# Ernst Mach
| #### An Austrian physicist who influenced the theory of relativity Ernst Mach (1838-1916) was a positivist philosopher and physicist from Austria. He graduated with a physics degree from Vienna University but his most prestigious early academic result was to reject Isaac Newton's concepts of absolute time and space before Albert Einstein did, a factor that strongly influenced the theory of relativity.
#### Mach's name lives on in the age of supersonic travel Mach was the first person to realize that if matter traveling through the air moved faster than the speed of sound it drastically altered the quality of the space in which it moved. Mach gave his name to the Mach Number, which expresses the speed of matter relative to the speed of sound at a certain temperature. When supersonic planes travel today, their speed is measured in terms that keep Mach's name alive.