over time in order to determine the planet’s location. By 5:20 a.m. the numbers were staying low, which was just enough to save this batch. At 5:51 a.m. we heard a cuckoo. The morning’s drive-down-the-mountain playlist appropriately began with the Rolling Stones’ “(I Can’t Get No) Satisfaction.”

  As day broke, the sky filled again with purples and pinks, the colors of dreams. We drove down the road and watched the landscape change: small reddish rocks turned into boulders remaining from the Ice Age, when these mountains were once covered in glaciers. A third of the way down, a random shrub appeared alone next to the road. As we approached Hale Pōhaku, small bee-size yellow wildflowers danced left to right in the breeze, and tall stalk-like plants nestled into the ancient volcanic rock. Anyone would say it was beautiful here, the thick marshmallow clouds hovering in the valley below, always threatening the mental well-being of the astronomers watching out the window.

  Back at base camp, around the same round table with the nylon tablecloth, Batygin and Brown reflected on the previous four years. “We had this conversation about a year ago,” said Batygin. “We were driving up to Mauna Kea, and Mike was like, ‘I think . . . this is kind of weird,’ and it is at the end of the day. It is weird because we get on a plane and we go to a beautiful island and instead of spending time like normal people do in Hawaii, we go to the only part of the island that is completely dead, and we stay up all night looking at the sky trying to find something that basically we imagine to be there. It’s a strange behavior but man, it’s so satisfying.”

  * * *

  I left Mauna Kea on Wednesday afternoon, right as the team was due to go to sleep. They observed five more nights and the weather cooperated for all of them. It was the first meaningful collection of data in more than a year. I waited until they both got back home to call and find out how it went. I spoke to Brown first. It had been just over two weeks and all of the images collected from the week of observing had not yet reached his desk at Caltech. “I’m depressed,” he said. “I’m in my we’re-not-going-to-find-it mode.” If they don’t find it this time, Brown said, “it’s perfectly plausible that we’ve pointed in the right direction and we’ve missed it.”

  Two more weeks passed, a new year arrived, and with it came their data. I asked if they found it but so far, Planet Nine has not made its big debut. They are just starting to sort through their data, though. There is still hope. The trip wasn’t exactly their last chance to find Planet Nine. They’ll return in February for another round of observing. If they don’t find it then? “We will just keep going,” Batygin told me, “and by ‘keep going’ what I mean is wait for LSST.” The LSST is the Large Synoptic Survey Telescope, which is being constructed in the Chilean desert. It will be fully operational in 2022; its mirror will be even larger than Subaru and will scan the skies every possible clear night. If Planet Nine is out there, this thing will find it. And at first, it will likely discover hundreds more long-period Kuiper Belt objects that will point the team to the direction of Planet Nine.

  “There’s a 5 or 10 percent chance anytime you look you’ll miss it because there’s a star in the way,” said Brown, “but you know, it just means—​increasingly when you don’t find it you have to wonder what the heck is really going on here. I don’t think the answer is that there is no Planet Nine; certainly the phenomena that Planet Nine does are not going away. I don’t think there’s any other solution aside from Planet Nine to explain those phenomena so the question is, why are we potentially failing in our prediction of where it is?”

  Batygin said that finding Planet Nine is so difficult that it is not just like searching for a needle in a haystack, it is like “you’re also looking for it with the lights off and a bunch of fog and your calculations tell you that there should be one more needle in this room somewhere.” Can the effort be worth it? According to Brown, yes. “This is like first-level exploration of our solar system. This is like, finding a new continent,” he said. “It’s hard to imagine that any effort that I could actually put in would be ridiculous if we can actually find this thing that’s in our solar system that nobody knows about.”

  Batygin said, “It’s really easy to miss something when you’re scanning the sky once, it’s true when you’re looking for the One Thing. We may or may not find Planet Nine, and of course if we find it, great, if we don’t find it then it doesn’t really mean anything.”

  If they do find their planet, our daily life will mostly remain the same. Sure, mobiles over children’s beds might have nine planets putting them into a peaceful sleep; science textbooks will have to be edited and books about our solar system rewritten. But after the hullabaloo of the news cycle and the introduction of a new planet to all of humankind, things will go back to normal. But for science and the field of astronomy, it will help complete a puzzle and make for many new ones as well. If Planet Nine exists, and if it is found, not only will it serve as a way to understand the bulk of exoplanets that have been discovered around other stars, but it will also help us understand the
history of our own solar system; it will help us understand more of how the planets came to be and why they settled where they did. It will be one of the twenty-first century’s greatest scientific discoveries. We have no idea what a six-Earth-mass planet looks like. Uranus and Neptune are fourteen and seventeen Earth masses; Mars is ten times less massive than Earth. There is nothing in our solar system that size. Six Earth masses could essentially be a core of a planet like Uranus and Neptune, and if Planet Nine exists that is likely its story. The team thinks that during the early days of the solar system, when the outer planets were forming, there was an additional planetary core, near where Uranus and Neptune were growing. But somewhere in those early days, the third core somehow got flung out by a gravitational interaction with Jupiter or Saturn, and as it was heading out of the solar system, became trapped by the gravity of the sun. Since that time it has been orbiting in the distant solar system, silently sculpting Kuiper Belt objects, marking evidence of its existence. If these objects do in fact point to Planet Nine, it will have been quite the planetary smoke signal, one so unlikely to be found.

  And they’re not the only ones who’ve been scooped when searching for something. In January 1613, while observing Jupiter and its moons, Galileo caught a glimpse of what he thought was a “fixed star.” He marked a dark spot in his notebook and moved on. He had unknowingly detected the light from Neptune. And just months before Le Verrier predicted its existence, an observatory in England detected it three separate times, noting it as a star. Batygin takes comfort in facts like these. “When there is one thing you’re looking for in the night sky—​even the world’s best astronomer, which certainly Galileo was really good—​you’re going to miss it the first twenty-five times,” he said.