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We are gradually beginning to find more Earth-like
planets out there in the
galaxy. As technology improves, we will be able to
measure the levels of
gases in their atmospheres, to determine which of them
have signs of
extant life. Ultimately, we can expect to know whether
life there has
photosynthesis, respiration, libraries and other indicators
of intelligence.
If past trends are anything to go by, we can expect to
identify many
thousands of promising planets where intelligence may
have arisen. We
can be confident that these intelligent beings will have
death and taxes,
and also that they, like we, will look up at their night
sky.
If so, they will probably have named various groups of
stars as
constellations, much as we have.
The constellations viewed from Earth are actually a
pretty feeble set of
dot-o-grams. The Great Bear doesn't look like a bear;
Gemini only
resembles twins insofar as there are two dots; Aquarius
doesn't hold water.
But, amongst all those thousands of life-bearing planets,
there must be at
least a few from which some uncannily perfect
constellations can be seen.
There is probably a planet, for example, on which the
inhabitants are
totally freaked out by the uncanny perfect resemblance
of a group of stars
to a wristwatch, a chihuahua shagging an umbrella, or a
pair of scissors.
What I propose, therefore, is that we feed the 3D
positions of stars and of
promising planets into a big computer. We also give the
computer a huge
library of objects. We then ask the computer to find the
best, most lifelike
constellations amongst all the possibilities, from all the
potentially
habitable planet.
You may be asking what the point of this is. I have a
truly marvellous
answer which this annotation box is too narrow to
contain.
ansible...
http://en.wikipedia.org/wiki/Ansible
[normzone, Jul 23 2014]
In The Tobacconist's
http://www.montypyt...cripts/phrasebk.php
So many opportunities for misunderstanding... [8th of 7, Jul 24 2014]
A great Christopher Baldwin comic...of course, it's all going wrong and driving the captain(s) mad...
http://baldwinpage.com/page/2/
[normzone, Jul 25 2014]
Betty Hill's star map
http://www.armaghpl...-map-the-truth.html
The sky as seen from Zeta Reticuli. [tatterdemalion, Jul 25 2014]
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Are we not seeing stars from our light-time wall? I wonder what differences there are, while the messenger is messaging. |
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Other than the big and little dippers none of the constellations look like what they are supposed to look like to me. |
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How could we ever guess what they might look like to aliens?
What if they don't have dippers? |
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//You may be asking what the point of this is// |
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Shirley, the answer is obvious. |
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And really quite short, despite any protestations to the contrary. |
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Immigrants' leaving earth will one day choose their new home according to the night-time view of the sky they find most appealing. |
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The Chihuahua shagging umbrella will I'm sure be a most popular destination, no doubt their descendants will curse them roundly for centuries for having been so whimsical ;) |
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I wonder what the scissors of a 5 meter tall bulb handed hexiped look like. |
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//3D positions of stars// I think you mean the 3D trajectories of stars over time. |
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//I think you mean the 3D trajectories of stars over
time.// |
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Only if we want to know what the constellations
looked like many millions of years in the past, or will
look like in the future. |
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Well no, because their location in our sky is not their actual location right now (ignoring for a second the problem with the idea that there is a "right now" that is constant across all space). |
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A planet millions of light-years away from us will not see the same stars as we do in the same positions, because the stars closer to us and further to them have young light to us but old light to them, hence they will see them in their previous positions. |
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That, [poc], is a damned good point. However, our
own galaxy is only a few tens of thousands of light-
years across. Therefore, any stars that we can
detect planets around (ie, ones in our own galaxy,
for the time being) will be seen at most a few tens
of thousands of years ago. During this time, stars
don't move that much. |
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Yes, OK. Out of curiosity, what percentage of our constellation stars are outside our galaxy? |
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//Yes, OK. Out of curiosity, what percentage of
our constellation stars are outside our galaxy?// |
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I think it's in the low zeroes. |
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Other galaxies appear, to the naked earthbound
eye, as slightly fuzzy blobs, and most are too faint
to see without a telescope or binoculars. |
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There are about a dozen galaxies which are visible
to the (keen) naked eye. The sky is divided up
into constellations, so every naked-eye-visible
galaxy is part of _some_ constellation. However, I
don't think any of them are key parts of any
constellation. |
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The brightest galaxy (other than our own) is the
Large Magellanic Cloud, which is so close and so
big that it's a patch rather than a fuzzy point; but
it's split between the territories of two
constellations in the southern hemisphere. |
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Sort of strange to depend on probable alien
observers at all, given that humankind will probably
never contact any even if they do exist. A more
simply stated idea would allow for constellation
images to be generated from any point of
observation inside the galaxy which can probably be
done with already available information, and a
