Equation 5 · Part 12 · From Origins to Frontier: A History of Planetary Science and Exploration
Numerator: 2 g r^2 (rho_m - rho_s)
What this part means
The complete quantity above the fraction bar.
Its job in the formula
2 g (rh - rh) occurs above the fraction bar. The numerator is divided by the entire denominator below it.
Full expression→Numerator: 2 g r^2 (rho_m - rho_s)→Article meaning
The passage around this formula
Comparative planetology treats a planet as a layered physical system rather than a point of light, and the physics of that layering is not exotic — it is gravitational settling under heat. A body accreting from a mixture of metal and silicate material differentiates because denser iron-rich material sinks relative to lighter silicate material, provided the interior is warm enough (from accretion energy, radioactive decay, and impacts) for solid-like material to behave as a slow-moving fluid over geological time. The basic settling physics is captured by a Stokes-law sinking velocity for a dense blob of radius r and density moving through a less dense, viscous mantle of density …
Learn the underlying idea
A fraction a/b means a divided by b. The top number is the numerator; the bottom number is the denominator, and it cannot be zero.
Open the illustrated fractions: division written vertically guide →
The article lists its research sources here.