The Moon Is Falling. It Just Keeps Missing.

Lex Fridman opens with a frame Don Lincoln has used himself: the search for a theory of everything is really a centuries-long effort to show that distinct phenomena are the same thing underneath. Lincoln, a particle physicist at Fermilab, says that is how particle physicists and cosmologists work. They are not collecting curiosities. They are hunting the underlying principles that govern matter, energy, space, and time.

Go back to the 1650s, he says, and suppose you are the most brilliant person around. You have noticed two facts that seem to have nothing to do with each other. Trip, and you fall: terrestrial gravity, the everyday kind. Look up, and stars march across the sky while planets wander through them: celestial gravity, the astronomy of the heavens. Drop a sandwich and the dog grabs it. That mishap does not look like the Moon. Newton's leap was to treat the Moon as something that is falling and missing the Earth.

The textbooks still call the result Newton's law of *universal* gravitation, and Lincoln lingers on the adjective. Universal is doing real work. Before Newton, the two regimes really did look like two sets of laws. After him, there is just gravity. Lincoln calls it the first unification that a modern listener can state in plain language, and he ranks Newton among the most brilliant humans he knows of. Particle physics, in his telling, is the same impulse pushed all the way down: not only the smallest LEGO bricks, but the rules for how they snap together.

By about 1830, scientists were getting a grip on electricity, generating parlor sparks, while magnets were still mostly bits of iron that stuck to steel. A lightning bolt blazing across the sky did not look related to either. Over the next few decades, experimenters found scraps of a connection: run a current through a wire and a magnetic field appears. In the 1860s James Clerk Maxwell took fifty years of those results and wrote the laws of electromagnetism. Forget the calculus, Lincoln says, and look at the shape. One side of the equations is electricity. The other side is magnetism. Electricity equals magnetism.

Apply a little more math and Maxwell's equations become a wave equation: electric and magnetic fields oscillating and traveling. The speed that falls out is the speed of light, unbidden. Nobody told Maxwell to compute that number; it appeared. Electromagnetism also holds atoms together, so chemistry itself sits on the same unification. Lincoln climbs onto a small soapbox here. People asked why anyone was messing around with magnets and sparks. The spinoff, a century or two later, is the entire technological society. Without control of electricity, he says, we would still be farmers and shoemakers.

The same pattern, he adds, is already visible in nuclear physics. A hundred years ago, people were trying to understand how protons and neutrons hold together and split. That work led to nuclear power: contentious, powerful, and one of the few energy sources large enough to wean a civilization off fossil fuels. Fridman notes the longer horizon — antimatter, dark energy, maybe propulsion — and the double edge. Lincoln's answer is fire. Fire can burn your house or cook your steak. Scientists figure out how the world works. Society decides whether and how to use what they find.

Einstein's 1905 miracle year included special relativity, which says something that still sounds wrong if you have not sat with it: two people experience time differently. Newton had treated time as universal — yours, mine, a clock on Mars, a clock at Alpha Centauri, all the same. Einstein showed that people moving at different speeds relative to one another do not share that clock. Most popular accounts then credit him with inventing spacetime. The person who wrote space and time as components of one thing, Lincoln says, was Einstein's teacher Hermann Minkowski, who in 1908 looked at the equations and saw that one person's space and time equal some numbers times another person's space and time.

The hard part is not the algebra. Time, viscerally, just runs. Space lets you walk away and walk back. Time offers one easy direction. Special relativity starts from two premises. The first is Galilean and uncontroversial: the laws of nature look the same for everyone. The second sounded dumb in 1905: everybody measures the same speed of light, no matter how they are moving. Take those together and the weirdness of special relativity follows. For a long time the second premise was trusted because the predictions worked. Now particle physicists can test it directly.

Some subatomic particles decay by emitting light. Collide two particles so you know when the new one was born, surround the point with a detector, and time how long the light takes to arrive. It is the speed of light. Sometimes the parent is itself flying at 95 or 97 percent of that speed when it decays into photons. If Einstein were wrong, those photons should arrive in about half the time, as if they had inherited the parent's velocity. They do not. Light from a nearly-light-speed parent still crawls to the detector at c. Lincoln's first encounter with that speed limit, he says, peaked the weirdness meter. Once you treat it as the speed of things through spacetime — a property of space, like how strong an electric field space can support — it becomes comfortable.

