# How big is the moon Titan compared to the Earth? How is the gravity different between these two planetary bodies?

Nov 30, 2015

Around half of Earth's radius is the radius of Titan. The surface gravity of Titan is ${\text{1.353 m"//"s}}^{2}$, meaning that the gravity on Titan is about 7.3 times weaker than on Earth.

#### Explanation:

Size:

The radius of Earth is:
$\text{6,371 km}$ or $\text{6,371" * 10^3 "m" = "6,371,000 m}$

Whereas the radius of Titan is:
$\text{2,575.5 km}$ or $\text{2,575.5" * 10^3 "m" = "2,575,500 m}$

Then

Difference in Size $= \text{Titan's Radius"/"Earth's Radius}$

$\text{2,575,500"/"6,371,000} = 0.404 \cong 0.5$

Meaning about half the size of Earth's radius.

Here is a comparison of the size of Titan (in the middle) compared to that of Earth and the Moon.

(from en.wikipedia.org)

Gravity:

The surface gravity on Earth is $9.807 {\text{m/s}}^{2}$ and the surface gravity on Titan is $1.353 {\text{m"//"s}}^{2}$

So the difference between these two gravitational bodies is around:

Difference in Gravity $= \text{Earth's Gravity"/"Titan's Gravity}$

$\frac{9.807}{1.353} = 7.248 \cong 7.3$

Meaning that the gravity on Titan is about 7.3 times weaker than on Earth.