{ "reviewDate": "2026-10-26", "scope": "Catalogue dimensions, definitions, factual text and scaling conventions. Representative illustrations are not measured photographs. This review does not certify each depicted anatomical, geological or astronomical detail.", "entries": [ { "name": "Planck length", "status": "uncertain", "basis": "CODATA 2022: 1.616255e-35 m. Proton charge diameter / Planck length is about 1.04e20, consistent with the rounded hundred-billion-billion comparison.", "sources": [ "https://physics.nist.gov/cuu/Constants/Table/allascii.txt", "https://doi.org/10.1103/PhysRevD.67.064019" ], "notes": "The numerical length is verified. A literal universal pixel size or minimum length is unproven. The scientific review distinguishes this metaphor from an established physical limit; no experimentally resolved structures populate the gap.", "checked": "2026-10-26", "metres": 1.616255e-35, "measurement": "Fundamental length scale", "displaySize": "1.616255 × 10⁻³⁵ m", "symbolic": false }, { "name": "Quark structure probe", "status": "verified", "basis": "CMS April 2026 report explicitly states a 1e-20 m substructure probe with no evidence for constituents.", "sources": [ "https://home.cern/cms-looks-deep-inside-quarks/" ], "notes": "This is model-dependent experimental sensitivity, not a measured quark size.", "checked": "2026-10-26", "metres": 1e-20, "measurement": "Approximate experimental sensitivity", "displaySize": "~10⁻²⁰ m · no substructure found", "symbolic": false }, { "name": "Tau neutrino", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · no single known mass scale", "symbolic": true }, { "name": "Muon neutrino", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · no single known mass scale", "symbolic": true }, { "name": "Electron neutrino", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · no single known mass scale", "symbolic": true }, { "name": "Tau antineutrino", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · no single known mass scale", "symbolic": true }, { "name": "Muon antineutrino", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · no single known mass scale", "symbolic": true }, { "name": "Electron antineutrino", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · no single known mass scale", "symbolic": true }, { "name": "Photon", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-gauge-higgs-bosons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · massless", "symbolic": true }, { "name": "Gluon", "status": "uncertain", "basis": "No finite known rest-mass Compton wavelength is assigned to this entry.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-gauge-higgs-bosons.pdf" ], "notes": "The stored 1e-19 m is a navigation placeholder only. Neutrino flavour states mix mass eigenstates; photon/gluon are massless in the Standard Model. Must remain excluded from physical size comparison and continuous journey.", "checked": "2026-10-26", "metres": 1e-19, "measurement": "Symbolic representation", "displaySize": "Symbolic · massless", "symbolic": true }, { "name": "Top quark", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 172.56 GeV: 1.14352678e-18 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-quarks.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.143526775614279e-18, "measurement": "Reduced Compton wavelength", "displaySize": "1.144 × 10⁻¹⁸ m · reduced Compton wavelength", "symbolic": false }, { "name": "Higgs boson", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 125.2 GeV: 1.57609409e-18 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-gauge-higgs-bosons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.5760940926517571e-18, "measurement": "Reduced Compton wavelength", "displaySize": "1.576 × 10⁻¹⁸ m · reduced Compton wavelength", "symbolic": false }, { "name": "Z boson", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 91.188 GeV: 2.16395776e-18 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-gauge-higgs-bosons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 2.163957761986226e-18, "measurement": "Reduced Compton wavelength", "displaySize": "2.164 × 10⁻¹⁸ m · reduced Compton wavelength", "symbolic": false }, { "name": "W boson", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 80.3692 GeV: 2.45525625e-18 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-gauge-higgs-bosons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 2.455256247418165e-18, "measurement": "Reduced Compton wavelength", "displaySize": "2.455 × 10⁻¹⁸ m · reduced Compton wavelength", "symbolic": false }, { "name": "Bottom quark", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 4.183 GeV: 4.7173555e-17 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-quarks.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 4.717355496055463e-17, "measurement": "Reduced Compton wavelength", "displaySize": "4.717 × 10⁻¹⁷ m · reduced Compton wavelength", "symbolic": false }, { "name": "Tau", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 1.77693 GeV: 1.11049383e-16 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.1104938314958947e-16, "measurement": "Reduced Compton wavelength", "displaySize": "1.110 × 10⁻¹⁶ m · reduced Compton wavelength", "symbolic": false }, { "name": "Antitau", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 1.77693 GeV: 1.11049383e-16 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.1104938314958947e-16, "measurement": "Reduced Compton wavelength", "displaySize": "1.110 × 10⁻¹⁶ m · reduced Compton wavelength", "symbolic": false }, { "name": "Charm quark", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 1.273 GeV: 1.55009411e-16 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-quarks.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.5500941115475258e-16, "measurement": "Reduced Compton wavelength", "displaySize": "1.550 × 10⁻¹⁶ m · reduced Compton wavelength", "symbolic": false }, { "name": "Proton", "status": "corrected", "basis": "Twice CODATA 2022 proton RMS charge radius 0.84075 fm gives 1.6815 fm, rounding to the existing 1.7 fm.", "sources": [ "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Standardized metadata to the same RMS-charge convention as the other nuclei. Surface and constituent illustration remain schematic.", "checked": "2026-10-26", "metres": 1.6815e-15, "measurement": "Twice RMS charge radius", "displaySize": null, "symbolic": false }, { "name": "Muon", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.1056583755 GeV: 1.86759431e-15 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.867594305384716e-15, "measurement": "Reduced Compton wavelength", "displaySize": "1.868 × 10⁻¹⁵ m · reduced Compton wavelength", "symbolic": false }, { "name": "Antimuon", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.1056583755 GeV: 1.86759431e-15 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 1.867594305384716e-15, "measurement": "Reduced Compton wavelength", "displaySize": "1.868 × 10⁻¹⁵ m · reduced Compton wavelength", "symbolic": false }, { "name": "Strange quark", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.0935 GeV: 2.11044899e-15 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-quarks.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 2.110448988235294e-15, "measurement": "Reduced Compton wavelength", "displaySize": "2.110 × 10⁻¹⁵ m · reduced Compton wavelength", "symbolic": false }, { "name": "Alpha particle", "status": "corrected", "basis": "Updated to twice CODATA 2022 RMS charge radius 1.6785 fm: 3.357 fm.", "sources": [ "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Previously used the explicitly dated 2013 IAEA compilation. This update is minor and does not imply a hard surface.", "checked": "2026-10-26", "metres": 3.3570000000000003e-15, "measurement": "Twice RMS charge radius", "displaySize": null, "symbolic": false }, { "name": "Deuteron", "status": "corrected", "basis": "Updated to twice CODATA 2022 RMS charge radius 2.12778 fm: 4.25556 fm.", "sources": [ "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Previous 2013 IAEA radius 2.1421 fm was dated rather than fabricated; updated for consistency with current CODATA.", "checked": "2026-10-26", "metres": 4.25556e-15, "measurement": "Twice RMS charge radius", "displaySize": null, "symbolic": false }, { "name": "Carbon-12 nucleus", "status": "verified", "basis": "IAEA Angeli/Marinova 2013 compilation gives RMS charge radius 2.4702 fm, doubled to 4.9404 fm.", "sources": [ "https://www-nds.iaea.org/radii/charge_radii.csv" ], "notes": "Fetched CSV and checked isotope row directly. Historical compiled estimate and explicit RMS convention retained; nucleon placements are schematic.", "checked": "2026-10-26", "metres": 4.9404e-15, "measurement": "Twice RMS charge radius", "displaySize": null, "symbolic": false }, { "name": "Iron-56 nucleus", "status": "verified", "basis": "IAEA Angeli/Marinova 2013 compilation gives RMS charge radius 3.7377 fm, doubled to 7.4754 fm.", "sources": [ "https://www-nds.iaea.org/radii/charge_radii.csv" ], "notes": "Fetched CSV and checked isotope row directly. RMS radius is not a sharp outer edge.", "checked": "2026-10-26", "metres": 7.4754e-15, "measurement": "Twice RMS charge radius", "displaySize": null, "symbolic": false }, { "name": "Uranium nucleus", "status": "corrected", "basis": "Standardized to uranium-238: twice IAEA RMS charge radius 5.8571 fm = 11.7142 fm.", "sources": [ "https://www-nds.iaea.org/radii/charge_radii.csv" ], "notes": "The previous ~15 fm geometric nuclear diameter mixed conventions with the other nuclei. Isotope and convention now explicit; image remains schematic.", "checked": "2026-10-26", "metres": 1.17142e-14, "measurement": "Uranium-238 · twice RMS charge radius", "displaySize": "≈ 11.7 fm · U-238 charge size", "symbolic": false }, { "name": "Down quark", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.0047 GeV: 4.19844639e-14 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-quarks.