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Cosmos curious? Ask a spaceman


Fall
2017

In a galaxy close, close at hand, astrophysicist Paul Sutter answers your questions about … the universe. Think of him as our very own agent to the stars.

Paul Sutter is an astrophysicist who, in addition to studying things like cosmic voids and galaxy clusters, enjoys helping those of us who aren’t astrophysicists understand how the universe works. He is a researcher at Ohio State’s Center for Cosmology and Astro Particle Physics as well as the chief scientist at the Center of Science and Industry in downtown Columbus. And he’s a writer, TV producer and featured expert, speaker and host of the popular “Ask a Spaceman” podcast. He took questions from alumni who were curious about space, stars and everything galactic.

My 10-year-old son wants to know if there is more than one universe. His name is Camden, and he wants to be an astronaut when he grows up.
— Duane Pullins ’95

We define “the universe” to be everything there is, so there can be only one. There is, however, a limit to the observable universe. There are definitely more stars and galaxies than we can see. But there’s only one universe. (Tell Camden to shoot for the stars!)

What are your thoughts on the mysterious ninth planet?
— Sue Binkley ’73, ’81 MSW

The hints that there might be a new planet in the solar system are very interesting, but at this stage very speculative. The subtle motions of dwarf planets in the very distant solar system — past the orbit of Pluto — suggest that there might be another massive object out there, but we know so little about that region that it’s hard to say.

What do you feel are the chief obstacles to sustained life on Mars? As someone who is moved by Elon Musk’s passion and dedication to getting there, I am interested to hear an esteemed scientist’s thoughts on the matter.
— Marina Bilaver ’05

Mars is hard. It’s cold. There’s almost no air, and what is there is poisonous carbon dioxide. It’s exposed to constant high-energy radiation. There’s almost no liquid water. The soil has rocket fuel dust in it. Visiting Mars is definitely challenging, but it is technically feasible in the next few decades. Staying there long-term? That’s a bit more difficult.

Can you explain the physics behind the popular fidget spinners that kids are using? I want to teach the concepts to my students!
— Judy Leddy ’78

The physics of the fidget spinner are pretty neat. It’s simply angular momentum at work. I’m sure you’re familiar with Newton’s laws, so just apply those to objects moving in a circle and you’re basically there: Objects in motion tend to stay in motion, and objects spinning tend to stay spinning. The only thing that stops a free-spinning object is friction, and fidget spinners are designed to be as low-friction as possible.

As a student, what was your favorite class?
— Alexia Ciontea ’07

I took one of my favorite classes in my junior year of college. It was a course on classical mechanics, and I thought I already knew everything there was to know about Newton’s laws, friction and drag, and so on. I was wrong. That was the first class that totally upended everything I had been taught before, and it was the first step on the road to viewing the world as a physicist.

What are the chances of Earth getting hit by an asteroid within the next few hundred years? And, if they are high, are there plans that could help us avoid the collision?
— Omar Ganoom ’77, ’81 MA

The chances of Earth getting hit by an asteroid are exactly 100 percent! That’s because out planet is constantly getting hit by rocks from space. Most of it them are tiny. (When you see the brilliant flash of a meteor streaking across the sky, that’s a small bit of dust screaming into our atmosphere at tens of thousands of miles per hour.) Larger rocks that are a few meters in diameter or so strike about once a year, releasing the equivalent energy of a nuclear bomb. City-destroying and civilization-ending monster asteroids are very rare, happening every few million years or so. And lucky for us, we haven’t seen any of those in our vicinity. Yet. So, there’s essentially no chance of getting hit by a monster in the next few centuries, but if we did spot one early enough, we could attach some rockets or bombs (or both) to it to gently nudge it off course.

With all we know about the universe already, what is left to discover, and what is the value proposition for that discovery?
— Adam Smith ’09

It’s true that we know a lot about the universe — but you may have noticed that the universe is a big, complex place. For every question we answer, a dozen more pop up to replace it. We don’t fully understand how supernovas are triggered, for example, or how our solar system formed, how common life is, what the nature of dark matter and energy is. The list goes on and on. There’s a lot more work to do!

Recently, a potential “straight to black hole from a star” was discovered. Where’s the boom? Isn’t there always a boom?
— Paul Braun ’91

Researchers, including my colleague Chris Kochanek, did indeed observe a star that appears to have died without the brilliant explosion that we expect from such a phenomenon. We don’t fully understand the complex processes that lead to these deaths. We do know that the intense gravitational pressures in the cores of these stars are enough to overwhelm all other forces and form a black hole. That process is usually accompanied by a fantastic supernova explosion — but apparently not always. Why is there almost always a boom, but sometimes not? Sounds like something for a grad student to figure out!

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