Light has been observed bouncing off light instead of simply passing through it—a phenomenon predicted by quantum field theory.

Photons are both particles of light and messengers of the electromagnetic force

Visualize quantum field theory, where observable forces like electromagnetism result from energy and momentum being exchanged between universe-sized fields.

Virtual particles are not real—they cannot be directly observed—but they help scientists resolve how forces affect particles in quantum field theory.

Quantum electrodynamics is considered the first true quantum field theory, which applied quantum mechanics to the electromagnetic radiation field.

Every fundamental particle is a vibration in a field that spans the entire universe, according to quantum field theory.

Because they move at the cosmic speed limit through space, photons—particles of light—do not 'perceive' distance or the passage of time.

Light appears to slow as it travels through transparent materials due to interactions with the charged particles in the atoms of the material.

Light has been modeled as a wave and a stream of particles throughout history

Particle interactions follow rules related to specific quantum properties

Leptons do not experience the strong nuclear force that binds quarks together

Metal plates can be pushed together by empty space—the Casimir effect—because of virtual particles that cannot be observed but are predicted by quantum field theory.

Watch the motion of an individual photon using a high-speed camera

The Higgs boson provides a mechanism that explains why some particles have mass

A 1947 discovery of an unexpected energy level in hydrogen provided evidence of quantum field fluctuations and quantum field theory.

Despite fears of creating black holes, the Large Hadron Collider produces collisions with energies of 13.6 trillion electronvolts, about one million times smaller than the energy needed to create the lightest possible black holes.

Emergent quantum phenomena can produce nonfundamental quasiparticles

Quantum tunneling allows particles to pass through classically impenetrable barriers.

The double-slit experiment is observational evidence for the wave-particle duality

Quantum mechanics explains how particles behave like both matter and waves

At the Large Hadron Collider, scientists have transformed lead into gold—a process known as chrysopoeia, which alchemists sought for centuries.

Antimatter particles possess the same mass and spin as their normal particle counterparts, but possess an opposite charge and transform into pure energy upon colliding with normal matter.

The Higgs boson is a fluctuation of the Higgs field, which gives elementary particles, such as quarks and electrons, mass as they travel through it.

Light appears to slow down as it travels through different materials

Fundamental particles of the same type, such as all electrons or all photons, are identical because they are all vibrations in the same quantum field.

The High Luminosity Large Hadron Collider will provide a tenfold increase in particle collisions compared with the initial LHC infrastructure by increasing the number of ions in collision bundles and by concentrating the ion beams.

Scientists have determined the properties of cosmic rays by analyzing their trajectories in bubble chambers—containers filled with a vapor that clings to charged particles.

Observations of colliding neutron stars by the Laser Interferometer Gravitational-Wave Observatory in 2017 confirmed that gravity travels at the speed of light.

Particles moving faster than the speed of light give nuclear reactors an eerie blue glow.

Discoveries in electromagnetism, which suggested that light traveled at a single speed, became the catalyst for overturning Isaac Newton's view that all speeds are relative.

Stephen Hawking predicted that black holes evaporate by analyzing the interaction between quantum fields and spacetime curved by black holes.

Light waves can interfere and cancel each other out

It may be possible to create dark matter in particle accelerators

There is no such thing as nothing in physics—even the vacuum of space is full of undetectable particle-antiparticle activity called 'quantum foam.'

Antimatter can be created from dark lightning—high-energy light emitted by deflected electrons after they are accelerated to near the speed of light by thunderstorms.

The one-electron theory describes the universe as having only one electron

The finite speed of light means we can only perceive the world's past

The structure of the Bullet Cluster—a collision between two clusters of galaxies—cannot be explained without dark matter, and serves as evidence for the existence of the invisible substance.

According to the equivalence principle, objects in a closed space cannot tell the difference between whether they are accelerating or experiencing a uniform gravitational field.

If particle accelerators did create black holes by packing tremendous energy into a small volume, then trillions would be created in Earth's atmosphere daily by cosmic rays.

Light takes approximately eight minutes to travel from the sun's surface to Earth, but it takes thousands of years to reach the star's surface from its core—a distance more than 200 times shorter.

How string theory explains gravity on the quantum scale, but may be untestable

The wave nature of matter can produce phenomena like negative time and retrocausality

Photons emitted via stimulated emission have identical characteristics

One of Einstein's papers challenged quantum theory but helped confirm entanglement

Quantum field theory overestimated the value of dark energy by 120 orders of magnitude—a prediction considered among the worst in the history of physics.

Research shows that cosmic rays may trigger the cascade of displaced electrons needed to produce lightning, which is also enabled by pointed ice crystals that create strong electric fields.

Protons contain countless gluons and virtual quark-antiquark pairs at any given time, though they are modeled as composed of just three quarks.

Quantum mechanical principles are responsible for chemical properties

Electrical energy transfers at near light speed, even though the electrons carrying the energy in circuits only move a fraction of a millimeter per second.

Some particles that mediate fundamental forces in nature are their own antiparticles, such as photons—particles of light and mediators of the electromagnetic force.