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Colin Robinson
2012-Sep-25, 01:26 AM
Could cultural distance make interstellar messaging unworkable?

By "interstellar messaging", I mean use of a medium such as radio. I don't mean crewed or robotic missions.

SETI advocates, such as Frank Drake and Carl Sagan, have suggested that mathematics could serve as a bridge between worlds. Others have raised doubts... The ideas that "they are too alien" or "their mathematics are different" appear on standard lists of possible approaches to the Fermi Paradox. (See Wikipedia page Fermi Paradox (http://en.wikipedia.org/wiki/Fermi%27s_paradox), and also the University of Oregon page Fermi Paradox (http://abyss.uoregon.edu/~js/cosmo/lectures/lec28.html))

Please consider:

1. The difference between the mathematics of ancient Greece (say, around the time of Euclid) and the world today.
2. The possible difference in mathematical concepts between ourselves and interstellar neighbors.

The ancient Greeks were mathematically minded and intellectually adventurous. Many of their mathematical concepts are still current — they knew about prime numbers for example. However, they used a system of numerals similar to the Roman numerals we still use occasionally today: a decimal system without place value or a symbol for zero.

What if a bunch of ancient Greeks mathematicians had been shown a message like Frank Drake's Arecibo message?

The Arecibo message was

* intended to be as comprehensible as possible to intelligent beings anywhere,
* based on prime numbers and the binary system.

After all, the binary system does use place value, and it does use the zero... The fact that it isn't decimal would have made it all the more foreign to the ancient mathematicians... So I think Euclid and company would have found the Arecibo message an unsolvable riddle.

If we did get a message from extraterrestrials (even if they were very like us, and only a few thousand years more advanced), perhaps we would be in the same position as ancient Greeks trying to read the Arecibo thing?

OK. So if the extraterrestrials' maths are different, and their messages are incomprehensible, then where are those incomprehensible messages? (This point is from the University of Oregon page Fermi Paradox (http://abyss.uoregon.edu/~js/cosmo/lectures/lec28.html))

Well, if interstellar messaging is unworkable, our more-advanced neighbors presumably know it is unworkable... If they liked the idea, they may have tried the experiment earlier in their history, and they found that it just doesn't work... Why would you keep sending out messages that you know are not going to be understood?

Noclevername
2012-Sep-25, 02:06 AM
Well, if interstellar messaging is unworkable, our more-advanced neighbors presumably know it is unworkable... If they liked the idea, they may have tried the experiment earlier in their history, and they found that it just doesn't work... Why would you keep sending out messages that you know are not going to be understood?

While differences in communication, mathematics, etc. could indeed make messages incomprehensible, I think they might still send messages, in hopes that someone out there will develop the capacity to interpret those messages. They may know it's unworkable at present, but if they are more advanced, they might also be more patient.

Besides, even getting an incomprehensible message is still getting a message, it means there's someone out there, someone who understands the basic concept of communication with alien intelligence.

JCoyote
2012-Sep-25, 02:16 AM
I think though the concept of zero is not inherent to being able to understand that a communication is binary in nature and working from there. Once they realize it is two values alternating back and forth... a lot can be figured out from there.

ravens_cry
2012-Sep-25, 03:25 AM
Once each side realizes both are trying to communicate, they can seek to cobble together a pidgin both understand.

iquestor
2012-Sep-25, 12:01 PM
Please consider:

1. The difference between the mathematics of ancient Greece (say, around the time of Euclid) and the world today.
2. The possible difference in mathematical concepts between ourselves and interstellar neighbors.

The ancient Greeks were mathematically minded and intellectually adventurous. Many of their mathematical concepts are still current they knew about prime numbers for example. However, they used a system of numerals similar to the Roman numerals we still use occasionally today: a decimal system without place value or a symbol for zero.

What if a bunch of ancient Greeks mathematicians had been shown a message like Frank Drake's Arecibo message?

The Arecibo message was

* intended to be as comprehensible as possible to intelligent beings anywhere,
* based on prime numbers and the binary system.

my feeling is that any civilization who has the capacity to acheive radio astronomy technology will have the Maths necessary to understand most, if not all communications which are soley based on Math.

the reason math is used is because it is universal and the laws immutable.

Any serious message to unknown alien recipients will teach the recipient how to decode it using universal math laws, so it stands to reason it could be decoded by a culture who had a basic grasp of Mathematical laws. Ancient Greeks would have had no way to receive the message having not acheived Radio Astronomy, and therefore would not be a great candidate. However they might very well have been able to glean something from it and eventually break it. You dont need to understand 0 to understand Binary.

