X-ray and gamma ray wavelengths are not able to travel through Earth's atmosphere. In other words, the atmosphere is opaque to those wavelengths. Therefore, any study of x-ray and gamma ray light from space must be done above the Earth's atmosphere. Sound is a wave, but is not electromagnetic. EM radiation is a transverse wave, is electromagnetic in nature, and needs no medium to travel.
Light travels very well through the vacuum of space.
Visible light is a tiny part of the EM spectrum. A Blackbody emits lights in many wavelengths, creating a continuous spectrum. They are the same. Short Answer Hubble Space Telescope. Very fine resolution, highly sensitive to light.