字幕表 動画を再生する 英語字幕をプリント Ever since the first astronaut went to space almost 60 years ago, over 500 people have blasted out of Earth's atmosphere. They lived and worked in space at different times. But nobody's ever been born there. What if you were the first space baby to be carried aboard a space station? This is WHAT IF, and here's what would happen if you were born on a space station. So, what's so different about being born in space anyway? No gravity? Well, in fact, gravity on the International Space Station is about 90% as strong as it is on the surface of the Earth. So why do we see astronauts floating around inside it? Let me explain. Earth's gravity is pulling the ISS down. But the ISS is moving very fast - at the same speed that the Earth's surface is turning underneath it. The space station is constantly falling to Earth but it will never hit it. The free fall is what causes microgravity, making the astronauts float around. So what would it be like to be born weightless? Before we get to the birth part, let us just say nobody's ever had sexual intercourse on a space station, let alone made a baby. It wouldn't be any kind of out-of-this-world experience. Fluids work differently in microgravity. You may not have the blood flow to get you or your partner aroused. Sweat would build up around your body making it wet and sticky all over. And that's if you could figure out how not to push your partner away upon contact. Conceiving a child would be a whole other problem. In addition to a low-gravity environment, there's also so much radiation in space, that it can affect a man's sperm count, possibly even cause infertility. And we don't even know exactly what kind of changes space conditions would cause to a human embryo. But let's imagine your pregnant mother arrived on a space station to give birth to you. The trip to space alone would be hard enough on your mother. Pushing you out of her body without the help of gravity wouldn't be a piece of cake either. If you made it out of the womb, a low-gravity environment would affect your body systems as you grew up, including your muscular development and eyesight. When grown-up astronauts work aboard the space station, their bone density depletes at a rate of about 1% per month. Because it takes no effort to float in space, they also tend to lose muscle strength. Now, since there's no way to force a baby run on a treadmill to keep its muscles forming, as you grew on the space station, your skeleton might become deformed. Your heart would be weak as it's never had to work against Earth's gravity. Then there's space radiation. It would increase the probability of cancer, dysfunction of the heart and central nervous system, and eyesight problems. If, after surviving all that, you made the trip to Earth, you wouldn't be able to walk or balance properly. You might also struggle with interacting with people on Earth since you grew up crammed into a very small space your whole life. Until someone invents a gravity polarizer to generate artificial gravity fields on a space station, we probably shouldn't think about having babies in space. But once they do, how long do you think it would it take for us to become a galactic civilization? That's a question for another WHAT IF.