Stephen Baxter - Coalescent

thur-ius . He smiled at her, and turned away to issue crisp commands to his soldiers.

When I got back to my hotel room after my visit with Lou, I used the room’s clunky pay-for-use plug-in keyboard to check my email. There were two significant notes.

The first was a long missive from Peter McLachlan.

“Most of the universe is dark,” Peter wrote. “ Dark matter. An invisible, mysterious substance that makes up some ninety percent of all the mass of the universe. You can tell it’s there from gravitational effects — the whole Galaxy is embedded in a big pond of it, and turns like a lily leaf in a pail of scummy water. But otherwise it passes through our planet like a vast ghost. How marvelous, how scary, that so much of the universe — most of it, in fact — is quite invisible to us. Who knows what lurks out there in the glassy dark? … I’m inspired, George. Something about my contact with you, this little mystery in your life, has sparked me off. That and Kuiper. I’ve been in touch with the Slan(t)ers again …” He was an unusual email correspondent. There was no BTW or abt or lol , no smiley faces for Peter. His mails were clearly thought through, composed, even spellchecked, like old-fashioned letters: they were genuine correspondence. “… Of course we do have a handful of human-built space probes that have reached almost as far as the Kuiper Belt. They aren’t capable of studying the Anomaly, sadly. But they are running into strangeness …”

My finger hovered over the DELETE button. Part of me responded to all this stuff. But the adult part of me was beginning to regret letting this strange obsessive into my life.

I read on.

He told me about the Pioneers: two deep-space probes launched in the seventies by NASA. They had been the first probes to fly past Jupiter and Saturn. And after that, they had just kept on going. By now, more than three decades after their launch, they had passed far beyond the orbit of Pluto — and there was nothing to stop them, it seemed, until they swam among the stars a few hundred thousand years from now.

But something was slowing them down. More anomalous information he and his pals the Slan(t)ers had dug up.

“The two Pioneers are decelerating. Not by much, a mere ten-billionth of an Earth gravity, but it’s real. Right now the first Pioneer is off-course by the distance between the Earth and the moon. And nobody knows what’s causing it.” But perhaps it was dark matter. “Maybe for something as isolated and fragile as a Pioneer, dark matter effects start to dominate. It’s interesting to speculate what will happen if we ever try to drive a starship out there—”

Or it might be a fuel leak, I thought. Or just paint, sublimating in the vacuum. Oddly, I felt reluctant to discourage him.

“I’m coming to think dark matter is the key to everything …”

I pressed a key to store the file.

The second notable mail was from my ex-wife.

Linda had heard about my dad’s death from our mutual friends, and wanted to see me. We had always gotten together regularly. I suppose we both accepted that after a decade of marriage, now buried in the irrevocable past, we had too much in common to ever cut the ties completely. Over an exchange of mails, we agreed to meet on neutral territory.

I flew back to London the next day. I left Florida without regrets.

It was my idea to meet Linda at the Museum of London. I was starting to become intrigued by what I’d heard of the Roman British girl Regina, who according to our dubious family legend was supposed to have traveled from the collapsed province of Britain, across Europe, all the way to the fading glory of Rome itself. Somehow she, or at least her legend, seemed to be central to what had happened to my family. And if any of it was true, perhaps she once traveled through London itself — Londinium, as the Romans had called it. But like most of London’s peripatetic population, even though I’d spent much of my working life in the City, I’d paid no attention whatsoever to its history. I’d never so much as been inside the Tower, though it had only been a quarter hour’s walk away from the offices where I once worked. Anyhow, now was a chance to put some of that right.

A check on the Internet showed me that the Roman city had been confined by a wall that contained much of the modern City of London — the financial center — excluding the West End, and points farther east than the Tower. The Museum of London was itself set on a corner of the old wall, or rather, on the line it had once traced out. It might give me a few clues about Regina.

And two thousand years of history might distract Linda and me sufficiently to keep us from bickering for a couple of hours.

The museum turned out to be just outside the Barbican, that concrete wilderness that seems to have been designed for cars, not humans. The museum itself is set on a traffic island cut off by a moat of roaring traffic. I seemed to walk a mile before I found a staircase that took me up to an elevated walkway that crossed the traffic stream and led into the museum complex itself. I was early — I’m always early rather than late, while Linda is the opposite — and I spent the spare time poking around the museum’s show-and- tell displays and scale models, showing Londinium’s rise and fall.

After Caesar’s first foray, the Emperor Claudius, equipped with war elephants, had begun the true conquest of Britain. By sixty years after the death of Christ, Londinium had grown into a city big enough to be worth being burned down by Boudicca. But in the fifth century, after Britain became detached from the Empire, Londinium collapsed. The Roman area would not be reoccupied for four hundred years, the time of Alfred the Great. I picked through the little models and maps, trying to figure out what date Regina must have come through here, if she ever did. I didn’t know enough to be able to tell.

I dug around in the gift shop. I felt like the only adult in there; the museum’s only other visitors were some Scandinavian tourists, all long legs, backpacks, and blond hair, and a batch of young-teenager schoolkids who seemed to swarm everywhere, their behavior scarcely modified by the yells and yips of their teachers. Eventually I found a slim guidebook to the “Wall Walk,” a tour around the line of the Roman wall. I queued up to pay behind a line of the schoolkids, each of them buying a sweet or a sparkly pencil sharpener or an AMO LONDINIUM mouse pad. An old fart in a duffel coat, I gritted my teeth and stayed patient, reminding myself that all this junk was helping keep the museums free to enter.

Linda found me in the coffee shop. She had come from work; she was an office manager in a solicitor’s office, based on the edge of Soho. She was a little shorter than me, with her hair cut sensibly short, a bit flyaway where it was going to gray. She wore a slightly rumpled blue-black suit. Her face was small, symmetrical, with neat features set off by a petite nose. She had always been beautiful in a gentle, easy- on-the-eye way. But I thought I saw more lines and shadows, and she looked a little stressed, her eyes hollow. She always programmed herself right up to the last minute, as no doubt she had today; she’d have had to make room for me in her schedule.

I bought her a coffee and explained my scheme to do the Wall Walk.

“In shoes like these?”

She was wearing plain-looking flat-soled black leather shoes, the kind I used to call “matron’s shoes,” when I dared. “They’ll do.”

“Not mine. Yours. ” I was wearing a pair of my old Hush Puppy slip-ons. “When the hell are you going to get yourself some trainers?”