Chirality in the Mirror Universe: Astrobiology and Star Trek
I’ll confess, Star Trek is probably my favorite franchise when it comes to discussing complex scientific concepts through the lens of popular fiction. Over the past half a century and numerous TV series, Star Trek has delved into various aspects of astrobiology, including an intriguing exploration of molecular chirality in its portrayal of the "mirror universes."
Today, I’m going to delve into that overlap of astrobiology and science fiction, focusing on the chirality of amino acids in Star Trek's mirror universe. This is a topic I first found fascinating when I was teaching a 300-person “life in the universe” class. These days, my favorite necklace is a string of decorative amino acids representing my initials, so I frequently find myself talking to strangers asking about my jewelry with a prolonged explanation of all things amino acids, chirality, and star trek.
Part 1: What the heck is molecular chirality
Molecular chirality, at its most basic, is a form of molecular "handedness." Certain molecules, including amino acids, have a unique geometric property where they exist in two mirror-image forms that are non-superimposable, much like left and right hands.
Most amino acids in life on Earth are "left-handed," or have "L-" chirality. This concept is known as homochirality—the phenomenon where a majority of a certain type of molecule in a living organism have the same chirality. The origins and implications of homochirality in Earth's biochemistry are topics of active research in astrobiology.
Part 2: Into the looking glass, or chirality in the Star Trek mirror universes
The Star Trek franchise uses the concept of a "mirror universe" across multiple series. This parallel universe showcases characters, events, and even molecules existing in a state opposite to the "prime" universe.
Intriguingly, in the mirror universe, it's suggested that life is based on "right-handed," or "D-" chirality amino acids. This is referenced in the "Star Trek: Deep Space Nine" episode "Crossover." Dr. Bashir, the ship's medical officer, makes this observation when he notices that the chirality in a blood sample from the mirror universe is the opposite of what he would expect.
What do we make of this?
The mirror universe's chirality shift offers a speculative exploration of how life might form under different circumstances. Could life, if it originated independently elsewhere in the universe, demonstrate different chirality? What if life on Earth had evolved with "right-handed" amino acids instead of left?
Scientists have long speculated on the reasons behind homochirality. Seriously, I’ve been at those astrobiology conferences. Some theories range from the influence of polarized light in the early universe to a simple matter of chance, a so-called "frozen accident."
The "mirror universe" in Star Trek is a narrative experiment in how homochirality might play out differently in a parallel universe.
Connecting Star Trek to real-world science
While the mirror universe's chirality concept remains speculative, it's not entirely unfounded in real science. Researchers are actively exploring environments that could favor D-amino acids, including regions in space exposed to circularly polarized light.
Furthermore, the mirror universe concept has influenced real-world science. For instance, it has inspired scientists to develop mirror-image versions of enzymes, which could have potential applications in medicine and industry.
Take aways
The exploration of chirality in Star Trek’s mirror universe offers a blend of science fiction and how life works in the real world. Yes, it underscores how the series has consistently used its narrative to examine complex concepts in astrobiology and other scientific disciplines. More importantly though, it shows the power of imagination and as we learn more about how life could exist in the universe, we can leverage this to our entertainment. Plus, if you happen to rock nerdy science jewelry like I do on a regular basis, it’s a great talking point.
Want to learn more?
1. What is chirality: Google it. Or look at any chemistry or o-chem text book
2. Barron, L. D. (2008). Homochirality and life. Chemistry in Action, 91, 15-18.
3. Star Trek: Deep Space Nine, "Crossover." (1994), but do yourself a favor and just watch from season 3 on
4. Podlech, J. (2001). Origin of Organic Molecules and Biomolecular Homochirality. Cellular Origin and Life in Extreme Habitats and Astrobiology, 1.
