On Mar 22, 4:55 pm, Igor <thoov...@excite.com> wrote:
> On Mar 22, 8:31 am, Albertito <albertito1...@gmail.com> wrote:
> 
>> "Astronaut Takao Doi 'threw a boomerang and saw it come back'
>> during his free time on March 18 at the International Space Station,
>> a spokeswoman at the Japan Aerospace Exploration Agency said
>> on Friday."http://www.physorg.com/news125297819.html
> 
>> My questions are:
>> 1. Would that boomerang describe an elliptical orbit with a lot of
>>     revolutions until its motion were interrupted? If so,
>>     1.1. why could a body (i.e. boomerang) move in elliptical orbit
>>            around a massless focus?
> 
> Learn Newton's laws of motion.  They'll provide your answers.
> 
>> 2. Would that boomerang work in empty space (vacuum)? If so,
>>     2.1. Would that mean the spinning boomerang propels itself in
>>            each spin, changing the direction of motion (making it
>>            curvilinear)?
> 
> A boomerang in empty space would move, but couldn't return.  Maybe you
> need to look up how a boomerang works.  Google is your friend.

There is a kind of boomerang called 'returning boomerang'.
When you throw a returning boomerang, it spins eccentrically.
It is saying the axis of rotation does no pass through the center
of masses. That spinning eccentricity along with its moment of
inertia, regarless the medium it can fly (air/vacuum), is the cause
of the boomerang's return, even in empty space (vacuum)!
Australian Aborigines knew that phenomenon since thousand
of years ago.