Re: Sci.astro & Truth-Seekers
<<When discussing the mass of the moon and why Newton's laws are right,
Greg Neill again says that "The moon is in free-fall, hence weightless"
due to its orbit around the Earth, yet I have not seen anyone claiming
the Earth and the other planets are weightless due to their orbit around
Greg Neill wrote:
<<Fine. I shall do so now. The planets are in free-fall and
hence are also weightless.>>
<<Any references for this interesting theory?>>
And Greg answered:
<<Albert Einstein, The General Theory of Relativity, and in
particular, the equivalence principle.>>
I saw that you recently lost a discussion with Ian Stirling on this matter.
In case Ian's posting is no longer available on your news server, I enclose
"Weighing something is a way to obtain its mass. If its mass can be
determined, its weight can be calculated. Putting the moon on a scale is
impractical and unnecessary.
A quote from the glossary of "A Brief History of Time" by Stephen W.
"weight: The force exerted on a body by a gravitational field. It is
proportional to, but not the same as, its mass."
The moon's weight towards the earth keeps it accelerating towards the earth.
An astronaut orbiting the earth feels weightless because he or she doesn't
feel the reaction of their weight. From Newton's third law, there is a
reaction and it's the force which is accelerating the earth towards the
A quote from "Foundations of Astronomy" by Michael A. Seeds ( an excellent
book which my wife bought for twenty five American cents at a garage sale )
"Rather than say astronauts are weightless, it is more accurate to say they
are in free-fall."
That's because being weightless and being in free-fall are not equivalent:
_feeling_ weightless and being in free-fall are."
If anyone should wonder, Greg did of course not accept this answer, leading
to Ian's final comment:
"My hat off to you sir, you must be very clever to contradict Stephen
Hawking and Michael Seeds."
No comment necessary, I think...