# How to detect if you are in orbit?



## Vertigo (Apr 23, 2012)

Let's see if I can explain what I'm after here.

Imagine a moderately large habitat style spaceship, a rotating cylinder, say something like a 1000m in diameter and several km in length. Assuming no access to any kind of external sensors and no windows, is there any way you could tell if you were in orbit around a planet or just coasting through interstellar space?

I'm pretty sure I read something a while back that described a way of doing this.

Also how would such a thing orbit? Would it orbit end on, so that the cylinders axis points at the centre of the planet, or lengthwise so the axis is pointing along a tangent to the orbit?

I was wondering if you could do something like this:

The orbit radius is dependent upon the speed; faster speed, bigger radius. If the ship is orbiting end on then the orbit radius would be based on the speed of the cylinder's centre of gravity. So if you floated a balloon at one end of the cylinder would it then naturally drift towards the centre to get it's (the balloon's that is) orbit radius right for it's speed.

If it was orbiting lengthwise, would there be a measurable difference in the centrifugal pseudo-gravity when the spin of the cylinder places you closest to the planet as oppopsed to when it places you farthest away from the planet?

Hope that makes sense!


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## Bowler1 (Apr 23, 2012)

The first is easy enough, assuming you were standing in the middle of the habitat, I don't think you'd be able to tell if you were coasting through deep space or not. 7km Is a long distance visually. The sky would be low if there was one. Only at the ends of the tube then outside space would be visable. Think how far away is your nearest shop, your distance to work. A lot of people would stay within 7km of their home most of the week!

The rest of the question was difficult for me to follow. But, I think with a small radius habitat, if you dropped a weight it might look to fall a little to one side, because you would have moved with the structure while the object dropped/centrifugul force takes hold. A structure with a bigger radius then this would be harder to see/measure - assuming 1g gravity. Thats what I think, I'd like to have that confirmed or debunked myself.

I don't see why the axis of the habitat would matter in relation to a nearby planet. 

Good question.


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## RJM Corbet (Apr 23, 2012)

Very simply, it would appear that in a state of weightlessness, with no windows or sensors of any kind, there's be no way to tell. Imagine being completely weightless and completely in the dark, for instance? What would you know? 

But ... let's wait for Crispen


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## Metryq (Apr 24, 2012)

There's no reason for the habitat to change orientation as it orbits the planet—doing so would use up power. Hold a pen between thumb and index finger so that it is horizontal. This becomes a model of the cylindrical habitat. Now sweep the pen in a wide circle, keeping it horizontal. Relative to its own reference frame, the habitat does not change orientation, although different sides of the structure face the planet as it orbits.

(ISS generally maintains the same orientation relative to Earth with gyroscopes, but does change orientation on occasion.)

Could some simple test of dynamics, like a bearing rolling down a ramp or maybe a pendulum, tell the difference between orbit and coasting freely through space? I doubt it. The rotation of the habitat on its axis would likely overwhelm any tiny effects caused by orbiting. (Like the urban myth about water spiraling down drains in different directions between north and south hemispheres of Earth, there are other factors that completely overwhelm any Coriolis or other effects.)


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## Vertigo (Apr 24, 2012)

Thanks for the responses!

Bowler - You can't see out of the ends of the cylinder, so you have no way of see outside at all. That is the problem my protagionists face. They have been told they are cruising to another star but they now believe (as is the case) that they are actually in orbit around a planet. What I need is some way for them to prove it. 

RJM - I am certain there is some dynamic way of confirming it. In both cases the cylinder's speed is constant however when in orbit your velocity is constantly changing (ie the direction of your motion) whereas when cruising it is not.

Metryq - I wasn't talking about changing the orientation of the habitat whilst orbiting but just wondering which orientation would be the logical one to use for an orbit. I suspect it would be the lengthwise orientation. Actually now I come to think about it without applied power I suppose you would actually slowly roll (relative to the planet) through 360 degress each orbit. In order to maintain the same orientation to the planet would you actually have to have a very slow rotation? In the same way that the moon has a slow rotation of one revolution per orbit.


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## RJM Corbet (Apr 24, 2012)

Vertigo said:


> ... RJM - I am certain there is some dynamic way of confirming it. In both cases the cylinder's speed is constant however when in orbit your velocity is constantly changing (ie the direction of your motion) whereas when cruising it is not ...


