Lab report · The science of the Force

Midi-chlorians

Microscopic life inside every living cell — and the reason a Jedi can hear the Force. Here we put midi-chlorians under the microscope: what the films and series actually say, what George Lucas had in mind, and how much of it real biology backs up.

First mentioned
Episode I — The Phantom Menace · 1999
Lives in
every living cell
Highest count on screen
Anakin: over 20,000
Real-world model
mitochondria

What the films say

Midi-chlorians arrive in The Phantom Menace, when young Anakin asks Qui-Gon Jinn what they are:

Midi-chlorians are a microscopic life-form that resides within all living cells… Without the midi-chlorians, life could not exist, and we would have no knowledge of the Force. They continually speak to us, telling us the will of the Force.

— Qui-Gon Jinn, The Phantom Menace (1999)

So midi-chlorians aren't the Force itself — they're the line to it. The more of them in your cells, the better you hear it. A high count is talent, not mastery: it says nothing about training, and nothing about which side you'll choose.

The count is measured in the blood, and Anakin's test produces the most famous number in the saga:

The reading's off the chart… over twenty thousand. Even Master Yoda doesn't have a midi-chlorian count that high.

— Obi-Wan Kenobi, The Phantom Menace

“No Jedi has,” Qui-Gon replies. Since then midi-chlorians have come up on screen only a handful of times — here is every one of them.[1]

Every mention on screen

  1. 1999

    Episode I — The Phantom Menace

    Qui-Gon explains what midi-chlorians are, Anakin's blood test reads “over twenty thousand”, and Qui-Gon suggests the boy was conceived by them.

  2. 2005

    Episode III — Revenge of the Sith

    Palpatine tells Anakin the tragedy of Darth Plagueis, who “could use the Force to influence the midi-chlorians to create life”.

  3. 2014 · Season 6

    The Clone Wars

    Qui-Gon's voice teaches Yoda about the Living and the Cosmic Force through midi-chlorians, and Yoda travels to the Wellspring of Life — the planet midi-chlorians come from.

  4. 2020

    The Mandalorian — Season 2

    Dr. Pershing's recordings: experiments with transfusions of Grogu's blood, prized for its high “M-count”.

  5. 2024 · Season 3

    The Bad Batch

    Project Necromancer: the Empire tries to carry a high M-count over into clones, and Omega's blood turns out to be the key.

  6. 2024

    The Acolyte

    A Jedi test shows that twins Osha and Mae have identical midi-chlorians — something that can't happen naturally, even in twins.

Anatomy of a midi-chlorian

No film has shown a midi-chlorian up close, so here is a reconstruction based on the organelle they were modeled on: the mitochondrion. Parts 1–4 are real mitochondrial anatomy; 5 and 6 are our guesses at what a midi-chlorian would need on top of that.

Fig. 1
  1. Outer membrane: the border between the symbiont and its host cell.
  2. Inner membrane folded into ridges. In mitochondria these cristae make the cell's energy.
  3. A ring of its own DNA — a leftover from the days when mitochondria were free-living bacteria.
  4. Ribosomes, tiny protein factories of the bacterial kind.
  5. A “Force antenna”: whatever lets midi-chlorians sense the Force. Nothing in biology works like this.
  6. Signals to the host: how they “speak to us”. Real cells and microbes do talk — with molecules.
A midi-chlorian drawn on a mitochondrion's blueprint. A speculative reconstruction.

The real-world blueprint: mitochondria

George Lucas has described midi-chlorians as “a loose depiction of mitochondria” — tiny partners without which, as he put it, there wouldn't be any life.[2] Their name is usually read as a blend of mitochondrion and chloroplast, the two parts of living cells that were once free-living bacteria.[3]

That part is real science. About two billion years ago, a cell swallowed a bacterium and, instead of digesting it, kept it. The guest got shelter and food; the host got a power plant. Their descendants are the mitochondria in almost every cell of your body. They still carry their own DNA — 16,569 letters, 37 genes — and multiply on their own. Lynn Margulis made the idea famous in 1967.[4][5]

Fig. 2
Endosymbiosis: how a bacterium became part of the cell. Midi-chlorians are the same story with the Force added.

