Physics

One plate, many entries

The banner is a family signal. Each entry keeps its own meaning and receives the same copper accent without repeating a full image.

• 4242 cosmology plate

  A walk, not a mass. GW231029 remains the measured 42 M⊙. This plate is the chamber that holds the questions.

• 420 → 159420 on Earth · 159 on Mars

  The same 420, a third field. NASA’s Mars fact sheet prints 3.71 m/s² against Earth’s 9.80. The ratio is 0.379. Four hundred twenty times that is 159. The Moon gave 69. Mars gives 159. Thirty-eight percent of Earth is not forty-two. Close. Not a 42. The body did not change. Anyway.

• 420 → 69420 on Earth · 69 on the Moon

  If you weigh 420 pounds on Earth, the Moon pulls with about 69. The body is the same. The field is not. NASA’s fact sheet prints lunar surface gravity 1.62 m/s² and Earth’s 9.80. The ratio on that table is 0.165. Four hundred twenty times 0.165 is 69.3. One-sixth would be 70. The table’s ratio is 69. A child can feel the lighter step. A physicist still writes W = mg.

• ⁴²ArArgon-42

  ⁴²Ar is argon with mass number 42. In 2026 Wan, Liang, Jia et al. counted it in air. Abundance (6.1 ± 0.5) × 10⁻²¹. Distinct from molybdenum, which is Z = 42.

• ⁴²Ar → ⁴²KArgon-potassium · A = 42 generator

  ⁴²Ar decays by β⁻ to ⁴²K, and ⁴²K decays to stable ⁴²Ca. NNDC prints the parent half-life as 32.9 y. The daughter half-life stays on the potassium-42 plate: 12.355 h. Parent and daughter both carry A = 42.

• ⁴²CaCalcium-42

  Calcium-42 is the stable A = 42 isotope of calcium (Z = 20). NIST lists relative atomic mass 41.95861783(16) and natural isotopic composition 0.00647(23). Among A = 42 isobars it is the stable endpoint.

• 10^42Dirac large number

  Dirac noticed ratios near 10⁴⁰–10⁴² between atomic and cosmological scales. The exponent is a scale, not an integer 42 sitting in the world.

• ΔS ≥ 0Entropy

  Left alone, a closed room runs downhill. Heat spreads. Eggs do not unscramble. A living body is not a closed room. It pays, with food and waste heat, to keep a shape. Schrödinger called that negative entropy. He later told physicists he meant free energy. Forgetting has a heat price too. Landauer, 1961. Love named as craft against forgetting is a living reading, not a new laboratory.

• ~42.2 minGravity tunnel

  A uniform Earth gives about 42 minutes 12 seconds, the same for any straight hole. A PREM Earth, denser at the core, gives 38 minutes 11 seconds for a diameter. The 42 is the textbook model, not the present geophysical value.

• SNR 42.4GW230814

  LIGO Livingston recovered GW230814 at SNR 42.4 · the loudest event in GWTC-4.0. Forty-two is the loudness, not the mass.

• 4.2221 KHelium-4 boiling point

  Liquid ⁴He boils at 4.2221 K at 101 325 Pa on the EPT-76 table. Labs say 4.2 K. That is the 4.2 rail. It is not 42.

• ~42 miHubble in miles

  Planck reports the Hubble constant in kilometres. Switch the unit to miles and you can print about 42. The source did not.

• 1420.405… MHzHydrogen line

  The 21-centimetre line sits at 1420.405751768 MHz. It is not 42.

• ≈ 42.3%Kerr ISCO

  For a = M, specific energy at ISCO is 1/√3, so η = 1 − 1/√3 ≈ 42.3%. Physical spin is less than 1.

• ~42°Primary rainbow

  Red light in the primary bow sits near 42° from the antisolar point.

• ~42.7 MlyRecombination

  The universe used to be fog. When the fog cleared, the whole patch we can see today was only about forty-two million light-years across. Those first free photons are the cosmic microwave background.

• M42Recombination light

  The Orion Nebula glows by hydrogen recombination. Catalogue seat M42. The process is physics. The forty-two is the Messier number, not a measured angle of recombination.

• 42.1 km/sSolar escape at 1 AU

  To leave the Sun from where Earth is, you need about 42.1 kilometres a second. Not a rounded light-year. A vis-viva number. Earth’s own orbital speed is about 29.8. The extra is the door out.