- #1

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## Homework Statement

(a) Given that the period of the Moon's orbit about the Earth is 27.32 days and the nearly constant distance between the center of the Earth and the center of the Moon is [itex]3.84 \cdot 10^8 m[/itex], use [itex]T^2 = (\frac{4\pi^2}{GM_E})a^3[/itex] to calculate the mass of the Earth.

(b) Why is the value you calculate a bit too large?

## Homework Equations

## The Attempt at a Solution

For (a), I solved for [itex]M_E[/itex] and got a value of [itex]6.01 \cdot 10^{24}~kg[/itex], of which I am certain is the correct answer, though not 100%. However, my main concern is with part (b); I am honestly don't know how to answer this question. Could someone possibly help me?