computer. Then some really useful 'space faring'
constellations could be possible, maybe. |
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Hmm, yes, I was suspecting that even as I asked. So, my suggestion is merely irritatingly pedantic rather than interesting. How far does your average star move in 10,000 years? Thinking about the archaeo-astronomy reconstructions I have failed to avoid I am thinking enough to distort constellations but not make them unrecognisable. I still rekon you need to account for this in your idea. |
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Hmm. Well, [poc], it appears that you are not failing
to avoid being incorrect. A gentleman from NASA
has produced images showing that our familiar
constellations will be noticeably distorted in 50,000
years time. |
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That said, most of the naked-eye stars are within
about 2000 lightyears of Earth, and shifts over 2000
years will for the most part be teeny. |
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It might be cool to look for locations within the
starfield that yield the clearest, sensiblest
constellations possible where by chance the
arrangement of stellar objects form up into neatly
identifiable shapes. Computers might start off looking
for simple (if boringly named) geometric patterns -
the circle, the square, the hexagon etc - should these
computer scientists patent the associated coordinates,
perhaps licencing them to future space-tour operators
to ferry folk around to look at them, their
descendants may yet benefit from a hitherto untapped
income stream. |
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[+] I like this and am amused that aliens will see a
Maxwell Buchanan portrait constellation with a
mustache painted on it. |
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Don't worry, as soon as we improve the ansible to be able to send image as well as voice this will all get a lot simpler. |
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To take this to the logical next level, the hobbyists and corporations who terraform suitable candidate planets for entertainers such as ourselves, when faced with multiple choices in a zone, may choose their targets in this manner when opportunities permit. |
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> send image as well as voice |
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There's an ancient technology which might help
you here, called a "modem." |
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Last I checked they were limited by reality (link). |
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This is a great idea. It will create many jobs, and can
give a whole new objective for NASA and the space
race against Russia and Iran. |
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Six-legged unicorn as in Carl Sagan. |
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If this were possible, and if we implausibly found a
distant planet with intelligent life somewhere in
the galaxy, and if we developed a propulsion
technology that could propel us at faster than the
speed of light, and we had created a stable form
of cryo-stasis to keep our astronauts alive for
thousands of years, and if those astronauts didn't
go utterly apeshit Space Mad at the sheer insanity
of their distance from Earth... then the
constellations we had found would make a good
starting point for first contact – a sort of, "Hey, we
like shapes too," commonality. |
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//if we developed a propulsion technology that could propel us at faster than the speed of light, and we had created a stable form of cryo-stasis// |
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If you have one you perforce don't need the other. |
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Even at the speed of light, these places might be 10s
of 1000s of light years away, so, I'd wager, we'd probs
need both. |
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[Skewed] Hmm, really? FTL doesn't mean instantaneous -
certainly quicker - and even taking time dilation into
account, any subjective trip time of more than 30
years is going to have to somehow address the "death"
problem. Our closest star is 6 light-years away, but
I think it's probably fair to say most/any habitable
planets we find that also have constellations of
unique enough configurations to go visit, are going to
be more widely distributed than that. The centre of
the galaxy is 30,000 light years from earth, so taking
that as a mean, we'd need to be breaking the light
barrier by a pretty high factor in order to get
subjective travel times down to say 10 years. |
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Sorry [theleop] cross posted - yes - that's what I was
trying to say. |
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//The centre of the galaxy is 30,000 light years from
earth, so taking that as a mean// |
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That argument doesn't really work. That's a bit like
saying "I don't know how far it is to the nearest
tobacconist is, but circumference of the earth is
25,000 miles, so let's take half that as a best guess." |
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That sounds reasonable, seeing as how one would only want to go to a good tobacconist, and many of the contributors here seem to reside in the ex-Colonies. |
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//one would only want to go to a good tobacconist // |
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Just make sure you have a genuine English-Hungarian phrasebook if
you do. |
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//one would only want to go to a good
tobacconist// |
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Ah, but a good tobacconist will not only take your
order by telephone, but will also deliver your
cigarettes once they've been made. |
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//That argument doesn't really work.// |
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It's not an argument, it's an estimation - if you've
got
a better estimation, then let's have it. I figured
we're talking about searching a space that's the
size
of the galaxy, and that we'll find what we're
looking
for somewhere halfway - and viola! It's a logical
starting assumption - please feel free to improve
upon it. |
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//circumference of the earth is 25,000 miles, so
let's take half that as a best guess// and in terms
of a first stab - it's an ideal way of establishing the
likely lower and upper bounds - we can be pretty
confident that the answer is somewhere between
0
miles and 12,500 miles - wherever you may be on
the
planet. Anything further is just a matter of detail. |
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M: Oh look, this isn't an argument! |
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M: It's just contradiction! |
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"and if those astronauts didn't go utterly apeshit Space Mad at the sheer insanity of their distance from Earth." |
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Ah yes - Samuel R. Delany and his "golden". The lucky few who could pilot spacecraft beyond a certain distance from our planet without going crazy. |
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//please feel free to improve upon it.// |
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Let us assume that Earth, and its night sky, are
fairly typical. Let us also assume that
constellations that are significantly better than
our own pathetic distorted ones are 1,000,000
times rarer. |
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Given that there are something on the order of
100 constellations defined from Earth (and, hence,
from any other typical planet), it follows that 1
planetary system in 10,000 will have at least one
constellation that is significantly better than any
of ours. |
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Assume (on the basis of information to date) that
one star in 100 has potentially habitable planets. |
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Therefore, we may assume that one star in
1,000,000 will have (a) a habitable planet and (b)
at least one constellation which is much better
than any of ours. |
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Therefore, such a star would be expected to be
about cube-root-of-a-million = 100 stars away from
us. |
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Average distance between stars (except in the
galactic core) is oto 5 light years. |
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Hence, a planet meeting our requirements will be,
on average, 500 light years away. |
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Excellent - so, having established that, how much
faster than the speed of light would an astronaut
need to be travelling in order to be confident of
not going potty on the way? |
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I don't like being on the train for more than 30
minutes (though I'll confess, I've not yet gone as
far as considering stasis as an option yet) the
prospect of more than 6 months in a can isn't one
I'd relish without some level of extended sleep
equipment. (Nor is it one I'd relish if I did have the
equipment, but being asleep it would matter a
great deal less) |
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I think I'd be fairly happy for the first 15-20 years, as
long as there were books and maybe a piano. |
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A piano? Maybe not you, but SOMEBODY'S going to go crazy. |
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Now I'm wondering how to cash in on the upcoming constellation tourism craze. |
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Just returned from "In the Tobacconists" and had to say "How did I get here" ? |
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At high speed time moves more slowly relative to the rest of reality, according to the theory of relativity (as I understand it?) at light speed time should effectively stop for the traveller, as [leopard] was talking about this kind of speed any travellers will experience no time at all even if it takes a million years for them to reach their destination from our earth bound planetary perspective. |
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Ergo you don't need the cryo chamber. |
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Interestingly enough gravity is interchangeable with speed for this purpose & the further you are from the earths centre of gravity the less you feel it, which means if you want your brain to work faster in relation to everyone else's you can go to the top of a tall mountain (which is why so many hermits live on them). |
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//FTL doesn't mean instantaneous// |
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I don't even want to think about what happens under the rules of relativity if you go faster than light [zen_tom], just as well you can't. |
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Relative to you're own perspective that is, relative to the perspective of someone else moving in the opposite direction to you at similar speed though? |
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//which is why so many hermits live on them// |
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Of course not every hermit can afford their own mountain so some of them have to resort to a tall pole instead (but the ones with mountains all look down on them as second rate / not really hermits at all). |
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You know what - I stand corrected - seems time
really does appear to stand still if you're going at c,
and rather counter-intuitively - at least to the
traveller - appears to flow backwards at speeds
'faster' than that. I always assumed it just slowed
down. |
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appears is a good word. Do you have time if you can't sense light? |
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The time dilation effect is determined by (recent
googler, first time looking at the maths here) |
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t' = t * V¯ (1 - (v^2 / c ^2) ) |
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Where t' is the time experienced by the traveller,
t is the time measured by a static observer, v is
the speed of the traveller, and c is the speed of
light. |
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In the above, if v > c then you get V¯ (1 - (a
number > 1) ) which resolves to |
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Square Roots of negative numbers are decidedly
tricky. If you carried on with the calculation, you'd
end up with |
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Where i is an imaginary number, and x was the
"warp factor". |
