Weightlessness
Weightlessness - Related Videos
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Weightlessness
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2023
When an object is dropped, it accelerates toward the center of the Earth. If the net external force on the object is its weight, it is said to be in free fall; that is, the only force acting on the object is gravity. Galileo was instrumental in showing that, in the absence of air resistance, all objects fall with the same acceleration g. However, when objects on the Earth fall downward, they are never truly in free fall, because there is always some upward resistance force from the air acting...
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Coherence between Brain Cortical Function and Neurocognitive Performance during Changed Gravity Conditions
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Cited by 17 •
2011
The effect of weightlessness and hypergravity on both hemodynamic and electrophysiological processes in the brain is going to be followed during parabolic flight by EEG and NIRS techniques. A feasibility study of a more complex experiment, which is planned to carry out during medium- and long-term space flight.
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Reduced-gravity Environment Hardware Demonstrations of a Prototype Miniaturized Flow Cytometer and Companion Microfluidic Mixing Technology
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Cited by 9 •
2014
Spaceflight blood diagnostics need innovation. Few demonstrations have been published illustrating in-flight, reduced-gravity health diagnostic technology. Here we present a method for construction and operation of a parabolic flight test rig for a prototype point-of-care flow-cytometry design, with components and preparation strategies adaptable to other setups.
FAQs
The key change is not the removal of gravity but the reduction of supporting force. During continuous free fall, an object and its surroundings accelerate together, so they exert little or no contact force on one another. This explains why a crew member inside an orbiting spacecraft can experience weightlessness even while Earth’s gravity continues to influence the spacecraft’s motion.
A spacecraft and its crew must undergo continuous free fall together for weightlessness to occur. Because both experience the same acceleration, the spacecraft does not need to provide ordinary support to the crew in the usual way. The resulting lack of substantial contact force produces the sensation associated with weightlessness and establishes the relevant physical condition for microgravity studies.
Weightlessness is identified by the supporting force acting on an object, not simply by asking whether gravity is present. An object may remain under gravitational influence while experiencing little or no contact force from its surroundings. This distinction helps physicists interpret motion correctly and separates the sensation of having no weight from the broader action of gravity.
Weightlessness provides conditions for examining fluid behavior, combustion, biological changes, and material processing under microgravity. These areas can reveal how physical and biological processes respond when ordinary supporting forces are greatly reduced. The resulting observations help researchers develop a broader understanding of fundamental processes that may be difficult to isolate under typical conditions.
In physics, weightlessness serves as an experimental condition rather than merely a sensation experienced by spacecraft crews. Researchers can investigate how fluids, combustion systems, biological systems, and materials behave in microgravity. This connects the mechanics of free fall and contact forces with experimental studies of processes whose behavior may change when supporting forces are minimal.
Investigations conducted under weightlessness improve understanding of fundamental physical processes and can inform several technologies. The overview identifies space exploration, spacecraft design, and advanced manufacturing as key beneficiaries. Results from microgravity studies therefore connect basic physics with practical decisions about spacecraft and with efforts to develop or improve manufacturing approaches.