Biggest Mysteries in Physics: Antimatter, Dark Energy & ToE - Don Lincoln | Lex Fridman Podcast #497

Summary · 5 min read instead of 2 h 54 m

Lincoln is a particle physicist at Fermilab who has spent decades working at the frontier of high-energy physics. He co-authored one of the two 1995 top quark discovery papers and now works on the CMS detector at CERN's Large Hadron Collider. He wrote Einstein's Unfinished Dream for Oxford, and he grew up poor, with parents who did not go to college.

Lincoln describes physics as a history of unifications, from Newton's gravity and Maxwell's electromagnetism to the electroweak force and the Higgs field. He holds that a theory of everything is very far off, because unification energies are about a quadrillion times beyond today's accelerators. He doubts string theory can be tested, and he favors chasing open anomalies such as dark matter and dark energy. The conversation also covers how accelerators make antimatter and why the universe holds more matter than antimatter. Lincoln closes on the puzzles of dark energy and dark matter, which he cannot yet explain.

Minute by minute

1. 0:36

   Physics advances by unifying forces. Lincoln traces unification from Newton, who joined celestial and terrestrial gravity, to Maxwell, who in about the 1860s joined electricity and magnetism. Maxwell's equations also produce waves that move at the speed of light. Lincoln argues that digging into mysterious fundamental questions pays off later in technology, such as electrical power and nuclear power.

2. 15:16

   Einstein unified space, time and gravity. Lincoln explains that special relativity rests on two premises: the laws of nature are the same for everyone, and everyone measures the same speed of light. Minkowski then showed that space and time form one space-time. Collider experiments with fast-moving particles that decay into photons confirm the constant speed of light. Lincoln says general relativity came from seeing acceleration and gravity as alike, and that genius needs a spark plus discipline and critique.

3. 32:26

   The Higgs field fixes electroweak theory. Lincoln says physicists knew four forces by the 1930s. In 1967 Weinberg, Glashow and Salam unified electromagnetism and the weak force, but the weak force has a tiny range and electromagnetism an infinite one. The Higgs field, proposed in 1964, gives the W and Z particles mass and leaves the photon massless. Lincoln says it switched on about 10 to the minus 12 seconds after the Big Bang, and he calls the theory a Band-Aid on electroweak theory.

4. 45:01

   Colliders turn energy into new particles. Lincoln explains that colliders convert collision energy into matter and antimatter pairs. Fermilab needed about 100,000 protons to make one antiproton. The LHC has about seven times the energy per collision and about a hundred times more collisions per second than the Tevatron. His 1995 top quark paper had 38 candidates, about half background, while the LHC now makes one top quark a second. Triggers cut 40 million pictures a second to about a thousand recorded.

5. 1:02:06

   The Higgs discovery was only provisional at first. Lincoln says Fermilab and CERN could each find or rule out the Higgs, but the LHC had the advantage. Two days before the July 4, 2012 announcement, Fermilab could not yet exclude the region where it must lie. He stresses that CERN first found a particle consistent with the Higgs boson. Later measurements confirmed its spin of zero and its decay rates. He says the God particle nickname came from a book whose publisher wanted sales.

6. 1:12:45

   Gravity and a theory of everything remain distant. Lincoln says a grand unified theory would merge the electroweak and strong forces and leave gravity outside. He believes rules governing reality exist and can be learned, but not within his grandchildren's grandchildren's lifetimes. The unification scale is a quadrillion times beyond today's accelerators, and accelerator energy rises only about a factor of seven every 20 years. At that rate he calculates about 500 years, and he expects the pace to slow.

7. 1:21:37

   Extrapolating a quadrillion times is arrogant. Lincoln compares physicists to an australopithecus who cannot predict oceans, the Alps or penguins from a few miles of walking. Extrapolating a quadrillion times past current data, he argues, is the pinnacle of arrogance, and he thinks string theory is probably wrong. He prefers exploring open puzzles such as dark matter, dark energy and the nature of space and time. He cites Vera Rubin's galaxy rotation measurement as a clue that came from a surprise, not from theory.

8. 1:32:30

   String theory is hard to kill but stalled. Lincoln says string theory's huge landscape of possible universes could shrink if a measurement ruled options out. He thinks a theory is only killed by a failed prediction, but that researchers are leaving it after 50 years without a solution. Loop quantum gravity, he says, only aims to quantize gravity. Its old prediction of light speed varying with wavelength failed against gamma ray bursts, though Rovelli says the theory has since changed.

9. 1:42:25

   Empty space is full of virtual particles. Lincoln explains that quantum field theory fills space with fields, and that vibrations of those fields that are not quite particles are virtual particles. He gives two tests. The Casimir effect pushes two close parallel plates together, and the 1948 measurement of the electron's magnetic properties differed from older theory by 0.1%. Quantum electrodynamics explains it, and theory and data now agree for 10 places of 12 measured.

10. 1:49:25

    Antimatter was predicted, then made. Lincoln recounts that Paul Dirac predicted antimatter in 1928 from his equations and Carl Anderson discovered the positron in 1932. Accelerators later produced antiprotons, antineutrons and antihelium nuclei, and CERN makes antihydrogen. In 2023 the ALPHA experiment found that antihydrogen falls down, at 0.75 of the strength for matter with uncertainties of about 0.29, consistent with 1.

11. 1:55:01

    Antimatter is too costly to use. Lincoln says Fermilab produced roughly a nanogram of antimatter a year, so a gram would take a billion years. Fridman cites a NASA estimate of 62 to 63 trillion dollars per gram of antihydrogen. Lincoln calls antimatter propulsion an engineering problem, with containment the big danger. He says only concentrating energy into proton-sized volumes makes antimatter, and he expects no new physics to make it easier.

12. 2:04:00

    Why matter outlasted antimatter is unknown. Lincoln says the early universe had about a billion and one matter particles for every billion antimatter particles, and no one knows why. Proposals fall under baryogenesis, and Fermilab pursues leptogenesis by comparing how neutrinos and antineutrinos oscillate. A group in Japan is racing Fermilab on this. Lincoln bets they oscillate at the same rate but says the measurement will decide.

13. 2:10:25

    Dark energy clashes with quantum field theory. Lincoln explains that in the late 1990s astronomers found the universe's expansion speeding up, which implies a repulsive effect called dark energy, like Einstein's cosmological constant. Quantum field theory predicts a vacuum energy 10 to the 120 times too large, or 10 to the 60 times even with new physics at today's accelerator energies. He mentions a recent unconfirmed hint that dark energy is shrinking, and he floats the speculative idea that space is quantized.

14. 2:27:35

    Dark matter looks real but stays unidentified. Lincoln lists galaxies spinning too fast, clusters moving too quickly and gravitational lensing as evidence. He once favored modified gravity or inertia, but the Bullet Cluster and the Dragonfly galaxies DF2 and DF4 moved him toward real dark matter. Black holes and rogue planets are ruled out, and WIMP searches have found nothing. The possible mass ranges from an asteroid to far below an electron, and dark matter is about five times more prevalent than ordinary matter.

Published May 29, 2026.