{"response":"{\"What is gravitational redshift?

Gravitational redshift is when light loses energy and changes color as it escapes a strong gravity, like climbing stairs.

Imagine you're holding a ball on the bottom floor of a tall building. If you throw the ball up to the top floor, it slows down because it has to fight gravity all the way up. That’s like what happens to light when it tries to escape from something huge, like a star or a black hole, it loses energy as it climbs out of the strong gravity.

Think of light as a super-fast runner who is trying to climb a very steep hill. The stronger the gravity, the steeper the hill. As the runner goes up, they get more and more tired. Their speed decreases, just like how light loses energy. This makes the light shift toward the red end of the color spectrum, which we call redshift.

So when scientists see red in the light from faraway stars or galaxies, it's a clue that something heavy is pulling on that light, maybe even a black hole!