In Mary Roach's "Packing for Mars: The Curious Science of Life in the Void," she explores the concept of weight and the unnoticed burden of our internal organs. The author illustrates how our body parts, from the heart to the hair, exert weights and pressures that we often overlook. This culminates in a realization of how the body's composition can impose a constant sensation of heaviness.

When one experiences weightlessness, such as in space, these burdens vanish, leading to a unique sense of freedom and euphoria. The floating organs create an indescribable feeling of lightness, allowing individuals to experience a new reality where they are unencumbered by the usual weight of their own bodies. Roach's observations provide a fascinating glimpse into the human experience of gravity and its absence.