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Science > Physics |
| User: |
"" |
| Date: |
01 Apr 2006 08:18:42 PM |
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What shape is the universe? |
Let's say a mother has two babies on a space ship going 99.9999% the
speed of light relative to the Earth. The universe is 100,000,000,000
light years. People have developed the technology to live over 100,000
years. Then, all of a sudden, one of the siblings departs back to
Earth, while the other one takes a speed pod going 99.9999% the speed
of light relative to the space ship in the space ship's frame of
reference. When the speed pod passes Earth, how old will the Earth
bound twin be and how old will the twin in the speed pod be?
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| User: "=?UTF-8?Q?Jeff=E2=80=A6Relf?=" |
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| Title: Eric_Gisse, Give it a rest. |
04 Apr 2006 02:21:48 AM |
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Hi Eric_Gisse, Day in and day out you flood Sci.Physics
with a torrent of direct replies to me.
But, no matter how bad you're hallucinating today, I must inform you that
nothing you wrote was even remotely on-topic for this newsgroup.
In fact, 99 pecent of your other posts were also off-topic.
So why don't you give it rest ?
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| User: "T Wake" |
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| Title: Re: Jeff has nothing to say |
04 Apr 2006 12:38:49 PM |
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"Jeff.Relf" <Jeff_Relf@Yahoo.COM> wrote in message
news:Jeff_Relf_2006_Apr_4_4rHf@Cotse.NET...
Hi Eric_Gisse, Day in and day out you flood Sci.Physics
with a torrent of direct replies to me.
But, no matter how bad you're hallucinating today, I must inform you that
nothing you wrote was even remotely on-topic for this newsgroup.
In fact, 99 pecent of your other posts were also off-topic.
So why don't you give it rest ?
Jeff, you have said this hundreds of times. Does it make you feel better?
Do the voices in your head stop shouting when you keep posting this?
You have nothing of value to say, but you keep on saying it...
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| User: "Y.Porat" |
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| Title: Re: Gisse, The lack of content in your life and mind is well documented here. |
04 Apr 2006 02:35:09 AM |
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you are right
i noticed long a ago that t Erick Shaise
is Eric Shaise and nothing more
a fucken opportunist with zero science
if you are right that he is just a student
than the impertinence is even more obvious !!
just a parasite parrot - pain in the neck
that is unemployed (no wonder!!)
so shitting his frustration here
and he should be recognized as such.
oops i was spending more than one line on that Shaise sorry
Y.P
---------------
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| User: "T Wake" |
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| Title: Re: Gisse, The lack of content in your life and mind is well documented here. |
04 Apr 2006 12:39:14 PM |
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"Y.Porat" <maporat@012.net.il> wrote in message
news:1144136109.159339.33680@t31g2000cwb.googlegroups.com...
<snip nonsense>
Shhh. Adults are talking.
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| User: "Eric Gisse" |
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| Title: Re: Gisse, The lack of content in your life and mind is well documented here. |
04 Apr 2006 03:55:56 AM |
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Y.Porat wrote:
you are right
i noticed long a ago that t Erick Shaise
is Eric Shaise and nothing more
a fucken opportunist with zero science
if you are right that he is just a student
than the impertinence is even more obvious !!
just a parasite parrot - pain in the neck
that is unemployed (no wonder!!)
so shitting his frustration here
and he should be recognized as such.
oops i was spending more than one line on that Shaise sorry
Y.P
---------------
Your whining amuses me.
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| User: "Eric Gisse" |
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| Title: Re: _Minor_ details. |
02 Apr 2006 01:05:36 AM |
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Jeff...Relf wrote:
[snip]
Another Relfian word salad. Supported as usual by nothing.
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| User: "" |
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| Title: Re: What shape is the universe? |
01 Apr 2006 08:21:38 PM |
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Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
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| User: "Sam Wormley" |
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| Title: Re: What shape is the universe? |
01 Apr 2006 08:41:16 PM |
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wrote:
Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
What have you calculated so far?
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| User: "" |
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| Title: Re: What shape is the universe? |
01 Apr 2006 09:51:14 PM |
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Sam Wormley wrote:
Starbles@Earthlink.net wrote:
Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
What have you calculated so far?
So far, I can only guess... I'm waiting for the real scientists to do
all the work. LOL! :P
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| User: "Eric Gisse" |
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| Title: Re: What shape is the universe? |
01 Apr 2006 10:04:48 PM |
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wrote:
Sam Wormley wrote:
wrote:
Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
What have you calculated so far?
So far, I can only guess... I'm waiting for the real scientists to do
all the work. LOL! :P
Open a book on special relativity and use the relevant Lorentz
transform.
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| User: "" |
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| Title: Re: What shape is the universe? |
02 Apr 2006 01:49:32 AM |
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Eric Gisse wrote:
Starbles@Earthlink.net wrote:
Sam Wormley wrote:
Starbles@Earthlink.net wrote:
Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
What have you calculated so far?
So far, I can only guess... I'm waiting for the real scientists to do
all the work. LOL! :P
Open a book on special relativity and use the relevant Lorentz
transform.
I did. It told me that the one going around the universe will be
younger. However, that might not square with general relativity!
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| User: "" |
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| Title: Re: What shape is the universe? |
01 Apr 2006 11:03:09 PM |
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What shape is the Universe? The Universe is, well, it's kind
of.......Universe shaped.
