Hi, my name is Jade, and I'm Lauren, we're PCS students, and we're staying genetics in art class. And we want to ask you a question. Is it genetically possible to grow wings under back and be able to fly? Hi, I'm Dr. Sarah Thornton, and I'm a biologist here at MIT. If you haven't already seen the videos about how we would build a human with wings, I really recommend that you watch this video. But even if you can make a human with wings, without human being able to fly, Professor Perrari is going to answer the other half of your question. My name is Jaime Perrari, I am a faculty member here in the Department of Astronautics and Astronautics at MIT. Humans obviously cannot fly, and the reason is because they've been able to successfully develop and reproduce and thrive without having to fly. Unlike birds that require flying in order to be able to survive and develop. From an engineering perspective on the other hand, we can look at what are the shortcomings of the human body in order to be able to fly. And the first one that comes to mind is essentially the shape, because we are very heavy relatives to the surface that we have. And this surface is very important because in order to fly, you need to be able to generate the dynamic forces, and that can only be done if you have sufficient surface. If you look at birds, the ratio of a wing surface to the weight is much larger than the surface of our body in order to have a weight. If you look at a large bird, like an albatross, it would have a wingspan of about two meters and weigh approximately 20 kilograms. Two meters is about the wingspan we might have with our open arms, if we were to think of our arms as wings. But obviously we are a lot heavier than 20 kilograms. The Dedeleus aircraft, which is a human-powered aircraft, was built here a few decades ago. At that time it held a wall record for human power flight. It flew for about 100 kilometers, perhaps even more. And essentially what you have here is a human edling, but what is around the human is an aircraft, which is about 30-40 kilograms. And the wingspan is probably of the order of 15 meters maybe. And that's the type of surfaces that it would take to lift the human. We really were not to go to wings of this size and we were to stay with a smaller wings. That would be possible if we were able to fly faster. But you're not to fly faster than the energy consumption would be quite significant. The faster you fly, the more energy you need and the less wings you need. But to fly, say, in a bird-like class, you would need a significant amount of energy. And our bodies are just not created to deliver this amount of energy. A bird would eat about each weight, perhaps once or twice a day, in order to be able to fly. So that's the amount of food intake that a bird would take. On the other hand, humans do not usually eat their way in food every day. In fact, they eat a lot less. So here you can see that the amount of energy that a bird produces is much higher relative to their weight. And that's something that would have to be addressed, to make a body like that of a human to be able to fly.