 
I'm sure there must be. The weightlessness in orbit is a 'falling' weightlessness, the cruising weightlessness is 'no gravity' weightlessness?

Edit: So it follows that a cruising vehicle would be exposed to some slight gravity effects from the closest mass: a sun, a planet, an asteroid, etc?

So perhaps an object floating in the cabin of a crusing vessel would eventually be pulled in a certain direction, towards the gravity source? Instead of just hanging there as would be the case in orbit? Perhaps a floating water 'bubble' would assume a pear shape, with the narrow end towards the gravity source, instead of being spherical, and would gradually move in that direction?

Thus if floating objects tend to congregate in one area, you know you're not in orbit, and vv?


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## Vertigo (Apr 24, 2012)

Yeah now the problem is that theoretically everything - spaceship, dropped objects etc - are all in the same dynamic situation. They are all in orbit or just cruising through interstellar space. If there is a body acting on them - planet, star, whatever - then it should be acting on them all equally.

The only difference I can see is in the orbit situation an object in different parts of the habitat (or different stages in the habitats spin) is actually in a slightly different orbit to that of the habitat's centre of gravity and so should experience slightly different forces. But I'm not sure how big that difference would be.

It's driving me bonkers this  I might have to try visiting some astrophysics forums and see if anyone can help there!


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## RJM Corbet (Apr 24, 2012)

Oh yes, true ... hmmmm


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## Vertigo (Apr 24, 2012)

Killer, isn't it? The really annoying thing is that I'm sure I came across this problem (with a solution) in a book I read maybe a year ago but I can't remember it. I thought it might have been Bester's The Star's My Destination but I can't find it in there.

Arrrgh!!!!


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## RJM Corbet (Apr 24, 2012)

_Gully Foyle is my name_
_Terra my habitation_
_Deep space is my dwelling place_
_And death my destination ..._


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## Ursa major (Apr 24, 2012)

Vertigo said:


> Bowler - You can't see out of the ends of the cylinder, so you have no way of see outside at all. That is the problem my protagionists face. They have been told they are cruising to another star but they now believe (as is the case) that they are actually in orbit around a planet. What I need is some way for them to prove it.


This begs all sorts of questions, such as:

who told them they were cruising?
when?
why aren't they being told about being in orbit?
are the "who" still alive?
are the "who" automated systems?
if the "who" were still alive/functioning, would they know?
how would they know?
is there any way the people not in the know could get access to the part(s) of the ship where those that know/knew are/were?
why do those not in the know think they may be in orbit?
is it just a hunch (or a belief that the ship's be travelling about the right time)?
(I suppose that the reason they need to determine the ship's situation is because they mean to take some action, and the knowledge will help them persuade others to join in. If the latter, the demonstration that they're in orbit will have to be clear and conclusive.)

Intriguing situation.


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## RJM Corbet (Apr 24, 2012)

Going into the literary agency business, are you, Ursa?


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## Ursa major (Apr 24, 2012)

Didn't you know that I'm already a top literary agent (in the same way that I'm already a bestselling author, that is...).


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## RJM Corbet (Apr 24, 2012)

Ursa major said:


> Didn't you know that I'm already a top literary agent (in the same way that I'm already a bestselling author, that is...).


 
Now you've got me wondering.

You've sure been around here a long time. Coming up for 10k posts ...


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## Vertigo (Apr 24, 2012)

Basically most of those questions are what the (short) story is about!  Essentially the story is:

Aliens arrive at post apocalyptic Earth. All life has been destroyed some time ago but not too long ago. Through recovered computer records they learn human history and Earth biology. They recover DNA and 'grow' a bunch of children, plants and animals on a habitat (Earth is still polluted/radioactive or whatever) using android 'adults', indistinguisable from real humans, to bring them up and educate them. Their objective is to give them as 'natural' an upbringing as is possible based on the human history they have learnt.

They don't want the children to know the truth (ie that they are the only humans in existence) until they are older. So they create the story that they are a human spaceship off to colonise another star system. In actuality they are still orbiting Earth.

As the children get older they begin to notice anomalies. Things like the habitat technology seems to be significantly beyond the technology in the history they have learned. Why is there no new communication with Earth. They are supposed to be under permanent (though very low) acceleration and then deceleration (ramjet) but this is easy to check using pendulums and the oldest children have already figured that they are not under acceleration. So they begin to speculate that they must either be cruising or in orbit...

