Microgravity is a condition in which people or objects appear to be weightless. Micro-” means “very small,” so microgravity refers to the condition where gravity seems to be very small.
Is there any Gravity in Space?
Generally most people assume Gravity doesn’t exist in space, but the fact is minimal amount of gravity is found in space. To the effect that it holds planets move in their designator orbits . The ISS ( International Space Station ) is roughly at altitude from earth is 322- 402Km. where earth’s gravity is 90 percent.
Then how do space craft or station float in space?
The ISS moves at the speed of 28163.52Km per hour , the speed that matches to the earth’s surface curve. As a result there are constantly falling towards earth surface gravity but never hits the ground and they fall around the planet.
Can it be found on Earth?
Yes! it is found on earth at Amusements parks for example: the Gaint Roller Coaster, Free-fall rides and by using aircraft in parabolic fashion.
How the Human Body changes in space
when an Astronaut goes into space( weightlessness) , the natural up and down determined by our senses. Upon entry into space, Astronaut body gets confused with sudden change in gravity. As earthly beings our survival is dependent on gravity. But our human body is an extraordinary and complicated system. That it detects lack of gravity and responds quickly to external changes, for which the body establishes a space normal conditions.
In Human Body, Vestibular Organ is responsible for balance in response to the gravity. Due to absence of gravity the first few days of the mission the astronaut feel Space motion sickness, which is similar to the sea sickness. Upon the entering into Microgravity the body will no longer experience the downward pull of the gravity. The bodily fluids in the legs like blood and other fluids shift in upward direction called ‘UPWARD SHIFT’. Especially into facial cavities which give an appearance of ‘PUFFY FACE’, leaving the legs into a ‘Bird legs’.
The body depends on the fluid regulation. Due to excess accumulation of fluids in upper body the sensors in chest and heart senses the abnormality and send signals to the kidneys to excrete the extra fluids from the body. To which parallelly the astronaut doesnt feel thirsty and reduces the daily intake of water. The heart no longer need to work as hard as on earth due to gravity. The size of the shrinks and leads to “Cardio-Vascular Deconditioning” .
Effect on Bones
On long space missions, the loss of osseous on the bone at trabecular is high. Roughly on an average 1% to 1.5% of mineral density per month. The health of the bone is dependent on gravity and harmones, which is absent on microgravity.
Effect on Muscles
The primary reason for the muscle loss is due to mechanical stress on the muscles. Upon gravity when is loaded the fibers begin to signal the genes present in the cell nucleus to make RNA, which is responsible for protein synthesis for making muscle fiber. Iron activates these proteins to accumulate and enlarge muscle fibers. But in microgravity which is quite reverse to observe.