before Sebastian started appearing at lectures in a similar dandy’s uniform. Every morning they walked across the lawn in front of the Institute of Physics as if drawn to each other by an invisible string—bypassing all the other students in various different years who seemed to exist only to get in their way—and greeted each other with a handshake. They bought only one copy of every textbook because they liked bending their heads over each page together. The seats next to them in the lecture theater remained empty. Everyone found their getup odd, yet no one laughed at them, not even when they walked arm in arm on the bank of the Dreisam in the afternoons, stopping every couple of steps, because matters of importance could only be discussed while standing still. In their old-fashioned garb, they looked like something from a yellowing postcard, carefully cut out and pasted—but not seamlessly—into the present. The ripple of the Dreisam punctuated their conversation and the trees above them waved in the wind. Thelate-summer sun was never more beautiful than when one of them pointed at it and said something about the solar neutrino problem.
In the evenings, they met in the library. Oskar strolled along the shelves, returning from time to time to their shared table with a book. Ever since Oskar had got into the habit of putting his arm around his friend while bringing his attention to something interesting in a book, female students of German literature had started gathering on the benches behind the glass walls of the reading room. At parties, when Oskar and Sebastian glided through the crowds separately, Sebastian, with a heavy heart, sometimes kissed a girl. When he lifted his head, he could count on seeing Oskar smiling at him from across the room. At the end of the evening, the girl would be led to the door and handed over to anyone passing by, like a piece of clothing. Then Oskar and Sebastian would walk together through the night until they had to part ways. They came to a standstill, the light from a streetlamp falling around them like a tent that neither of them wanted to leave. It was hard to decide on a suitable moment to say good-bye—this one, or the next? As the headlights of passing cars caused their combined shadow to rotate on its axis, the friends made a silent vow that nothing would ever change between them. The future was an evenly woven carpet of togetherness unrolling before them. When the chirp of the first bird sounded, they turned away and each disappeared into his half of the coming morning.
On the first Friday of every month, Oskar allows himself to imagine for a few seconds that the InterCity Express is bringing him back to one of those farewells beneath the streetlamps of Freiburg. Back to a heated discussion on the banks of the Dreisam, or at least to a moment over a shared textbook. He feels his lips curve into a smile, but immediately falls into a peevish mood. Clearly the Freiburg of the streetlamps no longer exists. What does exist is this: a circular underground tunnel in Switzerland where he makes elementary particles collide at nearly the speed of light. And the Freiburg where he has been invited by Sebastian’s wife to dinner with the family. It was on aFriday that Oskar had met Liam—tiny as a doll then—for the first time. It was on a Friday that he had learned about Sebastian’s renown at the university. On Fridays, they look each other in the eye and try not to think about the past. On Fridays, they fight. For Oskar, Sebastian is not just the only person whose presence brings him pleasure. Sebastian is also the person whose slightest movement can turn him white-hot with rage.
WHEN THE TRAIN COMES TO A STANDSTILL on an open stretch of land, Oskar leans down to his bag to remove a rolled-up copy of Der Spiegel magazine, which falls open at the right page. He doesn’t need to read the article again—he practically knows it by heart. He looks at the photo instead: it shows a