Ernst Mach was an Austrian physicist and philosopher born in 1838. He is best known for his work in the field of aerodynamics and for introducing the concept of the Mach number, which measures the speed of an object relative to the speed of sound. His research contributed significantly to the understanding of shock waves and the behavior of objects moving at high speeds. In addition to his scientific contributions, Mach was influential in the philosophy of science. He advocated for a form of empiricism that emphasized observation and experience over theoretical constructs. His ideas influenced later thinkers, including Albert Einstein, and helped shape modern scientific thought.