“I’m sorry, ma’am,” Brady said. He didn’t turn to see which portraits she had indicated. “I didn’t mean to offend you. These portraits show what war really is, and I think it’s something we need to remember lest we try it again.”

When it became clear that time travel was even a remote possibility, the government bought a lot of scientists. Those who didn’t play got discredited.

A few documents, smuggled to the colonies on Earth’s Moon, suggested that stealth tech was based on interdimensional science—that the ships didn’t vanish off radar because of a “cloak” but because they traveled, briefly, into another world—a parallel universe that’s similar to our own.

I recognized the theory—it’s the one on which time travel is based, even though we’ve never discovered time travel, at least not in any useful way, and researchers all over the universe discourage experimentation in it. They prefer the other theory of time travel, the one that says time is not linear, that we only perceive it as linear, and to actually time travel would be to alter the human brain.

But what Squishy is telling me is that it’s possible to time travel, it’s possible to open small windows in other dimensions, and bend them to our will.

The exterior parts of the station move in a slower time frame. The interior part, nearest the stealth tech itself, is moving at an accelerated pace.

You know the arguments: If God had wanted us to travel through time, the devout claim, he would have given us the ability to do so. If God had wanted us to travel through time, the scientists say, he would have given us the ability to understand time travel—and oh! Look! He’s done that.

Werner Heisenberg’s controversial uncertainty principle was one of the cornerstones of quantum physics. Heisenberg postulated that it was possible to know a particle’s position or that it was possible to know how fast the particle moved, but no one could know both the position and movement of the particle at the same time. Berg had spent quite a bit of time in Oxford, talking with leading scientists as he prepared for this job, and one of them used a description that moved away from particles into theory, which Berg appreciated. That scientist had told Berg that at its core, Heisenberg’s principle meant this: The act of observing changes the thing being observed.

This day, the next hour, were the reasons he had built the device. Not so that graduate students in religion could travel back to Christ’s cruxifixion to see if it really happened as the Bible said. Not so that historians could add to their dissertations by actually speaking to Thomas Jefferson. Not so that techs could fruitlessly try to modify the device so that someone could finally shoot Hitler.