Moon Orbit: Perigee vs Apogee Percentage Difference

The Moon's orbit around Earth is not perfectly circular, causing its distance to vary. The closest point is called perigee, and the farthest point is called apogee.

Understanding Perigee and Apogee Distances

The question asks for the percentage difference concerning the Moon's perigee and apogee distances from Earth. While the exact distances vary, typical values are:

• Average distance: ~384,400 km
• Perigee distance (closest): ~363,300 km
• Apogee distance (farthest): ~405,500 km

Calculating the Percentage Variation

The difference in distance between apogee and perigee is:

$ \Delta D = D_{apo} - D_{per} $

Using typical values:

$ \Delta D \approx 405,500 \text{ km} - 363,300 \text{ km} = 42,200 \text{ km} $

The question asks for the percentage related to 'perigee than apogee'. A common interpretation, aligning with the options, is calculating this difference as a percentage of the perigee distance:

$ \text{Percentage Difference} = \left( \frac{\Delta D}{D_{per}} \right) \times 100\% $

$ \text{Percentage Difference} \approx \left( \frac{42,200 \text{ km}}{363,300 \text{ km}} \right) \times 100\% \approx 11.61\% $

This value is approximately 12%.

Conclusion

The variation in distance between the Moon's farthest point (apogee) and closest point (perigee) is about 12% of its perigee distance.