The post demonstrates how infeasible it is to travel to a location outside our solar system anytime in the next several generations.
What are some things you would like to see humanity do within our solar system within the next century? When do you think it is feasible to achieve that goal?
Why does microgravity cause blindness?
We don’t know yet https://youtube.com/watch?v=zXq5Uu1rRtA
I’m going off memory, but I’m pretty sure I read somewhere that the lack of gravity pushes all the blood in your body up to your head. On earth, your body has to fight gravity to get blood to your brain, so it evolved to squeeze blood out of your legs and lower body. In zero-g, the resistance is gone, but our bodies arent going to adapt so easily, so the blood is now being squeezed upward creating extra blood pressure in your head. I think i remember reading that some of that extra pressure concentrates right behind the eyes, which you can imagine is not great for them over time.