General relativity is the next unification, and Fridman thinks Einstein deserved a Nobel for it that he never got. The seed is the equivalence principle: in a quiet accelerating rocket, you feel as if you are in gravity. Einstein later called that one of his happiest thoughts. What impresses Lincoln is the step after the thought. If acceleration and gravity are indistinguishable, maybe gravity is not a force at all but the bending of the spacetime Minkowski had written down. East-west-north-south as a flat map is already hard. Now crumple the map. That crumple is gravity. "That is a staggering, mind-blowing idea."

Fridman asks how such an idea is generated. Lincoln's list is unromantic and then suddenly not. You need the history of what came before, the mathematics to extract consequences, and the discipline to argue with yourself because most ideas are wrong. On top of that sits an intuitive spark that is very hard to create, which is why we venerate the people who had it. Most of us get one aha in a lifetime, if that. Letters from creative thinkers who skip the history, the math, and the self-critique arrive in Lincoln's inbox regularly, and they are usually easy to kill. Genius, as he describes it, is the amalgam of the spark with the willingness to beat an idea to death.

Einstein himself is the cautionary case. He could live with spacetime bending and still find quantum mechanics too weird — Lincoln admits it is weird for him too. That did not make Einstein useless. He understood the theory well enough to say, if you are right, then this, and the this, including entanglement, turned out to be real. Critique that can kill a theory is as much a scientific instrument as the aha. Niels Bohr's line, which Lincoln loves, sits on the other side of the same coin: we all agree your idea is crazy, but is it crazy enough?

By the 1930s, physicists had four forces that did not look connected: gravity, electromagnetism, the strong nuclear force that holds nuclei together, and the weak nuclear force behind some kinds of radioactivity. Most people never meet the last two, because they live inside the nucleus. Four forces was already a triumph. The unification dream said they might be four faces of one. In the late 1950s and early 1960s some theorists started to suspect that the weak force and electromagnetism were the same thing. In 1967 Steven Weinberg, Sheldon Glashow, and Abdus Salam showed that at high enough energy they merge into a single electroweak force.

The obvious objection is brutal. Electromagnetism has infinite range: we see stars millions of light-years away. The weak force is effectively gone on distances much smaller than a proton. Calling those the same force sounds, Lincoln says, dumb. The rescue had already been written in 1964 by three groups, six people, in papers about what we now call the Higgs field. If forces are carried by particles — photons for electromagnetism, W and Z particles for the weak force — then a massless carrier reaches across the universe and a massive one does not. Postulate a field that fills space. Particles that interact with it get mass. Particles that ignore it do not. The photon laughs at the Higgs field. The W and Z do not.

Lincoln hangs the idea on gravity, which is sitting in the room whether you can see it or not. A pen has mass, so it falls. A massless particle would float, indifferent. Some particles, in this language, have a Higgs charge and some do not. At the huge energies just after the Big Bang the Higgs field's strength was zero, so even the weak-force particles were massless and could travel at light speed like the photon. When the universe cooled, at 10 to the minus 12 seconds, the field turned on: electroweak symmetry breaking. Photons stayed massless. W and Z got heavy. The electroweak theory itself, Lincoln says, does not need the Higgs at those high energies. Higgs theory is a Band-Aid so the equations still work in the cold world we actually live in.

No one has seen the Higgs field, just as no one has seen the electromagnetic field or the gravity field. What we see are effects. In quantum field theory every particle is a localized vibration of a field, the way a photon is a vibration of the electromagnetic field. The Higgs boson is the vibration of the Higgs field. You cannot photograph the drumhead, but you can hit it and listen. By the early 2000s, Lincoln says, accelerators looked powerful enough to make those vibrations. Fermilab's Tevatron, outside Chicago, was already colliding protons and antiprotons near light speed. It had found the top quark in 1995. An upgrade bought ten times the collision rate and a bit more energy, and the hunt for the Higgs was on.

The machine makes sense only if you take E=mc² the way physicists take it: energy and mass convert into each other, including motion into new particles. Smash two structureless particles head-on so their momenta cancel. If they stop, the energy has to go somewhere, and it can become mass. Nature's bookkeeping requires that a new particle come with an antiparticle. Accelerators are, among other things, factories for particles that do not hang around in ordinary matter. The positron showed up in 1932. The antiproton was made at Berkeley's Bevatron in 1955. The reverse works too: matter and antimatter meeting become energy. None of this, Lincoln says, is controversial. They do it all the time.

