Science + Pop Culture, writing

Science Tangents: The Expanse s3e01

Season 3 of The Expanse starts off with quite the literal bang — an officially declared war between Earth and Mars. But don’t let that get in the way of exploring all the small science lessons this science fiction show can offer!

Here, allow me…


Not wanting to be blown out of the proverbial sky by either party, the Rocinante’s got to get another makeover. Naomi asks Prax to provide the new name, and — like every good science nerd — he names it after his dissertation. Coincidentally, it’s thematically appropriate.

Prax actually offers a good science tidbit for us. The new name Contorta comes from the taxonomic name Pinus contorta – a species of pine native to western North America. There are a few subspecies, varying in size from a few meters-tall shrub to 50 meters-tall trees.

“10 years after the 1988 Yellowstone fires, Lodgepole pine forests reestablish themselves amongst still standing dead trees.” Credit: Jim Peaco

The trees have long been a source of lumber, and indigenous peoples used the pitch as medicine. Pretty cool fact, but not as cool as what Prax tells us.

Wait, did I say cool? That’s exactly the opposite of what I mean…

P. contorta forests require the destructive power of fire in order to live. Their seeds are protected by special cones that can only open in the presence of extreme heat. (His exact words: “In order for them to survive, they have to die with fire…The seeds come out of the fire.”)

Credit: C.J. Earle

The sciency word we’re looking for is “serotiny”, which refers to an adaptation certain plant species have to release their seeds only after an environmental trigger. Fire is a common one, but water, sunlight, and lack of humidity are also possible.

It’s obviously left out of the script because it’d ruin the moment, but not all P. contorta plants have serotinous (aka “closed”) cones. Certain subspecies have a higher proclivity for it than others, and even if an individual tree has mostly closed cones, another nearby might have mostly open ones whose seeds are dispersed yearly with no fire whatsoever.

Trees that do have serotinous cones don’t start growing them until they hit 50 years old. But once they do, the seeds inside are viable for about 8 decades; that’s what allow populations to successfully grow back after everything gets wiped out after a forest fire.

But not just any forest fire. If the temperature is too low (<50 °C/120 °F), it won’t melt the protective coating, and if the temperature is too high (>75 °C/167 °F) or the cones are exposed to fire for too long, the seeds get damaged and don’t germinate.

So while fire definitely has an important role in P. contorta’s life cycle, Prax isn’t getting into the nitty gritty.

That’s my job.

(As for whether or not they’re good company, we’ll just have to take him at his word)

But you’re watching a show that takes place in space, so how about some info about space?

Io was discovered all the way back in 1610, by none other than telescope non-inventor Galileo Galilei. It was just a pinprick of light back then, but thanks to the march of science we now know it looks like a cosmic pizza:

Credit: NASA/JPL

This image is color-enhanced, with extra infrared data that makes it look a little more dramatic than it would appear to a human eyeball. The yellow comes from an abundance of sulfur on the surface, which comes from its hundreds of volcanoes expelling sulfur dioxide gas plumes that can be as tall as 480 km (300 mi).

Credit: NASA/JPL/University of Arizona

You heard that right. Io has active volcanoes. It’s the most volcanically active object in the entire solar system.

You might wonder how such a tiny object so far away from the Sun could be hot enough to have lakes of lava on its surface. Well, you can thank Jupiter and lunar neighbors Europa and Ganymede. It’s their gravitational tugging on Io every which way that heats up its interior. It’s also what causes the surface of Io to rise and fall, like tides, by as much as 100 m (330 ft)!

The sulfur dioxide emitted also provides Io with what little an atmosphere it has…unless it’s in the shadow of Jupiter, where the gases all condense into a solid. This happens once each Ioan day (1.7 Earth days), for about 2 hours.

You don’t just want to not visit Io due to probable death by lava, or death from lack of air. Because of its position within Jupiter’s intense magnetic field, you’ll also suffer death by radiation poisoning.

In The Expanse’s version of Io, humanity built (and eventually abandoned) a Helium-3 refinery. At the end of episode 1, the Contorta heads there to investigate what happened to Prax’s daughter. But we don’t care about that. We care about what the heck Helium-3 is and why we’d possibly need it.

The helium you’re familiar with is Helium-4. Its nucleus is comprised of 2 protons and 2 neutrons. Helium-3 is a different type (i.e. “isotope”) of helium; it has only 1 neutron.


It exists in nature, but is pretty rare. Only about 0.0002% of the helium in the universe is Helium-3. So, if we found it had some particularly good application(s), it’d make sense we need a place to get a bunch more.

We already use it for certain medical diagnostics – ones that require magnetic imaging of a patient’s lungs – but the stretch goal is to use it in nuclear fusion reactions.

Fusing a helium-3 particle with either a hydrogen-2 or with another helium-3 would produce a pretty good amount of energy, while only creating helium-4 and stray protons. In other words, there aren’t any nasty radioactive daughter particles like what we get out of modern nuclear reactors, or conventional hydrogen isotope fusion reactions.


Right now, research facilities like the National Ignition Facility that are working on the fusion problem are using the simplest possible version: hydrogen-2 (aka Deuterium) + hydrogen-3 (aka Tritium). That’s simply because you don’t need to get these particles as energetic to get around their Coulomb barrier (which I discussed for SYFY Wire, here).

We have successfully completed helium-3 fusion, but only by pumping in more energy into the system than we got out…which doesn’t exactly work as a power source.

But if we can overcome that barrier, the amount of energy we could extract is predicted to be super high. As much as 70%, compared to the 30ish% we get by turning fossil fuels into electricity.

Helium-3 could theoretically be mined from the Moon and gas giant atmospheres, where the isotope exists in greater abundance than it does on Earth.

But why the refinery’s on death-trap Io, however, we’ll have to ask someone from a future alternate universe.

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