Mathematics
Calculus
Limits, derivatives, integrals, the chain rule, Taylor series, the Fundamental Theorem.
coreMultivariable Calculus
Partial derivatives, gradients, Jacobians, Hessians, the multivariable chain rule.
cross-field coreLinear Algebra
Vectors, matrices, dot products, projections, eigenvalues, SVD, PCA.
cross-field coreProbability
Random variables, distributions, expectation, Bayes, entropy, KL divergence.
cross-field coreStatistics
Estimation, maximum likelihood, confidence intervals, hypothesis testing, regression.
coreDiscrete Mathematics
Sets, logic, proof techniques, combinatorics, graph theory, number theory.
coreNumerical Analysis
Floating-point, conditioning, Newton's method, interpolation, quadrature.
advancedPhysics
Classical Mechanics
Newton's laws, energy and momentum, Lagrangians, Hamiltonians, and the principle of least action.
coreElectromagnetism
Electric and magnetic fields, Gauss, Faraday, Ampère, electromagnetic waves, and how light emerges.
coreThermodynamics & Statistical Mechanics
Temperature, entropy, the laws of thermo, partition functions, and why macroscopic laws come from counting.
cross-field coreSpecial Relativity
Time dilation, length contraction, Lorentz transformations, spacetime, and $E = mc^2$.
coreGeneral Relativity
Gravity as curved spacetime, the equivalence principle, the Einstein field equations, black holes.
advancedQuantum Mechanics
Wavefunctions, Schrödinger's equation, operators, measurement, entanglement, and the two-slit experiment.
coreQuantum Field Theory
Fields as the fundamental objects, creation and annihilation, Feynman diagrams, and renormalization.
advancedParticle Physics
Quarks, leptons, gauge bosons, the Higgs, and what's known (and unknown) about the fundamental constituents of matter.
advancedCosmology
Big Bang, inflation, the CMB, dark matter, dark energy, and the large-scale structure of the universe.
frontierFrontier Physics
String theory, loop quantum gravity, quantum information, topological matter, and what theorists argue about at conferences.
frontierNuclear Physics
Binding energy, radioactive decay, fission chain reactions and reactor types. Fusion and the race to ignition. Manhattan Project history, bomb designs, and nuclear energy in 2026.
newString Theory
One-dimensional strings as the fundamental objects, extra dimensions, T-duality, M-theory, the string landscape, and the AdS/CFT correspondence.
frontierHistory of Physics
From Aristotle's cosmos through Newton, Maxwell, Einstein, and Bohr to the present frontier. The ideas, the experiments, and the people who changed how we see the universe.
contextAstronomy & Space Exploration
Cosmology
Big Bang, CMB, dark matter, dark energy, and large-scale structure. The history of the universe from the first microsecond.
coreAstrophysics & Observatories
Every major telescope. The search for Earth-like exoplanets. Nearest stars, named galaxies, cosmic anomalies, and the fate of the universe.
newBlack Holes
Anatomy, types, metrics, Hawking radiation, the information paradox, gravitational waves, and imaging M87* and Sgr A*.
advancedDark Energy & Quantum Vacuum
Zero-point energy, the Casimir effect, Big Bang, inflation, dark energy, and the fate of the universe as one story.
advancedSpace Missions
Every major mission from the Space Race to Artemis — crew, cost, duration, images. Plus a full failures & disasters section covering Apollo 1, Challenger, Columbia, and Peregrine.
newChemistry
Atomic Structure
Orbitals, quantum numbers, electron configurations, and why the periodic table looks the way it does.
coreChemical Bonding
Ionic, covalent, and metallic bonds, Lewis structures, VSEPR geometry, hybridization, and molecular orbitals.
coreThermochemistry
Enthalpy, entropy, Gibbs free energy, Hess's law, and what makes a reaction spontaneous.
coreChemical Kinetics
Rate laws, reaction orders, Arrhenius equation, catalysis, and the activation-energy picture.
coreChemical Equilibrium
Le Chatelier's principle, equilibrium constants, acids and bases, buffers, and solubility.
coreOrganic Chemistry
Functional groups, reaction mechanisms, stereochemistry, and the logic of synthesis.
coreBiochemistry
Proteins, nucleic acids, enzymes, metabolism, and how cells run on catalyzed chemistry.
cross-field coreQuantum Chemistry
Solving the Schrödinger equation for molecules: Hartree-Fock, DFT, and computational methods.
advancedPeriodic Table
Click any element for its full details. Non-linear discovery timeline, atom model diagrams (Dalton→Schrödinger), orbital shapes, quark structure, spin, and spectroscopy.
newChemical Reactions
Synthesis, decomposition, combustion, redox, acid-base, and more. Exhaustive examples, industry uses, experiments you can do at home, and balancing problem sets.
