Back Spesiale relatiwiteit Afrikaans Spezielle Relativitätstheorie ALS ልዩ አንጻራዊነት Amharic Relatividat especial AN النسبية الخاصة Arabic نسبيه خاصه ARZ বিশেষ আপেক্ষিকতাবাদ তত্ত্ব Assamese Teoría de la relatividá especial AST Xüsusi nisbilik nəzəriyyəsi Azerbaijani اؤزل نیسبیت AZB
In physics, the special theory of relativity, or special relativity for short, is a scientific theory of the relationship between space and time. In Albert Einstein's 1905 treatment, the theory is presented as being based on just two postulates: The laws of physics are invariant (identical) in all inertial frames of reference (that is, frames of reference with no acceleration). The speed of light in vacuum is the same for all observers, regardless of the motion of light source or observer. The first postulate was first formulated by Galileo Galilei (see Galilean invariance).