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 4.1984463914893614e-14, "measurement": "Reduced Compton wavelength", "displaySize": "4.198 × 10⁻¹⁴ m · reduced Compton wavelength", "symbolic": false }, { "name": "Up quark", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.00216 GeV: 9.13550835e-14 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-quarks.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 9.135508351851852e-14, "measurement": "Reduced Compton wavelength", "displaySize": "9.136 × 10⁻¹⁴ m · reduced Compton wavelength", "symbolic": false }, { "name": "Electron", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.00051099895 GeV: 3.86159268e-13 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 3.861592678419398e-13, "measurement": "Reduced Compton wavelength", "displaySize": "3.862 × 10⁻¹³ m · reduced Compton wavelength", "symbolic": false }, { "name": "Positron", "status": "verified", "basis": "Recomputed reduced Compton wavelength hbar*c/(m*c^2) using PDG 2025 mass 0.00051099895 GeV: 3.86159268e-13 m.", "sources": [ "https://pdg.lbl.gov/2025/tables/rpp2025-sum-leptons.pdf", "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Quantum length, not particle diameter. Quark masses are renormalization-scheme dependent; no free isolated light quark radius follows from this number. Renderer correctly uses a physical-length bracket and a symbolic locator.", "checked": "2026-10-26", "metres": 3.861592678419398e-13, "measurement": "Reduced Compton wavelength", "displaySize": "3.862 × 10⁻¹³ m · reduced Compton wavelength", "symbolic": false }, { "name": "Gamma-ray wavelength", "status": "representative", "basis": "1 pm is a valid example in the gamma-ray range.", "sources": [ "https://lambda.gsfc.nasa.gov/product/suborbit/POLAR/cmb.physics.wisc.edu/tutorial/spectrum.html" ], "notes": "A wavelength, not a photon diameter; gamma/X-ray definitions overlap and can also depend on production mechanism.", "checked": "2026-10-26", "metres": 1e-12, "measurement": "Illustrative wavelength", "displaySize": null, "symbolic": false }, { "name": "1 picometer", "status": "verified", "basis": "The pico SI prefix is exactly 1e-12.", "sources": [ "https://www.bipm.org/en/measurement-units/si-prefixes" ], "notes": "Reference dot only; not a physical particle.", "checked": "2026-10-26", "metres": 1e-12, "measurement": "Reference length", "displaySize": null, "symbolic": false }, { "name": "X-ray wavelength", "status": "representative", "basis": "10 pm is a valid short-wavelength X-ray example.", "sources": [ "https://imagine.gsfc.nasa.gov/science/toolbox/cool_multi_fact2.html" ], "notes": "No universal X-ray wavelength or sharply defined boundary with gamma rays.", "checked": "2026-10-26", "metres": 1e-11, "measurement": "Illustrative wavelength", "displaySize": null, "symbolic": false }, { "name": "Hydrogen atom", "status": "verified", "basis": "Twice the CODATA Bohr radius is 1.058354421088e-10 m, rounding to 1.06e-10 m.", "sources": [ "https://physics.nist.gov/cuu/Constants/Table/allascii.txt" ], "notes": "Renderer uses a 1s exponential density slice and extends faint shading to 4 Bohr radii. This is a characteristic length, not an outer diameter. Nuclear positions are not represented at nuclear scale.", "checked": "2026-10-26", "metres": 1.06e-10, "measurement": "Twice Bohr radius, characteristic length", "displaySize": null, "symbolic": false }, { "name": "Water molecule", "status": "corrected", "basis": "NIST CCCBDB equilibrium O-H bond length 0.958 angstrom and H-O-H angle 104.5 degrees are represented in the renderer.", "sources": [ "https://cccbdb.nist.gov/listgeomexpx.asp?casno=7732185" ], "notes": "The 0.275 nm outer span is only an illustrative electron-cloud envelope, not a uniquely measured molecular diameter. Made this explicit; source added.", "checked": "2026-10-26", "metres": 2.75e-10, "measurement": "Illustrative electron-cloud span", "displaySize": null, "symbolic": false }, { "name": "Lead atom", "status": "verified", "basis": "RSC covalent radius 1.45 angstrom doubled gives 0.290 nm.", "sources": [ "https://periodic-table.rsc.org/element/82/lead" ], "notes": "A covalent-radius convention; atom shading is a qualitative envelope, not computed multi-electron density.", "checked": "2026-10-26", "metres": 2.9e-10, "measurement": "Twice covalent radius", "displaySize": null, "symbolic": false }, { "name": "Potassium atom", "status": "verified", "basis": "RSC covalent radius 2.00 angstrom doubled gives 0.400 nm.", "sources": [ "https://periodic-table.rsc.org/element/19/potassium" ], "notes": "A covalent-radius convention, not a sharp atom diameter.", "checked": "2026-10-26", "metres": 4e-10, "measurement": "Twice covalent radius", "displaySize": null, "symbolic": false }, { "name": "Cesium atom", "status": "corrected", "basis": "RSC covalent radius 2.38 angstrom doubled gives 0.476 nm.", "sources": [ "https://periodic-table.rsc.org/element/55/caesium" ], "notes": "Corrected source URL spelling to the live RSC caesium page. Numerical value retained.", "checked": "2026-10-26", "metres": 4.76e-10, "measurement": "Twice covalent radius", "displaySize": null, "symbolic": false }, { "name": "1 nanometer", "status": "verified", "basis": "The nano SI prefix is exactly 1e-9.", "sources": [ "https://www.bipm.org/en/measurement-units/si-prefixes" ], "notes": "Reference length, not an object.", "checked": "2026-10-26", "metres": 1e-9, "measurement": "Reference length", "displaySize": null, "symbolic": false }, { "name": "DNA double helix", "status": "verified", "basis": "PDB 1BNA is an experimentally determined B-DNA dodecamer, X-ray diffraction at 1.9 angstrom resolution. Nominal B-DNA duplex width ~2 nm.", "sources": [ "https://www.rcsb.org/structure/1BNA" ], "notes": "App uses measured heavy-atom coordinates and conventional space-filling atom radii. Drawn surface extends beyond nominal helix width. Approximate fragment length depends on terminal atoms and rendering radii; it is not claimed as an exact measurement.", "checked": "2026-10-26", "metres": 2e-9, "measurement": "Width", "displaySize": null, "symbolic": false }, { "name": "Ribosome", "status": "representative", "basis": "25 nm is a supported representative ribosome diameter.", "sources": [ "https://journals.iucr.org/d/issues/2022/11/00/jb5048/", "https://pdb101.rcsb.org/motm/121" ], "notes": "Species and conformation vary. Existing illustrative image is not asserted to be a measured atomic model of a named species.", "checked": "2026-10-26", "metres": 2.5e-8, "measurement": "Typical diameter", "displaySize": null, "symbolic": false }, { "name": "Influenza virus", "status": "representative", "basis": "100 nm lies in the commonly observed ~80-120 nm range for spherical influenza virions.", "sources": [ "https://www.nature.com/articles/nature04378", "https://www.nature.com/articles/s41564-025-01925-9" ], "notes": "Influenza can also form micron-long filaments. The existing entry correctly says representative spherical particle.", "checked": "2026-10-26", "metres": 1e-7, "measurement": "Representative diameter", "displaySize": null, "symbolic": false }, { "name": "Boundary for cellular life", "status": "uncertain", "basis": "Research found viable ultrasmall bacterial cells passing a 0.2 micrometre filter; volume ~0.009 cubic micrometres.", "sources": [ "https://www.nature.com/articles/ncomms7372", "https://newscenter.lbl.gov/2015/02/27/ultra-small-bacteria/" ], "notes": "A filter size is not a universal cell diameter. Existing caveat no sharp boundary is essential; a rigorous lower size limit for life is unknown.", "checked": "2026-10-26", "metres": 2e-7, "measurement": "Approximate