The Ultimate Test of Time

"The observable universe is constantly expanding due to the expansion of space itself. As a result, the light from distant celestial bodies gets stretched out over time due to the phenomenon known as cosmological redshift. Eventually, this redshift can become so significant that the light from these objects shifts into longer wavelengths and becomes undetectable by our current observational instruments." - a paragraph from Aria's answer to "In how many years will we be unable to observe the light from the most distant celestial bodies as they go out of the observable universe?"

That, I believe, should make you understand my message.