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.

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

Light appears to slow down as it travels through different materials

Gold's electrical conductivity, reflectivity, and catalytic capabilities make it scientifically valuable

The outermost shell of electrons in an atom dictates how it bonds to other atoms, including those of the same element, and the properties of the materials composed of those atoms.

Breaking down sunlight and why the sun appears yellow despite emitting green light the most

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

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

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

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.

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

Although the color of light changes due to motion between a source and an observer—the Doppler effect—relativistic motion further alters it due to time dilation.

Gold has no nutritional value or flavor—but edible gold is still popular

Starting with red, colorful objects will appear to lose their colors the deeper they are submerged because water scatters light, reducing the amount available to reflect off objects and be observed.

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.

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.

The different energy levels of each element result in unique colors when burned

View an animation of how certain chemicals fluoresce—that is, emit visible light after having absorbed higher-energy light, such as ultraviolet radiation.

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

The RGB color system resembles how quantum chromodynamics models quarks and the strong nuclear force—both quarks and gluons carry color charge.

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

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.

Colored diamonds result from elemental impurities, structural deformities, and exposure to radiation.

All of the world's gold, visualized

By analyzing the color of starlight, astronomers can determine how fast stars within a galaxy are moving toward or away from Earth, revealing the expansion rate of the universe.

By separating light with tools such as prisms, scientists can reveal the presence and composition of celestial matter by identifying color fingerprints unique to specific elements and molecules.

Albert Einstein's theory of gravity arose from what he described as 'the happiest thought of his life': realizing that a person who fell off the roof of their house would not feel their own weight as they fell.

Gold can be dissolved by aqua regia—a combination of two acids that, on their own, cannot dissolve gold.

Visualize how the order of events changes, according to special relativity, when the perspective is changed between observers who move relative to one another.

As the universe expands, the color of light shifts as it travels through space

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

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.

Metals are considered noble if they are highly resistant to corrosion, rust, and tarnishing, and include gold, platinum, and palladium.

The underlying fabric of the universe—spacetime—changes shape in the presence of mass and energy, which affects measurements of space and time.

How scientists determine elemental composition based on the light emitted by cooling atoms

Through gravitational redshift, light loses energy as it leaves a massive object

Atmospheric composition and temperature impact the color of lightning

The colors of auroras change with the intensity of solar activity and with altitude because of differences in atmospheric density and chemical composition.

Earth's core is leaking precious metals, including gold

Watch some effects of special relativity become increasingly more apparent in 'A Slower Speed of Light,' a video game prototype from the MIT Game Lab.

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.

The chlorophyll in plants captures energy in the form of red and blue light

Relative motion between a source and an observer shifts the color of observed light

Egg yolks and carrots have the same pigments that contribute to the yellow and orange colors of fall foliage.

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

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

How the pigments that absorb light for photosynthesis contribute to plants' green color

Rayleigh scattering of light gives the atmosphere its blue skies and red sunsets

A gold standard is a system in which a country’s currency is pegged to, and can be converted into, a fixed amount of gold

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.

A gold standard is a system where every dollar in circulation can be exchanged for a set amount of gold