"how many senses? ". explain what astronauts experienced upon their arrival in space and on earth and what this might tell researchers about the vestibular system.

We know that all humans have five senses these are sight, taste, smell, hearing and touch. But actually, there is a “sixth sense”  which is  known as vestibular system.  

Vestibular system helps us to sense our body movement combined with our ability to maintain body balance. A body has ability  to sense and determine in which direction and with which speed the body is moving  and with the help of this information body can maintain its balance. A blind man rely on his vestibular  sense for this information. Body vestibular system  is designed to work on the ground. So in space it can provide  erroneous or disorienting information. Astronouts are trained for adaptation  strategies to enter in a  microgravity environment. When astronouts return back to earth in normal environment they feel  dizziness and disorientation.