reference region", "displaySize": "~0.2 μm · no sharp boundary", "symbolic": false }, { "name": "Herpes simplex virus", "status": "representative", "basis": "Mature HSV-1 outer diameter approximately 225 nm including glycoprotein spikes; published mean envelope diameter of 186 nm excludes the spikes.", "sources": [ "https://ictv.global/report/chapter/orthoherpesviridae/orthoherpesviridae", "https://doi.org/10.1126/science.1090284", "https://journals.asm.org/doi/full/10.1128/mbio.00825-17" ], "notes": "Representative reference near 200 nm replacing the supercoiled DNA silhouette. Virions are pleomorphic. The generated intact-envelope rendering is illustrative, not microscopy or a measured atomic reconstruction; colour, surface details and exact glycoprotein positions are not empirically verified.", "metres": 2.25e-7, "measurement": "Representative diameter including spikes", "displaySize": "≈ 225 nm · including spikes", "symbolic": false }, { "name": "Mycoplasma", "status": "representative", "basis": "400 nm lies within the often-observed 300-800 nm range reported by Rideau et al. 2022.", "sources": [ "https://pubmed.ncbi.nlm.nih.gov/35638916/" ], "notes": "Representative generated cell; no single species or universal dimension claimed.", "checked": "2026-10-26", "metres": 4e-7, "measurement": "Representative cell diameter", "displaySize": null, "symbolic": false }, { "name": "E. coli bacterium", "status": "representative", "basis": "2 micrometres is a defensible typical body length; growth state affects size.", "sources": [ "https://www.nature.com/articles/srep29516" ], "notes": "Body length excludes flagella. Image appearance is illustrative.", "checked": "2026-10-26", "metres": 0.000002, "measurement": "Typical length", "displaySize": null, "symbolic": false }, { "name": "Red blood cell", "status": "representative", "basis": "Normal human red-cell disc diameter is approximately 8 micrometres.", "sources": [ "https://pmc.ncbi.nlm.nih.gov/articles/PMC139218/", "https://www.cellimagelibrary.org/images/38811" ], "notes": "Biconcave shape and deformability are supported. Diameter and thickness must not be confused.", "checked": "2026-10-26", "metres": 0.000008, "measurement": "Typical diameter", "displaySize": null, "symbolic": false }, { "name": "Red blood cell cluster", "status": "representative", "basis": "Individual cells ~8 micrometres; total 22 micrometres is a constructed cluster arrangement.", "sources": [ "https://www.cellimagelibrary.org/images/38811" ], "notes": "There is no standard cluster size. Electron-microscope-style generated image is explicitly an illustration, not microscopy.", "checked": "2026-10-26", "metres": 0.000022, "measurement": "Illustrative cluster span", "displaySize": null, "symbolic": false }, { "name": "Human sperm cell", "status": "representative", "basis": "Guidobaldi et al. studied human sperm cells approximately 60 micrometres long.", "sources": [ "https://arxiv.org/abs/1501.01508" ], "notes": "Generated cell illustration. The app distinguishes total contour length from shorter projected span. Morphological detail is illustrative rather than a validated electron micrograph.", "checked": "2026-10-26", "metres": 0.00006, "measurement": "Representative total length", "displaySize": "≈ 60 μm · including tail", "symbolic": false }, { "name": "Human hair", "status": "representative", "basis": "80 micrometres is within reported scalp-hair diameter ranges.", "sources": [ "https://doi.org/10.1067/mjd.2003.276", "https://bionumbers.hms.harvard.edu/bionumber.aspx?id=114258&s=n&v=0" ], "notes": "A representative diameter, not a universal hair thickness.", "checked": "2026-10-26", "metres": 0.00008, "measurement": "Representative width", "displaySize": null, "symbolic": false }, { "name": "Human egg cell", "status": "representative", "basis": "~120 micrometres is a supported fully-grown human oocyte body diameter; zona pellucida increases outer size.", "sources": [ "https://pmc.ncbi.nlm.nih.gov/articles/PMC10335168/", "https://journals.physiology.org/doi/full/10.1152/physiol.00028.2019" ], "notes": "App measuredFraction .81 makes outer rendered span ~148 micrometres. Generated illustrative unfertilized cell, not a photograph or universally exact morphology.", "checked": "2026-10-26", "metres": 0.00012, "measurement": "Representative cell-body diameter", "displaySize": "≈ 120 μm · cell body", "symbolic": false }, { "name": "Grain of sand", "status": "representative", "basis": "0.5 mm falls within the sedimentary sand class ~0.0625 to 2 mm.", "sources": [ "https://pubs.usgs.gov/of/2006/1195/htmldocs/nomenclature.htm" ], "notes": "Size class, not one mineral or universal grain size.", "checked": "2026-10-26", "metres": 0.0005, "measurement": "Representative diameter", "displaySize": null, "symbolic": false }, { "name": "Ant", "status": "representative", "basis": "A 5 mm ant is plausible; University of Maine identifies photographed Camponotus nearcticus workers of this length.", "sources": [ "https://extension.umaine.edu/home-and-garden-ipm/fact-sheets/common-name-listing/carpenter-ants/" ], "notes": "The app does not identify this illustration to species. Keep generic representative length rather than claim all ants have this size.", "checked": "2026-10-26", "metres": 0.005, "measurement": "Representative length", "displaySize": null, "symbolic": false }, { "name": "Pearl", "status": "representative", "basis": "7 mm is a normal cultured pearl diameter; GIA describes common akoya pearls in the 6-8 mm range.", "sources": [ "https://www.gia.edu/gems-gemology/spring-2018-gemnews-very-small-akoya-cultured-pearls" ], "notes": "Not a universal pearl diameter or an assertion that the rendered pearl has a known provenance.", "checked": "2026-10-26", "metres": 0.007, "measurement": "Illustrative diameter", "displaySize": null, "symbolic": false }, { "name": "Housefly", "status": "uncertain", "basis": "University of Florida gives adult body length 6-7 mm; app shows 9 mm illustrative span including legs/wings.", "sources": [ "https://edis.ifas.ufl.edu/publication/IN205/pdf" ], "notes": "9 mm is not an independently measured biological dimension. Kept as explicitly illustrative visible span, repaired source URL and removed obsolete reference-recording interpretation from fact text.", "checked": "2026-10-26", "metres": 0.009, "measurement": "Illustrative visible span including legs", "displaySize": null, "symbolic": false }, { "name": "1 centimeter", "status": "verified", "basis": "Exact decimal SI prefix: 10^-2 m.", "sources": [ "https://www.nist.gov/pml/owm/metric-si-prefixes" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 0.01, "measurement": "Exact length", "displaySize": null, "symbolic": false }, { "name": "Honeybee", "status": "corrected", "basis": "15 mm is an illustrative worker body length near the upper end of the 12–15 mm extension reference. Body excludes wings, legs and antennae.", "sources": [ "https://extension.psu.edu/the-bumble-bee-lifestyle" ], "notes": "Adjusted artwork measuredFraction to0.8 after visual inspection of body versus protruding antennae/wing/leg span. Calibration is approximate because generated image is oblique.", "metres": 0.015, "measurement": "Representative worker body length", "displaySize": "≈15 mm · body length", "symbolic": false }, { "name": "1 euro cent coin", "status": "verified", "basis": "European Commission specification: 16.25 mm diameter; copper-covered steel.", "sources": [ "https://economy-finance.ec.europa.eu/euro/euro-coins-and-notes/euro-coins/common-sides-euro-coins_en" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 0.01625, "measurement": "Diameter", "displaySize": null, "symbolic": false }, { "name": "Tennis ball", "status": "representative", "basis": "67 mm is within the ITF Type 1/2 range 65.4–68.6 mm, not a unique regulation diameter.", "sources": [ "https://www.itftennis.com/media/15639/2026-technical-booklet.pdf" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 0.067, "measurement": "Representative regulation diameter", "displaySize": "≈67 mm · diameter", "symbolic": false }, { "name": "Small fish", "status": "representative", "basis": "80 mm is an explicitly illustrative fish length, with no identified species or measured individual.", "sources": [], "notes": "Illustrative selected size only. No empirical verification of the depicted specimen is claimed.", "metres": 0.08, "measurement": "Illustrative total length", "displaySize": null, "symbolic": false }, { "name": "Football", "status": "representative", "basis": "68–70 cm circumference implies 216.5–222.8 mm spherical diameter; 220 mm is a rounded example.", "sources": [ "https://theifab.com/laws/latest/the-ball/" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 0.22, "measurement": "Approximate diameter", "displaySize": null, "symbolic": false }, { "name": "1 foot", "status": "verified", "basis": "International foot is exactly 0.3048 m.", "sources": [ "https://www.nist.gov/pml/us-surveyfoot/revised-unit-conversion-factors" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 0.3048, "measurement": "Exact length", "displaySize": null, "symbolic": false }, { "name": "Penguin chick", "status": "representative", "basis": "450 mm is an illustrative stage of growth. The source describes emperor penguin biology but does not measure this chick.", "sources": [ "https://www.antarctica.gov.au/about-antarctica/animals/penguins/emperor-penguin/" ], "notes": "Illustrative selected size only. No empirical verification of the depicted specimen is claimed.", "metres": 0.45, "measurement": "Illustrative chick height", "displaySize": null, "symbolic": false }, { "name": "House cat", "status": "representative", "basis": "460 mm excludes tail and is an illustrative domestic-cat body length, not a measured breed average. The general source gives total length and cannot establish this pictured individual.", "sources": [ "https://animaldiversity.org/accounts/Felis_catus/" ], "notes": "Illustrative selected size only. No empirical verification of the depicted specimen is claimed.", "metres": 0.46, "measurement": "Representative body length", "displaySize": null, "symbolic": false }, { "name": "Porcupine", "status": "corrected", "basis": "800 mm is now explicitly the illustrated outer span including quills. It cannot accurately be called head-and-body length because quills occupy much of the picture. Crested porcupines can have body lengths up to about900 mm and long projecting quills.", "sources": [ "https://animals.sandiegozoo.org/animals/porcupine" ], "notes": "Relabelled metric as outer span including quills, because existing silhouette width is not an anatomical body measurement.", "metres": 0.8, "measurement": "Illustrative outer span including quills", "displaySize": "≈80 cm · including quills", "symbolic": false }, { "name": "1 meter", "status": "verified", "basis": "Exact SI length reference.", "sources": [ "https://www.nist.gov/si-redefinition/definitions-si-base-units" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 1, "measurement": "Exact length", "displaySize": null, "symbolic": false }, { "name": "Emperor penguin", "status": "representative", "basis": "1.15 m is a representative adult within the 1.1–1.3 m range.", "sources": [ "https://www.asoc.org/learn/emperor-penguin/" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 1.15, "measurement": "Representative adult height", "displaySize": null, "symbolic": false }, { "name": "Cheetah", "status": "representative", "basis": "1.3 m head/body falls within San Diego Zoo 1–1.4 m; tail excluded.", "sources": [ "https://animals.sandiegozoo.org/animals/cheetah" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 1.3, "measurement": "Representative head–body length", "displaySize": "1.3 m · body length, excluding tail", "symbolic": false }, { "name": "Human", "status": "representative", "basis": "1.75 m is a chosen adult-height reference, not a demographic average or a measurement of the generated figure.", "sources": [], "notes": "Illustrative selected size only. No empirical verification of the depicted specimen is claimed.", "metres": 1.75, "measurement": "Representative height", "displaySize": "1.75 m · illustrative height", "symbolic": false }, { "name": "Ostrich", "status": "representative", "basis": "2.4 m is a plausible illustrative adult; Smithsonian gives adults up to about2.74 m, with sex differences.", "sources": [ "https://nationalzoo.si.edu/animals/ostrich" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 2.4, "measurement": "Representative adult height", "displaySize": null, "symbolic": false }, { "name": "Atlantic bluefin tuna", "status": "representative", "basis": "3 m is a large adult example, not average. NOAA lists maxima around13 feet (~4 m).", "sources": [ "https://www.fisheries.noaa.gov/species/western-atlantic-bluefin-tuna" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 3, "measurement": "Representative total length", "displaySize": "3 m · large adult length", "symbolic": false }, { "name": "Walrus", "status": "representative", "basis": "Representative adult male length of 3.3 m, within the published 3–3.5 m range.", "sources": [ "https://npolar.no/en/species/walrus/" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 3.3, "measurement": "Representative adult male length", "displaySize": "3.3 m · adult male length", "symbolic": false }, { "name": "Giant manta ray", "status": "representative", "basis": "4 m disc width is a representative example, not maximum; NOAA states wingspan up to26 feet (~7.9 m).", "sources": [ "https://www.fisheries.noaa.gov/species/giant-manta-ray" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 4, "measurement": "Representative disc width", "displaySize": "4 m · wingspan", "symbolic": false }, { "name": "Volvo EX30", "status": "verified", "basis": "Manufacturer overall length 4.233 m, height approximately 1.55 m.", "sources": [ "https://www.volvocars.com/static/support-content/pdfs/uk_en-GB_ex30_2026_UM_1261071e0caa5674b16bfecc0384c9c5.pdf" ], "notes": "Generated side-profile illustration, not an official photo. The app calibrates the bumper span to 4.233 m and roof-to-tire span to approximately 1.55 m. Individual styling details are illustrative.", "metres": 4.233, "measurement": "Manufacturer overall length", "displaySize": "4.233 m · overall length", "symbolic": false }, { "name": "African elephant", "status": "representative", "basis": "Approximately 5.3 m horizontal silhouette in the illustrated pose; approximately 3.3 m shoulder height retained.", "sources": [ "https://ielc.libguides.com/sdzg/factsheets/african_elephant/characteristics" ], "notes": "Horizontal posed span replaces shoulder height as the comparison dimension. It includes visible tusks and tail; the curved trunk is not extended. This is an assigned illustrative span constrained by realistic shoulder height, not a measured specimen or the 6–7.5 m anatomical length including an extended trunk. Clean isolated artwork removes the adjacent whale fin.", "metres": 5.3, "measurement": "Illustrative horizontal length in this pose", "displaySize": "≈ 5.3 m · length in this pose", "symbolic": false }, { "name": "Giraffe", "status": "representative", "basis": "5.5 m matches San Diego Zoo upper male height, rather than an average giraffe.", "sources": [ "https://animals.sandiegozoo.org/animals/giraffe" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 5.5, "measurement": "Large adult male height", "displaySize": null, "symbolic": false }, { "name": "Deciduous tree", "status": "representative", "basis": "10 m illustrative specimen height", "sources": [ "https://commons.wikimedia.org/wiki/File:Tree_Transparent_Background.png" ], "notes": "Reduced from the previous illustrative 20 m height. The species and actual height of the photographed specimen are unknown; this is an assigned comparison scale, not a field measurement.", "metres": 10, "measurement": "Representative height", "displaySize": "10 m · illustrative height", "symbolic": false }, { "name": "Tyrannosaurus rex", "status": "representative", "basis": "12 m is the NHM representative adult total length; very large specimens approach13 m. Reconstruction and posture add uncertainty.", "sources": [ "https://www.nhm.ac.uk/discover/dino-directory/tyrannosaurus.html" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 12, "measurement": "Representative total length", "displaySize": null, "symbolic": false }, { "name": "Blue whale", "status": "representative", "basis": "25 m is a representative adult length; NOAA confirms largest living animal and examples reaching30 m or more.", "sources": [ "https://www.fisheries.noaa.gov/species/blue-whale" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 25, "measurement": "Representative length", "displaySize": null, "symbolic": false }, { "name": "Giant sequoia", "status": "representative", "basis": "85 m is a large mature-tree example. NPS measured General Sherman at83.8 m; this generated tree is not General Sherman. NPS records sequoia ages up to3,400 years.", "sources": [ "https://www.nps.gov/seki/learn/nature/sherman.htm" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 85, "measurement": "Large mature-tree height", "displaySize": "≈85 m · large mature tree", "symbolic": false }, { "name": "SpaceX Starship · full stack", "status": "representative", "basis": "SpaceX manufacturer page specifies 124 m overall,52 m upper stage,72 m booster and9 m body diameter for its October 2026 design configuration.", "sources": [ "https://www.spacex.com/vehicles/starship/design" ], "notes": "User-supplied reference with edited background