Gravity

Gravity In Avatar

There's one thing that I didn't like about Avatar: the gravity.

The motion from the motion capture and digital art is incredible. All the movement looks extremely life-like. And therein lies the problem.

The motion of the aliens is very human in the way the jump, run, and interact with their environment. There are two issues with this:

• the aliens are approximately twice the physical size of humans; and
• Pandora allegedly has a lower gravity field (referenced twice: once on landing in the load master's disembarkation speech, and then again when the security chief is pumping iron).

Grab yourself something and drop it. Watch how it drops.

Now, pretend you are twice the size you really are, and so is the object you are dropping. In other words, the only thing we have changed is the apparent physical size of a meter. So when the big you drops the big object, it would still accelerate at 9.8 meters per second per second. But keep in mind, these are "short" meters! Visually, it would appear to drop slower. In order for the big object to apparently drop at the same acceleration rate, it would have to cover more of these "short" meters in the same period of time, something you would only get with a higher gravity field.