Even Qui-Gon's definition of symbionts — “life-forms living together for mutual advantage” — is exactly how biologists describe mutualism.

How many are there?

On screen there is exactly one number: Anakin's “over twenty thousand”, with no units — per cell? per drop of blood? George Lucas was more specific when he explained the idea to Terry Brooks, who wrote the novelization: an ordinary being has one, two or three midi-chlorians in each cell, while Anakin has “like a thousand”.[6]

The exact counts on fan wikis — Yoda 17,700 and so on — come from neither the films nor the series. Here are the numbers that do exist, next to real mitochondria:

Fig. 3
  • Star Wars
  • Real biology
  • Ordinary being, according to Lucas 1–3 per cell
  • Anakin, according to Lucas ≈ 1,000 per cell
  • Mitochondria in a liver cell 1,000–2,000 per cell
  • Anakin, in the film over 20,000 — units unknown
  • Mitochondria in a human egg cell 100,000–600,000

Logarithmic scale: each grid line is ten times the one before.

Midi-chlorian counts next to mitochondria.[7][8]

Would twenty thousand even fit?

A liver cell holds 1,000–2,000 mitochondria, and together they fill about 22% of it.[7][9] Take 1,500 as the middle: one mitochondrion is roughly 1/7,000 of the cell. Twenty thousand mitochondrion-sized midi-chlorians would then need almost three cells' worth of room — even with everything else thrown out. Lucas's thousand per cell would take a modest 15%.

So either the film's number isn't per cell, or midi-chlorians are much smaller than mitochondria. Try it yourself:

Fig. 4
20,000
Size compared to a mitochondrion

293% of the cell's volumeDoesn't fit: the cell would burst

The picture is a thin slice of the cell. In a slice, the share of the area equals the share of the volume, so the proportions are true.

Interactive: how much of a liver cell midi-chlorians would take up.

The blood test

On Tatooine, Qui-Gon takes a drop of Anakin's blood and sends the reading to Obi-Wan aboard the queen's ship. Real labs do something very similar: they measure how many copies of mitochondrial DNA a cell carries — the mtDNA copy number — by quantitative PCR, and use it as a marker in research on aging and disease.[10]

One catch: mature red blood cells, which make up most of the cells in a drop of blood, have no mitochondria at all, so labs count the white cells instead.[10] If midi-chlorians behaved like mitochondria, a Jedi analyzer would have to do the same.

Fig. 5
Obi-Wan's scanner: the needle runs past the end of the scale.

“There was no father”

Shmi Skywalker says Anakin had no father, and Qui-Gon suggests the boy was conceived by the midi-chlorians. In Revenge of the Sith, Palpatine tells of Darth Plagueis, who could make midi-chlorians create life, and fans have suspected the Sith ever since. Lucasfilm's Story Group says no: Palpatine had nothing to do with Anakin's birth.[11]

Virgin births are real. In 2006, two Komodo dragons in British zoos laid eggs that hatched without any male; sharks, snakes and birds can do it too.[12] Mammals can't: some genes only work when they come from the father. Even so, in 2022 scientists grew a mouse from a single unfertilized egg by rewriting seven of these “imprinted” regions.[13]

But midi-chlorians would face a harder problem. A mother has two X chromosomes, so a child made from her genes alone gets X and X — a girl. Anakin is a boy, which means something had to write a whole Y chromosome: about 62 million letters of DNA.[14] Komodo dragons have it the other way round: their females are ZW, so a virgin birth gives only sons.

Fig. 6
Usual birth eggXspermX/YXX♀︎/XY♂︎
Without a father eggXcopy of the egg's genesXXX♀︎
Anakin eggXthe Force??XY♂︎
Komodo dragon eggZ/Wcopy of the egg's genesZ/WZZ♂︎/WW✕
Why a fatherless boy is the hardest part: the Y chromosome has to come from somewhere.

The heredity puzzle

We get our mitochondria from our mothers only: an egg brings 100,000–600,000 of them, while the sperm's few arrive without intact DNA and vanish.[8][15] If midi-chlorians were inherited like that, Luke and Leia would carry Padmé's midi-chlorians, not Anakin's — and Anakin's own would have ended with him.