removal, retaining natural image proportions. Overall displayed height uses the manufacturer 124 m configuration. The exact version depicted in the reference and its original source are unknown; the image is not a certified engineering drawing.", "metres": 124, "measurement": "Manufacturer full-stack height", "displaySize": "124 m · full stack", "symbolic": false }, { "name": "Eiffel Tower", "status": "verified", "basis": "330 m including 2022 antenna is verified by the tower operator.", "sources": [ "https://www.toureiffel.paris/en/news/events/eiffel-tower-grows-330-meters-tall" ], "notes": "Existing measuredFraction and baseline crop calibrate visible architectural height separately from transparent pixel padding. Generated image details are illustrative.", "metres": 330, "measurement": "Height including antenna", "displaySize": null, "symbolic": false }, { "name": "Burj Khalifa", "status": "verified", "basis": "828 m architectural height verified by its architect SOM.", "sources": [ "https://www.som.com/projects/burj-khalifa/" ], "notes": "Existing measuredFraction and baseline crop calibrate visible architectural height separately from transparent pixel padding. Generated image details are illustrative.", "metres": 828, "measurement": "Architectural height", "displaySize": null, "symbolic": false }, { "name": "Tesla Gigafactory Texas", "status": "uncertain", "basis": "The retained1.2 km main-building length is a rough estimate from earlier secondary reporting. Tesla verifies the facility and floor area but does not give this length on its official page; authoritative surveyed linear dimension remains unverified.", "sources": [ "https://www.tesla.com/giga-texas" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 1200, "measurement": "Rough main-building length estimate", "displaySize": "≈1.2 km · rough length estimate", "symbolic": false }, { "name": "1 mile", "status": "verified", "basis": "International mile is exactly 1,609.344 m.", "sources": [ "https://www.nist.gov/pml/us-surveyfoot/revised-unit-conversion-factors" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 1609.344, "measurement": "Exact length", "displaySize": null, "symbolic": false }, { "name": "Mount Fuji", "status": "verified", "basis": "3,776 m rounded summit elevation confirmed by Japan GSI, including after the2024 survey. It is not relief from the photographic base.", "sources": [ "https://www.gsi.go.jp/WNEW/PRESS-RELEASE/keikaku61003.html" ], "notes": "Important visual limitation: the cutout is scaled to an elevation reference; its visible foot is not sea level and its width/relief are not a surveyed terrain model. This is stated in the size label and fact.", "metres": 3776, "measurement": "Summit elevation above sea level", "displaySize": "3'776 m · elevation above sea level", "symbolic": false }, { "name": "Comet 67P", "status": "verified", "basis": "4.3 km longest principal-axis nucleus dimension supported by the Rosetta morphology review; projected silhouette depends on orientation.", "sources": [ "https://link.springer.com/article/10.1007/s11214-019-0602-1" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 4300, "measurement": "Approximate longest nucleus dimension", "displaySize": "≈4.3 km · longest nucleus axis", "symbolic": false }, { "name": "Mount Everest", "status": "verified", "basis": "8,849 m is rounded from8,848.86 m snow-summit elevation above sea level, in Nepal government mountaineering figures.", "sources": [ "https://giwmscdnone.gov.np/media/pdf_upload/Mountaineering%20Fact%20and%20Figure%202023_aolusdr.pdf" ], "notes": "Important visual limitation: the cutout is scaled to an elevation reference; its visible foot is not sea level and its width/relief are not a surveyed terrain model. This is stated in the size label and fact.", "metres": 8849, "measurement": "Elevation above sea level", "displaySize": "≈8'849 m · elevation above sea level", "symbolic": false }, { "name": "Mariana Trench", "status": "verified", "basis": "10,935 m Challenger Deep estimate matches NOAA; survey uncertainty and differing estimates remain.", "sources": [ "https://oceanservice.noaa.gov/facts/oceandepth.html" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 10935, "measurement": "Challenger Deep depth", "displaySize": "≈ 10'935 m · Challenger Deep", "symbolic": false }, { "name": "Kola Borehole", "status": "verified", "basis": "12,262 m total borehole depth stated by the 1999 research paper. Some institutional listings say12,261 m. Keep source precision and do not equate bore length with exact vertical penetration.", "sources": [ "https://doi.org/10.1016/S0040-1951(99)00065-7" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 12262, "measurement": "Reported drilled depth below ground", "displaySize": "12'262 m · depth", "symbolic": false }, { "name": "Neutron star", "status": "representative", "basis": "25.4 km is the2019 NICER/Riley-team J0030 model diameter, not a universal neutron-star diameter; second model gave26 km.", "sources": [ "https://svs.gsfc.nasa.gov/13240/" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 25400, "measurement": "Model-estimated diameter", "displaySize": "≈25.4 km · J 0030 model diameter", "symbolic": false }, { "name": "Marathon", "status": "verified", "basis": "42,195 m official race distance verified by World Athletics.", "sources": [ "https://worldathletics.org/disciplines/road-running-event/marathon" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 42195, "measurement": "Race distance", "displaySize": null, "symbolic": false }, { "name": "100 kilometres", "status": "verified", "basis": "Exact decimal SI reference: 100,000 m.", "sources": [ "https://www.nist.gov/pml/owm/metric-si-prefixes" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 100000, "measurement": "Reference distance", "displaySize": null, "symbolic": false }, { "name": "Vesta", "status": "verified", "basis": "525 km mean diameter matches NASA Vesta Trek. Irregular shape prevents one diameter describing every silhouette span.", "sources": [ "https://trek.nasa.gov/vesta/jpl/assets/quickfacts/vesta/quick-facts.html" ], "notes": "Numerical comparison checked against the stated dimension; illustrations are not metrology or independently verified anatomy.", "metres": 525000, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Ceres", "status": "verified", "basis": "2×469.7 km mean radius from NASA/JPL gives939.4 km mean diameter. Ceres is oblate; its photographed polar extent differs from this spherical-equivalent comparison.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Image fit=height and548/600 visible-disc fraction remove blank image margins. Its mean diameter is used as a characteristic size, not an exact angularly calibrated polar axis.", "metres": 939400, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Pluto", "status": "verified", "basis": "Mean diameter: 2376.6 km; JPL radius 1188.3 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 2376600, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "USA", "status": "representative", "basis": "Approximately 2,700 km north–south extent of the generalized contiguous-US outline.", "sources": [ "https://www.naturalearthdata.com/downloads/110m-cultural-vectors/" ], "notes": "Schematic 1:110m outline with equirectangular longitude scaled at 37°N. Projection changes east–west distances with latitude; Alaska/Hawaii omitted. Not a survey-accurate map or a national longest-distance measurement.", "metres": 2700000, "measurement": "Approximate north–south span", "displaySize": "≈ 2'700 km · north–south span", "symbolic": false }, { "name": "Europa", "status": "verified", "basis": "NASA radius 1,560.8 km gives 3,121.6 km diameter.", "sources": [ "https://nssdc.gsfc.nasa.gov/planetary/factsheet/joviansatfact.html", "https://science.nasa.gov/jupiter/jupiter-moons/europa/" ], "notes": "Galileo image is partially illuminated. Subsurface ocean is inferred from multiple lines of evidence, not directly photographed.", "metres": 3121600, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Moon", "status": "verified", "basis": "Volumetric mean radius 1,737.4 km gives 3,474.8 km diameter.", "sources": [ "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html" ], "notes": "Physical globe diameter; its position on the orbital reference is schematic.", "metres": 3474800, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Mercury", "status": "corrected", "basis": "Mean diameter: 4878.8 km; JPL radius 2439.4 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 4878800, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Titan", "status": "verified", "basis": "Solid-body diameter 5,149.4 km is consistent with NASA’s rounded 2,575 km radius.", "sources": [ "https://nssdc.gsfc.nasa.gov/planetary/factsheet/saturniansatfact.html", "https://science.nasa.gov/resource/cassinis-view-of-titan-natural-color-composite/" ], "notes": "550-pixel visual disc calibration excludes dark frame; the haze is diffuse, so its visible edge cannot supply an exact solid-body measurement. The fixed 660/766 baseline is a visual alignment.", "metres": 5149400, "measurement": "Mean solid-body diameter", "displaySize": null, "symbolic": false }, { "name": "Mars", "status": "corrected", "basis": "Equatorial diameter: 6792.38 km; JPL radius 3396.19 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 6792380, "measurement": "Equatorial diameter", "displaySize": null, "symbolic": false }, { "name": "Sirius B", "status": "corrected", "basis": "Bond et al. 2017 radius 0.008098 R☉ corresponds to about 11,270 km diameter.", "sources": [ "https://arxiv.org/abs/1703.10625" ], "notes": "The retained size matches Bond2017; the previous link was Joyce2018, which reported a slightly smaller, statistically consistent radius. Artist rendering is not a surface photograph.", "metres": 11270000, "measurement": "Approximate white-dwarf diameter", "displaySize": null, "symbolic": false }, { "name": "Venus", "status": "corrected", "basis": "Equatorial diameter: 12103.6 km; JPL radius 6051.8 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 12103600, "measurement": "Equatorial diameter", "displaySize": null, "symbolic": false }, { "name": "Earth", "status": "verified", "basis": "Mean diameter: 12742 km; JPL radius 6371.01 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 12742000, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Neptune", "status": "verified", "basis": "Mean diameter: 49244 km; JPL radius 24622 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 49244000, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Uranus", "status": "verified", "basis": "Equatorial diameter excluding rings: 51118 km; JPL radius 25559 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 51118000, "measurement": "Equatorial diameter excluding rings", "displaySize": null, "symbolic": false }, { "name": "Saturn", "status": "verified", "basis": "Equatorial globe diameter: 120536 km; JPL radius 60268 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 120536000, "measurement": "Equatorial globe diameter", "displaySize": null, "symbolic": false }, { "name": "Jupiter", "status": "corrected", "basis": "Mean diameter: 139822 km; JPL radius 69911 km.", "sources": [ "https://ssd.jpl.nasa.gov/planets/phys_par.html" ], "notes": "Mean diameter is volume-equivalent; equatorial diameter is explicitly distinguished. Photographic disc boundaries and generated illustrations are approximate visual references, not independent shape measurements.", "metres": 139822000, "measurement": "Mean diameter", "displaySize": null, "symbolic": false }, { "name": "Brown dwarf", "status": "representative", "basis": "Mamajek T5: radius 0.101 R☉; temperature 1160 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 140531400, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "M5 red dwarf", "status": "representative", "basis": "Mamajek M5V: radius 0.196 R☉; temperature 3060 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 272714400, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "Moon’s orbit", "status": "verified", "basis": "Twice the 384,400 km semimajor axis gives a 768,800 km reference diameter.", "sources": [ "https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html" ], "notes": "Circular Earth-centred reference, not the real eccentric orbit or an ephemeris for a date.", "metres": 768800000, "measurement": "Reference orbital diameter", "displaySize": "768'800 km · orbital diameter", "symbolic": false }, { "name": "K5 orange dwarf", "status": "representative", "basis": "Mamajek K5V: radius 0.701 R☉; temperature 4440 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 975371399.9999999, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "Sun", "status": "corrected", "basis": "Nominal solar radius 695,700 km gives a consistent 1,391,400 km comparison diameter.", "sources": [ "https://www.iau.org/static/resolutions/IAU2015_English.pdf", "https://sdo.gsfc.nasa.gov/data/aiahmi/" ], "notes": "Uses the same IAU conversion as all stellar examples. Nominal radius is a defined conversion near the observed photospheric radius. The retained 304 Å image shows solar plasma in assigned orange colour, not natural visible light.", "metres": 1391400000, "measurement": "Nominal solar diameter", "displaySize": null, "symbolic": false }, { "name": "Sirius A", "status": "verified", "basis": "Interferometric radius 1.713 ± 0.009 solar radii; current diameter 2,383,468 km.", "sources": [ "https://arxiv.org/abs/1010.3790", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "2010 measured estimate. Art is a spectral-class illustration, not resolved surface imagery.", "metres": 2383468200, "measurement": "Photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "F0 main-sequence star", "status": "representative", "basis": "Mamajek F0V: radius 1.728 R☉; temperature 7220 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 2404339200, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "A0 main-sequence star", "status": "representative", "basis": "Mamajek A0V: radius 2.193 R☉; temperature 9700 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 3051340200, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "Wolf–Rayet star", "status": "representative", "basis": "Illustrative chosen radius 5 R☉; not a measured or population-average class radius.", "sources": [ "https://science.nasa.gov/universe/stars/types/", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "The source supports stellar evolution/class interpretation, not this arbitrary exact example radius. Real members span broad ranges. Wolf–Rayet wind/photosphere conventions are model dependent.", "metres": 6957000000, "measurement": "Illustrative representative diameter", "displaySize": "≈ 6.957 million km · illustrative diameter", "symbolic": false }, { "name": "B0 main-sequence star", "status": "representative", "basis": "Mamajek B0V: radius 7.16 R☉; temperature 31400 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 9962424000, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "O5 main-sequence star", "status": "representative", "basis": "Mamajek O5V: radius 11.45 R☉; temperature 41400 K. Diameter = radius ratio × 1,391,400 km.", "sources": [ "https://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "A class example, not a uniquely measured star. Stellar radii vary with age/composition. Artwork is illustrative; spectral class does not determine a detailed surface map.", "metres": 15931529999.999998, "measurement": "Representative photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "Sagittarius A*", "status": "corrected", "basis": "Schwarzschild diameter for 4 million solar masses ≈23.626 million km. EHT field: 140 μas at 8,150 pc.", "sources": [ "https://www.eso.org/public/images/eso2208-eht-mwa/", "https://doi.org/10.3847/2041-8213/ac6674" ], "notes": "Clarified 2017 observations released2022. Radio ring (~51.8 μas) is lensing/accretion emission, not the event horizon. Asset fraction0.1384 maps horizon scale to whole field. Spin and emission structure are not resolved by the Schwarzschild size convention.", "metres": 23626000000, "measurement": "Estimated non-rotating horizon diameter", "displaySize": null, "symbolic": false }, { "name": "Red giant", "status": "representative", "basis": "Illustrative chosen radius 25 R☉; not a measured or population-average class radius.", "sources": [ "https://science.nasa.gov/universe/stars/types/", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "The source supports class interpretation, not this chosen exact example radius. Real members span broad radii. Artwork remains an illustration.", "metres": 34785000000, "measurement": "Illustrative representative diameter", "displaySize": "≈ 34.785 million km · illustrative diameter", "symbolic": false }, { "name": "Blue supergiant", "status": "representative", "basis": "Illustrative chosen radius 80 R☉; not a measured or population-average class radius.", "sources": [ "https://science.nasa.gov/universe/stars/types/", "https://www.iau.org/static/resolutions/IAU2015_English.pdf" ], "notes": "The source supports class interpretation, not this chosen exact example radius. Real members span broad radii. Artwork remains an illustration.", "metres": 111312000000, "measurement": "Illustrative representative diameter", "displaySize": "≈ 111.312 million km · illustrative diameter", "symbolic": false }, { "name": "Earth–Sun Distance = 1 AU", "status": "verified", "basis": "1 au = 149,597,870,700 m exactly.", "sources": [ "https://www.iau.org/static/resolutions/IAU2012_English.pdf" ], "notes": "The defined astronomical unit is close to