That was a tautology.
A tautology is a tautology.
That's a metatautology.
A metatautology is a meta.....WONK WONK WONK CYBERNETIC ALARM # 62927
PROGRAM GOING INTO INFINITE REGRESS JOOTS JOOTS JOOTS
I feel better now.
I never metatautology I didn't like - Free Will Rogers.
Contradiction
Escape to the metasystem
Morphogenesis.
GENESIS
GENE and SIS
Repopulate the Earth you two - have at it. Too bad the humans created
all those weapons.
Blarp.
Have a nicean day.
Toodle-lewd-wench-sky.
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| User: "platopes" |
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| Title: Re: What shape is the universe? |
02 Apr 2006 12:01:45 AM |
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wrote:
Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
If you know how a magic trick works, it's not a magic trick. Rascally
reality might be the same. Upside might be endless exploration/mystery.
Food for the mind and soul.
p
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| User: "Henning Makholm" |
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| Title: Re: What shape is the universe? |
02 Apr 2006 06:58:30 PM |
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Scripsit
Let me rephrase this. One of the twins lands on their destination. The
other one goes off into space and passes by the twin. Also, I think I
said the universe has a certain distance around, but let me clarify.
What affect will the shape of the universe have on how old the twin is
when the twin passes the other twin?
I think you're trying to construct an instance of the Twin Paradox in
which the standard resolution (based on which on the twins accelerated
during his trip) does not work. But you have selected a somewhat
convoluted way of expressing it; here's a simpler one:
Assume a static universe (no gravity on cosmological scales) with one
spatial dimension with the topology of a large circle. We can have
other spatial dimensions too, but they are irrelevant because nobody
in the following experiment are going to travel along them. We can
visualize this model universe by rolling a Minkowski diagram into a
cylinder such that the space axis becomes compact and the time axis
stays unbounded.
At T=0, both of the proverbial twins leave Earth (which is stationary
at space coordinate 0°) at relativistic speed, travelling in opposite
directions. At the event of leaving, either twin can observe the other
twin's watch tick slowlier than his own, and this continues for the
entire journey. When the two twins meet at the opposite end of the
universe (space coordinate 180°), which is the older one?
The answer depends on how you set up the large-scale topology of the
universe. It turns out that under the assumptions before, there *is* a
globally privileged standard of rest at any point, even if it is not
_locally_ special.
Consider an astronomer on the stationary Earth. If he does not know
that space curves back on himself, but is equipped with a good
telescope, he will discover that a certain distance to the right is a
planet that looks mysteriously like his own. Since light has finite
speed he cannot see what happens there _now_, but if he is patient he
can make corrections for this delay and correlate events on the
distant planet with events on his own Earth. After observing for a
sufficiently long time he may find that at precisely the moment he
discovered the distant planet, an astronomer there, looking
suspiciously like himself, discovered a planet to _his_ right, and so
forth. In other words, corresponding events on the two planets unfold
simultaneously, as viewed from the stationary astronomer's frame.
However, if we switch our attention to one of the twins in their
relativistic spaceships, they will _not_ observe a similarly nice
situation. Again, one twin will eventually observe that directly ahead
of him seems to be a spaceship similar to his own and traveling at the
same velocity, and another one astern of him. However, when he
observes the clocks in those co-moving spaceships he will find that
though they tick at the same rate as his own, they do not reach
particular times _simultaneously_ with his. (Again, this is after he
makes corrections for the time it takes light to reach is on-board
telescope). The moving observer sees space filled with an unending
rows of copies of himself, but _all with different ages_.
Similarly, the right-moving traveler can eventually conclude that he
shares his universe with an unending row of copies _of his twin_
moving towards the left, and all of different ages too. All of the
copies have watches that appear to tick too slowly, always, but when
he meets one of them at the 180° point of the universe, it will be an
older one than the copy he said good-bye to at Earth, which magically
works out just so that the two brother's clocks agree at the instant
they pass each other.
In summary, the cylindrical universe has a global standard of rest,
namely that in which you see your (apparent) copies to the left and
right do things in synchrony with yourself. (More technically, there
is a unique _closed_ spacelike geodesic through every event, and the
worldlike orthogonal to it is "at a better rest" than other
worldlines). When the twins meet after having traveled around the
world, which one is the younger depends on who has moved faster
compared to this local standard of rest.
This thought experiment takes place in a 1D world. It is not
completely trivial to extend it to our 3D universe, because one cannot
have closed spacelike geodesics _and_ still have both global istotropy
_and_ a locally flat space where we can use SR at arbitrarily large
separations. But the general principles ought to be the same.
--
Henning Makholm "En tapper tinsoldat. En dame i
spagat. Du er en lykkelig mand ..."
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| User: "" |
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| Title: Re: What shape is the universe? |
04 Apr 2006 05:57:46 AM |
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(*Snip*)
Thanks. That helps. A lot.
--
Henning Makholm "En tapper tinsoldat. En dame i
spagat. Du er en lykkelig mand ..."
(...Starblade Riven Darksquall...)
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| User: "Henning Makholm" |
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| Title: Re: What shape is the universe? |
04 Apr 2006 02:31:54 PM |
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Scripsit
(*Snip*)
Thanks. That helps. A lot.
Glad to be of service :-)
--
Henning Makholm "These are a nasty breed. They sting
you without waiting to be insulted first."
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