What does microgravity mean?
Microgravity is the condition of extremely weak gravitational acceleration, most famously encountered by astronauts in orbit. It is not the same as the complete absence of gravity: astronauts aboard a space station are still subject to Earth's gravitational pull, but they and the spacecraft are continuously falling around Earth. In this situation, the station and its occupants appear to float because they experience little or no supporting force. Scientists use microgravity environments to investigate how materials, fluids, cells, and organisms behave when the normal effects of gravity are reduced. The word is especially common in discussions of spacecraft, the International Space Station, space medicine, manufacturing, and research. Although it can describe any environment with unusually weak gravity, its strongest everyday associations are with spaceflight and orbital laboratories.
nounAn environment or condition in which gravitational acceleration is very small, especially near or in orbit. It is commonly used to describe the conditions experienced by astronauts and spacecraft.
- An environment or condition in which gravitational acceleration is very small, especially in space.
- The reduced gravitational force experienced by people, objects, or spacecraft in such an environment.
"The crew conducted experiments in microgravity to study how fluids behave without the usual effects of gravity."
"Researchers used microgravity to examine the growth of crystals in space."
"The spacecraft's interior was designed to provide a controlled microgravity environment for the crew."
The noun is usually used in the singular or as an uncountable concept; the plural is uncommon.
"The laboratory has simulated several microgravities on Earth."
Astronauts are not beyond Earth's gravity: they are falling around it in continuous free fall, which creates the microgravity environment used aboard the International Space Station.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does microgravity come from?
“Microgravity” was formed in the 20th century by combining the prefix “micro-,” meaning very small, with “gravity,” the force or acceleration that gives objects weight. Its development was closely associated with the emergence of spaceflight and the need to describe the unusual conditions encountered in orbit. The word belongs to the same Latin-root family as “gravity,” “gravitate,” “gravid,” and “gravitas.”
Related word forms
How microgravity is actually used
The term is especially common in spaceflight, science, and engineering contexts. It is usually used as an uncountable noun, although the plural “microgravities” is occasionally used when referring to different environments or levels of reduced gravity.
Easily confused with microgravity
Microgravity describes an environment with greatly reduced gravitational force, whereas weightlessness describes the apparent absence of weight experienced by an object in free fall.