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Equation 1 · Part 2 · How We Know What Is Inside a Planet

Symbol C

I∗=CMR2I^{*} = \frac{C}{MR^{2}}
CC

What this part means

C occurs above the fraction bar. The numerator is divided by the entire denominator below it.

Its job in the formula

C occurs above the fraction bar. The numerator is divided by the entire denominator below it.

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 I∗=CMR2I^{*} = \frac{C}{MR^{2}}. and it measures how mass is distributed radially rather than how much there is. A uniform sphere has I∗I^{*} = 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.

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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Sources cited in the article section

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