Re: Twin Paradox a blasphemy to Relativity

From: PD (pdraper_at_yahoo.com)
Date: 02/09/05 

Date: 9 Feb 2005 08:36:52 -0800

TomGee wrote:
> PD wrote:
> > TomGee wrote:
> > > PD wrote:
> > > > TomGee wrote:
> > > > > Of course you can tell who is moving faster. In order for
the
> > ship
> > > > to
> > > > > leave Earth, it must move faster than the Earth is moving.
In
> > > order
> > > > > for the ship to catch up with the Earth on its return to it,
> the
> > > ship
> > > > > must go faster than the Earth.
> > > > > TomGee
> > > >
> > > > You're kidding, right?
> > > >
> > > > I throw an apple out of a moving car moving at 60 mph and it
> leaves
> > > the
> > > > car with a relative velocity of 5 mph.
> > > >
> > > >
> > > You can throw an apple out of a car at 5mph but you cannot escape
> the
> > > gravity of Earth at 5mph.
> >
> > You have no idea what you're talking about. The escape velocity
from
> > the Earth does not imply that a rocket has to be launched in the
same
> > direction as the Earth is moving.
> >
> >
> Who said that it does?
> >
> >
> > If the Earth is moving at V with
> > respect to the rest of the solar system and the escape velocity of
> the
> > rocket is v, then if the rocket might have any velocity between V+v
> and
> > V-v with respect to the solar system and still escape the Earth's
> > gravity.
> >
> > > >
> You should tell that to NASA, if you haven't already. They could
save
> a ton of fuel on their space take-offs.
> >
> > > >
> > > > Now, on the basis of that information, you tell me whether I
> threw
> > it
> > > > forward (so it's going faster than the car) or backward (so
it's
> > > going
> > > > slower than the car).
> > > >
> > > >
> > > Not the same at a rocketship having to go faster than the Earth
in
> > > order to escape its gravity. Your car is moving faster than the
> > Earth
> > > even if it's only going 5mph. The 5mph is IN ADDition to the
speed
> > of
> > > the Earth since your car is moving at Earth speed when standing
> > still.
> >
> > And this is crap, too. The Earth rotates from west to east at 1000
> mph
> > at the equator. An airplane traveling with ground speed 500 mph
will
> be
> > going 1500 mph with respect to the sun if flying from west to east,
> and
> > 500 mph with respect to the sun if flying from east to west.
> >
> > >
> Crap? No, I don't think so. You seem to have airplanes confused
with
> cars, too.
> > > >
> > > >
> > > > Timmy gets hit with the apple and so he picks up a rock and
> throws
> > it
> > > > at me in the moving car and it hits me in the nose with a
> relative
> > > > velocity of 80 mph.
> > > > Now, on the basis of that information, you tell me whether he
> threw
> > > it
> > > > forward (so it's going faster than the car) or backward (so
it's
> > > going
> > > > slower than the car).
> > > >
> > > He has to throw it faster than the car is moving in order for it
to
> > > catch up with the car. Whether Tim threw it forward or backward
is
> > not
> > > relevant in this experiment.
> >
> > And this is still further crap. If Timmy is in front of the car,
and
> he
> > throws it backward at 20 mph, it will hit me in the nose at 80 mph.
> If
> > Timmy is in back of the car, he will have to throw it 140 mph to
have
> > it hit me in the nose at 80 mph. Either way is possible and you
can't
> > distinguish them from the information given.
> >
> > Tom, you have little to no understanding of relative motion. I
could
> > give you some practice problems to try to correct that, if you
> like...
> >
> > >
> No, thanks, I'll pass on that. You seem to have the wrong notions
> about relative motions, I wonder where they came from. I hope that's
> not what is being taught in the schools today.
>
> TomGee

Let's start from scratch.
What is the speed of the Earth?
You tell me.

PD

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