So in answer to your final points the (well-meaning) aliens are deliberately keeping the children in the dark but the children are beginning to get suspicious. Once they, hopefully, figure out they are in orbit then they will begin trying to get a 'peek' outside.

Incidentally the reader will know none of that background until the end. The POV will be with the children.


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## Ursa major (Apr 24, 2012)

Good set up. (I almost wish I hadn't asked, now.)


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## RJM Corbet (Apr 24, 2012)

Ursa major said:


> Good set up. (I almost wish I hadn't asked, now.)


 
Well, we know certain agents do lurk.

Yes, Vertigo, busy (good) plot ... phew: lot of work ahead of you.


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## Vertigo (Apr 24, 2012)

Ursa major said:


> Good set up. (I almost wish I hadn't asked, now.)


 
It was the current 75 worder that got me thinking about it!

My big problem is to come up with anomalies that the 'adults' can explain away but just implausibly enough to eventually make the older children suspicious.


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## Vertigo (Apr 24, 2012)

Ah I've found the passage! It was another SF Masterworks story: Babel 17 from Samuel Delaney. Here it is, a bit long I'm afraid even though I've cut some incidental stuff out:




> "A watch," saidRydra, "and a—bag of marbles!"
> "Huh?" asked Calli.
> "Mar-bles?" articulated Mollya wonderingly. "Marbles?"
> "One of the kids in the platoon must have brought along a bag of marbles. Get it and meet me in G-center."
> ...


 
It's possibly a bit complicated for even older teenagers to have worked out but then on such a ship astrophysics is certainly something they would be studying. Also since the book was written in the 60s I'm not sure if the technique is a valid one.


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## Ursa major (Apr 24, 2012)

Imagines:
"You need marbles?" asked Jill.

Bill explained what he intended to do.

Jill smiled. "So you _have_ lost yours."​


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## Vertigo (Apr 24, 2012)

Yes, I also like that fact that Delaney assumed marbles would still be played with the same enthusiasm as in the 60s - "One of the kids in the platoon must have brought along a bag of marbles." I remember back then no self respecting kid was without their little bag of marbles (sane or otherwise!).


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## Bowler1 (Apr 24, 2012)

I can remember the name of the book I'm going to discuss, maybe someone else will remember but is one of the SF Masterworks series.

A generational star ship traveling between planets but its traveling so long the passengers regress and have different tribes between the levels. Eventually one of the characters discovers a control room and the plot quickly descends into a nice quick ending, in orbit around earth I think which felt like a cheat.

Anyway, sealed in or not there would be a control room somewhere. The discovery and finding of said room could be interesting. Just try and have a better ending than the one above Veritgo, I hate lazy endings.

Do they still make marbles?


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## RJM Corbet (Apr 24, 2012)

Cool. You found it.

Reads quite well, at first.

But I faded at: 'The summation of the angles of intersection ...'

Nevertheless, there you are.

I think ...?


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## Vertigo (Apr 24, 2012)

Yes I am rather daunted by that Delaney's explanation (I started glazing at the same point RJM and seem to remember doing so first time I read it as well) and any attempt to simplify it without fully understanding it would probably be... unwise. However I do quite like the idea that they would need to make their way to the habitat axis (zero centrifugal force) to test that one out. Problem would be setting the marbles (or whatever) up without any intial motion. Delaney's 'iron cores' struck me as a bit of a deus ex machina; I don't think I've ever come across marbles with iron cores. Ball bearings might be a bit more plausible and surely something that would be knocking around somewhere in the machine shop of a spaceship.

Bowler once they have figured out they are in orbit I thought a little pilfering of an 'adult's' logon details followed by hacking of the system to get the real sensor data... 

I'm sure you could still get marbles somewhere...


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## RJM Corbet (Apr 24, 2012)

Vertigo said:


> ... I'm sure you could still get marbles somewhere...


 
Oh, you can.

A marble is a good way of getting a shelf or table level, if you haven't got a spirit level handy ...


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## chrispenycate (Apr 24, 2012)

So, is the thing in free fall, or rotating to simulate gravity? If weightless you could, with a sufficiently large block of fluid detect tides in it geometrically, or use a 'Forward mass detector', (yes, invented by the same Robert L. Forward who wrote Dragon's egg, and Rocheworld) http://www.gravityresearchfoundation.org/pdf/awarded/1965/forward_bell_morris.pdf
which can detect mountain ranges from orbit, let alone planets.