Making antimatter is brutally inefficient. At Fermilab, 100,000 protons had to hit a target for one antiproton. Protons are garbage cans, not point particles, so you cannot just dial in a resonance the way you can with electrons. CERN's LHC now holds the energy frontier — about seven times the energy per collision and about a hundred times the collision rate of the old Tevatron — which is why Lincoln and many colleagues moved there once the Fermilab program had taken the measurements it could. Scale is not a slogan. The 1995 top-quark discovery paper Lincoln co-authored had 38 candidates after six months to a year of running, half of them background, maybe 19 real tops. The LHC makes a top quark every second. Tops are now a nuisance to be cut away.

The LHC, when it is running, produces about a billion collisions per second: roughly 40 million beam crossings, with about 20 collisions in each. The beams are hair-thin spaghetti, swarms of bees that mostly pass through each other. Two giant cameras sit around the collision points. CMS, Lincoln's experiment, is the "small" one: 70 feet long, 50 feet high, 14,000 tons. ATLAS is 150 feet long and 80 feet across. They take 40 million pictures a second. Fast electronics keep about 100,000 that look interesting — gobs of energy, or energy on one side and nothing on the other — and a computer farm writes about 1,000 per second to tape. Graduate students then pick through petabytes for the handful that might be the next Nobel Prize. Lincoln wants his competitors to do extremely well, he says, just not quite as well as CMS.

The people hunting the Higgs wore two hats, and the fit was neurotic. In Fermilab colors they were desperate to find it on the Tevatron. In CERN colors they knew the LHC would find it if it existed. Lincoln was not sure the particle was real — theories can be wrong, the way dark matter might not be — but there was a lot of evidence pointing that way, and both machines could either discover a simple Higgs or rule it out across every possible mass. Look at 100, not there. Look at 103, not there. The LHC, though, had ten times the collisions per second and three and a half times the energy. The writing was on the wall.

Fermilab had already excluded most of the mass range. If a Higgs existed, Lincoln recalls, it sat somewhere between about 120 and 145 in the units they were using. Another two or three years of Tevatron running would have been enough; they did not have the data in July 2012. The LHC had turned on in 2008, broken, come back in 2010, run poorly in 2011, and in 2012 pushed up its sleeves. Two days before CERN's announcement, Fermilab put out a result: some regions excluded, some not, and if the Higgs existed it had to live in the unexcluded window. On July 4, CERN said they had it.

Lincoln is careful about the sentence they actually uttered. They had found a particle *consistent with* the Higgs boson. Supersymmetry predicted five Higgs particles; the original 1964 theory predicted one. All they knew that day was that a particle had shown up. Fourteen years of running later, the mass is measured, the spin is zero, and the decays match the old theory: preferentially into the heaviest particles energy conservation allows — bottom quarks, W and Z bosons, and, by a strange route, photons. It is too light to decay into top quarks. Lincoln is now comfortable saying Peter Higgs, Robert Brout, François Englert, and their colleagues were right in the 1960s. On July 4 they were not sure.

Was it the God particle? Lincoln does not rank it with Einstein. It was the last unvalidated piece of the Standard Model, a punctuation mark after fifty years, not a change in how we see the world. The nickname comes from Leon Lederman's book. Lederman, who had run Fermilab and written a foreword for one of Lincoln's books, joked that they should have called it the goddamn particle because it was so hard to find. The publisher preferred a title that would sell. Lederman never meant a theological claim. The Standard Model still does not answer every question. It is, Lincoln says, mostly right as far as it goes.

After electroweak unification, the next hoped-for stop is a grand unified theory that folds the electroweak force together with the strong force, leaving gravity outside. A theory of everything would then pull gravity in. Lincoln does not see fast progress. Gravity looks fundamentally different, and ideas from the early 1980s that were tested did not pan out. Does a theory of everything exist? He believes there are rules that govern matter, energy, space, and time, including phenomena we have not met, and that with enough time, technology, and effort we can find them. That is not a project for his lifetime, or his grandchildren's, or theirs.

The pace of past unifications is not the comfort it appears to be. Two hundred years from Newton to Maxwell, a hundred from Maxwell to electroweak, so maybe it is speeding up. The unification scale is of order 10^15 — a quadrillion times the energy of the best accelerator we can build. Accelerator energy has historically risen by a factor of about seven every twenty years. At that rate you are talking five hundred years, and Lincoln does not believe the curve continues, any more than Moore's Law does. A beautiful internally consistent theory is not enough. It has to make falsifiable predictions, and someone has to be able to build the experiment.

