Learn why modern scientific patterns have been described as theories rather than laws

Distinguishing between scientific theories and laws, and why both are on equal footing

Scientific laws describe outcomes of specific conditions, and scientific theories explain why those outcomes occur. Both are supported by observational and experimental data and can each inform one another, but neither can become the other. Instead, additional data can improve each towards more accurate descriptions and explanations of reality.

How facts, hypotheses, theories, and laws in science differ from everyday language

Facts are observations of the world, and they can be pooled together for a given phenomenon to develop a hypothesis—a proposed explanation consistent with observations that requires further investigation. Experiments and additional data can rule out many hypotheses or graduate a proposed explanation into a widely accepted and validated theory.

Unlike quantum mechanics, classical physics suggests free will does not exist

Models based on Newton's laws of motion suggest all actions are predetermined and must follow specific trajectories and outcomes, such that everything that will ever occur in the future has already been set in motion by past causes. However, quantum mechanics challenges determinism because it is based on probability, where no outcome is certain.

Particle interactions follow rules related to specific quantum properties

Like a business whose purchased inventory matches sold inventory, physicists identified specific patterns across decades of particle accelerator data, which became new conservation laws for elementary particles. These laws help identify which particle decays are expected or forbidden.

Science is rarely a linear progression of understanding

Particularly at the frontiers, investigations conducted based on established knowledge can provide unexpected results. This opens the door to revising existing models, inspiring new lines of research, and ultimately leading to better future comprehension. For instance, experiments on the speed of light and the expansion of the universe yielded then-confusing data that led to revolutionary insights.

Classical mechanics describes the motion of and forces on everyday objects

Newton's laws form the core of classical mechanics, suitable for everyday objects and speeds. The term is relatively new, distinguishing the branch of physics from quantum and relativistic mechanics.

Quantum field theory, which has made predictions accurate to 12 decimal places, explained

Instead of being made of indivisible particles, all visible matter in the universe is built from underlying quantum fields—smooth, invisible entities that behave like waves and extend throughout space and time. The theory suggests these fields are fundamental, and particles are disturbances that move through them.

Scientific progress works toward absolute truth, but can never reach it

Through the acquisition of scientific knowledge, scientists construct explanations of the world, which are rigorously tested and verified until they narrow down to a leading theory of the natural world. However, because of how science works, these ideas will never become factual, as they must always remain open to be iteratively revision based on new data.

Time may be an emergent, rather than a fundamental, property of the universe

Some theories of everything—mathematical models that try to explain all aspects of the universe, including quantum phenomena and gravity—do not incorporate time. If a time-neglecting version of such a theory were ever validated, it might suggest that time is a feature that emerges from our limited perception of the universe.

Modern physics suggests that many universes with different physical laws could exist

Physicists suggest that quantum fluctuations in the early universe could have given rise to these universes. Ancient Greek philosophers like Chrysippus proposed a version of the multiverse over 2,000 years ago—millennia before its adoption into various theoretical frameworks today.

Explore an interactive map of the unified theories of everything

This interactive concisely describes many highly complex theories ranging from quantum gravity and black holes to dark matter and energy. Supplementary resources, key questions, and possible solutions accompany each description. As of 2026, no developed theory provides an accepted explanation of all observed phenomena in the universe at all scales.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Critics say Nobel Prizes need updating to reflect how science and society work today

The rules still favor individuals over teams and may reflect outdated views on who does science. In 2013, the Nobel Prize in physics went to two theorists, even though over 5,000 scientists helped confirm the Higgs boson.

How upheavals in accepted scientific theories helped popularize the term 'paradigm'

When Thomas Kuhn published "The Structure of Scientific Revolutions" in 1962, he described the history of science as comprising periods of "normal science" where these accepted frameworks—paradigms—gradually accumulate anomalies until they cannot describe nature. Revolutionary science, such as the development of a new theory, results in a paradigm shift, another term Kuhn helped popularize. (Some readers may experience a paywall.)

Is time travel really possible?

