What is the effect of space expansion on light waves from distant galaxies?

Cosmological redshift, stretching visible light into infrared or microwave regions

The ongoing expansion of space since the Big Bang causes a critical dimming effect on light originating from distant sources. As space stretches while light waves travel across it toward the observer, the waves themselves are stretched proportionally. This stretching increases the wavelength of the electromagnetic radiation, shifting it toward the lower energy, longer wavelength end of the spectrum—a phenomenon termed cosmological redshift. Light from the most distant visible objects, which would have been visible light in a static universe, is stretched so dramatically that it moves entirely out of the visible range, appearing instead as extremely low-energy infrared, microwave, or radio radiation, significantly reducing the perceived brightness.