The Protomolecule Unleashed: Evolutionary Horizons in The Expanse Season 3

One of the enduring mysteries in The Expanse is the protomolecule. The series has delivered some answers regarding the alien substance over the course of three seasons and actually showed what it could do to humans and its potential destructive power to the Solar System at large. The series still hasn’t really explained how it can destroy planets, but it was mentioned that the protomolecule actually is a weapon designed to destroy worlds.

While there are still plenty of unanswered questions up to the finale of The Expanse Season 3, it doesn’t mean we know nothing about it.

During the first two seasons, much of what we know about the protomolecule relates to its capability to manipulate humans and take control over their physical and mental functions. And it is precisely for that reason that Protogen, a research company owned by Mao, wants to harvest and use the substance as a weapon. Mao’s end goal is to sell it to the highest bidder. But before he can do that, he needs a weaponized version of it to convince potential buyers.

One of the first experiments leads to the death of Julie, Mao’s daughter, because of protomolecule infection, and the complete destruction of Eros, a near-Earth asteroid with a population reaching 100,000 people. The experiment involves secretly releasing the protomolecule in the populated area on the asteroid. Nearly everyone gets infected, and Eros is deemed irrecoverable. It’s bad luck that Eros is close enough to Earth, that its trajectory shows an inevitable collision. If that happens, the event might be the end of the planet as we know it.

Holden and Miller plan to use OPA’s Nauvoo to crash land on Eros to prevent the collision. The mission fails, and Miller ends up getting stranded on Eros. Miller is a detective hired to find the missing Julie; by the time he gets stuck on the asteroid, Julie has been dead for quite some time. This is where The Expanse gets supernatural; the protomolecule is now under Julie’s control because they have somehow become one. Miller convinces Protomolecule-Julie to redirect to Venus. The detective dies saving humanity.

The protomolecule is not like a typical viral infection; it doesn’t simply cause a type of sickness to the infected. Whoever is in contact with the substance is literally consumed. It absorbs not only the victims’ bodies, but their consciousness as well. It might not be a life-form in itself, but certainly capable of taking control over any replicating organism, including humans.

Another major experiment happens on Ganymede, where Mao secretly deployed a human-protomolecule hybrid as a test run. The hybrid is a special weapon developed by Protogen, as part of Project Caliban, involving both the UN and MCR. Ganymede is home to the UNN (United Nations Navy) and the MCRN (Martian Congressional Republic Navy) military headquarters. When a hybrid gets released on the UNN side, many soldiers run toward the MCRN border for safety. Unaware of the hybrid, some Martian marines think that the running soldiers are launching an attack. They engage in a battle with casualties on both sides.

The hybrids are humanoids, but their head is about twice as large as a human and covered in strange-looking protruding growth. The hands are long and big, and the skin is covered in scales. The eyes have glowing blue light. It turns out that hybrids are created by injecting protomolecule into children with an immune system disorder. Protogen’s researchers can control the infection and turn the host into super-soldiers. A hybrid can survive vacuum, cling to any surface, move at great speeds, and is strong enough to punch through hull plating. If left uncontrolled, a hybrid would look for energy sources and feed on the radiation. The UN and MCR both have access to protomolecule. The incident on Ganymede is the first major conflict to start a large-scale UN-MCR War.

Before the problem with the hybrid is completely resolved, the protomolecule structure on Venus takes off and forms a massive ring-shaped structure (simply referred to as The Ring) beyond the orbit of Uranus. The UN, MCRN, and OPA embark on a joint mission to study The Ring. With a big help from Miller’s apparition, Holden takes a massive risk and approaches the station in the center of the structure. As he contacts the circuit, Holden sees a flashback in reverse order going back to billions of years. It’s revealed that the protomolecule was created by an ancient alien civilization to defend itself against a much stronger enemy, as it had enough power to destroy worlds.

That said, Holden doesn’t trigger the terrifying defense system. Instead, the protomolecule ring opens gateways or wormholes that connect the Solar System to hundreds of habitable planets throughout the galaxy.

We think The Expanse Season 3 does a good job at clearing many lingering questions about the protomolecule, including why it exists in the first place. We now know that it was once used as a weapon by its creator, but it didn’t actually turn into a weapon in the Solar System until some people tried to tinker with the substance. That it connects to other planetary systems also creates a host of fresh mysteries, and it remains to be seen if the gateways, which essentially are wormholes, will trigger another major conflict.

Do you think the alien civilization who created the protomolecule has really gone extinct? Will humans find any intelligent lifeforms in the other planetary systems connected to The Ring? We’d love to hear from you.

Other Things You Might Want to Know

When did the UN-MCR War end?

With the downfall of Errinwright for treason and the resignation of Esteban Sorrento-Gillis as the Secretary General of the United Nations, the UN-MCR War officially ended. The looming unknown threats of the protomolecule also played a part in unifying major military forces in the face of a likely common enemy.

How many hybrids were created?

Apart from the three hybrids released on Ganymede, Project Caliban created numerous other super-soldiers stored in stealth pods. All of them were killed by long-range missiles. By the end of Season 3, there’s no more hybrid.

Now that the protomolecule has become wormholes, is everybody safe from infection?

There’s no obvious answer at this point. Fred Johnson actually has a protomolecule sample from Naomi. We still don’t know what he would do with the substance.

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