Modern Physics

Exploring relativity, quantum mechanics, and the fundamental nature of matter and energy

Subcategories

Nuclear Physics

Understanding atomic nuclei, nuclear reactions, and nuclear energy

Particle Physics

Understanding fundamental particles and the Standard Model

Quantum Mechanics

Understanding the quantum world, wave-particle duality, and quantum phenomena

Relativity

Understanding Einstein's theories of special and general relativity

Topics

Subatomic particles are particles smaller than atoms, including protons, neutrons, and electrons that make up atoms, as well as many other particles discovered in particle physics. They include quarks (which make up protons and neutrons), leptons (like electrons), and force-carrying particles.

What is an atom?

An atom is the smallest unit of an element that retains the element's properties. Atoms consist of a nucleus (containing protons and neutrons) surrounded by electrons. The number of protons determines the element, while electrons determine chemical behavior.

What is antimatter?

Antimatter is matter made of antiparticles—particles with opposite charge to normal particles. Antielectrons (positrons) have positive charge, antiprotons have negative charge. When matter and antimatter meet, they annihilate, converting to energy.

What is the Higgs boson?

The Higgs boson is a fundamental particle discovered in 2012 that is associated with the Higgs field, which gives other particles mass. The Higgs field fills all space, and particles interact with it to acquire mass, explaining why some particles are heavy while others are light.

What is the standard model?

The Standard Model is the theory describing all known fundamental particles and three of the four fundamental forces (electromagnetic, weak, and strong). It organizes particles into quarks, leptons, and force carriers, and has been extremely successful in predicting and explaining particle behavior.

How do quantum computers work?

Quantum computers use quantum bits (qubits) that can exist in superposition (multiple states simultaneously) and entanglement (correlated states). This allows quantum computers to process many possibilities in parallel, potentially solving certain problems much faster than classical computers.

How does quantum mechanics work?

Quantum mechanics describes how particles behave at atomic and subatomic scales, where they exist in probability states rather than definite positions. Particles can be in multiple states simultaneously (superposition) until observed, and measurements affect what we observe.

What is a quantum?

A quantum is the smallest discrete unit of a physical property. In quantum mechanics, many properties like energy, momentum, and angular momentum come in discrete packets (quanta) rather than continuous values. A photon is a quantum of light energy.

What is quantum entanglement?

Quantum entanglement is a phenomenon where two or more particles become correlated so that measuring one instantly affects the other, regardless of distance. Entangled particles share a quantum state and behave as a single system, even when separated.

What is the uncertainty principle?

The uncertainty principle states that we cannot simultaneously know precise values of certain pairs of properties, like position and momentum. The more precisely we know one, the less precisely we can know the other. This is a fundamental limit, not a measurement limitation.

How does gravity bend space-time?

Gravity bends space-time because mass and energy curve the four-dimensional space-time fabric. According to general relativity, objects with mass create curvature, and other objects follow these curved paths, which we experience as gravitational attraction.

What is E=mc²?

E=mc² is Einstein's famous equation showing that energy (E) and mass (m) are equivalent, with c being the speed of light. It means mass can convert to energy and vice versa, explaining nuclear reactions and the energy in matter.

What is relativity?

Relativity is Einstein's theory describing how space, time, and gravity work. Special relativity deals with objects moving at constant speeds, showing that time and space are relative. General relativity describes gravity as the curvature of space-time.

What is space-time?

Space-time is the four-dimensional combination of three spatial dimensions (length, width, height) and one time dimension. According to general relativity, mass and energy curve space-time, and this curvature is what we experience as gravity.

What is time dilation?

Time dilation is the effect where time passes slower for objects moving at high speeds relative to an observer. According to special relativity, moving clocks run slower than stationary ones, and this effect becomes significant near light speed.