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Showing 1–30 of 1709 reference entries

Mathematics & logicExamples and counterexamples

Learn what a claim covers, explain why it works, and recognise an allowed case that shows it needs changing.

Method
Mathematics & logicCounting and zero

Count each object once, explain the final count, and distinguish quantity, position and identifying labels. Make zero’s role explicit.

Definition
Mathematics & logicNumber lines and order

Use number-line positions to compare whole numbers. Read the scale, recognise equality, and distinguish numerical distance from drawing size.

Definition
Mathematics & logicAddition and subtraction

Combine separate counts, remove a part, and find differences or missing parts. Connect objects, equations and number-line moves, then use tens and ones to regroup without changing value.

Definition
Mathematics & logicMultiplication and division

Count equal groups, distinguish sharing from making groups, and check with multiplication. Split calculations into parts; interpret zero and remainders in context.

Definition
Mathematics & logicFractions

Choose a whole, count equal fractional units, and connect sharing with division. Place fractions on the number line, including values beyond one, and explain what their numerator and denominator mean.

Definition
Mathematics & logic · Physics · MeasurementRatios and rates

Distinguish part-to-part ratios, fractions of a whole and rates with units. Scale quantities together, compare unit rates, and explain when a relationship is proportional. Check zero cases, starting amounts and whether a result fits its context.

Definition
Mathematics & logic · Physics · MeasurementQuantities and units

Describe a quantity as a numerical value with a unit, and distinguish its physical kind from its dimension. Build length, area, volume and rate units, check meaningful combinations, and separate exact unit relations from measurement uncertainty.

Definition
Mathematics & logic · Physics · MeasurementUnit conversions

Convert quantities with exact unit ratios, track cancellation through compound units, and apply the correct powers to area and volume. Distinguish temperature readings from differences, check dimensions and context, and retain measurement uncertainty when reporting.

Method
Mathematics & logic · Physics · MeasurementEstimation and uncertainty

Distinguish exact model values, rounded approximations and estimates from measurements. Declare the rounding rule, preserve information through calculations and unit changes, and interpret resolution, precision, accuracy and the stated uncertainty type without turning a report’s digits into guaranteed bounds.

Definition
Mathematics & logicVariables and expressions

Use symbols to name numbers or quantities, describe their allowed values, and evaluate expressions by replacing every occurrence consistently. Preserve grouping, signs, fractions and units, and distinguish a calculated value from solving an equation or proving two rules equivalent.

Definition
Mathematics & logicEquality and equations

Read equality as a relationship, find the permitted values that make an equation true, and justify one-step solutions by reversible operations on both sides. Work exactly with negative numbers and fractions, recognize all-solution and no-solution cases, and check the original equation, units and context.

Definition
Mathematics & logic · PhysicsCoordinates and tables

Locate a point from an ordered pair, read named axes and their scales, and connect the same values in words, tables and plots. Keep signs, fractions and units exact, distinguish an axis point from a quadrant point, and separate selected observations from a stated rule and its domain before drawing connections.

Definition
Mathematics & logic · PhysicsSlope and straight lines

Read a straight line as a stated relationship, calculate its slope from consistent signed coordinate changes, and interpret its intersections with the axes. Keep horizontal, vertical and coincident-point cases distinct, attach units and domain conditions to context models, and use numerical scales rather than appearance alone to judge a line’s change.

Definition
Mathematics & logic · Physics · MeasurementReading graphs

Read a graph’s quantities, units, ticks and context before judging its visual impression. Calculate differences, reference-based percentages and interval rates from the represented values; distinguish legitimate zoom from distorted spacing; and keep samples, interpolation, missing information, uncertainty and causal explanations separate.

Method
Physics · MeasurementObservables and measurement

Choose the physical quantity you want to investigate, specify the point, event or location involved, and explain how a reading relates to that quantity.

Method
PhysicsSystems and boundaries

Choose what belongs to an investigation, describe its condition at a stated time, and identify interactions with what lies outside its boundary.

Method
PhysicsModels and assumptions

Choose what a model represents, make its simplifications explicit, and check whether its predictions answer the physical question you actually asked.

Method
PhysicsHypotheses, laws and theories

Identify what a scientific statement does, examine its evidence and conditions, and avoid treating its name as a score for certainty.

Method
Mathematics & logic · PhysicsApproximations

Build a useful estimate, compare a correction with a stated reference scale, and check what is lost when you leave out a term.

Approximation
Mathematics & logic · PhysicsSymmetry and invariance

Specify a transformation, identify what stays unchanged, and distinguish symmetry of an object from invariance of a physical model.

Mathematical statement
PhysicsConservation laws

Use a defined system and a named quantity to track transfers, distinguish changing parts from conserved totals, and check the conditions of energy and momentum balances.