It would still be possible to detect tiny differences in weight between the 'bow' and 'stern' of your orbiting cylinder, or use the Forward detector if it were spinning on its axis to keep people stuck to the walls, but be much more difficult, the centripetal force masking the minute variations. Obviously, you'd know you were spinning, but that would be the case whether you were next to a planet or lightyears from anything.

Bowler, I suspect 'Non-Stop', by Brian Aldiss. And marbles are still for sale in toy shops, despite the obvious H&S risks, of swallowing them or trading on them and falling over…


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## RJM Corbet (Apr 24, 2012)

chrispenycate said:


> ... despite the obvious H&S risks, of swallowing them or trading on them and falling over…


 
Shhh ... they'll hear you!


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## Vertigo (Apr 24, 2012)

Yes, it's definitely a spinning habitat Chrispy and I agree that does complicate things, but it seems too implausible to have it otherwise. This is why I thought it would make a nice plot excursion for the children to head off to the axis (at either bow or stern) to get to a weightless environment. Actually that might not be such an 'adventure' as they would almost certainly have such weightless chambers in the ship for anything from manufacturing special materials to a play area.

Unfortunately that document comes up as corrupt when I download it and try to open it 

Actually I do still like the Delaney idea. Let's see if I can simplify it for my purposes since I don't need to figure our position only that we are in orbit around something.

So anything orbiting another body will have it's centre of orbit at the centre of gravity of the other object, the planet in this case. At least that is true (as in this case) where there is a massive difference in the masses of the two bodies. So you get to the axis area of the ship and so have no relative gravity. Suspend several objects reasonably far apart and motionless with respect to each other (that could be difficult but a long electromagnet and several steel ball bearings 'stuck' to it might work when the electromagnet current is turned off. Now assuming we are orbiting a planet each object will naturally 'fall' in a great circle centred on the same point of the planet. These orbits _must_ intersect twice each time they (and the ship) orbits around the planet. So their paths will tend to converge and cross. They won't necessarily collide since it is highly unlikely they have been placed so each orbit is exactly in phase. However the converging and diverging should be visible over the period of an orbit, which would likely only be an hour or so. Whereas if they are not in orbit around a planet they will never converge.

What do you think? I'll need to work on it to make it clearer - a drawing would make it so much easier


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## RJM Corbet (Apr 24, 2012)

Vertigo said:


> ... What do you think? I'll need to work on it to make it clearer - a drawing would make it so much easier


 
You can do that you know Vertigo, in an appendix, although I know you've said this is a story, not a book. 

I've got two appendices already, one contains drawings and tables of figures, another scans of old letters ...


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## Vertigo (Apr 24, 2012)

Yes and occasionally they do appear in the text of novels. But you are right in that I see this as a short story, I don't think the idea has enough in it for a novel. However I suspect a magazine would baulk at the idea. Not that I ever exepct to publish, it's just a fun idea at the moment.


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## Bowler1 (Apr 24, 2012)

I like your idea Vertigo but I'd worry about the pace of the story. Have you considered the habitat having some sort of small accident that would give the game away to your characters, also give you a dramatic opening. This could have caused a slight shift in the habitat axis before spin/gravity returned to normal. It’s a large living space so there may be water features and if the axis shifted then the water in the habitat would also have shifted (splashed about!!) before returning to normal. 

After that the deductions by your characters clearly don't add up with what they're being told and off you go.


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## Vertigo (Apr 24, 2012)

well as I said earlier it's not enough for a book and I don't want to make it too much for a short story. It is still only in the ideas stage (after all I've only been thinking about it for a few weeks) so anything is possible.


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## Metryq (Apr 24, 2012)

Vertigo, I realize the big puzzle is supposed to be the focus of this story, but I'm lost as to why the aliens are doing all of this. Was the "apocalypse" natural, or man-made? If man-made and the aliens recovered various records, they must know how dangerous Mankind was. Why reconstruct them—especially since so much effort is being made to produce specimens as close to the lost human civilization as possible? For that matter, how could the aliens know they were getting it right?

