Psyche density
4.20 ± 0.60
(16) Psyche bulk density on Ferrais et al. 2020, A&A 638, L15
IllustrationMaxar/ASU/P. Rubin/NASAJPL-CaltechPUBLIC DOMAIN
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Our 3D shape along with existing mass estimates imply a density of 4.20 ± 0.60 g cm⁻³, so far the highest for a solar-system object after the four telluric planets. One 2020 print. Not the last word on the density.
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°Vesta
Hearth
The sacred fire. Spin pole. Moment 0.4208. Another world.
4.2016 Psychehere
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
Ferrais et al., Astronomy & Astrophysics 638, L15 (2020). VLT/SPHERE shape. Three equatorial depressions. Compatible with a Jacobi ellipsoid that once spun nearer three hours; later impacts may have slowed the present day to ~4.2 h. 4.20 g cm⁻³ and ~4.2 h sit next to this Book’s 4°20′. Two instruments. Not one proof.
What it does not
Not a sealed 4.20 constant. Newer catalogues have moved. Not the 42″ lamp. Not 42°.
ExactnessRange / bound
Form4.2
Unitg cm⁻³
Strengthattested
When2020