The amazing things astronauts experience in space, Explained!
From slow aging to having to learn to walk again, Astronauts experience a lot of wonderful, amazing as well as bizzare things in space. Here is a look at some of them, along with their explainations.
There are a lot of things we need to keep in mind when sending someone to space. It can take a lot out of someone, and thats not even considering the harsh conditions, supply shortages and other situations.
Generally, we see astronauts in space stations such as the ISS, or when they return safely from space. In the second case, they are helped out of the spacecraft by someone, and that is because of happens in space.
What really happens in Space?
All of us can agree that astronauts do not feel the same gravitational pull that we feel on Earth. What really is fascinationg, is that the same force of gravity makes them move at about 7.88 kms/seconds! These two are the main reasons that astronauts need to be helped out of the aircraft,learn to walk again and the reason for aging slower than us surface dwellers.
All this of course, is indirect, but has a lot of reprecussions in the long run.
Let’s start by why they age slowly.
Time Dialation
Lets start at an unfamiliar point, time dialation, the brain child of Einstein’s theory of Special Relativity. We all know that Speed is total distance covered devided by the total time taken, i.e,
S=D/t.
Thus, the faster you move, the lesser time you are likely to spend in travelling. Time Dialation is similar to this. It states that the closer you are to the source of gravity, or the faster you move, the slower time passes for you. So, if you are travelling at the speed of light, time wont pass for you at all, since nothing can go faster than the speed of light. Of course one cannot move at that speed, but that is just an example. The rate of time that you experience, or the time ticking for you, is governed by something called the Lorentz Constant. This expression, makes use of the speed of moving observer and that of light. The expression is
γ= 1/ √(1-v²/c²), where γ is the factor by which time moves, v is the speed of moving observer and c is the speed of light. So, if you move at 86% the speed of light, time, for you, will pass twice as fast. And for you is key, YOU AND ONLY YOU WILL EXPERIENCE THE FASTER PACE OF TIME.
Since they (astronauts) move at a blistering fast speed,(still only about 0.005% the speed of light!) time passes slowly for them and hence they age a little slowly, about 1 microsecond or 1 x 10^-6 second, per 4 hours, and that all adds up, as the longer you stay there, the younger you will be than the people on Earth. Christina Koch, who spent a record 328 days in the International Space Station, was 1968 microseconds, or 0.001968 seconds younger that a person exactly her age, when she touched down in Kazakhstan, on her journey home.
Gravity’s role
Did you notice, how Koch is helped out of the Soyuz capsule in which she returned? Well thats because she cant walk, which is due to the gravitational force back up in outer space.
When working on yet another aspect of relativity, General Relativity this time, Einstein thought up an experiment, while napping in his break time. This experiment, often called the greatest idea of his life, may seem suicidal at first, but its brilliant. He imagined a man falling off a building to his death, with a weighing machine. He wondered what the machine would show when he is in freefall. He then apllied the classical approach, and found out that the man will be weightless in freefall. The same happens to Astronauts. The international Space Station, is sort of a satellite, and in it’s orbit, it stands at a tangent to the earth’s gravity field, i.e is perpendicular to the centre of the earth at all points in it’s orbit. And when an object is perpendicular to the centre of the earth, it is in freefall.
Thus, they(astronauts) are always in freefall. Therefore, they feel no weight. Although artificial gravity is available, it doesnt really make much of a difference.
This leads to the muscles in their legs thinking that they dont need to do their job, leading to loss in muscle mass and reduction in muscular activity. This means they cannot support their own weight when they stand up, and hence need to be helped up, and rehabbed to go about their daily lives again.
Credit:- Third eye gamer(aka kanishk for the idea for this article)