Equation 1 · Part 6 · How We Know What Is Inside a Planet
fraction
fraction
What this part means
Divide the expression above the line by the one below it.
Its job in the formula
The expression above the fraction bar is divided by the complete expression below it. The denominator must not be zero.
Full expression→fraction→Article meaning
The passage around this formula
The fourth quantity is the one that does real work. The polar moment of inertia, normalised by mass and radius, is . and it measures how mass is distributed radially rather than how much there is. A uniform sphere has = 0.4 . Anything smaller means mass concentrated toward the centre; anything approaching 0.4 means a body that is close to uniform in density, which for a rocky planet means undifferentiated.
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 →
Sources cited in the article section
- [7] Gravity field and internal structure of Mercury from MESSENGER ↗
- [9] Geodetic evidence that Mercury has a solid inner core ↗
These citations provide research context; check each source for the exact claim it supports.