It’s because they have the same time velocity, you don’t notice it. Like when you’re riding in a car and toss a ball up from your lap. The ball is moving at the

It’s because they have the same time velocity, you don’t notice it. Like when you’re riding in a car and toss a ball up from your lap. The ball is moving at the same speed as you so you don’t even notice its speed since it travels along with you.