# When Mars is at its closest proximity to Earth does it affect our tides?

##### 1 Answer
Mar 17, 2016

Only the Sun and Moon have any significant effect on our tides.

#### Explanation:

To determine how much impact something in the Universe has on our tides, calculate the DIFFERENCE in gravitational force the object exerts across the diameter of rhe Earth.

Let M be the mass of the object in the heavens, d be its distance to the center of Earth, and r be the radius of the Earth. Using Newton's laws to determine gravitational forces, the difference across the Earth's diameter is proportional to

$M \left(\frac{1}{{\left(d - r\right)}^{2}} - \frac{1}{{\left(d + r\right)}^{2}}\right)$

This is much greater for the Sun and Moon than for anything else up there, including Mars at closest approach.