If you find it at all unusual that an astrophysicist — even an astrophysicist as renowned as Neil deGrasse Tyson — is giving a talk in a venue the size of Comerica Theatre, you're not alone.

Tyson, himself finds it all "kind of weird to begin with."

But he gets it, too.

"There's a lot of fun, interesting things to talk about," he says.

The presentation he's giving in Phoenix is on the search for life in the universe — "which of course," he says, "we're all interested in; we've all wondered about it."

And that makes it easy, he says, because he doesn't have to "earn" your interest with that kind of topic. You're already interested.

The director of the Hayden Planetarium at the Rose Center for Earth and Space in New York City says he'll tackle the subject of life in the universe from many different angles: biology, chemistry, physics, astrophysics.

People basking in cosmic knowledge

"It's a night out," says Tyson, who may be familiar from hosting "Cosmos: A Spacetime Odyssey" or guesting on "The Big Bang Theory." "But instead of being entertained by a music group or a play, it's an evening of fun learning."

You may wonder if Tyson has people who follow his appearances from theater to theater — like Deadheads, but for science.

"There are a few," Tyson says, with a laugh. "Maybe out of a thousand people, there could be 10 who do that."

If you were to follow Tyson on the road, it is worth noting that each night is different, even when the subject is the same.

"I respond to the audience and what the demographic mix is, what the city is," he says. "The prevailing news from pop culture or politics or sports gets folded in on some level."

Tyson hands the organizer of each show a list of 12 to 15 different topics on which he's prepare to give a presentation and the organizer chooses one.

There will be people in the audience who show up having no idea what that topic is. There always are.

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"I'm always flattered when I get a show of hands and see that people came without regard for that night's topic," Tyson says. "It means they just like basking in cosmic knowledge, and that's always a good thing."

Astrophysics for people in less of a hurry

This is not a book tour, Tyson says, although there may be copies of his latest book, "Accessory to War: The Unspoken Alliance Between Astrophysics and the Military," for sale at the venue.

"My talks are not based on my books," Tyson says, "unless I'm specifically requested by the host to do so."

"Accessory to War" is Tyson's second book in two years.

It follows "Astrophysics for People in a Hurry," which the author sums up as "a consolidation of all the most mind-blowing cosmic facts I know put into one volume, so it's packing a big punch in a small book."

These are very different books. As Tyson explains, with a laugh, "If you're not in a hurry," you would read the new one, which as Tyson says, was 13 years in the making.

"It's a reminder to people that the moving frontier of science has mattered to the moving frontier of war ever since humans have been in conflict," Tyson says.

"You needed a good physicist and engineer to invent a good catapult. Just imagine you're in a castle and you see them roll up with a catapult for the first time. The asymmetric advantage that that represented would have been staggering."

Science as an accessory to war

The role science has played in warfare should be obvious, he says, from the physicists who invented the bomb to the biologists weaponizing anthrax and the chemists who invented mustard gas and napalm.

"Those roles are well-known and well-documented," Tyson says. "What's less well-documented is what role the astrophysicists have played in this."

This is partly because it's a humble profession.

"We go to the mountaintop and wait for the photons to come to us," Tyson says.

"Then we gather them and talk about them in the coffee lounge. We don't bake or boil or splice or operate on. We don't interact with our samples the way other sciences do. We're the last people you might think who would become a handmaiden to military conquest."

But navigation can make all the difference in war.

"If you go back far enough, navigation was quite the problem, pre-GPS and all this," Tyson says.

"We know that the sky looks different depending on where you are on Earth. So if you understand the sky, you can infer where you are on Earth. And this connection was very well-known by all the naval powers, so they would tap the expertise of the astronomer."

Then there's invention of the telescope.

"Galileo, who really perfected the telescope, the first thing he does is show it to the doge of Venice," Tyson says.

"They go to the clock tower, the highest point in the city, and he points out ships in harbor and says, 'You can identify whether it's friend or foe by the flags 10 times farther than you could the unaided eye. So the doge bought a slew of them."

The telescope is not a weapon, Tyson says. "But half of war is reconnaissance."

George Washington, he says, "wrote lovingly of the role his telescope played in the Revolutionary War." That's why he's holding a telescope in the famous painting of Washington crossing the Delaware.

From Sputnik to the Space Force

Tyson's book is an exploration of the connection between astrophysics and the military from antiquity to the Space Force.

"It turns out that space has militarized since the 1960s, with the United States and the Soviet Union involved in a space race," Tyson says.

"Americans lost their (expletive) when Sputnik got launched. Here we are telling ourselves we're the top of the world and we want to convince the world that we're better than our adversary. And they put up a satellite, and we're nowhere near capable of doing that at the time."

The military implications of the Sputnik, he says, were obvious.

"How did the Russian get Sputnik into orbit?" Tyson asks. "In the hollowed-out shell of an intercontinental ballistic missile. It happened to be just a radio transmitter. But if they could put a ballistic missile over our heads, oh my gosh, that was like a chess move in the Cold War."

The U.S. founded NASA a year later, in 1958, the same year Tyson was born.

"There's NASA, a civilian agency, but who do they send into space?" Tyson asks. "Military pilots. Do they ever send a scientist into space? Once. What mission was that? The last moon mission. So it wasn't about the science. Ever. It was about the display of might."

Science has benefited, though, from the use of science by the military.

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"We have access to research funds through the National Science Foundation," Tyson says.

"We also get it from NASA. But the really big funded projects are military. So those of us who are peaceniks might turn a blind eye and say, 'Oh if you're going to the moon anyway for geopolitical reasons, could you take this new experiment with you and grab some rocks while you're there?' "

Science has piggybacked, he says, "on other, more expensive, differently motivated activities; and it's science that would not have happened any other way."

Neil deGrasse Tyson

When: 7:30 p.m. Wednesday, Oct. 17

Where: Comerica Theatre, 400 W. Washington St., Phoenix.

Admission: $35 and up.

Details: 800-745-3000, livenation.com.

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