You described the iron cores of the marbles as deus ex machina, but your whole premise sounds like that to me. It's like the trope used in so many sci-fi stories where the enemy attempts to urge some critical bit of information—upon which the entire invasion depends—out of their prisoner by faking his home base/spaceship/whatever. If the enemy already knew that much about the prisoner's familiar surroundings...

You see what I'm saying? I don't buy this scenario at all. What are the aliens up to? And make it good.


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## Vertigo (Apr 25, 2012)

Well why are we considering trying to use mammoth DNA to recreate a mammoth? Why are we trying to save other animals from extinction? 

If you were an alien explorer and found evidence of another intelligent species would you not be interested in them? Especially since I am personally convinced that higher order life and in particular intelligent life is probably pretty rare out there. (And please I don't want to go into that debate again here ). So if we explored and found intelligent life out there, wouldn't we want to know and understand them even if they were now extinct. I think that if we had the technology it is quite possible, even very likely, that we would try to 'bring them back'.

As for us being dangerous, I don't think we are really any more dangerous than any other predator would be given intelligence. And again I personally don't think any non-predators are likely to achieve intelligence (the evolutionary pressures just aren't there, but again I don't want to churn out that old argument again here ). So if there are other intelligences out there I'm not convinced we would be atypical. I am sure we will eventually evolve out of our self-destructiveness (so long as we don't destroy ourselves first!) and I am equally sure any aliens out there sufficiently advanced to to explore the stars would understand this.

So I stand by the fact that I think reviving an extinct species is something an alien might well consider if the possibility was there.

Of course the aliens couldn't know they are getting it right. Just as we couldn't know for sure with mammoths. After all, today's elephants are the product, not just of nature, but also the nurture of their family group. So any mammoth we recreated (is that the right word?) would not receive that nurture so would not behave exactly as an ancient mammoth would. But that fact isn't going to stop us recreating them. With computer records, books, films etc. the aliens could get a pretty good idea of our civilisation and so recreate it as best they could.

Curiosity and thirst for knowledge are powerful motivations.

Is the story believable? I don't really know. If I can come up with a believable sequence of events, then yes. If I can't, then no.  It is only an idea I'm kicking around at the moment. Would I even use this particular idea of detecting if they are in orbit? Again I don't know I was just exploring different ideas. The solution to this particular one seems to be a little more complicated than I really wanted so maybe not. But it did intrigue me as an intellectual exercise, which is why I put the question here rather than aspiring writers.

As for the 'apocalypse', again at this point in time I don't really know. The only critical thing would be for it to not be nuclear as that would severely reduce the chances of finding undamaged DNA. Maybe something natural or manmade that has resulted in another 'snowball Earth'. That would give a higher chance of aliens finding viable DNA.

Remember this is still just an idea I'm kicking around. I enjoy doing that. As to whether it will ever make it to paper...


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## Bowler1 (Apr 25, 2012)

Vertigo the idea is fine, Metryg is being  unfair in my oponion. Any good story will depend on the telling and as a writer, do what you like. If it sells later great, if not, have fun while writing mate.


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## Vertigo (Apr 25, 2012)

Bowler1 said:


> Vertigo the idea is fine, Metryg is being unfair in my oponion. Any good story will depend on the telling and as a writer, do what you like. If it sells later great, if not, have fun while writing mate.


 
Well it's no bad thing really. It makes me stop and try to look at it a little more objectively.


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## Metryq (Apr 25, 2012)

Bowler1 said:


> Metryg is being  unfair in my oponion.



Well, forgive me for expressing _my_ opinion. I did not mean to sound so negative. I'm sure no one else will raise such questions when reading the described story.

I have no problem with the "reconstructing a dead species" angle, I just want to know why the aliens would do it. To make one mundane observation, the project sounds like it would cost a lot of money. 

I'm also not suggesting the aliens wouldn't revive humanity just because it was a dangerous species. However, there is a liberal trope in sci-fi that it might be desirable to avoid: namely, the benevolent, god-like, do-gooder aliens who travel the cosmos "guiding" violent species through the shoals of their youthful violence. Gene Roddenberry was real big on the idea in several of the original STAR TREK episodes, as well as other projects, like THE QUESTOR TAPES. Granted, there are species going extinct due to Mankind's abuses, but some species may be going extinct all on their own. In the hysteria to halt _any_ change in the natural world, there is even a US government effort to shoot one type of owl in order to give a lesser breed a "fair chance." 

