Neil deGrasse Tyson Graciously Addresses Space Questions From My Children
For a nearly infinite number of reasons, I am profoundly under-equipped to interview astrophysicists like Neil deGrasse Tyson. I do not know the age of the sun, I have zero ideas about how to deflect murderous asteroids rocketing at us from deep space, and I know precisely two facts about Saturn, which are the same two you do.* (It has rings and would float in an enormous bathtub.)
For this reason, and to preview Tyson’s December 5 appearance at Old National Centre, I have outsourced the following interview to two much more knowledgeable associates: my 13-year-old and 6-year-old, who joined me in listening to Tyson’s endlessly enjoyable StarTalk podcast on the drive home from Thanksgiving and have, as such, come to regard Tyson as Earth’s Smartest Person. Tyson, quite graciously, is happy to go along with this. “All you need is curiosity, and kids have it in abundance,” he says. “A professional scientist is simply a kid who never grew up.” (My 6-year-old, on the morning drive to kindergarten, asked me, “Is this the day you talk to that guy who’s the biggest expert on everything?”)
Indeed, as a best-selling author, podcast host, director of the Hayden Planetarium in New York City, owner of a Twitter account with 10 million followers, host of the revival of the Cosmos television program, and teacher of unceasing charm and enthusiasm, Tyson has achieved the superstar status afforded to scientists like Carl Sagan, the MythBusters and, y’know, Einstein. He’ll bring all that expertise to town in a one-man show titled An Astrophysicist Reads the Newspaper, all about the current scientific climate, as well as asteroid collisions, cosmic travel, dark matter, and purely theoretical objects known as “newspapers.” (The show’s about two and a half hours and for all ages, though some language may be PG-13, because when discussing your potential extermination by enormous flying mountains from space, it’s appropriate to curse a little.)
So now, if you’ll permit, my sons throw a few questions to the biggest expert on everything:
Is there an answer to the question, “What is on the other side of the edge of the universe?”
The answer is: We have no clue! (laughs) I’m delighted to be able to answer that for you!
But the thing is: That question presumes that the universe has an edge. You don’t ask, “What is on the other side of the edge of the Earth?” or, in a more absurd example, “What kind of cheese is the moon made out of?” The question makes an assumption, and then you’re trying for an answer based on a false assumption. The greatest scientists are not so much the ones who know how to come up with answers, they’re the ones who know how to come up with questions. A mature scientist will learn to love the questions themselves.
How can gas make a planet like Jupiter? What do you stand on?
This is a matter of gravity. If you have enough gravity, it can hold onto gas particles. On Earth, hydrogen would escape at the temperature of our atmosphere. But on Jupiter, it doesn’t escape—all the gas just stays there. And there is a surface way, way deep down on Jupiter, but you’d be incinerated by the high gas temperatures long before (you got there).
So we’re not thinking about landing on Jupiter. What we are thinking about is: Let’s land on the moons of Jupiter. Those are cool! Jupiter has a very delightful assortment of moons of all kinds of properties, and four of them are so big they were discovered by Galileo 400 years ago. The moons are where the action is—they’re way cooler than the planet itself. So first we want to do reconnaissance of those moons with an orbiter, and that’ll help inform how to design the spacecraft that would land there on the next round.
How close could a sensor get to a black hole before it crumpled up and got crushed into a little ball, lost forever in the cold, endless darkness of space?
Oh, you could transmit data right up to the edge of the event horizon (the point at which gravity becomes so strong that nothing can escape it, even light). That’s the only issue. If you cross the event horizon, there’s no coming back.
And if you’re falling into a black hole, it’s not the strength of the gravity that will matter to you, anyway. It’s the difference in gravity between your head and your feet as you fall. That difference grows the closer you get to the black hole center, and as it does, your feet accelerate faster than your head does. So you don’t get crushed, you get ripped apart. Yeah, it’s not pleasant. But if you stay outside the black hole, and don’t fall all the way to the center, you’d be OK.
I find that kids like black holes because I think all kids respect anything that can eat them. What’s every kid’s favorite dinosaur? T. Rex, of course, not the old brontosaurus or apatosaurus. T. Rex can eat you! What’s a kid’s favorite astronomical object? Not Earth, not Pluto. The black hole.
If there’s a black hole, is there such a thing as a white hole?
So, back when the mass of black holes was explored, there was a solution to one of the black-hole equations that was the mathematical opposite of a black hole, where everything only ever came out of it. The only obvious thing to call that was a ‘white hole.’ At the time, people said, “Well, if black holes exist in this universe, maybe white holes exist, too.” So they looked. But they couldn’t find anything in the universe whose signature, through our telescope, resembled the white-hole calculation we came up with. So we concluded that there are no white holes in the universe.
But you could also ask: Could a black hole be connected to a white hole in another universe? Are there black holes that correspond to white holes in other universes? Stuff goes into a black hole—where does it go? That led to the idea of a wormhole, where you might connect a black hole to a white hole and matter could move through it. So wormhole mass became a frontier to black-hole physics.
Here’s what we know: Our universe has black holes. Our universe does not have white holes. Our universe is not likely to have wormholes in any way we’ve conceived them, because they’re not stable. If we tried to pry one open, it would close back immediately when we let go of it, and who knows what your fate would be if you were in the wormhole when that happened. If you’re taking a thrill ride through a wormhole and it collapses on you, yeah, that could get ugly.
Tardigrades can survive in space, so could other weird animals do it, too?
Ha! Well, I don’t know if you saw my tweets, but I suggested they should use tardigrades for Macy’s Thanksgiving Day parade balloons. (laughs) They have this little proboscis thing that comes out, and it would be cool if that moved around, extended out forward, and then, you know (makes vacuuming noise). It’d be like offering up children to the tardigrade god! That would straighten them up right on the spot! (laughs)
But yeah, the tardigrade is one bit of a category of bacteria that thrives in extreme environments. They’re called extremophiles. It’s a whole community of microbes that enjoy high-pressure, low-pressure, vacuum, freeze-dried, high-radiation situations. All these things that would kill us, they thrive in. And they’re of huge interest to astrobiologists, because you want to know how wide of a net you should cast when looking for life on other planets. Are you looking for 72-degree tidepools as the only places life can form, or are you adding these high-acid, high-radiation places in your search list? If so, you increase the number of places you might find life.
If you had the power to witness any galactic phenomena since the creation of the universe, what would it be?
Well it’s hard to argue against the Big Bang—it’s just not clear where I would stand for that (laughs).
So if we include the criteria that I’d need a place to stand, I’d like to see the formation of Earth’s moon. Current models suggest that we got sideswiped by an Earth-sized protoplanet, and our crustal material got scattered into an orbital ring that ultimately coalesced to form our moon, which, back then, would have been 20 times closer than it is now. At that closeness, it would have raised tides a thousand times higher than we see today. And all of this would have taken six months to a year. That’ s a human-time scale, so I could watch that. It would be stunning! It would be the coolest thing ever!
How could the whole universe start with a big explosion?
All the evidence points to this. It sounds odd and fantastical. But the universe is expanding. We know this. That means yesterday the universe was smaller than it is today. The day before that, it was smaller still. If you keep subtracting days, the universe gets littler and littler and littler and littler. And if you run the math, you reach a point in the past, 13.7 billion years ago, where all the matter, all the space, and all the time in the universe is collapsed into a single point. A primeval fireball. And it’s the expansion of that primeval fireball that we call the Big Bang.
An Evening With Neil deGrasse Tyson: An Astrophysicist Reads the Newspaper. 7:30 p.m. Tuesday, Dec. 5. Murat Theatre at the Old National Centre. $53–$103. livenation.com