Earth’s mean Sun distance; the actual instantaneous distance varies.", "metres": 149597870700, "measurement": "One astronomical unit", "displaySize": null, "symbolic": false }, { "name": "Betelgeuse", "status": "uncertain", "basis": "Diameter = 2 × 764 nominal solar radii; Joyce et al.2020 gives R=764(+116/-62) R_sun. Model and distance dependent.", "sources": [ "https://arxiv.org/abs/2006.09837" ], "notes": "Adopted historical estimate is defensible; texture is an illustration, not a resolved surface photograph.", "checked": "2026-10-26", "metres": 1063029600000, "measurement": "Model-estimated photospheric diameter", "displaySize": null, "symbolic": false }, { "name": "1 light-hour", "status": "verified", "basis": "299792458 m/s ×3600 s =1079252848800 m.", "sources": [ "https://physics.nist.gov/cuu/Constants/Value/c.html" ], "notes": "Ring diameter represents distance; not radius.", "checked": "2026-10-26", "metres": 1079252848800, "measurement": "Ring diameter: distance light travels in one hour", "displaySize": null, "symbolic": false }, { "name": "UY Scuti", "status": "uncertain", "basis": "2013 photospheric radius1708±192 R_sun, diameter2376511200000m.", "sources": [ "https://arxiv.org/abs/1305.6179", "https://www.uv.es/beato4/thesis/Tesis_BelenArroyoTorres.pdf" ], "notes": "This is one published estimate, not a settled current ranking or largest-star record; distance and atmosphere matter.", "checked": "2026-10-26", "metres": 2376511200000, "measurement": "Published photospheric diameter estimate", "displaySize": null, "symbolic": false }, { "name": "Saturn’s orbit", "status": "representative", "basis": "Approximately twice orbital semimajor axis; NASA J2000 mean a=9.53707032 AU. Current rounded2.864e12m differs by less than0.4%.", "sources": [ "https://nssdc.gsfc.nasa.gov/planetary/factsheet/saturnfact.html" ], "notes": "Circular schematic replaces eccentric orbit; retain rounded comparison.", "checked": "2026-10-26", "metres": 2864000000000, "measurement": "Approximate orbital major-axis diameter", "displaySize": null, "symbolic": false }, { "name": "Largest theoretical star", "status": "uncertain", "basis": "No unique established maximum diameter; catalogue already marks placementOnly and symbolic.", "sources": [ "https://arxiv.org/abs/1305.6179" ], "notes": "3e12m is a chapter location, not a measured or theoretical bound. Should not be narrated as a physical-size record.", "checked": "2026-10-26", "metres": 3000000000000, "measurement": "Concept marker, not a measured diameter", "displaySize": "No single established maximum", "symbolic": true }, { "name": "Voyager 1 · 1980–2026", "status": "verified", "basis": "NASA/JPL Horizons dated heliocentric ephemeris stored with raw response; final172.16084201066573 AU at2026-10-26.", "sources": [ "https://ssd.jpl.nasa.gov/horizons/" ], "notes": "Dated prediction/ephemeris, not live telemetry; straight distance reference is not spacecraft trajectory.", "checked": "2026-10-26", "metres": 25754895382714.7, "measurement": "Heliocentric distance · dated ephemeris", "displaySize": "172.16 AU · 26 Oct 2026", "symbolic": false }, { "name": "Heliosphere", "status": "representative", "basis": "36e12m diameter corresponds to120.3AU radius, near observed Voyager heliopause distances120–122AU.", "sources": [ "https://science.nasa.gov/mission/voyager/interstellar-mission/" ], "notes": "The full shape is neither spherical nor directly measured by these two crossings; illustrative only.", "checked": "2026-10-26", "metres": 36000000000000, "measurement": "Illustrative span", "displaySize": null, "symbolic": false }, { "name": "Phoenix A black hole", "status": "uncertain", "basis": "Schwarzschild diameter4GM/c² using10billion solar masses =approximately59.1billion km. NASA2025 uses roughly10billion solar masses.", "sources": [ "https://science.nasa.gov/missions/webb/webb-maps-full-picture-of-how-phoenix-galaxy-cluster-forms-stars/" ], "notes": "Do not use widely circulated100billion-solar-mass figure as settled. Disk simulation is illustrative. Nonrotating shadow diameter/horizon diameter=3sqrt(3)/2.", "checked": "2026-10-26", "metres": 59065000000000, "measurement": "Estimated non-rotating event-horizon diameter", "displaySize": null, "symbolic": false }, { "name": "TON 618", "status": "uncertain", "basis": "Schwarzschild diameter4GM/c² using40.7billion solar masses =approximately240.4billion km. Aggarwal2025 cites Ge et al.2019 for4.07e10M_sun.", "sources": [ "https://doi.org/10.1093/mnras/stae2732" ], "notes": "Virial-mass estimates have large systematic uncertainty; no direct horizon image. Nonrotating model retained.", "checked": "2026-10-26", "metres": 240394550000000, "measurement": "Estimated non-rotating event-horizon diameter", "displaySize": null, "symbolic": false }, { "name": "1 light-month", "status": "verified", "basis": "299792458 ×30×86400=777062051136000m.", "sources": [ "https://physics.nist.gov/cuu/Constants/Value/c.html" ], "notes": "30days explicitly defined; calendar months are not constant.", "checked": "2026-10-26", "metres": 777062051136000, "measurement": "Distance light travels in 30 days", "displaySize": null, "symbolic": false }, { "name": "One light-year", "status": "verified", "basis": "c × Julian year365.25days =9.4607304725808e15m, rounded in app to9.4607e15m.", "sources": [ "https://iauarchive.eso.org/public/themes/measuring/", "https://physics.nist.gov/cuu/Constants/Value/c.html" ], "notes": "Rounding error0.00032%, negligible compared with object uncertainty.", "checked": "2026-10-26", "metres": 9460700000000000, "measurement": "Distance travelled by light in a year", "displaySize": null, "symbolic": false }, { "name": "Southern Ring Nebula", "status": "verified", "basis": "NASA image metadata states2.4arcmin/1.4light-years for NIRCam field.", "sources": [ "https://science.nasa.gov/asset/webb/southern-ring-nebula-nircam-image/" ], "notes": "Correct field width, not the visible shell diameter.", "checked": "2026-10-26", "metres": 13244980000000000, "measurement": "Approximate image-field width", "displaySize": "≈ 1.4 light-years · image field", "symbolic": false }, { "name": "Helix Nebula", "status": "representative", "basis": "ESA/Hubble quotes nearly3ly ring diameter at650ly distance.", "sources": [ "https://esahubble.org/images/heic0307a/" ], "notes": "MeasuredFraction0.596 separates approximate bright ring from surrounding image; diffuse boundary is not precise.", "checked": "2026-10-26", "metres": 28382100000000000, "measurement": "Approximate bright ring diameter", "displaySize": null, "symbolic": false }, { "name": "Oort cloud", "status": "corrected", "basis": "NASA estimates outer radius up to100000AU, hence adopt200000AU outer diameter ≈3.16ly.", "sources": [ "https://science.nasa.gov/solar-system/oort-cloud/facts/" ], "notes": "Previously2ly diameter was an underspecified illustrative scale. Extent remains uncertain; not a measured hard shell.", "checked": "2026-10-26", "metres": 29919574140000000, "measurement": "Illustrative outer diameter", "displaySize": "≈ 3.16 light-years · outer diameter", "symbolic": false }, { "name": "Distance to Proxima Centauri", "status": "verified", "basis": "Rounded4.24ly distance; official sources quote about4.2–4.25ly.", "sources": [ "https://science.nasa.gov/exoplanets/other-stars-other-worlds/our-nearest-celestial-neighbor-an-exotic-3-star-system/" ], "notes": "Distance from Solar neighbourhood, not diameter; AU-scale baseline difference is negligible here.", "checked": "2026-10-26", "metres": 40113368000000000, "measurement": "Approximate distance from the Sun", "displaySize": null, "symbolic": false }, { "name": "Pleiades", "status": "corrected", "basis": "Spitzer Science Center astrometrics:58.1arcmin square at430ly yields7.27ly field.", "sources": [ "https://www.spitzer.caltech.edu/image/ssc2007-07a-the-seven-sisters-pleiades-pose-for-spitzer-and-for-you", "https://www.spitzer.caltech.edu/image/ssc2007-07b1-the-seven-sisters-pleiades-pose-for-spitzer-and-for-you" ], "notes": "43ly was not calibrated to this photograph and resembles a tidal radius, not diameter. Correct to field width; broader cluster and Greater Pleiades Complex extend far beyond image.", "checked": "2026-10-26", "metres": 68753367789807500, "measurement": "Approximate infrared image-field width", "displaySize": "≈ 7.3 light-years · image field", "symbolic": false }, { "name": "Pillars of Creation", "status": "corrected", "basis": "Approximately 8 light-years, full Webb image-field width", "sources": [ "https://science.nasa.gov/asset/webb/pillars-of-creation-nircam-image/" ], "notes": "The complete NIRCam observation is displayed immediately. The label describes the familiar subject; the measured span is the entire image field, not one pillar. A later registered transition shows the