newComputer Science
Algorithms & Data Structures
Arrays, hash tables, trees, heaps, graphs. Sorting, BFS/DFS, Dijkstra, DP, greedy methods.
coreComplexity & Big-O
Formal Big-O, amortized analysis, the Master Theorem, decision-tree lower bounds.
coreTheoretical CS
Turing machines, the halting problem, P vs NP, NP-completeness, Cook-Levin.
advancedMathematical Optimization
Convexity, GD/SGD/Adam, KKT conditions, linear programming, duality.
cross-field coreAI / Machine Learning
The Perceptron
The first learning algorithm that worked on a machine. One neuron, a weight vector, a threshold.
originActivation Functions
Sigmoid, tanh, ReLU, GELU, SwiGLU. The nonlinearity that makes depth meaningful.
coreGradient Descent
Three lines of math, one idea, every neural network on Earth.
coreBackpropagation
The chain rule applied efficiently through a network. Derived with worked numbers.
coreConvolution (CNN)
The operation that taught neural networks to see. Kernels, strides, feature maps.
visionRNNs & LSTMs
Hidden state, vanishing gradients, and the gates that made sequence learning work.
historicalWord Embeddings
king − man + woman ≈ queen. How strings became geometry.
NLPSelf-Attention
Every token looks at every token. The core operation of the transformer.
coreState Space Models & Mamba
Attention's O(n²) is too expensive for long contexts. SSMs give you O(n).
frontierGANs
A forger and a detective locked in a zero-sum game.
historicalDiffusion Models
Start with noise, unwind it into an image. The math behind Stable Diffusion and Sora.
productionFoundation Models
Pretrain once, adapt everywhere. GPT, Claude, Gemini. Scaling laws.
productionRetrieval-Augmented Generation
Look up facts in a vector DB, then generate. The cheapest productivity win.
productionMixture of Experts
Trillion-parameter models that run as cheap as a 30B one.
frontierReasoning & Test-Time Compute
Models that think before answering. The new scaling axis.
frontierNeuro-Symbolic AI
Neural networks that learn plus symbolic systems that reason.
researchEdge & On-Device AI
Quantization, pruning, distillation, compilation. Fit an LLM on a phone.
deploymentAI Safety & Alignment
Making a trained model act the way you meant to ask.
safetyAGI — The Goal
What AGI means, what the benchmarks show, and how close we might be.
speculativeThe Singularity
Recursive self-improvement, takeoff speeds, the asymptotic case.
speculativeAI & Society
Measured effects on jobs, information, democracy, and warfare.
policyBlockchain
Cryptographic Foundations
SHA-256, ECDSA on secp256k1, Merkle proofs, and how they make tamper-evident ledgers possible.
coreConsensus Mechanisms
The Byzantine Generals Problem, Nakamoto consensus, Proof of Stake, and BFT protocols (Tendermint, HotStuff).
coreSmart Contracts
The Ethereum Virtual Machine, Solidity patterns, ERC-20/721, reentrancy attacks, and gas optimization.
coreZero-Knowledge Proofs
Prove without revealing. R1CS, Groth16, FRI, and how ZK proofs power the next generation of scaling.
frontierBitcoin
UTXO model, the mempool, the halving, Script, Taproot, and the Lightning Network's payment channels. Why Bitcoin is censorship-resistant money.
deep diveEthereum
The EVM, gas, the Merge (PoS), EIP-1559, rollup-centric roadmap, blobs, restaking. How Ethereum became the settlement layer for DeFi.
deep diveSolana
The Proof of History clock, Tower BFT, Sealevel parallel execution, and how Solana achieves 50,000+ TPS. Tradeoffs vs Ethereum.
deep diveCardano
Ouroboros PoS, extended UTXO model, Plutus smart contracts, peer-reviewed development, and Cardano's phased Shelley/Alonzo/Voltaire roadmap.
deep diveCosmos
Tendermint BFT, the Cosmos SDK, Inter-Blockchain Communication (IBC), sovereign app-chains, and the hub-and-zone architecture.
deep diveQuantum Computing
Qubits & Superposition
The qubit state vector, Dirac notation, measurement and the Born rule, multi-qubit tensor products, decoherence.
coreQuantum Gates & Circuits
Pauli gates, Hadamard, rotations, CNOT, universality with {H, T, CNOT}, circuit identities, and a working 2-qubit simulator.
coreQuantum Algorithms
Deutsch-Jozsa, Grover's O(√N) search, Shor's factoring via the QFT, phase estimation, and near-term VQE/QAOA.
frontierEntanglement & Bell States
Bell states, the CHSH inequality and its experimental violation, quantum teleportation, superdense coding, entanglement entropy.
core