A number of so-called smaller platforms have been developed to do μ-gravity research on the earth, with or without people doing the experiments presented on board. The first half of this book will focus on the platforms and their usage with a detailed discussion of their technology, availability and limitations as well. According mainly to the limited duration of μ-gravity on these platforms, some experiments should be performed with a relevant timescale shorter than the duration of μ-gravity, and these are still a lot to be done. These are the questions to be addressed in the second half of this book, in which we will demonstrate in details that not only the well-known human sensory apparatus for gravity perception in the vestibular system responds to gravity, but even single molecules, cells and parts of neuronal tissue as the entire brain do as well.