wider Eagle Nebula.", "checked": "2026-10-26", "metres": 75685600000000000, "measurement": "Approximate image-field width", "displaySize": "≈ 8 light-years · image field", "symbolic": false }, { "name": "Orion Nebula", "status": "verified", "basis": "ESA field30.03arcmin at1400ly gives12.23ly width.", "sources": [ "https://esahubble.org/images/heic0601a/" ], "notes": "Correct image width, not total nebula diameter; source caption and metadata differ on distance, so rounded field retained.", "checked": "2026-10-26", "metres": 115704361000000000, "measurement": "Approximate image field", "displaySize": "≈ 12.2 light-years · image field", "symbolic": false }, { "name": "Cosmic Cliffs", "status": "verified", "basis": "NASA NIRCam metadata gives7.3arcmin corresponding16ly.", "sources": [ "https://science.nasa.gov/asset/webb/cosmic-cliffs-in-the-carina-nebula-nircam-image/" ], "notes": "Image field only; wavelengths are mapped to visible colours.", "checked": "2026-10-26", "metres": 151371200000000000, "measurement": "Approximate image-field width", "displaySize": "≈ 16 light-years · image field", "symbolic": false }, { "name": "Eagle Nebula", "status": "verified", "basis": "ESO field32.08arcmin; at adopted6500ly distance,60.66ly before rotation. Rotated padded square63.59ly.", "sources": [ "https://www.eso.org/public/images/eso0926a/", "https://science.nasa.gov/asset/webb/pillars-of-creation-nircam-image/" ], "notes": "App uses one distance for registration, rather than inconsistent older7000ly ESO caption. Square frame not nebula boundary.", "checked": "2026-10-26", "metres": 601640269075348900, "measurement": "Approximate rotated image-frame width", "displaySize": "≈ 64 light-years · image frame", "symbolic": false }, { "name": "Tarantula Nebula", "status": "corrected", "basis": "PIA14415/2012 Chandra composite has13arcmin/~600ly field.", "sources": [ "https://chandra.si.edu/photo/2012/30dor/", "https://science.nasa.gov/photojournal/pj-a-new-view-of-the-tarantula-nebula/" ], "notes": "1000ly described broad nebula but overstated this cropped field. Chandra page alt-text repeats older1100ly; its explicit Fast Facts13arcmin converts to605ly at160000ly, supporting600ly.", "checked": "2026-10-26", "metres": 5676420000000000000, "measurement": "Approximate composite image-field width", "displaySize": "≈ 600 light-years · image field", "symbolic": false }, { "name": "Local Bubble", "status": "representative", "basis": "CfA/STScI study describes roughly1000ly cavity.", "sources": [ "https://www.cfa.harvard.edu/news/1000-light-year-wide-bubble-surrounding-earth-source-all-nearby-young-stars" ], "notes": "Irregular cavity; rendering is explanatory, no hard spherical boundary or literal visible colours.", "checked": "2026-10-26", "metres": 9460700000000000000, "measurement": "Approximate cavity span", "displaySize": null, "symbolic": false }, { "name": "Triangulum Galaxy (M33)", "status": "representative", "basis": "ESO quotes stellar galaxy span50000–60000ly; app adopts60000ly.", "sources": [ "https://www.eso.org/public/images/b13/" ], "notes": "Image is a telescope photo but no sharp isophotal edge exists; screen footprint is an approximate depiction of this adopted disc diameter, not precision image-field astrometry.", "checked": "2026-10-26", "metres": 567642000000000000000, "measurement": "Approximate stellar-disc diameter", "displaySize": null, "symbolic": false }, { "name": "Milky Way", "status": "representative", "basis": "NASA quotes roughly100000ly stellar-disc diameter; observer26,000ly fromcentre in Orion Spur.", "sources": [ "https://www.nasa.gov/science-research/astrophysics/how-big-is-space-we-asked-a-nasa-expert-episode-61/", "https://science.nasa.gov/wp-content/uploads/2023/10/Exploring_the_Milky_Way.pdf" ], "notes": "Artist concept and arm placement approximate; disc edge convention excludes much larger halo.", "checked": "2026-10-26", "metres": 946070000000000000000, "measurement": "Approximate stellar-disc diameter", "displaySize": null, "symbolic": false }, { "name": "Andromeda galaxy", "status": "representative", "basis": "NASA quotes152000ly across for stellar disc.", "sources": [ "https://science.nasa.gov/centers-and-facilities/goddard/hubble-zooms-into-the-rosy-tendrils-of-andromeda/", "https://science.nasa.gov/photojournal/andromeda/" ], "notes": "Adopted galaxy diameter, not full halo. GALEX field background and wavelength-dependent disc edges mean visual outline is approximate.", "checked": "2026-10-26", "metres": 1.4380264e+21, "measurement": "Approximate stellar-disc diameter", "displaySize": null, "symbolic": false }, { "name": "IC 1101", "status": "uncertain", "basis": "2026 ultradeep imaging locates main-body semi-major edge radius260kpc, giving520kpc diameter.", "sources": [ "https://arxiv.org/abs/2607.15340" ], "notes": "Recent study estimate, not universal definition; intracluster light extends farther. Asset is illustrative, not this measured deep image.", "checked": "2026-10-26", "metres": 1.604545315984e+22, "measurement": "Estimated main-body diameter", "displaySize": null, "symbolic": false }, { "name": "Local Group", "status": "representative", "basis": "NASA gives roughly10millionly diameter.", "sources": [ "https://imagine.gsfc.nasa.gov/features/cosmic/local_group_info.html" ], "notes": "Survey projection is a neighbourhood map, dots and glows are not individual galaxy diameters.", "checked": "2026-10-26", "metres": 9.4607e+22, "measurement": "Approximate span", "displaySize": null, "symbolic": false }, { "name": "Virgo Supercluster", "status": "representative", "basis": "Conventional approximate extent110millionly, as documented by NASA-funded OpenSpace science visualization.", "sources": [ "https://docs.openspaceproject.com/latest/content/universe/deep-sky-surveys/supercluster-labels/index.html" ], "notes": "Different from Virgo Cluster; larger flow-defined Laniakea includes this region. Map draws projected galaxy positions, not a definitive membership boundary.", "checked": "2026-10-26", "metres": 1.040677e+24, "measurement": "Approximate span", "displaySize": null, "symbolic": false }, { "name": "Laniakea Supercluster", "status": "uncertain", "basis": "Tully et al.2014 flow-based supercluster approximately160Mpc across,~522millionly.", "sources": [ "https://www.nature.com/articles/nature13674", "https://doi.org/10.3847/0004-6256/152/2/50" ], "notes": "Cosmicflows-3 distances used for map, whereas original boundary used peculiar-velocity reconstruction. Not a bound object or exact spherical edge.", "checked": "2026-10-26", "metres": 4.937084130386188e+24, "measurement": "Approximate flow-defined span", "displaySize": "522 million light-years · approximate span", "symbolic": false }, { "name": "Dark-matter streams", "status": "verified", "basis": "Diemer L0125 density field125Mpc/h width,12.5Mpc/h depth; WMAP7 H0=70 so h=.7.", "sources": [ "https://www.benediktdiemer.com/visualization/images/" ], "notes": "Simulation, not photographed local structure. Credit Mansfield&Diemer, tetrahedron method following Kaehler et al.", "checked": "2026-10-26", "metres": 5.510138538377442e+24, "measurement": "Simulation field width", "displaySize": null, "symbolic": false }, { "name": "1 Gly = 1 billion light-years", "status": "verified", "basis": "Giga prefix10^9 times astronomical light-year.", "sources": [ "https://www.nist.gov/pml/owm/metric-si-prefixes", "https://iauarchive.eso.org/public/themes/measuring/" ], "notes": "Distance line only; same roundedLY constant as rest of app.", "checked": "2026-10-26", "metres": 9.4607e+24, "measurement": "Reference distance", "displaySize": "1 Gly = 1 billion light-years", "symbolic": false }, { "name": "Large-scale cosmic web", "status": "verified", "basis": "Diemer L2000 density field2000Mpc/h width,160Mpc/h depth with h=.7.", "sources": [ "https://www.benediktdiemer.com/visualization/images/" ], "notes": "Periodic simulated field is repeated to cover display, not actual observed universe map; description already states this.", "checked": "2026-10-26", "metres": 8.816221661403907e+25, "measurement": "Simulation field width", "displaySize": null, "symbolic": false }, { "name": "Observable universe", "status": "representative", "basis": "NASA2025 uses approximately92billionly present-day observable diameter.", "sources": [ "https://www.nasa.gov/science-research/astrophysics/how-big-is-space-we-asked-a-nasa-expert-episode-61/", "https://www.benediktdiemer.com/visualization/images/" ], "notes": "Conventional cosmology-dependent rounded size; boundary is observational horizon, not physical edge of all space. Repeated simulation image is illustrative and not a light-cone.", "checked": "2026-10-26", "metres": 8.703844e+26, "measurement": "Approximate present-day diameter", "displaySize": null, "symbolic": false } ] }