What phenomenon suggests that light from distant stars is shifted out of the visible spectrum?

The phenomenon that suggests light from distant stars is shifted out of the visible spectrum is known as redshift. This occurs when the light emitted from an object is stretched to longer wavelengths as the object moves away from the observer. In the case of distant stars and galaxies, the expansion of the universe causes these celestial bodies to recede from us, leading to a measurable redshift in the light they emit. This shift can move light from the visible spectrum into the infrared range, which is beyond what the human eye can see.

Redshift plays a crucial role in both astrophysics and cosmology, providing evidence for the expansion of the universe and helping astronomers measure the distance and speed of the objects in the universe. As objects move away, the wavelengths of light become longer, thus appearing redder, which is the basis for the term "redshift."

Understanding redshift is fundamental in studying the universe's behavior and its evolution over time, making it a vital concept in astrophysics.