Microgravity
Microgravity
Microgravity (/maɪkroʊˈɡrævɪti/), also known as weightlessness, is a condition in which objects or individuals are subjected to very little net gravitational acceleration.
Etymology
The term "microgravity" is derived from the prefix micro-, meaning small, and gravity, the force that attracts a body towards the center of the earth, or towards any other physical body having mass.
Definition
Microgravity is a state of free-fall, creating the sensation of weightlessness, which is experienced by astronauts in orbit. It is not a complete absence of gravity, as this is impossible due to the presence of the Earth's gravitational field. Instead, it is the condition where the force of gravity is only slightly detectable.
Effects on the Human Body
Exposure to microgravity has numerous effects on the human body. These include bone loss, muscle atrophy, and fluid redistribution.
- Bone loss - In a microgravity environment, the body's skeletal system begins to lose minerals, with up to 1% of bone mass lost each month. This is similar to the bone loss experienced by osteoporosis patients on Earth.
- Muscle atrophy - Without the need to support the body's weight, muscles begin to weaken and shrink, a condition known as atrophy.
- Fluid redistribution - In microgravity, bodily fluids are redistributed, with more fluid going to the upper body, leading to a puffy face and thin legs, a condition known as "puffy head bird legs syndrome".
Related Terms
- Zero gravity - A condition of weightlessness referring to the absence of weight, which is a result of being outside a gravitational field.
- Gravity - The force that attracts a body towards the center of the earth, or towards any other physical body having mass.
- Free-fall - Any motion of a body where gravity is the only force acting upon it.
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