The photographs make me shiver. Antarctica. Vast white mystery. The snow an endless slick of white, broken only by gray rocks on the coast and blue-shadowed glaciers. Ninety percent of the world’s ice is here, yet because Antarctica is so dry—the coldest, windiest, iciest, driest place on Earth—the continent is categorized as desert. I close my eyes and imagine the silence, the only sounds for miles the haunting trill of a Weddell seal, the soft tap of penguin feet, or the ominous crack of an iceberg.
Antarctica suits my mood; it is, psychologically, what I fear this winter will be for all of us. No burble of conversation on outdoor patios, no meeting for wine with neighbors, just quick shuddery nods and a dash back inside. However will we find the patience? How do researchers in Antarctica endure it? I go to see Brian Rauch, research assistant professor of physics at Washington University, who has spent quite a bit of time in that icy desert. What is it like? How does he endure it?
“Before a supply ship can arrive, they need to send an icebreaker,” he begins. He is not talking about a joke at a cocktail party. An icebreaker is a Coast Guard ship that “either plows right into the ice or glides up on top of the ice and uses its weight to crush it.”
Rauch studies cosmic ray astrophysics, and what he wants from Antarctica is not hope or example, but the building blocks of the universe.
By flying a balloon above 99.5 percent of the earth’s atmosphere, researchers can collect and measure cosmic rays. And if you launch your balloon in Antarctica, with all that cold, dry air, and you do so in December, when the polar stratospheric vortex whips the air into a circle, the balloon will do little daisy chains around the continent for as long as the winds keep it aloft.
The point of this white balloon, rising in a white sky above white snow, is to carry instrumentation that can analyze cosmic rays. Back in 1912, a brave physicist named Victor Hess went up in a balloon, bringing an electroscope with him. He found that cosmic rays’ ionization increased as you went higher. They were not energized by radioactive elements in the Earth, as previously thought. They were extraterrestrial.
Some cosmic rays are high-energy, accelerated here from far outside the Milky Way at nearly the speed of light. Those are the sexy ones, says Rauch. But he is interested in the lower energy, heavier elements that come from our own galaxy, because they carry subtle clues to the cosmos.
This research started with TIGER, an unmanned balloon flight in 2001. Now the team has moved to SuperTIGER, which set a record in 2012 by flying for fifty-five days. “That record could easily stand for the rest of time,” Rauch concedes. But that has not stopped the team from trying, because SuperTIGER is capable of analyzing even the heaviest cosmic rays, which are rarer, so take longer to detect and collect.
In the December 2017 season, the team tried sixteen times to launch the balloon, but the weather refused to cooperate. Rauch spent a lot of those days (and nights, because the sun never sets in December in Antarctica) sitting out on the ice, listening to the wind howl, and hoping.
“How do you bear the waiting?” I ask.
“Practice absurd optimism.”
Finally, the following December, the balloon was able to take off. He shows me a map, a green pin near the Prince Albert mountains marking the end of a soul-crushing disappointment: a flight of only seven hours. After all that waiting, the balloon had a leak.
The team finagled a tricky recovery of the payload (the balloon’s structure, and all its support equipment), which was almost entirely buried in the middle of a crevasse field. Rauch was determined to retrieve it, on the off chance that it would be sufficiently intact to try again the following season.
“Everyone thought I was crazy,” he admits, “but we got lucky.” After a hovering sort of touchdown with a helicopter, they probed the ice and, realizing it was precarious, managed to extract pieces of the payload and fly them a few miles away to a compression zone, ice squeezed together, where it was safe to land a plane. “We got it back, reassembled it, rewired it, and tested it,” Rauch says, just in time to get it out of there before all scientists were shooed off the continent. Winter was setting in.
The team returned in 2019, and a balloon went up on December 16 in what NASA’s Balloon Program Office called a “picture-perfect launch.” Two weeks later, it completed its first full revolution of Antarctica. It stayed up thirty-two days all told, which was good, but after day three, lost half of its instrumentation. The team did not manage to double the 2012 data, as they had hoped. They would try again.
“The galaxy has certain fractions of each element, and its composition has evolved over the history of the universe,” he explains. “When we analyze the composition of all these cosmic rays, it’s going to tell us where the material that makes up our world comes from.” He looks up, meets my eyes. “We will know what made us.”
My breath catches. I did not expect an answer so simple, or so profound.
It does not stay simple, though, when he begins to explain various ways the cosmos mixes it up. There are rare possibilities, mergers of black holes with neutron stars, but what is most likely to send cosmic rays shooting toward Earth is a supernova explosion. Stars live millions of years, even the massive “rock stars” that live hard and die young, he explains. After years of fusion, their core turns to iron, and because fusion to heavier elements no longer creates energy, it collapses. The shock wave of the star’s death is known as a supernova explosion.
“SuperTIGER measurements have shown that the ultra-heavy cosmic rays, the ones heavier than iron, are enhanced with material from these massive stars,” Rauch continues. “The cosmic rays are a very recent sample, only a couple million years old. We believe they come from groups of massive stars that don’t live long enough to spread apart. They die together, but the most massive die first. A more massive star will have died and spilled its material into the interstellar medium that makes up our galaxy.”
SuperTIGER will continue flying and measuring, tracing the rare, heavy elements in cosmic rays that can tell us where they were made. Or how cosmic rays were accelerated to nearly the speed of light. Supernova explosion is the likely point of origin, but as SuperTIGER keeps measuring heavier and heavier elements, there may be some that show an excess of such enhancement, which could tweak our understanding considerably. There may also be elements that do not show enhancement from massive stars, and the absence of such star stuff would also be significant, pointing to a different origin, maybe a binary neutron star merger.
“A neutron star is a massive star remnant, usually more than the mass of our sun, crammed down into a super dense sphere,” Rauch says. “We don’t really know what’s at its core; it could be strange, exotic stuff. Two neutron stars can start orbiting each other and spiral closer until they finally collide and merge, and at some point, gravity is going to win, and you will get a black hole. Most of the mass goes into the black hole, but some of the super dense material can get squirted out and become part of the material of the galaxy. It kind of condenses and evaporates into heavy elements. With gamma rays, you can see the afterglow of the material that got ejected, so we know this process does spit material out.”
Dazed after the conversation, I read more about Antarctica, which no longer seems bleak and colorless. There are black worms in the ice, “red snow” on the glaciers (caused by a red algae that is fertilized by penguin poop), and green algae in the summer season. And if you are patient, really patient, there are answers to the biggest questions in the universe.
A long, solitary winter can pay off big—if you practice absurd optimism.
Read more by Jeannette Cooperman here.
