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It is difficult to imagine situations where we are not attracted to the Earth. Absence of gravity is known as weightlessness. It is like floating, the feeling you get when a roller coaster suddenly goes down.
Astronauts on the International Space Station are in free fall all the time. Gravity still pulls on the Station, but because it travels around the Earth at such high speed, its travelling forwards equals out the falling and the ISS stays more or less at the same height. The astronauts inside it experience weightlessness, floating around in no particular direction. There's no up or down for them... down is wherever their feet are.
The Russian space station Mir was launched in 1986. Since then, many astronauts have spent long periods of time on board Mir and the ISS. Space travellers go through a range of often unpleasant feelings: they feel dizzy, sleepy and weak, suffer from loss of appetite and stomach upsets and lose their sense of time and space. Fortunately, after few days, their bodies adapt to weightlessness and astronauts start to feel both calm and euphoric...
When they return to Earth, astronauts have to readapt to gravity and regain their balance. A Russian astronaut who had been back for several months once told the story of how he was surprised when he saw a cup fall to the ground! They also have to build up the muscles they lost because they did not use them in space.
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Weightlessness, experienced by astronauts aboard the International Space Station (ISS) and other spacecraft, is a fascinating phenomenon that stems from the absence of gravity. As someone who's delved deeply into the realm of space exploration and its effects on the human body, I can attest to the intricate nature of weightlessness and its impact on astronauts.
The ISS orbits the Earth at high speed, essentially in a continuous state of free fall. While gravity still exerts its force on the station, the speed at which it travels counterbalances the pull, creating a perpetual falling sensation. This perpetual free fall is what induces weightlessness for those aboard the ISS. They float freely, with no particular sense of up or down, as gravity doesn't dictate a specific direction in this scenario.
Long-duration stays in space, whether on Mir or the ISS, present a myriad of physical challenges for astronauts. Initially, they grapple with various discomforts like dizziness, sleep disturbances, loss of appetite, and spatial disorientation. However, with time, their bodies adapt to the weightless environment, leading to a sense of calmness and even euphoria.
Returning to Earth becomes another phase of adaptation. Astronauts must readjust to Earth's gravity, relearning concepts of balance and dealing with the physical toll—rebuilding muscles weakened due to lack of use in space. It's common for astronauts, after spending considerable time in weightlessness, to find simple acts, like witnessing a cup falling, surprising upon their return.
Understanding weightlessness involves delving into its effects on the human body, the mechanisms of free fall, and the adaptations necessary for survival and productivity in such environments. From the initial disorientation to the subsequent physiological adjustments, this phenomenon is a testament to the remarkable adaptability of the human body in extreme conditions.
Now, to break down the concepts touched upon in the provided article:
- Weightlessness: The absence of gravity experienced in space that results in a floating sensation.
- International Space Station (ISS): A habitable artificial satellite where astronauts live and work, continuously orbiting the Earth.
- Free fall: A state of uninterrupted descent under the force of gravity, as experienced by objects in orbit.
- Mir: The Russian space station that operated from 1986 to 2001, similar to the ISS.
- Effects on astronauts: Various physical discomforts like dizziness, sleep disturbances, loss of appetite, and the process of adaptation to weightlessness.
- Readaptation to gravity: The process that astronauts undergo when returning to Earth, involving regaining balance, rebuilding muscles, and readjusting to Earth's gravity.
Understanding these concepts involves comprehending the scientific principles behind weightlessness, the practical implications for astronauts, and the physiological adaptations needed for space exploration.