Superstrings, he says, are a fascinating idea. He does not believe them. He loves them. He hopes they are true. Then he quotes the aphorism: you should absolutely never believe what you think. Even if strings are a hundred percent correct, until they are validated they are a wild guess, and he does not care. Theorists have been working since the 1980s with approximate solutions to approximate equations. Someone listening to the podcast might find a way to push those equations down to the mass of the electron. Lincoln would then retract. His reason for betting against that is not that theorists are dull. It is that new things appear when you turn up the energy. Chemistry never predicted nuclear physics. People calculated that the Sun could only be ten million years old because they were burning the wrong fuel.

His analogy is an Australopithecus, a meter tall, wandering Kenya two million years ago. Walking a hundred meters, a prediction of the next hundred meters is fair. Walking 500 miles east, that walker has no concept of the Indian Ocean, sperm whales, the seafloor, the Alps, or Antarctica. We measure around 10^4 GeV. Strings live around 10^19 GeV. The gap is not a factor of a hundred. It is a quadrillion. Practical progress, for an experimentalist, is to tug at questions we can actually reach: are there things smaller than quarks, is dark matter real, what is dark energy, what are space and time? Loop quantum gravity, he notes, is not a rival theory of everything; it only tries to quantize space. An older version predicted that high-frequency light should outrun low-frequency light, which gamma-ray bursts a billion light-years away do not show. Carlo Rovelli wrote him a prickly note: they had changed the theory. A cleaner measurement still stands. Light and gravitational waves from two neutron stars colliding 140 million light-years away arrived within 1.7 seconds of each other. Gravity travels at the speed of light. They had thought so. Now they have the stopwatch.

Empty space is not empty, which Lincoln agrees is bizarre, and we still do not know what space is. Start, he says, with the space of calculus, infinitely divisible, even if the real thing is probably quantized. Quantum field theory then fills that space with a field for every known particle: photon, electron, up quark, down quark, and the rest. Characteristic vibrations of those fields are the particles we name. Vibrations that are a little off are virtual particles, which do not truly exist as you usually mean exist. A simpler picture says matter and antimatter pairs flicker into being and annihilate again. Both descriptions, he says, are correct. They happen too fast to see, but they have consequences.

The Casimir effect is one. Place two metal plates very close together. Between the plates, only short-wavelength virtual particles fit; outside, long and short wavelengths both appear. More particles outside than inside means a net pressure that pushes the plates together. The plates do push together. A second test is older and sharper. In 1948 the measured magnetic moment of the electron disagreed with 1930s quantum mechanics by 0.1 percent. On the way home from the Shelter Island conference, that discrepancy helped invent quantum electrodynamics, which quantizes the fields as well as the matter. A bare spinning electron sits in a bath of appearing and disappearing particles, and the bath shifts the magnetism by that 0.1 percent.

This is not a rough check. The magnetic properties of the electron and the muon have been measured to twelve significant figures. Theory and data agree, number for number, for ten of those places. Only at the last digits, where both sides have some imprecision, do they start to disagree — which may be a clue, or may be the edge of the calculation. Ten figures of agreement is, Lincoln says, staggering. Virtual particles sound nuts when you look at a quiet room. The room, according to the best theory we have, is busy anyway.

Paul Dirac predicted antimatter in 1928 while merging quantum mechanics with relativity. The Schrödinger equation was not relativistic. His new equation was something like equation squared equals one, so the square root came in a plus-one version, the electron, and a minus-one version he did not recognize. For a while people wondered whether the minus was the proton. Dirac insisted the math was right and that a positively charged sibling of the electron should exist. Carl Anderson and Seth Neddermeyer saw the positron in 1932. The antiproton was created at Berkeley in the mid-1950s; the antineutron a year later. CERN has since made antihelium nuclei and antihydrogen, cooled almost to absolute zero, and measured its light. The spectrum matches ordinary hydrogen. In 2023 the ALPHA experiment put antihydrogen in a bottle, released it, and watched. It fell down. The strength came out about 75 percent of ordinary gravity, with uncertainties large enough that the result is still consistent with one. They are tightening the measurement.

