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Author Topic: Why do astonauts float?  (Read 2720 times)

Offline thedoc

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Why do astonauts float?
« on: 11/07/2014 13:30:01 »
Leslie and Jenny Wolf asked the Naked Scientists:
   
Please give me your explanation of why the astronauts inside the International Space Station just float around in all directions without any sensations or feelings of upwards nor downwards ....... just floating around.

Many thanks,
Leslie Wolf.

What do you think?
« Last Edit: 11/07/2014 13:30:01 by _system »


 

Offline Bill S

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Re: Why do astonauts float?
« Reply #1 on: 11/07/2014 14:57:39 »
Apparently, they float because they are in “free fall”.   Richard Wolfson, (Simply Einstein), uses the term “free-float” to describe this, and even links it to the twin paradox. 
 

Offline chiralSPO

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Re: Why do astonauts float?
« Reply #2 on: 11/07/2014 17:05:58 »
It's kind of like when you are playing on a swing set, and feel weightless for just a moment when the swing is at the highest point, just before it starts to fall back down.
 

Offline dlorde

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Re: Why do astonauts float?
« Reply #3 on: 11/07/2014 19:45:41 »
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Offline jccc

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Re: Why do astonauts float?
« Reply #4 on: 11/07/2014 23:43:54 »
In space, the gravity from your surrounding is very small, almost zero force act on you in any direction. So you float.

On Earth, the strong gravity force pulls you toward mass center, so you stick to the ground.
 

Offline chiralSPO

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Re: Why do astonauts float?
« Reply #5 on: 12/07/2014 00:05:53 »
In space, the gravity from your surrounding is very small, almost zero force act on you in any direction. So you float.

On Earth, the strong gravity force pulls you toward mass center, so you stick to the ground.

Well, it's true that in deep space there isn't any heavy body nearby to pull one "down," but so far no astronauts have gone that far away from the Earth. Except for the few missions to the moon, all astronauts have been in low Earth orbit, only a couple hundred km above the surface of the Earth. The gravitational force there is almost as strong as it is on the surface. The main reason they float is that they are in constant free-fall (orbiting is a very special type of falling).
 

Offline jccc

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Re: Why do astonauts float?
« Reply #6 on: 12/07/2014 01:24:11 »
In space, the gravity from your surrounding is very small, almost zero force act on you in any direction. So you float.

On Earth, the strong gravity force pulls you toward mass center, so you stick to the ground.

Well, it's true that in deep space there isn't any heavy body nearby to pull one "down," but so far no astronauts have gone that far away from the Earth. Except for the few missions to the moon, all astronauts have been in low Earth orbit, only a couple hundred km above the surface of the Earth. The gravitational force there is almost as strong as it is on the surface. The main reason they float is that they are in constant free-fall (orbiting is a very special type of falling).

You are 100% right. I misread his question, space station is not in deep space at all. Thanks!
 

Offline PmbPhy

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Re: Why do astonauts float?
« Reply #7 on: 12/07/2014 02:22:19 »
An astronaut appears to float in what is called his locally inertial frame of reference because his frame of reference doing exactly the same thing he is. That means that the cabin he’s in orbits the earth in the same path that he orbits. This is allowed to happen because the inertial mass of the astronaut is the same as his passive gravitation mass. The same is true for his capsule and therefoe each moves in an orbit which independent of the astronaut and cabin. That’s why all things fall at the same rate.
« Last Edit: 12/07/2014 07:03:12 by PmbPhy »
 

Offline jccc

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Re: Why do astonauts float?
« Reply #8 on: 12/07/2014 06:19:59 »
All of those posts and not one of them even comes close?

An astronaut appears top float in what is called his locally inertial frame of reference because is frame of reference doing exactly the same thing he is. That means that the cabin he’s in orbits the earth in the same path that he orbits. This is allowed to happen because the mass of the inertial mass of the astronaut and cabin are both proportional to the passive gravitational mass. That’s why all things fall at the same rate. Had it not been this way then the astronauts would have had a terrible time of it.

Pete, I like the way you fire that shot gun!
 

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Re: Why do astonauts float?
« Reply #8 on: 12/07/2014 06:19:59 »

 

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