The laws of physics, as currently understood, don’t categorically reject the possibility of time travel. But, scientists are skeptical, especially when it comes to traveling to the past. Hopping between past, present and future would require the world to have some wacky yet-to-be-discovered physical properties like negative mass, negative energy, and infinite density. Time travel also introduces philosophical questions about free will, causality, and chronology.

Explore a simulation of ideal gas behavior, which can be explained by kinetic molecular theory

The theory describes particles as moving in random directions, with a distribution of velocities determined by the gas's temperature. The particles collide elastically like billiard balls, are negligibly small, and do not exert forces on one another. The gas laws can be derived from these principles using statistics or observed via this interactive.

The general theory of relativity defines gravity as the curvature of spacetime

The breakthrough that redefined Isaac Newton's picture of gravity came when Albert Einstein realized that freely falling is indistinguishable from weightlessness, leading him to the principle of equivalence between gravity and acceleration. His prediction that gravity bends light was confirmed in 1919 during a solar eclipse.

Learn how natural systems exhibit characteristics of chaos theory

In biology, some mathematical models of ecosystem populations and heart irregularities show strong sensitivity to initial conditions, which scientists can simulate to determine quantitative tipping points at which these systems become unstable. Within the social sciences, crowd behavior and the virality of social media posts have shown how human behavior fits within the framework of chaos theory.

Turbulence has been called the most important unsolved problem in classical physics

Despite being the most common type of fluid flow in our world, scientists have struggled to model turbulent flow accurately. Though behaving unpredictably, understanding inertia and viscosity can help determine whether turbulence will occur.

The simple grandeur of atomic theory

Is the universe made up of a continuous substance, or a finite amount of tiny, indivisible atoms? The atomic hypothesis, largely vindicated in the 20th century, was forgotten for nearly 2,000 years after first being formulated by the Greek philosopher Democritus. Learn more about the theory and its implications for science and human life with this reflective essay.

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

Isaac Newton first identified white light as composed of a spectrum of colors, which he believed consisted of particles of different hues. Various light phenomena, including refraction, led Christiaan Huygens to develop an alternative wave model. Quantum mechanics validated both models through the concept of wave-particle duality.

A list of five scientific theories that were accepted and later disproved

Humoral theory held that everyone's personality derived from different combinations of four bodily fluids: blood, phlegm, yellow bile, and black bile. The phlogiston theory stated that all combustible materials possessed a fire element—phlogiston—that was released and absorbed by the air during burning. When the air became saturated with phlogiston, the fire would go out.

Neural networks mimic the structure and behavior of real physical systems

Early generative AI systems were inspired by scientific models such as the Ising model, which explains how atoms interact with one another and align in magnets. As these networks have expanded, their behavior has more closely resembled that of quantum fields, enabling them to be used in exploring complex particle physics interactions.

Dow Theory laid the groundwork for modern market analysis

Developed by Charles Dow in the late 19th century, Dow Theory argued that markets move in trends. Its principles—confirmation, trends and volume—still influence technical analysis today.

Climate models use complex equations and supercomputers to predict future climate

The equations apply the laws of thermodynamics, fluid motion, and radiative transfer to a 3D grid along Earth's surface. After solving them for each cell in the grid over a time interval, the results carry over to neighboring cells, and the process repeats into the future.

The history of the 10 axioms of Zermelo–Fraenkel set theory with choice, regarded as the most universal foundations of math

Like postulates in geometry—accepted truths that form the logical building blocks for formal proofs of more complex theorems—axioms cannot be proven, but set the underlying logic and rules for systems. The ZFC axioms resulted from painstaking work to identify the underlying rules of mathematics and are built on the premise of sets, or well-defined collections of elements.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

Watch how algorithms can be designed to train themselves and self-improve without human input, to the point where the optimized code is too complex for programmers to understand.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

In recent years a child anxiety expert has created and tested a novel phobia and anxiety treatment approach for children, focused on changing how parents respond to the fears.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

The Brothers Grimm were lawyers before they were storytellers, and became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

Frank Lloyd Wright's houses are historically hard to sell because they're old, subject to local landmark commissions, and often unfashionable

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

'Silent' fireworks have gained more interest in recent years as a quieter celebratory option.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.