Ok, I'm not sure if I know enough to even phrase this question properly so
if anything in the question makes no sense let me know and I'll clarify if I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star (Lets
call it Alpha).
II.) I have at my disposal a spaceship capable of taking me to Alpha and
back reaching a significant percent of the speed of light.

I board the spaceship which is at rest with repect to the Earth. I take a
measurement of my current distance to Alpha and then begin my acceleration
to maximum cruising speed. Every minute along the entire trip I will
measure my current distance from Alpha and record the time (On my clock in
the ship) the measurement was taken. I reach maximum speed relative to
Earth or Alpha (Whichever makes the question easier to answer) and continue
to measure my current distance from Alpha. Whenever appropriate I decelerate
turn around and head back by passing around Alpha and accelerate back toward
Earth. Eventually I decelerate to arrive at earth and end up at rest with
respect to Earth.

The data I will have is total time for my trip from my own clock, a huge
database of measurements of distance from Alpha with timestamps and time
elapsed on a clock left at earth that I read the instant I stop relative to
earth.

Now, according to everything I've read on the twin scenarios my internal
clock readings will be less than a clock that remained on earth. Assuming
relatively high accelerations to .99c then if Alpha is 8 light years from
earth the time elapsed on a clock left on the earth will be a little more
than 16 years and the time on the clock in my ship will be less than 16
yearrs. Right so far?

Assuming everything I've said so far, where in the data from my mesurements
will I calculate an average velocity c? My first measurment was at rest
from earth(Or very close to Earth) and showed 8 light years to Alpha and my
last piece of data is also at Earth (Or very close) and shows 8 light years
distance and I know I traveled there and back so I know I traveled ~16 light
years but my clock shows less than 16 years so at some point in my data if I
take an interval of distance covered and divide by total time(Again this is
total time from clock in my ship) I will get a value greater than c. I am
in no way implying that at any given point I would be able to measure my
instantaneous velocity with respect to Alpha or Earth to be greater than c
but given the fact I traveled 16 light years in less than 16 years
subjective time at some point my average speed for a given interval would
have to be greater than c right?


---
Thomas

"The idea of God is the sole wrong for which I cannot forgive mankind."
--Le Marquis de Sade

Dear Thomas Jones:

"Thomas Jones" wrote in message
...
Ok, I'm not sure if I know enough to even phrase this question properly
so
if anything in the question makes no sense let me know and I'll clarify
if I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star (Lets
call it Alpha).

How would you do this?

II.) I have at my disposal a spaceship capable of taking me to Alpha and
back reaching a significant percent of the speed of light.

I board the spaceship which is at rest with repect to the Earth. I take
a
measurement of my current distance to Alpha and then begin my
acceleration
to maximum cruising speed. Every minute along the entire trip I will
measure my current distance from Alpha and record the time (On my clock
in
the ship) the measurement was taken. I reach maximum speed relative to
Earth or Alpha (Whichever makes the question easier to answer) and
continue
to measure my current distance from Alpha. Whenever appropriate I
decelerate
turn around and head back by passing around Alpha and accelerate back
toward
Earth. Eventually I decelerate to arrive at earth and end up at rest with
respect to Earth.

The data I will have is total time for my trip from my own clock, a huge
database of measurements of distance from Alpha with timestamps and time
elapsed on a clock left at earth that I read the instant I stop relative
to
earth.

Now, according to everything I've read on the twin scenarios my internal
clock readings will be less than a clock that remained on earth. Assuming
relatively high accelerations to .99c then if Alpha is 8 light years
from
earth the time elapsed on a clock left on the earth will be a little more
than 16 years and the time on the clock in my ship will be less than 16
yearrs. Right so far?

Yes.

Assuming everything I've said so far, where in the data from my
mesurements
will I calculate an average velocity c?

You won't.

My first measurment was at rest
from earth(Or very close to Earth) and showed 8 light years to Alpha and
my
last piece of data is also at Earth (Or very close) and shows 8 light
years
distance and I know I traveled there and back so I know I traveled ~16
light
years but my clock shows less than 16 years so at some point in my data
if I
take an interval of distance covered and divide by total time(Again this
is
total time from clock in my ship) I will get a value greater than c.