Again, I'd just like a compelling reason why the aliens are doing this. Perhaps the aliens see humanity as a possible catalyst to their own civilization—assuming humanity's engine gets a "governor" to keep it from burning out. The first three novels of James P. Hogan's "Giants" series are one example. 

As for the do-gooder aliens, the super race in Clarke's 2001: SPACE ODYSSEY were said to "sow the seeds of intelligence—sometimes they reaped, and sometimes they had to weed." Chilling thought, but it strikes me as realistic. Everything has its time, and preserving everything is impractical and counter productive.

****

The effort to clone a mammoth probably has more to do with the budding technology than the actual desire to revive the species.


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## Vertigo (Apr 25, 2012)

As I say good to push me into thinking objectively  Maybe it might be interesting to play with the idea that the aliens accidentally caused the apocalypse with their arrival. Thinking along the lines of the thread a while back about possible FTL drives being potentially very dangerous for anything that happens to be too close to their arrival point. Nothing like a bit of guilt as a motivator!


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## Parson (Apr 25, 2012)

*Vertigo,* it seems to me that we are putting human impulses into the skin of an alien. When it comes to matters of higher ethics why an alien(s) would or would not do something might be absolutely incomprehensible to us humans. I would not be worried about their motivation, especially in a short story.


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## Metryq (Apr 25, 2012)

Parson said:


> I would not be worried about their motivation, especially in a short story.



Two very good points—

Although the "Giants" series I referred to above does a commendable job of inventing a non-aggressive alien race, the evolutionary reasons for that non-aggressiveness, and the convoluted reasons why they repeatedly cross paths with humanity. One other point about motivation: the reading audience is human. You can create incomprehensibly alien minds if you wish. I don't always take "human-like" aliens at face value; sometimes they are allegorical.

And the outlined concept sounds "bigger" than a short story. Either flesh it out properly as a novella, or come up with some other scenario for the "free-flight or orbit" puzzle. 

I actually like the "oops, we fried Earth on our approach" idea. It's got a certain tongue-in-cheek absurdity to it that might give atmosphere to the relationship between the humans and the aliens—once the humans figure out there _are_ aliens. That might even be an angle—write it from the perspective of a parent learning just how smart even young children can be. They're not as stupid as you thought.


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## Vertigo (Apr 26, 2012)

I actually go against the general thoughts of many on this point. I think the thought processes, motivations and attitudes of aliens are unlikely to be all that different to our own. The evolutionary pressures on species are always going to be very similar; survival and procreation. Now that can be very different whether you are looking at a herbivore or carnivore but if you look at most herbivores on Earth their fundamental behaviour is actually very similar, the same goes for carnivores. Yes in both cases some are solitary and some social and that creates differences and there are of course many other differences. But they are really not that big when you get right down to it. We can relate to and understand the behaviour of pretty much all the creatures on our planet.

I would also go further and argue that intelligence is unlikely to develop in non social creatures and also less likely in herbivores. All the smartest animals on our planet tend to be social; higher intelligence required to communicate, and carnivore; hunting animals requires more intelligence than fleeing ones.

But again that is a whole other topic for discussion. However the bottom line is I personally think that if we ever do encounter intelligent aliens we might find they are surprisingly like us. Right down to physiology. Big brains must be kept cool, so dump that fur and get a better cooling system like our sweating. Outside of insects evolution has never produced any land animals with more than four limbs (I suspect extra limbs would be too complex to control conciously). An intelligent species (at least technological ones) need manipulators so it would logically become bipedal to free up two of those limbs. I could go on  The more I think about the requirements of an intelligent, technological creature the more logic points at a configuration similar to our own.


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## Dozmonic (Apr 26, 2012)

I like the story premise. Plato's cave for genetically engineered humans  I also think this and just about any idea is enough to make a novel out of. 99% of any novel is the journey, not the destination


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## Vertigo (Apr 26, 2012)

Thanks Dozmonic. I think it could go to novel; as you say it's all about the journey. But I think as it stands the idea would be a little weak. It would need more conflict; maybe a different alien faction with a very different agenda for the children etc.

Actually an interesting possibility might be something along the lines of, I think, Tany Huff's Confederation. Ancient intelligent confederation of races helps younger races and let them join their confederation if they will fight their war for them. So maybe one faction of aliens see the revived humans as a possible indentured race of soldiers.


