What if....???
This is a special episode of Science Moab. “Dear Ovis” is taken from a live radio show during a recent Radiothon at KZMU Moab. Host Jordan Lister and local scientist Robin Reibold answer hypothetical science questions from the fourth-grade class at HMK Elementary School in Moab. Robin, a biogeochemist with diverse expertise, addresses interesting scenarios such as what would happen if the Earth were split in half, the consequences if all toilets in Moab were flushed simultaneously, and the impacts on humans if we had no pores. It’s a fun show that blends scientific facts and insights with humor.
Jordan Lister:
Jordan Lister is a volunteer with Science Moab, a DJ and board member of KZMU, and he uses science regularly in his job as a paramedic at Grand County EMS in Moab, UT.
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Robin Reibold:
I’m a biogeochemist, and I’ve got about nine years of professional experience. I got my undergraduate degrees in biochemistry, human physiology, ecology, and evolutionary biology, as well as anthropology, and because I didn’t have enough to do, I got a minor in chemistry.
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Interview Excerpt - Dear Ovis... Vol. 1
This show is the first installment of what we’re calling our Dear Ovis show. Ovis is our beloved bighorn sheep mascot, and in the spirit of learning, and a little humor, we will be answering science questions from fourth graders. Our host for the show, Jordan Lister, and local scientist, Robin Reibold, tackle these questions head on.
Lister: Our first question comes from Evelyn, and she wants to know What would happen if the earth got cut in half?
Reibold: In this case, we’re gonna assume that the earth just suddenly got split in half by some unseen force and one half of the earth disappeared.
Lister: Okay, cool. So we’re not worried about there’s a giant space laser and it’s causing forest fires or there’s an oreo twisting motion and all the centrifugal forces that are going to be pulling it apart. We don’t care about that.
Reibold: Exactly. That could get really complicated and go a whole bunch of different ways.
So we’re just going to deal with what happens if half the earth just disappeared. So the short answer is. Everything is going to die pretty quickly, unfortunately.
Lister: Okay, that’s not really how I was hoping to start the show off on that kind of dour note, but I guess my immediate follow up question is Robin, how are we all gonna die?
Reibold: It’s gonna be a combination of massive earthquakes, suffocation, burning to death.
Lister: Okay, that’s a little bit of a bummer. As that’s happening, we still have this hemispherical blob out in space and the interior layers are now on the outside edge of the planet, right?
Reibold: Yeah, I think this is where things actually get interesting. So I want to take a minute and just talk quickly about all those new exposed layers that we’re able to see. The surface layer is the crust. It’s about 40 kilometers deep, and it makes up roughly 1 percent of the earth’s mass. It’s mostly made up of silicates and oxides.
Lister: Right below the crust Isn’t that where the mantle is?
Reibold: Yes, the mantle, and it’s significantly larger. It’s about 2,900 kilometers thick and It makes up almost two thirds of the Earth’s mass, and it’s also made up of those same oxides and silicate compounds
Lister: Awesome. Then below that we have the core, right?
Reibold: Yeah the core is made up of the outer core and then the inner core. The outer core is about 2,300 kilometers thick and is made up mostly of liquid iron and nickel. it’s actively flowing and it’s got these currents which generate our Earth’s magnetic field.
The inner core is 1200 kilometers thick and is made up of mostly the same stuff, iron and nickel, but it’s solid instead. The reason that it’s solid is because it’s got this incredible pressure from the weight of all the other layers pressing down on it. So even though it’s incredibly hot That pressure keeps it from melting.
Lister: But that’s just changed, right? So now instead of that immense pressure pushing down, that’s all exposed to the cold vacuum of space. So what happens?
Reibold: We will get down to what’s happening down below, but we’re going to start with the surface effects first, because that’s what we’re going to see initially.
Now, if you happen to be right on the edge, right where the cut was happening, I’m sorry to say that you’re probably going to be one of the first to go. Right around the edge, the oceans are going to start flowing off this new precipice as if you had an infinity pool and just took away the glass.
The water isn’t going to just flow out into space, gravity still exists and is still right at the center of the planet. So it’s going to be pulling that water down the newly cut edge. All of that crust and mantle material is going to start getting pulled down as well.
Lister: So I’m imagining those classic science class cross sections of the earth, right? You’ve got these nice rings, but now it’s painted by Salvador Dali and everything’s melting together. Is that kind of the picture we’re painting here?
Reibold: Exactly. One of those melting clocks just folding in on itself.
On the surface, the remaining atmosphere, which we’ve only got half of left, is going to start rushing around to try to redistribute itself around the new Earth. Because we are about to lose the Earth’s magnetic field, a lot of this atmosphere is going to get lost into space, going to get stripped off the planet by the cosmic rays, so we might end up with an atmosphere about the same as what you find near the top of Mount Everest, but at the surface now.
The earthquakes are also going to start, and I’m not sure that earthquake is the right term for it. We don’t really have a term for this, but that inner core that was solid because it was under immense pressure, has now been relieved of most of its pressure, so it’s going to liquify and start to spurt out a little bit.
Because all of this material, thousands of kilometers thick, just spurted out the side, and so now there’s a big gap in the middle. That mantle and crust is just going to start collapsing. The unfortunate thing, beyond everything else that’s happened, is that the gravitational energy that’s going to generate as it falls It’s going to be more than enough to essentially turn everything on the surface molten.eventually that semi earth is going to coalesce somewhat back into a roughly spheroid shape, probably about half the volume of the old earth.
