What two fundamental invariants does the Special Theory of Relativity postulate?
Answer
The laws of physics are the same for all observers in uniform motion, and the speed of light in a vacuum is constant.
The Special Theory of Relativity is founded on two invariants: the principle that the laws of physics are invariant for observers in uniform motion, and the constancy of the speed of light ($c$) regardless of the observer's motion.

#Videos
Lean all about Einsteins life and his major discoveries - YouTube
Related Questions
For which specific discovery did Albert Einstein receive the 1921 Nobel Prize in Physics?What key proposal did Einstein make about light when explaining the photoelectric effect?What two fundamental invariants does the Special Theory of Relativity postulate?What was the primary consequence derived from the constancy of the speed of light in Special Relativity?How did the General Theory of Relativity redefine gravity compared to Newton's description?What observation provided the key empirical confirmation for Einstein's General Theory of Relativity?What is identified as the subtle, unifying philosophical thread behind Einstein's major scientific breakthroughs?Which modern technology absolutely requires corrections based on both Special and General Relativity to maintain accuracy?What concept, formalized in General Relativity, equates acceleration with gravity?What fundamental concept, proposed in 1905, was a foundational step toward quantum theory?