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So maybe you wouldn't go backwards in time (in
the normal forwards, backwards sense) but instead
step 'off' time and go in a whole new direction,
"sideways". |
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[zen] between you & [wjt]'s anno's (not you're last one (that came while I was typing & I haven't read it yet), the one before) I can smell an idea for a short story or novella (if I could write). |
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Or a new idea for here (if it wasn't complete & utter wibni with a generous dash of total bullocks). |
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A private investigator with a faster than light spaceship & a really big telescope (it's really big because he's compensating for other issues, but that's another story). |
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Who investigates by flying away faster than light before taking out his really big telescope to see what Mrs <insert name of client> husband was really doing last Tuesday when he said he had a business meeting. |
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Or maybe it would be an archaeology idea, catch up with the light that left earth in 1066 & record video footage of the battle of Hastings. |
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This is too good an idea for a sci-fi book, someone else must have already written it & I just haven't read it yet, or I have but I've forgotten & this is my subconscious waving a flag to try & remind me. |
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Not much cop with the math angle myself, but the major issue I see with it (FTL & even NL) is that with speed as well as time dilation the weight (wrong word?) of a moving object (your craft, luggage & self) also increases in relation to the rest of the universe. |
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At near c the mass of a moving object tends toward the infinite. |
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I seem to remember Einstein said at c it was infinite. |
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Which is why only things that have zero mass can travel at light speed I guess (presumably anything with mass collapses into a black hole on attaining c)? |
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Which gives rise to an interesting idea for a solar system destroying weapon (planet busters are just so.. small, aren't they). |
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A small craft accelerated up to 99.999(etc.)% of c & driven into the solar systems sun. |
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Collapsing it into a black hole or sending it nova. |
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Then again maybe I was just dreaming the whole thing about mass going up as well as time slowing, it's been a long time since I was at school, relatively speaking. |
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The aliens have heard our earliest broadcasts, they weren't impressed, & more than a little worried by our violent & imperial tendencies (as displayed in early episodes of Flash Gordon). |
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So under that guiding evolutionary principle of self preservation in an act of act of pre-emptive self defence they've sent one our way. |
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It's accelerating towards us as even we speak. |
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I don't care about the mass being infinite at the speed of light, what does it do above that? |
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//a really big telescope (it's really big because he's compensating for
other issues, but that's another story). // |
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Oh dear, back to Trelane ... |
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//It's accelerating towards us as even we speak. // |
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No, it's not. You're perfectly safe. As long as you're still hitting the
peak viewing figures on the Galactic Comedy Channel, no-one's going
to harm you. "Jackass Earth" and "Humanity's Been Framed" top the
ratings time after time. |
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Thank you [Skewed] for pointing out the fact that
the astronaut doesn't need to experience a long
delay to reach a very distant destination as long as
he's willing (and able) to burn enough fuel. But to
further expound on this point: to the astronaut,
there doesn't appear to be any cosmic speed limit.
From his point of view there as he speeds up,
there is length contraction between the beginning
and the end of his journey. He doesn't
"experience" time dilation. That is an effect on
him that the people back on earth observe. |
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If the astronaut is approaching the speed of light
as measured from earth, he would seem to be
"approaching" infinite speed, as much as you can
approach something that is infinite. I forget the
formulas exactly, but I think that near light speed,
if the astronaut doubles his perceived speed
relative to the earth and his destination, the
people on earth will perceive that the difference
between his speed and the speed of light got cut
approximately in half. |
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Therefore, from the point of view of the
astronaut, a speed higher than infinite is not
worth considering. Of course space warping and
wormholes are a completely different issue, but
you aren't actually going faster than light, just
taking a shortcut. |
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//as much as you can approach something that is infinite.// |
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You could use the US Federal Budget Defecit as a model ... |
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If there is a calendar date sent out, by packets of photons, from the other side of the galaxy, a ship that could travel faster than light could traverse the line to whatever date it wants. Even stay with one date or make the dates go backwards. But the ship, the Calendar and the travelling photons are all at t + big bang with different positions. |
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Clocks are physical entities moving them alters their timing ability and why wouldn't the universe have a friction/drag coefficient at ultra speed. |
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