Until 2011 Fermilab was the world's most powerful antiproton factory, and the recipe was grim. Every 2.3 seconds they smashed 10^13 protons into a target and got 10^8 antiprotons — one antiproton per 100,000 protons. Collect and cool for twelve to twenty-four hours and you have about 10^12 of them, a trillion. A gram of antimatter is 10^23 antiprotons. A day's run made something like a hundred-billionth of a gram; a year, about a nanogram, matching a NASA estimate Fridman quotes. At that rate, with almost no downtime, a single gram would take a billion years. Combine that gram with a gram of matter and the energy matches Hiroshima and Nagasaki together. A megaton wants about 25 grams, or 25 billion years of Fermilab running. NASA's cost estimate is $62 to $63 trillion per gram of antihydrogen. A one-megaton nuclear warhead, by contrast, costs on the order of $10 to $50 million.

As propulsion, Lincoln says, antimatter is not a physics problem. It is an engineering problem. You can heat matter with it and throw the exhaust out the back of a rocket. Containment is the nightmare: lose it for a millionth of a second and, as Scotty keeps telling the captain, the ship is gone. He would be shocked if some new law made production easier. You have to concentrate energy into a volume the size of a proton. Accelerators already know how. A thimble of energy is not dense enough. Cheaper concentrated energy would make antimatter a piece of cake. Until then, plutonium still runs Voyager, and there are far less expensive ways to make a bang.

The deeper mystery is cosmological. Energy after the Big Bang should have made equal amounts of matter and antimatter. We look at the sky and see matter. Where did the antimatter go? Nobody knows. Counting protons in galaxies against photons in the cosmic microwave background implies a tiny early asymmetry: for every billion antimatter particles, a billion and one matter particles. The billions annihilated. The extra one is every galaxy, star, planet, and person. One option is that the universe was born lopsided. Another is baryogenesis, a slight bias in how matter and antimatter oscillate, measured already in the 1960s in short-lived accelerator particles and far too small to explain us. Fermilab is trying a cousin called leptogenesis with the world's most powerful neutrino beam. Neutrinos change identity as they travel — Lincoln's picture is a beam of cats that becomes cats, jaguars, and tigers, then cats again — a fact known since 1998. Compare a neutrino beam with an antineutrino beam. If they oscillate at slightly different rates, and if several other improbable things are also true, that might be the clue. Lincoln would bet the farm they oscillate the same. Japan is racing the same measurement. If you are not confused, he says, you are not doing your job.

Lincoln's cleanest definition: dark energy is either the energy *of* space or energy *in* space. The usual statement is the energy of space, acting as a repulsive form of gravity. In the late 1990s astronomers measured the universe's expansion expecting one of three doors. Enough matter, and expansion slows, stops, and falls back in a Big Crunch. Too little, and it slows forever without stopping. Exactly critical, and it approaches zero only at infinity. They opened door number four. Expansion is speeding up. Gravity should slow it down, so something repulsive has to be pushing. Einstein had invented a cosmological constant to keep a static universe from collapsing, then yanked it out after Hubble found expansion and thought the idea had been dumb. In 1998 the repulsive term went back in.

What is it? Lincoln does not know. The common view is that it is a property of space itself. It is at least conceivable that a field sitting in space is pushing space apart, and he is not sure instruments can tell those apart yet. Then comes what he has called the worst prediction in physics. Measure the expansion, infer the dark-energy density. Then let quantum field theory add up the energy of every wavelength in a volume, down to the shortest you can imagine. The sum is 10^120 times the measured density — a one with 120 zeros. The integral runs as the highest energy to the fourth power, and fourth powers are brutal. Even if new physics appears at the LHC and you stop integrating there, the mismatch only falls to 10^60. Something in quantum field theory is badly wrong.

A canceling field is not outrageous. Matter and antimatter already cancel rather well. Canceling to zero is easy: plus one minus one. Dark energy is the leftover bit, so the cancellation would have to be imperfect, and imperfect cancellation is much harder. Theorists, Lincoln says, do perfect cancellation eight times before breakfast. A recent unconfirmed measurement hints that dark energy is getting smaller; nobody should believe it yet, but it is interesting because the working bias has been that the *density* is constant. Constant density in an expanding volume means the total energy is rising, while ordinary matter thins out. That is how dark energy takes over the energy budget. Lincoln's own guess — property of space, space quantized, new quanta appearing as the universe grows, each carrying a bit of energy — would explain a constant density. He immediately tells the audience not to believe a word of it. It is hand-waving. A nearer experiment, using quantum entanglement of masses, might at least show whether gravity itself is quantized, which would shut off a whole class of continuous-gravity theories even if it said nothing about what dark energy is.