The saga shows the opposite: the Force runs through fathers too. Real cells suggest a way out. How many mitochondria a cell keeps is largely set by genes in its nucleus, and those come from both parents. Maybe the symbionts come from the mother, but the count is inherited from both.

Fig. 7
  • Mitochondria from Shmi
  • Mitochondria from Padmé
  • Strong in the Force on screen
The Skywalkers: whose mitochondria they carry, and who is strong in the Force.

Real-life midi-chlorians

Midichloria mitochondrii

A real bacterium named after midi-chlorians, with George Lucas's permission. It lives inside the mitochondria of the castor bean tick and is passed from mother to offspring.[3]

Wolbachia

Lives in the cells of more than 40% of arthropod species and travels from mother to offspring inside the egg. In some tiny wasps it makes females give birth to daughters with no males at all — a real case of being “conceived by symbionts”.[16]

Vibrio fischeri

Glowing bacteria in the light organ of the Hawaiian bobtail squid that hide its shadow from predators at night. They switch on their light only once enough of them gather — and they find that out by “talking” to each other with chemical signals.[17]

Mitochondria and chloroplasts

Former bacteria that now power every animal cell and every green leaf. Without them complex life couldn't exist — exactly what Qui-Gon says about midi-chlorians.

What Lucas planned next: the Whills

In a 2018 conversation with James Cameron, Lucas said his own sequel trilogy would have dived into the “microbiotic world”: creatures he called the Whills, who feed off the Force and actually control the universe. Jedi, Sith and the rest of us would be vehicles for them to travel around in, with midi-chlorians as the go-between. Lucas admitted that a lot of fans would have hated it.[18]

Verdict: how scientific are midi-chlorians?

  • Life that lives inside our cellsRealMitochondria, Wolbachia, Midichloria
  • Symbionts passed from mother to childRealMitochondria, Wolbachia
  • Counting them in a drop of bloodRealmtDNA copy number by PCR
  • Twenty thousand in every cellPartlyOnly if they're far smaller than mitochondria
  • A boy without a fatherNoA Y chromosome has to come from somewhere
  • Symbionts that talkPartlyBacteria signal each other with molecules
  • Telling us the will of the ForceBeyond scienceNo instrument can check that

Midi-chlorians are closer to real biology than their reputation suggests: life inside life, symbionts passed down in the egg, counting them in blood — all of it exists. What science can't supply is the Force itself. Which is probably for the best.

Sources

  1. Wookieepedia — “Midi-chlorian”
  2. Wikipedia — “The Force”: George Lucas on midi-chlorians and mitochondria
  3. Wikipedia — “Midichloria”
  4. L. Sagan (Margulis). On the origin of mitosing cells. Journal of Theoretical Biology, 1967
  5. Wikipedia — “Mitochondrial DNA”
  6. StarWars.com — “So What the Heck Are Midi-Chlorians?”
  7. P. An et al. Hepatocyte mitochondria-derived danger signals directly activate hepatic stellate cells and drive progression of liver fibrosis. Nature Communications, 2020
  8. The Embryo Project Encyclopedia (Arizona State University) — “Mitochondrial DNA (mtDNA)”
  9. B. Alberts et al. Molecular Biology of the Cell, 4th ed., table 12-1
  10. R. J. Longchamps et al. Evaluation of mitochondrial DNA copy number estimation techniques. PLOS ONE, 2020
  11. ComicBook.com — Lucasfilm Story Group on Palpatine and Anakin’s birth (2019)
  12. P. C. Watts et al. Parthenogenesis in Komodo dragons. Nature, 2006
  13. Y. Wei et al. Viable offspring derived from single unfertilized mammalian oocytes. PNAS, 2022
  14. A. Rhie et al. The complete sequence of a human Y chromosome. Nature, 2023
  15. W. Lee et al. Molecular basis for maternal inheritance of human mitochondrial DNA. Nature Genetics, 2023
  16. Wikipedia — “Wolbachia”
  17. S. C. Verma, T. Miyashiro. Quorum sensing in the squid–Vibrio symbiosis. International Journal of Molecular Sciences, 2013
  18. Gizmodo — George Lucas’ ideas for his own Star Wars sequel trilogy (2018)

Now watch it all in order

Every movie, series and game in which the Force runs strong — on one timeline, with a progress tracker.

Open the timeline