<img class="moonPulse" src="https://i.pinimg.com/564x/a1/01/e2/a101e22fc458c1110d418ee309f240c8.jpg" alt="moon pic"/>

body{
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 5em;
  background: #000;
}
.moonPulse{
    animation: pulse 1s infinite;
      border-radius: 50%;
  width: 20em;
}

 @keyframes pulse{
      from{
 box-shadow: 0 0 0 0 rgba(198, 182, 179, 0.85);
      }

      to{
box-shadow: 0 0 0 30px rgba(201, 48, 48, 0);
      }
  }