“Mother—what ‘odd sky’?”

Maria replied caustically, “Maybe you should go take a look yourself. You are the Astronomer Royal, and—” The phone connection fizzed and cut out.

Siobhan was briefly baffled; that never happened. “Aristotle, redial, please.”

“Yes, Siobhan.”

Her mother’s voice returned after a couple of seconds. “Hello? …”

“I’m here,” Siobhan said. “Mother, professional astronomers don’t do much stargazing nowadays.” Especially not a cosmologist like Siobhan, whose concern was with the universe on the vastest scales of space and time, not the handful of dull objects that could be seen with the naked eye.

“But even you must have noticed the aurora this morning.”

Of course she had. In midsummer Siobhan always rose about six, to get in her daily quota of jogging around Hyde Park before the heat of the day became unbearable. This morning, even though the sun had long been above the horizon, she had seen that subtle wash of crimson and green in the northern sky—clearly three-dimensional, bright curtains and streamers of it, an immense structure of magnetism and plasma towering above the Earth.

Maria said, “An aurora is something to do with the sun, isn’t it?”

“Yes. Flares, the solar wind.” To her shame, Siobhan found she wasn’t even sure if the sun was near the maximum of its cycle right now. Some Astronomer Royal she was proving to be.

Anyhow, though the aurora was undeniably a spectacular sight, and it was very unusual to be so bright as far south as London, Siobhan knew it was nothing but a second-order effect of the interaction of solar plasma with the Earth’s magnetic field, and therefore not particularly interesting. She had continued her jogging, not at all motivated to join the rows of slack-jawed dog walkers staring at the sky. And she certainly wasn’t sorry she missed the brief panic as people had assailed the emergency services with pointless calls, imagining London was on fire.