Directed downward

"Directed downward" means that something is pointing or moving towards the ground. Think about when you drop a ball - it falls down because gravity pulls it downward. That's an example of something being directed downward. If you look at a picture of an airplane, you might notice that the wingtips are angled upward. That's because the wings are designed to create lift, which helps the plane stay in the air. But even though the wingtips are angled up, the plane itself is still directed downward because gravity is still pulling it towards the ground. So, "directed downward" just means that something is moving or pointing towards the ground.