Why do astronauts appear to move their limbs slowly when in zero gravity?

Question

D'oh! Brilliant answers from both of you. I'm actually embarrassed now. I never really thought about the question until just a bit ago. I too am a science fanatic. That little thing called inertia slipped my mind :-p Thanks you two!

Answer 1

When there is no gravity, you move slowly. Just like when your in water.

Answer 2

Because in zero gravity every move you make affects the position of your whole body.  Quick movements can send you spiraling through the spacecraft.

For an example, imagine being under water.  If you raise your arms suddenly, you move your whole body under the water.  Multiply the speed several times and that's what sudden movement can do to you in zero-g.

Answer 3

BECAUSE IF THEY MOVED QUICKLY, NOBODY WOULD BELIEVE THEY WERE IN SPACE, SILLY.

Answer 4

Wow "God" you're "cool."  ^^^

Answer 5

Also, additionally to the third law of Newton, already mentioned here, there is another important reason for astronauts to move careful: Even with the rescue rocket system SAFER, astronauts have only limited chances to return to the spacecraft, when they loose contact to the hand rails and EVA aids. The rule in astronaut training, for securing by tethers during work is "Make before break": When you move, you have to be always secured, and thus move in slow careful steps. When you drift away with more than only 5 cm/s, even the robot arm of ISS or Space Shuttle will not be able to catch up with you and give you something to secure yourself again - SAFER can save you once, but staying secured is always better.

Inside a spacecraft, where you have no risk of drifting out into space, you can actually move fast and astronauts are often seen floating through the space station like a young dolphin after some months of getting used to micro-gravity. But for the first 4 days, astronauts are often becoming spacesick (That is exactly like sea sick and the official medical term is space motion sickness), and the risk of becoming space sick, grows with rapid head movements and loss of visual orientation. So, most astronauts also move slowly and carefully inside the spacecraft, so they have time to adapt and don't get sick.

And finally: Moving inside a space suit is extremely difficult. Each small movement inside this not only moves the rather stiff space suit (imagine wearing many layers of clothes), but also pumps air inside the suit around. This is hard work and is not different at all to do the same work deep underwater.

So, there are many reasons to move slow and carefully in space:

- Action and Reaction (or Newtons third law)

- Work safety

- Avoiding space motion sickness

- Don't become exhausted in the first few minutes of the EVA, if you have 8 hours of work ahead of you.  

Answer 6

They don't just appear to move slowly, they do.  Darned Newton and his third law!  To paraphrase, every action has an equal but opposite reaction.  This means that when an astronaut in 'microgravity' tries to move, say by waving an arm, the rest of his body will be pushed in the opposite direction.

It's not a matter of being made to move slowly, it's a matter of being careful.  The astronauts don't want to throw their bodies all about.

I hope this helps you out.

Cheers!

Answer 7

no back pressure

Answer 8

plz help im home alone with my injured sister answer my question plz!!

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