a. X rays.b. slightly more energetic ultraviolet light.c. visible light.
by way of fact the universe's age is predicted to approximately 15 billion years, galaxies that are greater diatant than 15 billion gentle years from earth does not seem interior the evening sky by way of fact that their gentle did not have time to realize us.We in basic terms woulldn't understand approximately their life.
If light is coming from a very distant source, that source must be receding from us at a great speed due to the expansion of the universe. This causes the light waves to be stretched into having longer wavelengths, and therefore lower frequencies. This is called the Doppler effect and the light would be said to have been red-shifted. If the light was originally ultraviolet, it cannot reach us as X-rays or more energetic UV light because those have higher frequencies. Visible light is the only choice with a lower frequency/longer wavelength than UV light.
