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.

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.

By changing one's frame of reference in special relativity, electric forces can be reinterpreted as magnetic forces, highlighting how the two together constitute electromagnetism.

Explore how excitatory cells, such as neurons and muscle cells, transmit information in the body via electrochemical signals, which can travel up to 120 meters (390 feet) per second.

Watch a timeline of the history of electricity, from observations of static electricity in antiquity to the War of the Currents—a rivalry to establish the ideal system for electric grids.

Electricity can flow indefinitely along a ring of superconducting material, which provides zero resistance to the movement of charges due to quantum effects.

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

Light appears to slow down as it travels through different materials

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

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

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

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

Watch lightning strike a building at 40,000 frames per second

View the electromagnetic spectrum and the properties of different types of light

According to the special theory of relativity, the faster objects move through space, the less they move through time, and therefore age more slowly.

Electricity can be lethal because it can disrupt the nervous system, which controls critical bodily functions that rely on electrical signals between cells, such as breathing and heart rate.

While charges consistently move in the same direction in a direct current, the flow of charges changes multiple times per second in an alternating current.

The unpredictability and brevity of lightning make lightning power impractical

With a core consisting of a glass fiber roughly the width of human hair, fiber-optic cables transmit digital information via flashes of light that reflect within the glass.

On average, the human body produces about 100 watts of electricity—enough to power a light bulb—but some people can produce over 2,000 watts in short bursts, such as when sprinting.

Tesla's alternating current power's most of the world's electric grids

The hypothetical particle that travels faster than light

How brain cells carry information

At the Large Hadron Collider, protons are accelerated so close to the speed of light that they would lag behind a laser by just 10 feet after 14 minutes of travel.

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

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

Unlike other metals, mercury is a liquid at room temperature because of special relativity, which affects the spatial distribution of electrons in the atoms.

Units involving light, such as light-seconds and light-years, describe the distances traveled by light across that amount of time.

Electricity can be created by changing a magnetic field—a phenomenon known as electromagnetic induction.

For the speed of light to be constant for all observers, space and time cannot be absolute, universal dimensions that are identical for everyone.

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

You can measure the speed of light with a microwave oven and chocolate, cheese, or other uniformly thick foods.

If a source of music traveled past someone at twice the speed of sound, assuming sufficiently sensitive hearing and powerful equipment, they would hear the music backward.

Fluorescent bulbs can be illuminated by overhead power lines without making contact

Tachyons are theoretical particles that travel through space faster than light

The characteristic zigzag of lightning originates from columns of conductive oxygen

Gold has a yellowish appearance rather than the silvery color of most metals because of special relativity, which causes gold's electrons to absorb blue light.

Watch an animated derivation of the mass-energy equivalence, or E = mc², as a consequence of special relativity.

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.

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.

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

Individuals moving at different speeds may disagree on the order of observed events because each experiences the passage of time differently, according to special relativity.

While moving through space faster than the speed of light is forbidden by special relativity, dark energy makes about 97% of galaxies appear to do so.

Being near a lightning strike—even without getting struck—can be fatal

Simulate the buildup and discharge of static electricity through friction by dragging the arm and leg of 'John Travoltage' along surfaces.

The engineering underlying the electric grid and why it needs to be modernized

You have never made physical contact with anything in your life because electrons in the outer layer of atoms on the surface of objects repel one another.

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.

The air around lightning can reach a temperature of about 30,000 degrees Celsius (54,000 degrees Fahrenheit)—five times hotter than the surface of the sun.

Named after Nikola Tesla, who pioneered alternating current power systems, the Tesla coil was the first device to wirelessly transmit electricity.

While atomic clocks measure time using the movement of electrons between energy levels, nuclear clocks track energy shifts within atomic nuclei to achieve greater accuracy.