This news is about gravitational waves. Gravitational waves are like water waves. Put your finger in water and move it. You create water waves.
Things that move in space create gravitational waves. People know about gravitational waves for a long time. Einstein told us about them. One hundred years later, people notice the waves.
This is a historic moment. This can change science.
Difficult words: create (to make), told (past of “tell”), notice (to know something is there).