Space physics, also known as space plasma physics, is the study of plasmas as they occur naturally in the universe. As such, it encompasses a far-ranging number of topics, such as heliophysics which includes the solar physics of the sun: the solar wind, planetary magnetospheres and ionospheres, auroras, cosmic rays, and synchrotron radiation. Space physics is a fundamental part of the study of space weather and has important implications not only to understanding the universe, but also to practical everyday life, including the operation of communications and weather satellites. Space physics is unique from other fields of astrophysics which study similar phenomenon, in that space physics utilizes in situ measurements from high altitude rockets and spacecraft.

The term SPACE (capitalized) can refer to:

• SPACE, a Canadian science-fiction channel
• DSPACE, a term in computational complexity theory
• Small Press and Alternative Comics Expo, an annual comic book convention
• Society for Promotion of Alternative Computing and Employment, located in Trivandrum, Kerala, India
• Spectroscopic All Sky Cosmic Explorer, a proposed satellite designed to measure the baryon acoustic oscillations

Space is the boundless three-dimensional extent in which objects and events have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework.