Quasinormal mode

Okay, kiddo, so imagine you have a rubber ball. When you drop it, it bounces up and down a few times before it stops moving completely, right? That's because the ball has something called a natural frequency, which is how quickly it likes to bounce up and down. This is similar to how a guitar string has its own natural frequency and vibrates when plucked.

Now, in science, we use something called a quasinormal mode to study vibrations in things like black holes or other objects in space. Just like the rubber ball, these objects also have natural frequencies at which they like to vibrate.

When something like a black hole gets disturbed, it vibrates at a certain frequency, just like how the ball bounces up and down. This vibration slowly fades away over time, kind of like the ball's bouncing slowly stops.

Scientists study these vibrations because they can tell us important information about the object. For example, if we know the frequency of a black hole's quasinormal mode, we can figure out how big it is or how fast it's spinning.

So basically, quasinormal mode is just a fancy way of saying that objects in space vibrate at their own special frequency, and we can learn cool things about them by studying those vibrations. Hope that makes sense, little one!