Sound wave is a pressure caused by the vibration of something in a medium that transfers anergy, like air.
The statement is true.
As weird as it may sound, helium was indeed first discovered on the Sun, and after some time on Earth. The first evidence of helium was observed on August 18 1868, as a bright yellow line with a wavelength of 587.49 nanometers in the spectrum of the Sun's chromosphere. This line has been detected by a French astronomer by the name of Jules Janssen during a total solar eclipse in Gantur, India.
