Gravity is not directly sensed or understood by the brain through the visual system. The perception and understanding of gravity are not solely dependent on the visual system but are rather a combination of various sensory inputs and cognitive processes.
The brain primarily perceives and understands gravity through the vestibular system, which is responsible for detecting and processing information about balance, spatial orientation, and motion. The vestibular system, located in the inner ear, consists of fluid-filled canals and sensory organs that sense changes in head position and movement.
When your body experiences gravitational forces, the vestibular system detects these changes and provides signals to the brain, contributing to your sense of upright posture and balance. These signals, along with input from other sensory systems such as vision and proprioception (the sense of body position and movement), help the brain to form a comprehensive understanding of gravity and the body's relationship to it.
The visual system, in combination with other sensory systems, can indirectly provide information about gravity. For example, visual cues such as vertical lines or objects appearing to fall in a certain direction can be interpreted by the brain to make inferences about gravity and the orientation of the environment.
In summary, the brain's understanding of gravity is not solely derived from the visual system. It relies on a combination of inputs from the vestibular system, proprioception, and vision, among other sensory and cognitive processes, to perceive and comprehend gravitational forces and their effects on the body.