“How can we have missed a thing that size?” said the director, eyes creased in anxious fury.

“Until last Sunday,” I explained, “it was occulted by the planet Mars.” It was a lame excuse, but it happened to be true.

“So Mars just stepped aside… and there it was: coming straight at us?”

“And there it was,” I said. “Full stop.”

“What was it that excited your suspicion?”

“I was doing measurements on M8. It got in my way.”

The director snorted, as if he was hoping I’d say something more impressive. “Show me on the screen.”

I brought up yesterday’s shot of Messier 8, aka the Lagoon Nebula in the constellation of Sagittarius, close to the galactic centre. It stood out clearly for me because I knew what I was looking for, but it took him a while to see it.

But eventually he did. A patch of darkness in the field of stars. Those of course occur at random—but not circular patches.

He sat back with a sigh. “You can’t have been the only one to spot it. Hubble will show up every icicle.”

“Hubble’s fully booked on Ultra Deep Field Five.”

“Mauna Kea, then. Palomar. Kitt Peak…”

“Not a peep out of any of them.”

The director swayed his head as if his nose was a windscreen wiper. “Maybe they’re just keeping mum. Think of the damage an inappropriate disclosure would do. Imagine the effect on the stock market, for a start…”

“I don’t think the stock market’s going to matter all that much.”

He looked at me in silence for several seconds. Then he bawled at me “Are you absolutely certain of your calculations?”

“No one can be certain of anything yet. I’ll have to re-run the program daily. Soon it will be hourly.”

His voice, when he spoke again, was scarcely audible. “Will it really come to that?”

I shrugged. “What do you want me to say?”

In the end we decided to keep it to ourselves. Let some other observatory be the first to report it. It was credit of a sort we didn’t want.

It wasn’t as if we could put our own names to the object. It had a name already. It had been observed fifteen years earlier in solar transit and designated X/1994 H5 (Schott-Ito)—from which an astronomer would infer that it was a comet of unknown trajectory discovered in the second half of April 1994, the fifth such object.

But Messrs Schott and Ito never got round to tracking it. Their funding was cut—and it was lost. On its rediscovery, the IAU re-designated it A/1994 H5 (Schott-Ito), which emphasised that it was an asteroid mistaken for a comet. But to honour its original discoverers it was permitted to keep its cometary name.

This may serve to explain why we were in no rush to claim ownership, or rather, to own up to it. But then LINEAR, the Lincoln Near-Earth Asteroid Research project, announced it—and promptly awarded it 10 on the Torino scale.

Yes, you heard me correctly. Ten: the highest possible hazard rating.

Then people started to ask how we’d managed to lose it in the first place.

…to be continued