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Their constellations

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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.

MaxwellBuchanan, Jul 19 2014

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]

[link]






       Are we not seeing stars from our light-time wall? I wonder what differences there are, while the messenger is messaging.
wjt, Jul 19 2014
  

       Other than the big and little dippers none of the constellations look like what they are supposed to look like to me.   

       How could we ever guess what they might look like to aliens?
What if they don't have dippers?
  

       //You may be asking what the point of this is//   

       Shirley, the answer is obvious.   

       And really quite short, despite any protestations to the contrary.   

       Immigrants' leaving earth will one day choose their new home according to the night-time view of the sky they find most appealing.   

       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 ;)
Skewed, Jul 20 2014
  

       I wonder what the scissors of a 5 meter tall bulb handed hexiped look like.
Voice, Jul 20 2014
  

       //3D positions of stars// I think you mean the 3D trajectories of stars over time.
pocmloc, Jul 20 2014
  

       //I think you mean the 3D trajectories of stars over time.//   

       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.
MaxwellBuchanan, Jul 20 2014
  

       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).   

       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.
pocmloc, Jul 20 2014
  

       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.
MaxwellBuchanan, Jul 20 2014
  

       Yes, OK. Out of curiosity, what percentage of our constellation stars are outside our galaxy?
pocmloc, Jul 20 2014
  

       I like it.
doctorremulac3, Jul 20 2014
  

       //Yes, OK. Out of curiosity, what percentage of our constellation stars are outside our galaxy?//   

       I think it's in the low zeroes.   

       Other galaxies appear, to the naked earthbound eye, as slightly fuzzy blobs, and most are too faint to see without a telescope or binoculars.   

       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.   

       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.
MaxwellBuchanan, Jul 20 2014
  

       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.
rcarty, Jul 20 2014
  

       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.
pocmloc, Jul 20 2014
  

       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.   

       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.
MaxwellBuchanan, Jul 20 2014
  

       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.
zen_tom, Jul 21 2014
  

       [+] I like this and am amused that aliens will see a Maxwell Buchanan portrait constellation with a mustache painted on it.
xandram, Jul 21 2014
  

       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.   

       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.
normzone, Jul 21 2014
  

       > send image as well as voice   

       There's an ancient technology which might help you here, called a "modem."
Hive_Mind, Jul 22 2014
  

       Last I checked they were limited by reality (link).
normzone, Jul 23 2014
  

       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.
pashute, Jul 23 2014
  

       Six-legged unicorn as in Carl Sagan.
nineteenthly, Jul 24 2014
  

       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.
theleopard, Jul 24 2014
  

       //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//   

       Belt & braces?   

       If you have one you perforce don't need the other.
Skewed, Jul 24 2014
  

       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.
theleopard, Jul 24 2014
  

       [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.   

       Sorry [theleop] cross posted - yes - that's what I was trying to say.
zen_tom, Jul 24 2014
  

       //The centre of the galaxy is 30,000 light years from earth, so taking that as a mean//   

       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."
MaxwellBuchanan, Jul 24 2014
  

       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.
pocmloc, Jul 24 2014
  

       //one would only want to go to a good tobacconist //   

       Just make sure you have a genuine English-Hungarian phrasebook if you do.   

       <link>
8th of 7, Jul 24 2014
  

       //one would only want to go to a good tobacconist//   

       Ah, but a good tobacconist will not only take your order by telephone, but will also deliver your cigarettes once they've been made.
MaxwellBuchanan, Jul 24 2014
  

       //That argument doesn't really work.//   

       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.   

       //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.
zen_tom, Jul 24 2014
  

       M: Oh look, this isn't an argument!   

       (pause)   

       O: Yes it is!   

       M: No it isn't!   

       (pause)   

       M: It's just contradiction!   

       O: No it isn't!   

         

         

         

       "and if those astronauts didn't go utterly apeshit Space Mad at the sheer insanity of their distance from Earth."   

       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.
normzone, Jul 24 2014
  

       //please feel free to improve upon it.//   

       Certainly.   

       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.   

       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.   

       Assume (on the basis of information to date) that one star in 100 has potentially habitable planets.   

       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.   

       Therefore, such a star would be expected to be about cube-root-of-a-million = 100 stars away from us.   

       Average distance between stars (except in the galactic core) is oto 5 light years.   

       Hence, a planet meeting our requirements will be, on average, 500 light years away.
MaxwellBuchanan, Jul 24 2014
  

       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?   

       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)
zen_tom, Jul 24 2014
  

       I think I'd be fairly happy for the first 15-20 years, as long as there were books and maybe a piano.
MaxwellBuchanan, Jul 24 2014
  

       A piano? Maybe not you, but SOMEBODY'S going to go crazy.   

       Now I'm wondering how to cash in on the upcoming constellation tourism craze.
normzone, Jul 24 2014
  

       Just returned from "In the Tobacconists" and had to say "How did I get here" ?
normzone, Jul 25 2014
  

       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.   

       Ergo you don't need the cryo chamber.   

       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).
Skewed, Jul 25 2014
  

       //FTL doesn't mean instantaneous//   

       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.   

       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?
Skewed, Jul 25 2014
  

       //which is why so many hermits live on them//   

       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).
Skewed, Jul 25 2014
  

       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.
zen_tom, Jul 25 2014
  

       appears is a good word. Do you have time if you can't sense light?
wjt, Jul 25 2014
  

       The time dilation effect is determined by (recent googler, first time looking at the maths here)   

       t' = t * V¯ (1 - (v^2 / c ^2) )   

       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.   

       In the above, if v > c then you get V¯ (1 - (a number > 1) ) which resolves to   

       t * V¯ ( - warp factor)   

       Square Roots of negative numbers are decidedly tricky. If you carried on with the calculation, you'd end up with   

       t' = t * xi   

       Where i is an imaginary number, and x was the "warp factor".   

       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".
zen_tom, Jul 25 2014
  

       [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).   

       Or a new idea for here (if it wasn't complete & utter wibni with a generous dash of total bullocks).   

       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).   

       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.   

       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.   

       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.
Skewed, Jul 25 2014
  

       hmm...   

       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.   

       At near c the mass of a moving object tends toward the infinite.   

       I seem to remember Einstein said at c it was infinite.   

       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)?   

       Which gives rise to an interesting idea for a solar system destroying weapon (planet busters are just so.. small, aren't they).   

       A small craft accelerated up to 99.999(etc.)% of c & driven into the solar systems sun.   

       Collapsing it into a black hole or sending it nova.   

       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.
Skewed, Jul 25 2014
  

       //A small craft//   

       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).   

       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.   

       It's accelerating towards us as even we speak.
Skewed, Jul 25 2014
  

       I don't care about the mass being infinite at the speed of light, what does it do above that?
pocmloc, Jul 25 2014
  

       //a really big telescope (it's really big because he's compensating for other issues, but that's another story). //   

       Oh dear, back to Trelane ...   

       //It's accelerating towards us as even we speak. //   

       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.
8th of 7, Jul 25 2014
  

       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.   

       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.   

       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.
scad mientist, Jul 25 2014
  

       //as much as you can approach something that is infinite.//   

       You could use the US Federal Budget Defecit as a model ...
8th of 7, Jul 25 2014
  

       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.   

       Clocks are physical entities moving them alters their timing ability and why wouldn't the universe have a friction/drag coefficient at ultra speed.
wjt, Jul 26 2014
  
      
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