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

Gold has a yellowish appearance instead of the silvery coloration of most other metals because of special relativity, which causes its electrons to absorb blue light.

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.

Simulate the precession of Mercury's perihelion—the gradual shift in the closest point of Mercury's path around the sun as its elliptical orbit rotates.

Once cooled to temperatures just above 2 Kelvin, helium atoms exhibit a quantum property that removes internal friction, allowing the fluid to climb up walls.

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.

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.

In the 1910s, physicists proved that the existing laws of physics made it impossible for solid magnets to exist—a finding overturned by quantum mechanics.

Metallic hydrogen exists in Jupiter and Saturn due to high pressure and temperature

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

A breakdown of the experimental test results supporting the general theory of relativity

Earth's atmosphere regularly loses hydrogen and helium as these elements are accelerated enough by collisions with high-energy particles from the sun to escape Earth's gravity.

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

Instead of the tectonic plates found on Earth that produce earthquakes, volcanoes, and other geological activity when they interact, Mercury, Mars, and the moon have continuous, unbroken shells of rock called 'stagnant lids.'

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 speed of electricity may refer to the movement of electrons, which is on the order of a fraction of a millimeter per second, or energy, which is near the speed of light.

The properties of helium, which has the lowest boiling point of any element

The magnetic constant sets the strength of magnetic fields

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.

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.

Certain objects are magnetic because their electrons' magnetic moment—an intrinsic quantum property—align within the object in specific patterns.

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

Despite the name, antimatter does not behave as though subject to antigravity.

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

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

Heat slowly moves through Earth's mantle like softened wax

Lasers can be used to reduce the motion of atoms because particles of light—photons—can collide with particles of matter, as billiard balls do, to slow them down.

The invention of the barometer proved that air has weight

Light appears to slow down as it travels through different materials

Making up about three-quarters of the visible matter in the universe, hydrogen is the only element whose isotopes have distinct, recognizable names: deuterium and tritium.

While special relativity describes motion along flat spacetime—the underlying fabric of the universe—general relativity extends this theory to explain motion through curved spacetime.

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.

What is gravity made of?

In the absence of air resistance—as occurs in a vacuum chamber—all objects fall at the same rate.

Quantum mechanics explains how particles behave like both matter and waves

Almost three centuries before Albert Einstein presented the special theory of relativity, Galileo Galilei devised a principle of relativity involving uniform motion.

Measurements of an electron's magnetic moment help test the Standard Model

Plasma is the most abundant form of visible matter in the universe

Astronomical models suggest dark matter must be 'cold,' or slow-moving

Within quantum mechanics, the Heisenberg uncertainty principle limits how precisely one can simultaneously know the values of pairs of complementary properties for an object, such as position and momentum.

An overview of helium, the nonrenewable resource that's lighter than air

Uncertainties in measurements make finding gravity's Newtonian limit unclear

Why the edge of Earth's atmosphere varies depending on which property is considered

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

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

The strong nuclear force prevents most atoms from spontaneously breaking apart, even though protons in the nucleus repel one another.

Within Einstein's picture of the universe, gravity is technically not a force because forces cause accelerations that deviate objects from their natural path, and moving solely due to gravity is natural.

Temperatures colder than Pluto can allow electricity to flow resistance-free

Quantum mechanical principles are responsible for chemical properties

Where you are located in a gravitational field affects how quickly you age

If the entire universe were replaced with antimatter, except for Earth, our planet would slowly be annihilated from the outside in as it moved through space.