What should a 23-year-old be learning?
At age 23, 91 topics open up across Science, Mathematics, Computing. Each one has prerequisites that come first, so the order matters more than the list: Controlled Radical Polymerisation and Block Architecture is a typical starting point.
How do I know what a 23-year-old already knows?
LightMySky starts by assuming everything below the learner’s level is already known, then checks the assumption as they practise. What holds up stays lit; what does not comes back for review.
Science
- Controlled Radical Polymerisation and Block ArchitectureChemistry
- Electron Correlation and Methods Past Hartree-FockChemistry
- Excited States by Calculation and Simulated Electronic SpectraChemistry
- Functionalising a Carbon-Hydrogen Bond Without a HandleChemistry
- Glass Transition, Crystallinity and Entanglement in PolymersChemistry
- Molecular Recognition: Preorganisation, Complementarity and Binding ConstantsChemistry
- Olefin Metathesis and Ring-Closing StrategyChemistry
- Photoredox and Electrochemical Routes to Radical IntermediatesChemistry
- Putting the Solvent Into a CalculationChemistry
- Molecular Dynamics and Free Energy from SamplingChemistry
- Reaction Dynamics: Trajectories Across a Potential Energy SurfaceChemistry
- Risk Assessment for a Reaction Nobody Has Run HereChemistry
- Self-Assembly: Templates, Reversibility and Error CorrectionChemistry
- Taking a Route into Flow and Onto ScaleChemistry
- Reading a Total Synthesis as an ArgumentChemistry
- Writing a Research Proposal: Question, Feasibility and MilestonesChemistry
- Reporting Chemical Data: Statistics, Figures and Data AvailabilityChemistry
- Ultrafast Spectroscopy and Watching a Reaction HappenChemistry
- Adding Angular Momenta and the Coupled BasisQuantum & Modern Physics
- Identical Particles and the Symmetry of a Many-Body StateQuantum & Modern Physics
- Degenerate Perturbation Theory and the Variational MethodQuantum & Modern Physics
- Density Matrices, Entanglement and the Bell TestQuantum & Modern Physics
- Field Quantisation: Creation Operators and Particle NumberQuantum & Modern Physics
- The Klein-Gordon and Dirac EquationsQuantum & Modern Physics
- The Path Integral and the Sum Over HistoriesQuantum & Modern Physics
- Time-Dependent Perturbation Theory and Fermi's Golden RuleQuantum & Modern Physics
- Scattering: Cross-Sections and the Born ApproximationQuantum & Modern Physics
- Radiation from an Accelerating ChargeElectricity & Magnetism
- Crystal Lattices, the Reciprocal Lattice and Bloch's TheoremMatter & Materials
- Band Structure: Metals, Insulators and the GapMatter & Materials
- Semiconductors, Doping and the p-n JunctionMatter & Materials
- Phonons and the Heat Capacity of SolidsMatter & Materials
- Superconductivity: the Meissner Effect and Cooper PairsMatter & Materials
- The Ising model and the mean-field approximationThermal & Statistical Physics
- Critical exponents, scaling and universalityThermal & Statistical Physics
- Tensors and the metric on a curved manifoldAstronomy & Astrophysics
- Parallel transport, Christoffel symbols and the geodesic equationAstronomy & Astrophysics
- Curvature and the Einstein field equationAstronomy & Astrophysics
- The Schwarzschild solution: orbits, redshift and the horizonAstronomy & Astrophysics
- Linearised gravity and gravitational wavesAstronomy & Astrophysics
- Reading a Paper: the Claim, the Evidence and the AssumptionScientific Inquiry
- Writing Science: the Figure, the Error Bar and the ClaimScientific Inquiry
- Testing thousands of genes at once: false discovery rate and what q meansGenetics & Evolution
- From a gene list to biology: enrichment tests and their backgroundsGenetics & Evolution
- Single-Cell Analysis: Normalisation, Embedding and Naming Cell StatesGenetics & Evolution
- Modelling a Biological System: Rate Equations, Parameters and FitGenetics & Evolution
- From Hit to Lead: Structure-Activity RelationshipsChemistry
- Drug-Like Properties: Solubility, Permeability and Metabolic FateChemistry
- Chemical Biology: Bioconjugation and Reporting on a Molecule in a CellChemistry
- Reproducibility in Practice: Data, Code and What Another Lab Can RerunScientific Inquiry
- Proteomics: Mass Spectra, Quantification and Interaction MapsBiochemistry & Molecular Biology
- Target Validation and Lead Discovery: From a Biological Claim to a MoleculeBiochemistry & Molecular Biology
- Engineered Cell Therapy: Receptor Design, Manufacture and ToxicityThe Human Body
- Ethics of Emerging Biotechnology: Editing and BiosecurityScientific Inquiry
- Pooled Genetic Screens: Library Design, Selection and Reading a Hit ListGenetics & Evolution
- Clinical Trials: Phases, Endpoints and Why Most Candidates FailThe Human Body
- Synthetic Circuits: Switches, Oscillators and Why They Misbehave in CellsMicrobiology
- Metabolic Engineering: Redirecting Flux Through a Production HostMicrobiology
- The Host Microbiome: Composition, Causation and InterventionMicrobiology
Mathematics
- Conditioning, Stability and Floating-Point ErrorCalculus & Analysis
- Iterative Methods for Large Linear SystemsLinear Algebra
- Bounded Linear Operators and the Operator NormCalculus & Analysis
- Baire Category and the Uniform Boundedness PrincipleCalculus & Analysis
- The Hahn-Banach Theorem and the Dual SpaceCalculus & Analysis
- Hilbert Spaces and Orthogonal Projection in Infinite DimensionsCalculus & Analysis
- Compact Self-Adjoint Operators and the Spectral TheoremCalculus & Analysis
- Convolution, Plancherel and Transforming a DerivativeCalculus & Analysis
- Numerical Schemes for Evolution EquationsDifferential Equations
- Martingales and Optional StoppingProbability
- Brownian Motion and Its Defining PropertiesProbability
- Characters and the Orthogonality RelationsAbstract Algebra
- Decomposing a Representation from Its CharacterAbstract Algebra
- Topological Spaces: Continuity Without DistanceTopology
- Open Problems as a GenreMathematical Thinking
- Compactness and ConnectednessTopology
- The Fundamental Group and Loops on a CircleTopology
Computing
- Training Across Many Devices: Data, Model and Pipeline ParallelismMachine Learning
- Serving a Model: Batching, the Key-Value Cache and QuantisationMachine Learning
- Stream Processing: Windows, Watermarks and Late EventsData & Databases
- Cloud-Native Architecture: Containers, Schedulers and the Control LoopComputer Systems
- Observability and Tail Latency Across ServicesComputer Systems
- Model Checking and the State-Space ExplosionSoftware Engineering
- Hoare Logic and Proving a Program Meets Its SpecificationSoftware Engineering
- Type Soundness: Progress and PreservationComputer Systems
- Reproducibility: Seeds, Environments and the AblationSoftware Engineering
- Scoping and Writing a Thesis-Scale ProjectSoftware Engineering
- Temporal-Difference Learning and Q-LearningMachine Learning
- Policy Gradients and the Actor-Critic SplitMachine Learning
- Learning from Human Preferences: Reward Models and Policy OptimisationMachine Learning
- Cryptographic Security Definitions and Proof by ReductionNetworks & Security
- Interpretability: Probes, Features and CircuitsMachine Learning