Frame jump. Time in one frame, distance in another. Use two measurements
from the same frame, and you always get v c.

I am
in no way implying that at any given point I would be able to measure my
instantaneous velocity with respect to Alpha or Earth to be greater than
c
but given the fact I traveled 16 light years in less than 16 years
subjective time at some point my average speed for a given interval would
have to be greater than c right?

No.

David A. Smith

"Thomas Jones" wrote in message
...
Ok, I'm not sure if I know enough to even phrase this question properly
so
if anything in the question makes no sense let me know and I'll clarify if
I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star (Lets
call it Alpha).
II.) I have at my disposal a spaceship capable of taking me to Alpha and
back reaching a significant percent of the speed of light.

I board the spaceship which is at rest with repect to the Earth. I take a
measurement of my current distance to Alpha and then begin my acceleration
to maximum cruising speed. Every minute along the entire trip I will
measure my current distance from Alpha and record the time (On my clock in
the ship) the measurement was taken. I reach maximum speed relative to
Earth or Alpha (Whichever makes the question easier to answer) and
continue
to measure my current distance from Alpha. Whenever appropriate I
decelerate
turn around and head back by passing around Alpha and accelerate back
toward
Earth. Eventually I decelerate to arrive at earth and end up at rest with
respect to Earth.

The data I will have is total time for my trip from my own clock, a huge
database of measurements of distance from Alpha with timestamps and time
elapsed on a clock left at earth that I read the instant I stop relative
to
earth.

Now, according to everything I've read on the twin scenarios my internal
clock readings will be less than a clock that remained on earth. Assuming
relatively high accelerations to .99c then if Alpha is 8 light years from
earth the time elapsed on a clock left on the earth will be a little more
than 16 years and the time on the clock in my ship will be less than 16
yearrs. Right so far?

Right - much less than 16 years.

Assuming everything I've said so far, where in the data from my
mesurements
will I calculate an average velocity c? My first measurment was at rest
from earth(Or very close to Earth) and showed 8 light years to Alpha and
my
last piece of data is also at Earth (Or very close) and shows 8 light
years
distance and I know I traveled there and back so I know I traveled ~16
light
years but my clock shows less than 16 years so at some point in my data if
I
take an interval of distance covered and divide by total time(Again this
is
total time from clock in my ship) I will get a value greater than c.

It's all a matter of convention and definitions. When you arrive at Alpha,
you will have travelled 8 earth light years in less than 8 rocket clock
years. That result of c is in mixed units. If you normalise to standard
units of any inertial reference system, you will still get less than c. The
measured distance in your moving coordinate system is shorter.
You are right however that for your personal experience, you would have
bridged the 8 light years at an average speed greater than c. It's the
reason that space travel to other stars is still being considered by some.
But if you get back from such a trip, all your friends may be long dead...

Harald

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:J3O3d.212226$4o.97018@fed1read01...
Dear Thomas Jones:

"Thomas Jones" wrote in message
...
Ok, I'm not sure if I know enough to even phrase this question properly
so
if anything in the question makes no sense let me know and I'll clarify
if I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star
(Lets
call it Alpha).

How would you do this?

By asking this are you stating their is no method to measure a distance to a
star? If one exists here on Earth, then use it. If not most of cosmology
would be bull**** at this moment wouldnt it?


Snip the rest of my post.

--

---
Thomas

"The idea of God is the sole wrong for which I cannot forgive mankind."
--Le Marquis de Sade
"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:J3O3d.212226$4o.97018@fed1read01...
Dear Thomas Jones:

"Thomas Jones" wrote in message
...
Ok, I'm not sure if I know enough to even phrase this question properly
so
if anything in the question makes no sense let me know and I'll clarify
if I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star
(Lets
call it Alpha).

How would you do this?

II.) I have at my disposal a spaceship capable of taking me to Alpha and
back reaching a significant percent of the speed of light.