Dark matter, Lincoln says, is even more mysterious than dark energy, and the first question is why we believe in it at all. Astronomical measurements disagree with Newtonian gravity and with relativity: galaxies spin too fast, clusters of galaxies move too quickly, and gravitational lensing of distant galaxies does not match the matter we can see. Three independent mismatches. The easiest story is a spinning galaxy. Add up the visible mass, compute the gravity, and the stars are moving so fast the galaxy should fling itself apart. It does not. The equation is simple: the force needed for circular motion equals the force of gravity. So either Newton's inverse-square law is wrong, or F=ma is wrong, or there is mass we cannot see.

Twenty-five years ago Lincoln would have bet on modified gravity or modified inertia. Two observations moved him. The Bullet Cluster is two galaxy clusters that have passed through each other. Galaxies themselves barely interact and sail on; the huge gas clouds slam, stop, and get hot. If there were no dark matter, the gravitational lensing should peak on the hot gas, which outweighs the galaxies. If dark matter is real and does not interact with the gas, the lensing should sit on the galaxies. That is what is seen. More recently, Dragonfly 2 and Dragonfly 4 rotate exactly as Newton says they should. Whatever makes other galaxies spin too fast is not a property of matter as such, because some galaxies do not have it. A galaxy stripped of dark matter is, in Lincoln's phrase, strong evidence that dark matter can be taken out — which is to say, that it is a thing.

He knows what it is not. In the 1990s, MACHO, OGLE, and similar microlensing searches looked for unseen black holes and rogue planets. They found some, not enough. Dark matter is five times ordinary matter; if it were black holes we would be tripping over them. That leaves a particle, long nicknamed a WIMP, a weakly interacting massive particle. Direct detection puts underground detectors in the supposed dark-matter wind and has seen nothing. Indirect detection looks for gamma rays from annihilation at galactic centers and keeps getting confused with neutron stars. Colliders try to make the particle and infer it from missing momentum, the same signature neutrinos already produce, and that has not worked either. The allowed mass range runs from something like an asteroid down to far lighter than an electron. A few spots are ruled out. The map is still huge, which is why Lincoln does not run a dark-matter experiment: pick one mass window and you are blind to the rest. Many groups, many methods. He would like the answer in his lifetime. You have to get lucky, he says, and look in the right place.

Lincoln grew up poor in the boondocks. His parents did not go to college and could not guide him academically; they were, he says, very nurturing. His mother jokes that she had to stop helping with math after sixth or seventh grade. Three things folded into the physicist. He was a voracious reader of science fiction, a book a day, which drove his mother nuts and trained his imagination. In the 1970s, Isaac Asimov, Carl Sagan, and George Gamow were writing science for laypeople. A kid who could not parse a textbook could still get a hint. And he was irrepressibly curious, with a quasi-philosophical mind pointed at questions that had been theological, then philosophical, and are now scientific: how the universe began, why the laws are these laws, how it might end.

He minored in philosophy and religion in college, hoping the history would help. It taught him how the questions had been asked. The answers he wanted were not in those directions. The remaining choice was cosmologist or particle physicist. In the mid-1980s cosmology was long on thought and short on measurement. Particle physics let you do experiments and actually get an answer. That is why he writes books and makes videos. Somewhere in Iowa, Kansas, or Montana, he figures, there is another kid in a small town without highly educated parents. Some of them have already turned up as summer interns because they saw a video or read a book. One of Fridman's viewers, Lincoln says, might be the person who answers questions that have stymied very smart people for decades.

The early Fermilab years were not balanced. Unencumbered, with no family, he worked Monday through Saturday from 8 a.m. to midnight because he wanted to be there, and Sunday from 8 until 5 so he could wash clothes and buy groceries in the evening. He loved it. He cannot do that now, because of other obligations; if he had been rich he would have done the same. All scientists are smart. What separates the ones who finish measurements is drive and grit. A broken apparatus ticks him off. He is not going to let the universe, or the lab, beat him. Some people go home. He gets madder and puts in more effort. If the work does not bring you joy, it might not be for you, and you can still read and stay involved. If you want to be a real scientist, it has to be part of what you are. Fridman closes with Marie Curie: nothing in life is to be feared, it is only to be understood.