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## Bowler1 (Apr 26, 2012)

Nice idea about the numbers of limbs Vertigo and I agree evolution would produce similiar ends more often than not. 

I'm a very clumsy individual tripping over my two feet a lot, the last thing I need is more limbs, I never make it!


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## Vertigo (Apr 26, 2012)

Hehe, yeah I'v often thought that. 

Obviously I don't know but I suspect the number of limbs is an evolutionary compromise between function and the amount of extra brain capacity required to control them. Mind you on an exceptionally high gravity planet maybe the compromise would swing in favour of extra limbs to take the weight. So my thoughts are far from absolute on the matter.


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## Bowler1 (Apr 26, 2012)

Shorter stumps would be another solution in high gravity using bigger thicker bones with bigger muscles. Maybe even a skeleton scaffold structure for added support.


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## Vertigo (Apr 26, 2012)

Yup, and I actually think that is more likely than extra limbs. So still similar if a little squashed looking


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## Parson (Apr 26, 2012)

Vertigo said:


> I actually go against the general thoughts of many on this point. I think the thought processes, motivations and attitudes of aliens are unlikely to be all that different to our own. The evolutionary pressures on species are always going to be very similar; survival and procreation. Now that can be very different whether you are looking at a herbivore or carnivore but if you look at most herbivores on Earth their fundamental behaviour is actually very similar, the same goes for carnivores. Yes in both cases some are solitary and some social and that creates differences and there are of course many other differences. But they are really not that big when you get right down to it. We can relate to and understand the behaviour of pretty much all the creatures on our planet.



I actually agree with you on the base needs. I think they would be comprehensible. That's why I was speaking of higher moral questions -- Like should we save this race. For either a base carnivore/omnivore or herbivore the question could have a sensible answer in either direction. 



> I would also go further and argue that intelligence is unlikely to develop in non social creatures and also less likely in herbivores. All the smartest animals on our planet tend to be social; higher intelligence required to communicate, and carnivore; hunting animals requires more intelligence than fleeing ones.
> 
> But again that is a whole other topic for discussion. However the bottom line is I personally think that if we ever do encounter intelligent aliens we might find they are surprisingly like us. Right down to physiology. Big brains must be kept cool, so dump that fur and get a better cooling system like our sweating. Outside of insects evolution has never produced any land animals with more than four limbs (I suspect extra limbs would be too complex to control conciously). An intelligent species (at least technological ones) need manipulators so it would logically become bipedal to free up two of those limbs. I could go on  The more I think about the requirements of an intelligent, technological creature the more logic points at a configuration similar to our own.



This is logical, but I can't help the niggling suspicion that our limited experience makes what we think "obvious" likely less than that.


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## Vertigo (Apr 26, 2012)

Well of course we'll never know until we do, or if we do, make contact. But yes I would agree broadly that moral values would probably be quite different depending on evolutionary origins, particularly herbivore or carnivore. Of course, as omnivores, we sit somewhere in the middle. 

Actually, I also have a tendency to think that omnivores are the more likely origins of intelligence. By their nature omnivores are inclinded to a more varied diet which implies a mind less focussed on one particular way of acquiring food. This suggests to me a mind more open to new possibilities combined with an opportunistic approach to finding food. That combines with the need to communicate in a social group.

Hehe, sorry one of my pet subjects. I love trying to figure out what evolutionary pressures are most likely to produce intelligence. Or maybe more accurately what evolutionary niches where intelligence, and in particular abstract thought, would be useful from a survival perspective and therefore prove to be a successful mutation.


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## Metryq (Apr 26, 2012)

Dozmonic said:


> Plato's cave for genetically engineered humans



Not _quite_—the point of Plato's cave is that one does not perceive the real world, but only shadows or projections of it. In Vertigo's story, the young humans have been taught all the proper physics, yet told a lie about their actual situation. One of Plato's cave-dwellers would not even recognize a real, 3D object for what it was. 

And I'm with Parson on the "obviousness" of evolutionary design. Nature is not an engineer seeking the greatest efficiency. All it needs are solutions that _work_. Considering the diversity of forms on this one planet, I wouldn't make any bets on how weird something from another star system might be. That is, there might be factors rendering all life within one star system somewhat similar. However, I would _not_ be surprised if evolution produced many similar solutions elsewhere. (I just don't hold with the idea that there is one, _best_ way. Look at all the engineering buffoonery in the human design, but that didn't stop us from becoming the top predator on the planet.)