I board the spaceship which is at rest with repect to the Earth. I take
a
measurement of my current distance to Alpha and then begin my
acceleration
to maximum cruising speed. Every minute along the entire trip I will
measure my current distance from Alpha and record the time (On my clock
in
the ship) the measurement was taken. I reach maximum speed relative to
Earth or Alpha (Whichever makes the question easier to answer) and
continue
to measure my current distance from Alpha. Whenever appropriate I
decelerate
turn around and head back by passing around Alpha and accelerate back
toward
Earth. Eventually I decelerate to arrive at earth and end up at rest
with
respect to Earth.

The data I will have is total time for my trip from my own clock, a huge
database of measurements of distance from Alpha with timestamps and time
elapsed on a clock left at earth that I read the instant I stop relative
to
earth.

Now, according to everything I've read on the twin scenarios my
internal
clock readings will be less than a clock that remained on earth.
Assuming
relatively high accelerations to .99c then if Alpha is 8 light years
from
earth the time elapsed on a clock left on the earth will be a little
more
than 16 years and the time on the clock in my ship will be less than 16
yearrs. Right so far?

Yes.

Assuming everything I've said so far, where in the data from my
mesurements
will I calculate an average velocity c?

You won't.

My first measurment was at rest
from earth(Or very close to Earth) and showed 8 light years to Alpha and
my
last piece of data is also at Earth (Or very close) and shows 8 light
years
distance and I know I traveled there and back so I know I traveled ~16
light
years but my clock shows less than 16 years so at some point in my data
if I
take an interval of distance covered and divide by total time(Again this
is
total time from clock in my ship) I will get a value greater than c.

Frame jump. Time in one frame, distance in another. Use two measurements
from the same frame, and you always get v c.


I made all measurements from inside my ship. Where in my data will I
suddenly see the star at a shorter distance ahead of me than the total
distance I know Ive traveled based on my speed and time travelled? I'm not
arguing it wont happen. I'm trying to determine where in the data it will
show up.

If my average speed over any given interval never adds up to c then at
some point I should see an anomoly in the data that shows the star is closer
than it should be based on my speed.

I am
in no way implying that at any given point I would be able to measure my
instantaneous velocity with respect to Alpha or Earth to be greater than
c
but given the fact I traveled 16 light years in less than 16 years
subjective time at some point my average speed for a given interval
would
have to be greater than c right?

No.

Explain please. I have data that is distance from star and total time
traveled by my own clock at each measurment. Given the fact that the first
measurement will be 8 light years distance and total distance traveled will
be 16 light years and my total time is less than 16 years then if the only 2
measurements I use are the first data point and the last then I will get an
answer of average speed c. Im trying to determine where the anomolous
data shows up. I'm sort of assuming that during acceleration I will see
distance to the star shrink faster than expected. So fast I will be able to
tell the data is garbage.



David A. Smith



Sorry I responded to this in 2 different posts. My news reader screwed up
and didn't show me your entire answer the first time I read it.


---
Thomas

"The idea of God is the sole wrong for which I cannot forgive mankind."
--Le Marquis de Sade

Dear Thomas Jones:

"Thomas Jones" wrote in message
...
"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:J3O3d.212226$4o.97018@fed1read01...
Dear Thomas Jones:

"Thomas Jones" wrote in message
...
Ok, I'm not sure if I know enough to even phrase this question
properly
so
if anything in the question makes no sense let me know and I'll
clarify
if I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star
(Lets
call it Alpha).

How would you do this?

By asking this are you stating their is no method to measure a distance
to a
star? If one exists here on Earth, then use it. If not most of cosmology
would be bull**** at this moment wouldnt it?

Parallax, as the Earth orbits the Sun, provides a good estimate of
distance. Subtended size for closer objects, once distance is determined,
assists in determining solar mass.

Cosmology is not "bull****", but attitudes are. Will your very fast moving
ship be orbiting something?

