Alaric listened intently as the others spoke, his quill scratching lightly across his parchment as he took a few notes. The older Ravenclaw girl’s explanation about satellites and orbital revolutions sounded impressive, and a bit advanced, he admitted to himself, but it gave him an idea.

He raised his hand, his expression thoughtful but eager. Once Professor Burbage called on him, he spoke up.

“I was thinking about how orbits are not always perfect circles. They are usually more like stretched-out ovals... um, ellipses. The thing they orbit around isn’t exactly in the middle, it’s a bit off to one side.” He paused for a moment, making sure he was getting it right. “I read that comets do that. They go really far away and move slowly, but when they get close to the sun, they speed up a lot.”

He glanced around at the other students, hoping he was making sense. “So even though orbits repeat, they are not always the same shape or speed.”