Re: [Phys-l] Weightless

[<carmelo@pacific.net.sg>]

John Mallinckrodt wrote:
> I understand that lots of people (including apparently the folks at  
> NIST) want weight to be the same thing as gravitational force, but I  
> have yet to hear one compelling reason for that.  Moreover, I submit  
> that weight is demonstrably NOT the same thing as gravitational force  
> in common parlance.  Again, if astronauts are not "weightless," then  
> I simply don't see any good use for the word.

This reminds me of another urban legend...

The story goes like this: in the 1960s, NASA astronauts discovered that their pens did not work in zero gravity. So like good engineers, they went to work and designed a wonder pen. It worked upside down. It worked in vacuum. It worked in zero gravity. It even worked underwater! And it only cost a million dollars! The crafty Russians used a pencil.

I prefer to tell this story using "microgravity" instead of "zero gravity". Is there anywhere in the universe where the gravitation force is *exactly* zero, and whatever your frame of reference?

Alphonsus