Psychological differences are even harder to guess. Consider the differences between human civilizations—and I'm not talking about minor differences like language. South American civilizations had an entirely different perception of time than the European explorers who ran over them. There are many eastern philosophies that see everything in nature as cyclic, while most westerners view the universe as linear. 

I like the idea of different factions within the alien community. All too many sci-fi productions stamp all their aliens out of the same mold—they all look the same, they think the same, etc.


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## Bowler1 (Apr 27, 2012)

One of the fun bit about SciFi is creating aliens. So far my top two, a Killer Bird species and a Dog/Kangaroo cross. I have others but not as well developed yet. I nearly always have the aliens with different factions and the humans in the middle trying to figure out the local politics. Of course aliens would have different views and may even come to blows over these views, we do all the time. I do place human motivations on my aliens, simply because it is what I understand hence I can write up these motivations and weave my plot.


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## Vertigo (Apr 27, 2012)

Metryq, I can see both arguments for similiar and dissimilar aliens but I personally swing in favour of similiar rather than dissimilar. I actually think when you look closely at life on Earth, whilst there is huge diversity on the surface, underneath that diversity there are really only a handful of fundementally different 'types' of life. Like Insect, mammal, reptile etc. Sure there are lots of different types, sizes and shapes of mammal but inside they all work in pretty much the same way. However that said, we do only have the one sample planet to extrapolate from so I'm certainly not denying other possibilities. Though the absence of life anywhere else in the solar system is a rather telling point on life's likes and dislikes. Yes we might yet find some but I don't think it will be what we would call higher order life.

I like to think I keep an open mind but, based on the current evidence (and after all that is all we can do in science), I suspect similarities are more likely than dissimilarities.

Of course as Metryq says that are differences in thinking between different social groups of humans. But really those differences are still on very much on the surface. When it comes right down to fundamental motivators like love, hate, hunger, lust etc. I think you'll find we're all pretty similar.


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## Bowler1 (Apr 27, 2012)

Motivators like love, hate, hunger, lust etc. I think you’ll find are all closely linked to survival of the species. Metryg is correct in pointing out that aliens may have views so different to our that we may never understand each other but it would make plot and storyline difficult. So I’m taking the easy route for now as I have enough to get on with just polishing up my writing style.

When it comes to life out there, I think life will be reasonably common. My view is intelligent life will be rare and again I will use earth as the best example. We have popped up recently and we are an intelligent fluke of evolution that could have occurred earlier - a clever dinosaur type! But there have been millions of years and even a number of extinctions where life restarted without an intelligent species taking over. What does this tell me, a big brain is rare and there must be a good reason for this in evolution. So lucky for me this theory of mine will leave life giving planets available for human expansion which is nice. It will also give me aliens to play with. Levels of technology are a different question and this is where the SciFi comes in. Our spaceships will be the Wright brothers and the aliens will be whizzing around in the Euro Fighter. Some aliens will be happy to see us and some won’t and that could be different views from the same species. So its quick draw on the ray guns and blast my way out of trouble.


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## Vertigo (Apr 27, 2012)

Pretty comparable viewpoint there Bowler. And besides, never mind what I actually expect, it's fun coming up with weird and wonderful aliens. Just take Neal Asher's Spatterjay flora and fauna - imaginative doesn't really cover it. But he has worked out valid evolutionary backgrounds for all of them.


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## Bowler1 (Apr 27, 2012)

I have read that one it was out there like all the other stories he comes up with. I think I'll stick with my easy aliens for now and work on my writing. Everything was, in my mind at least, going so well until I joined Chrons. Now I know I have a bit of work to do! The good news is that I have discovered my imagination needs little improving on I just have to channel that beast.


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## Metryq (Jun 2, 2012)

Orbit detector with no windows: a Sagnac interferometer.

Michelson-Morley Experiment AAAS/NPA Conference Presentation  Holy Einstein, Batman!


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## Vertigo (Jun 2, 2012)

Interesting stuff Metryq, though possibly a little too complex for my immediate purposes.


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## Metryq (Jun 3, 2012)

Oh, come on! You mean none of the kids have a laser pointer for teasing the ship's cat? You could call the story "Fringe Science."


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## Vertigo (Jun 3, 2012)

Heh he!


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