MAR 14, 2017 8:47 AM PDT

The Gravity of Water in a Weightless Environment


Everyone has seen videos of the astronauts on board the International Space Station floating around, watching their food fly through the air and otherwise enjoying the zero gravity. The first thing to know is that zero gravity is a misleading term. Gravity on earth keeps us from floating away. Some people think there is no gravity in space, but the laws of physics show that there is. Gravity keeps the moon from crashing into the earth the other planets in their orbits. What's happening on the ISS is the physics of opposite forces. The pull of gravity from the earth is opposite of the gravity forces of the orbital motion of the ISS. They cancel each other out and you have weightlessness. Water droplets from the wash cloth that Commander Hadfield is wringing out in this video don't land on the floor because the ISS motion negates the pull of gravity.

In space, satellites, including the ISS are moving at tremendous horizontal speed. There is no anchored structure to exert any other physical force on them. As they move around in an orbit, the Earth's gravity is still acting on them but it is overcome by their speed. That's why things on board the ISS float, there is an absence not of gravity, but of other external forces that are greater than those on the ISS. All of these complex physics concepts make for a lot of fun for the astronauts, and a cool video that demonstrates the physical forces that keep us in motion on Earth and in space.
About the Author
  • I'm a writer living in the Boston area. My interests include cancer research, cardiology and neuroscience. I want to be part of using the Internet and social media to educate professionals and patients in a collaborative environment.
You May Also Like
JAN 17, 2021
Space & Astronomy
Astronomers Discover Planet with 3 Suns
JAN 17, 2021
Astronomers Discover Planet with 3 Suns
Having just one star in our solar system makes us an outlier in our galaxy. However, while most solar systems in the Mil ...
FEB 06, 2021
Space & Astronomy
Why Does Saturn Tilt?
FEB 06, 2021
Why Does Saturn Tilt?
Two scientists from France have figured out why Saturn sits at a tilt. And they say that over the next few billion years ...
MAR 26, 2021
Plants & Animals
Studies Confirm that Bottlenose Dolphins Vocalize to Synchronize Behaviors
MAR 26, 2021
Studies Confirm that Bottlenose Dolphins Vocalize to Synchronize Behaviors
The ability to communicate with one another to coordinate behaviors contributes to the success of social mammals, like b ...
JUN 04, 2021
Plants & Animals
What Elephant Trunks Teach Science about Suction
JUN 04, 2021
What Elephant Trunks Teach Science about Suction
How an elephant picks up a tortilla chip could inspire next-generation suction technology.
JUN 21, 2021
Space & Astronomy
Scientists Detect Signatures of Life on Earth Remotely
JUN 21, 2021
Scientists Detect Signatures of Life on Earth Remotely
An international team led by researchers from the University of Bern in Switzerland and the National Centre of Competenc ...
JUL 16, 2021
Earth & The Environment
Melting Mountain Glaciers in Asia Release Greenhouse Gas
JUL 16, 2021
Melting Mountain Glaciers in Asia Release Greenhouse Gas
High mountain glaciers that are melting in the Tibetan plateau in Asia contain greenhouse gases and should be counted in ...
Loading Comments...