David A. Smith

Dear Thomas Jones:

"Thomas Jones" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:J3O3d.212226$4o.97018@fed1read01...
Dear Thomas Jones:

"Thomas Jones" wrote in message
...
Ok, I'm not sure if I know enough to even phrase this question
properly
so
if anything in the question makes no sense let me know and I'll
clarify
if I
can.


For the purposes of this question I'm starting off with a couple of
assumptions.

I.) I can accurately measure my current distance from a given star
(Lets
call it Alpha).

How would you do this?

II.) I have at my disposal a spaceship capable of taking me to Alpha
and
back reaching a significant percent of the speed of light.

I board the spaceship which is at rest with repect to the Earth. I
take
a
measurement of my current distance to Alpha and then begin my
acceleration
to maximum cruising speed. Every minute along the entire trip I will
measure my current distance from Alpha and record the time (On my
clock
in
the ship) the measurement was taken. I reach maximum speed relative
to
Earth or Alpha (Whichever makes the question easier to answer) and
continue
to measure my current distance from Alpha. Whenever appropriate I
decelerate
turn around and head back by passing around Alpha and accelerate back
toward
Earth. Eventually I decelerate to arrive at earth and end up at rest
with
respect to Earth.

The data I will have is total time for my trip from my own clock, a
huge
database of measurements of distance from Alpha with timestamps and
time
elapsed on a clock left at earth that I read the instant I stop
relative
to
earth.

Now, according to everything I've read on the twin scenarios my
internal
clock readings will be less than a clock that remained on earth.
Assuming
relatively high accelerations to .99c then if Alpha is 8 light years
from
earth the time elapsed on a clock left on the earth will be a little
more
than 16 years and the time on the clock in my ship will be less than
16
yearrs. Right so far?

Yes.

Assuming everything I've said so far, where in the data from my
mesurements
will I calculate an average velocity c?

You won't.

My first measurment was at rest
from earth(Or very close to Earth) and showed 8 light years to Alpha
and
my
last piece of data is also at Earth (Or very close) and shows 8 light
years
distance and I know I traveled there and back so I know I traveled ~16
light
years but my clock shows less than 16 years so at some point in my
data
if I
take an interval of distance covered and divide by total time(Again
this
is
total time from clock in my ship) I will get a value greater than c.

Frame jump. Time in one frame, distance in another. Use two
measurements
from the same frame, and you always get v c.


I made all measurements from inside my ship. Where in my data will I
suddenly see the star at a shorter distance ahead of me than the total
distance I know Ive traveled based on my speed and time travelled? I'm
not
arguing it wont happen. I'm trying to determine where in the data it will
show up.

Find a method of measuring the distance in your ship first. If we were
flying towards a pulsar, counting pulses could be considered to be
measurements of distance (c*dt) in the rest frame (where dt is
established). I cannot think of another way to do this.

If my average speed over any given interval never adds up to c then at
some point I should see an anomoly in the data that shows the star is
closer
than it should be based on my speed.

*If* you could measure the distance to the star, with your ruler, then you
would see it in the recorded distances to the star. But you can't, since
no such method exists.

I am
in no way implying that at any given point I would be able to measure
my
instantaneous velocity with respect to Alpha or Earth to be greater
than
c
but given the fact I traveled 16 light years in less than 16 years
subjective time at some point my average speed for a given interval
would
have to be greater than c right?

No.

Explain please. I have data that is distance from star and total time
traveled by my own clock at each measurment.

Provide the method of measuring the distance.

Given the fact that the first
measurement will be 8 light years distance and total distance traveled
will
be 16 light years and my total time is less than 16 years then if the
only 2
measurements I use are the first data point and the last then I will get
an
answer of average speed c.

Frame jump. Time in one frame, and distance in another.

Im trying to determine where the anomolous
data shows up. I'm sort of assuming that during acceleration I will see
distance to the star shrink faster than expected. So fast I will be able
to
tell the data is garbage.

Data is not garbage, unless an instrument is damaged, or the instrument is
measuring fiction. If you have two widely spaced mirror-arrangements, and
use the deflected angle to establish distance, you will find reduced
distances immediately. (Such a real system would require you to stop
accelerating first, most likely. And there would be some error due to
travel time, if the mirrors were too wide.) And you will find that the
distances and times equate to something less than c.

