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0.4208 ± 0.0047
Vesta polar MOI
Normalized polar moment of inertia of (4) Vesta. Park et al. 2025. C̄/MR² = 0.4208 ± 0.0047.
Dawn’s gravity, reprocessed for a decade, prints Vesta’s polar moment of inertia as 0.4208, plus or minus 0.0047. Close to a uniform rock. The core is small. This is the 2025 paper. The spin pole is another room.
Four named
Hearth. Soul. Love. Longing.
Vesta is the hearth. Psyche is the soul. Eros is love. Himeros is longing. Four names from one old story, hung on four different rocks and one crater. The 42s are not the same kind. A spin pole is not a density. A cipher is not a catalogue number. The looking holds them without pretending they are one law.
42.23°Vestahere
Hearth
The sacred fire. Spin pole. Moment 0.4208. Another world.
- 4.2016 Psyche
Soul
Metal world NASA is flying toward. Not the crater on Eros.
- 433433 Eros
Love
The love asteroid. Catalogue seat, not a 42. The 42s are rooms.
- 42Himeros
Longing
Attendant of Eros. English letters. A bowl on the love rock.
What it supports
Park, Ermakov, Konopliv et al., Nature Astronomy 9, 824–834 (2025). Abstract: C̄/MR² = 0.4208 ± 0.0047. 6.6% below the homogeneous value 0.4505. DSN Doppler plus onboard imaging. A small core, or almost none.
What it does not
Not the spin pole 42.23°. Not an exact 0.42 constant. The uncertainty is 0.0047. Not 16 Psyche density 4.20. Two instruments. Two bodies.
Calculation
C̄/MR² = 0.4208 ± 0.0047. Homogeneous comparison 0.4505. 6.6% lower.
Joint gravity and rotation from Dawn DSN plus imaging. Polar MOI, not the pole latitude.
ExactnessRange / bound
Form4.2
UnitC̄/MR²
Strengthhard
When2025-04-23
Hung15 September 2026