who discovered that light is faster than sound
Speed of light Empedocles (c. 490–430 BC) was the first to propose a theory of light[116] and claimed that light has a finite speed.[117] He maintained that light was something in motion, and therefore must take some time to travel. Aristotle argued, to the contrary, that "light is due to the presence of something, but it is not a movement".[118] Euclid and Ptolemy advanced Empedocles' emission theory of vision, where light is emitted from the eye, thus enabling sight. Based on that theory, Heron of Alexandria argued that the speed of light must be infinite because distant objects such as stars appear immediately upon opening the eyes. Early Islamic philosophers initially agreed with the Aristotelian view that light had no speed of travel. In 1021, Alhazen (Ibn al-Haytham) published the Book of Optics, in which he presented a series of arguments dismissing the emission theory of vision in favour of the now accepted intromission theory, in which light moves from an object into the eye.[119] This led Alhazen to propose that light must have a finite speed,[118][120][121] and that the speed of light is variable, decreasing in denser bodies.[121][122] He argued that light is substantial matter, the propagation of which requires time, even if this is hidden from our senses.[123] Also in the 11th century, Abū Rayhān al-Bīrūnī agreed that light has a finite speed, and observed that the speed of light is much faster than the speed of sound.[124]
Quasar In 1962 a breakthrough was achieved. Another radio source, 3C 273, was predicted to undergo five occultations by the Moon. Measurements taken by Cyril Hazard and John Bolton during one of the occultations using the Parkes Radio Telescope allowed Maarten Schmidt to optically identify the object and obtain an optical spectrum using the 200-inch Hale Telescope on Mount Palomar. This spectrum revealed the same strange emission lines. Schmidt realized that these were actually spectral lines of hydrogen redshifted at the rate of 15.8 percent. This discovery showed that 3C 273 was receding at a rate of 47,000 km/s.[26] This discovery revolutionized quasar observation and allowed other astronomers to find redshifts from the emission lines from other radio sources. As predicted earlier by Bolton, 3C 48 was found to have a redshift of 37% of the speed of light.