The space discussed in this book is realistic physical space, is defined as “extensive property of matter and its motion”. This is the space we are familiar with in our daily life. Its basic property is it can be measured and validated.

In physical theory, there are “phase space” in statistical physics, “state vector space” in quantum mechanics, “complex number space”, “function space” in mathematics, and some noosphere in social scientific field. In Buddhism books, there are hells with eighteen layers, heaven with ninety-nine layers. These are all abstract spaces.

We will not discuss these kinds of spaces.

With the knowledge of space from our daily lives, we introduced a strict scientific definition of space and illustrated that space is a property of matter. In this book, the relationship of uniformity of space, centrosymmetry, law of momentum conservation and law of angular momentum conservation are introduced. Also we discussed the relation of space and motion, introduced special relativity and demonstrated that the space properties of a matter will change dramatically as it is moving with a speed close to the light velocity. We introduced the property of the smallest space we can observe at present and quantum mechanics which describes the micro world. Also we introduced the fact that gravitation will bend space of matter and general relativity which described this fact. We introduced cosmology which described the big space; about the related observed facts, related “standard model” and its difficulties; the related works of the author and the supports from observed facts. At last, this book introduced some thoughts on some questions from the author. Some of them will be solved with development of science later.