URL:http://hermes.physics.adelaide.edu.a...SR/rocket.html

David A. Smith

"Thomas Jones" wrote in message ...
Ok, I'm not sure if I know enough to even phrase this question properly so

I.) I can accurately measure my current distance from a given star (Lets
call it Alpha).

OK, it is interesting to consider how you might do this.

II.) I have at my disposal a spaceship capable of taking me to Alpha and
back reaching a significant percent of the speed of light.

OK

I board the spaceship which is at rest with repect to the Earth. I take a
measurement of my current distance to Alpha and then begin my acceleration
to maximum cruising speed. Every minute along the entire trip I will
measure my current distance from Alpha and record the time (On my clock in
the ship) the measurement was taken. I reach maximum speed relative to
Earth or Alpha (Whichever makes the question easier to answer)

Easiest to assume Alpha is at rest with respect to Earth.

and continue
to measure my current distance from Alpha. Whenever appropriate I decelerate
turn around and head back by passing around Alpha and accelerate back toward
Earth. Eventually I decelerate to arrive at earth and end up at rest with
respect to Earth.

The data I will have is total time for my trip from my own clock, a huge
database of measurements of distance from Alpha with timestamps and time
elapsed on a clock left at earth that I read the instant I stop relative to
earth.

Now, according to everything I've read on the twin scenarios my internal
clock readings will be less than a clock that remained on earth.

Correct.

Assuming
relatively high accelerations to .99c then if Alpha is 8 light years from
earth the time elapsed on a clock left on the earth will be a little more
than 16 years and the time on the clock in my ship will be less than 16
yearrs. Right so far?

Yes.

Assuming everything I've said so far, where in the data from my mesurements
will I calculate an average velocity c? My first measurment was at rest
from earth(Or very close to Earth) and showed 8 light years to Alpha and my
last piece of data is also at Earth (Or very close) and shows 8 light years
distance and I know I traveled there and back so I know I traveled ~16 light
years but my clock shows less than 16 years so at some point in my data if I
take an interval of distance covered and divide by total time(Again this is
total time from clock in my ship) I will get a value greater than c.

Yes you will, but this does not represent a speed measured in any
inertial frame. You are using the distance measured in the rest frame
of the Earth and your own elapsed proper time.

I am
in no way implying that at any given point I would be able to measure my
instantaneous velocity with respect to Alpha or Earth to be greater than c
but given the fact I traveled 16 light years in less than 16 years
subjective time at some point my average speed for a given interval would
have to be greater than c right?

Yes. Your explanation of this while you were in motion
would be that the distance to Alpha had shrunk.

Martin Hogbin

"Thomas Jones" wrote in message ...

[snip]

During acceleration/decelaration, there is no limit on what you
observe as the speed of something. The speed limit of c is valid only
for inertial frames, and an accelerating frame is not inertial.

During the part of the trip when you are travelling at a high constant
speed with respect to Alpha/Earth, you will observe that the distance
between Alpha and Earth is contracted, and that your speed with
respect to them is c.

Paul Cardinale

"Paul Cardinale" wrote in message
om...
"Thomas Jones" wrote in message
...

[snip]

During acceleration/decelaration, there is no limit on what you
observe as the speed of something. The speed limit of c is valid only
for inertial frames, and an accelerating frame is not inertial.

During the part of the trip when you are travelling at a high constant
speed with respect to Alpha/Earth, you will observe that the distance
between Alpha and Earth is contracted, and that your speed with
respect to them is c.

Paul Cardinale

Thanks, I sort of thought it was during acceleration that I would see what I
am calling odd results in my data. One question though. I thought that
when distances for me contracted I would be unable to tell. I assumed it
affected everything in my frame including anything I would use to measure
the distance. But, it sounds like you are saying that if I measured my
distance from Earth and distance from Alpha and added the 2 together I would
get a shorter distance than if I measured them when at rest to both. Or am
I now totally confused?

---
Thomas jones