Model
PhysicsEmergence and levels of description

Choose a descriptive level, connect collective quantities with component behavior, and check when a simpler physical description answers a specified question.

Model
Mathematics & logic · PhysicsVectors

Describe displacement with fixed-axis components, combine compatible vectors, and use small exact examples to introduce span, independence, basis and real vector spaces.

Definition
Physics · Information · MeasurementScientific records

Build an inspectable physics record, test and revise a bounded cart model, preserve processing history, and plan findable data with appropriate sharing conditions.

Method
PhysicsPosition, velocity and acceleration

Describe a point's motion on a chosen straight axis, then connect signed changes, instantaneous rates and one exact set of position, velocity and acceleration graphs.

Definition
PhysicsNewton’s laws and forces

Choose one body, identify the forces acting on it, and use their vector sum to distinguish acceleration, balanced motion and mutual interactions.

Model
PhysicsWork, energy and power

Connect force and displacement to changes in motion, follow a spring’s stored energy, and distinguish an energy transfer from its rate.

Model
Physics · MeasurementSpeed of light in vacuum

c denotes the speed of light in vacuum. Its numerical value is fixed exactly in SI units.

Definition
Physics · MeasurementPlanck constant

h denotes the Planck constant. Its numerical value is fixed exactly in SI units.

Definition
ModelSource checked

White-dwarf mass–radius relation and ideal limiting mass

Earth & cosmos

Cold noninteracting electron support and spherical Newtonian hydrostatic balance give a nonrelativistic n=3/2 polytrope with R proportional to μₑ^(−5/3)M^(−1/3).

Key knowledge

Cold noninteracting electron support and spherical Newtonian hydrostatic balance give a nonrelativistic n=3/2 polytrope with R proportional to μₑ^(−5/3)M^(−1/3). As electron momenta become relativistic, the pressure approaches K_URρ^(4/3), an n=3 polytrope whose mass is independent of central density. Its ideal limiting mass is M_Ch=4π ω₃[K_UR/(πG)]^(3/2), proportional to μₑ^(−2). This is a limiting electron-support model, not a universal initial stellar-mass threshold.

Values and equations

K_UR=ℏc(3π²)^(1/3)/[4(μₑm_u)^(4/3)]; M_Ch=4π ω₃[K_UR/(πG)]^(3/2)

K_UR
constant in P=K_URρ^(4/3) Pa (kg m⁻³)^(−4/3)
μₑ,ω₃
mean mass per electron in m_u units and Lane–Emden mass factor 1
m_u,M_Ch
atomic mass constant and ideal limiting mass kg
ℏ
reduced Planck constant J s
c
vacuum light speed m s⁻¹
G
gravitational constant m³ kg⁻¹ s⁻²

Conditions and scope

  • Define μₑ=ρ/(nₑm_u), with m_u the atomic mass constant, fixed composition, zero surface pressure and negligible rotation, thermal, magnetic and nonideal terms. ω₃=−ξ₁²θ′(ξ₁) for the regular n=3 Lane–Emden solution's first zero.
  • General relativity, Coulomb interactions, electron capture, composition and finite-temperature structure alter real stability. Reaching an approximate mass alone specifies neither a unique explosion mechanism nor neutron-star support.
Sources · 2

References

Sources retain their recorded scope. A source link alone does not establish verification of every statement.

  1. Stellar Structure and Evolution (2011), §§4.2.1 and11.2.1, equations4.20–4.22 and11.3Onno R. Pols — Utrecht UniversityReference guide · PDFucolick.orgRead source
  2. Astrophysics I Problem Set7, problem3: explicit composition and polytropic limitsIan J. M. Crossfield — MITReference guide · PDFmit.eduRead source

Evidence and review

Read Pols printed pp.49–50 and170–171, actual mass–radius/limiting-mass equations and noninteracting/Coulomb/electron-capture limits; read MIT problem3's explicit μₑ and n=3/2 versus3 setup. Derived composition powers by substituting nₑ=ρ/(μₑm_u) into the reviewed electron-pressure and Lane–Emden scales. No dated observational upper bound or universal source initial-mass assertion adopted.

2026-10-10 · Independent AI editorial review: All44 exact root-authored compact records, equations/variable units/conditions and140 origin edges accepted after independently reading final6/18 with bounded primary bodies and matching prior38/122 scientific fingerprints unchanged. Exact claim/edge review is distinct from combined inventory scope and separate CLE26 approval; no entire cited books or old-corpus experimental revalidation is asserted. Receipt: cosmos-completion-independent-content-and-inventory-review.1.

Entry detailsPermanent link to this entry ↗
Record identity
uni-cosmos-white-dwarf-support-limit
Revision
core.1
Structured reference record
University core expansion