The only exclusion I could think to this would be EM Creatures (ala Gregory Beneford, Galactic Center series) who had the natural capacity to receive and send such signals. (However those creatures had genetically modified themselves to be that way in order to hide from evil machines. )

Colin Robinson
2012-Sep-25, 12:32 PM
While differences in communication, mathematics, etc. could indeed make messages incomprehensible, I think they might still send messages, in hopes that someone out there will develop the capacity to interpret those messages. They may know it's unworkable at present, but if they are more advanced, they might also be more patient.

Besides, even getting an incomprehensible message is still getting a message, it means there's someone out there, someone who understands the basic concept of communication with alien intelligence.

A message to Earth from extraterrestrials would certainly be big news, even if we couldn't decipher it. There might be a degree of alarm here on Earth, as well as elation -- until we did decipher it, we wouldn't know whether the content was something like "hail, fellows well met" or "this is your final warning...".

Aleksandr Zaitsev, the Russian exponent of METI, thinks we should send out messages, not just in the hope of getting a reply, but to offer interstellar neighbors the gift of knowing they are not alone. It is certainly conceivable that there are beings elsewhere who would like to offer a similar gift to us.

On the other hand, even if they were somewhat altruistically inclined, they might see no need to do such a thing.

Perhaps they themselves came to the conclusion that they are "not alone" just a few decades after they first discovered exo-planets (i.e. planets beyond their own solar system). They came to that conclusion not by receiving a radio message, but by some other method, e.g. spectroscopic study of planetary atmospheres. They might expect that we earthlings are likely to make a similar discovery in a similar way, if we haven't already done so. In which case, why should they send us a radio message that would be not only undecipherable, but also unnecessary, and potentially alarming too?

Colin Robinson
2012-Sep-25, 01:12 PM
I think though the concept of zero is not inherent to being able to understand that a communication is binary in nature and working from there. Once they realize it is two values alternating back and forth... a lot can be figured out from there.

The fact that a signal consisted of two alternating values would certainly mean a lot to someone whose education involved Boolean algebra, logic gates etc. But neither Boolean algebra nor logic gates were known to the ancient Greeks.

So what would a signal consisting of two alternating values have meant to them?

I can think think of a couple of (approximately) two-state phenomena they would have known about: the rhythm of a drum, the beating of a heart. Perhaps they might have interpreted the Arecibo message as an instruction to a drummer, or as a doctor's record of a patient's irregular heart-beat?

mike alexander
2012-Sep-25, 01:17 PM
All else aside, I just love the idea of interstellar drums.

Colin Robinson
2012-Sep-25, 01:20 PM
Once each side realizes both are trying to communicate, they can seek to cobble together a pidgin both understand.

Haven't pidgins hitherto been cobbled together by people interacting face to face?

Would it really be feasible to construct a pidgin when

* the two sides trying to communicate are not face to face, but light-years away from each other
* neither side has prior knowledge even of what sort of face the other has -- what sort of sense organs?

mike alexander
2012-Sep-25, 01:28 PM
This is why it's such an endless source of fun for SF writers.

Colin Robinson
2012-Sep-25, 01:42 PM
my feeling is that any civilization who has the capacity to acheive radio astronomy technology will have the Maths necessary to understand most, if not all communications which are soley based on Math.

the reason math is used is because it is universal and the laws immutable.

Maths in itself may be universal and immutable. But don't cultures differ in how much they know about various aspects of maths, and in how they express what they know?

Does our culture now know all there is to know? Or is it possible that another culture on another world would know things about maths that we don't know? Things that might seem as basic to them as the zero numeral seems to us?


Ancient Greeks would have had no way to receive the message having not acheived Radio Astronomy, and therefore would not be a great candidate. However they might very well have been able to glean something from it and eventually break it. You dont need to understand 0 to understand Binary.

Don't you?

In Attic numerals,
I means one
II means two
III means three
IIII means four

In the binary system
1 means one
10 means two
11 means three
100 means four

How would you understand that without understanding what is meant by "0"?

Strange
2012-Sep-25, 02:13 PM
Maths in itself may be universal and immutable. But don't cultures differ in how much they know about various aspects of maths, and in how they express what they know?

There was an interesting point made in a debate on whether mathematics is invented or discovered; if there were intelligent aliens formed of fluids (or energy, to be really SF about it) then the basics of their "arithmetic" might correspond to quite advanced math for us (differential equations, fluid dynamics) while it might take some genius of abstract thought to come up with "integers" or "number theory". However, the underlying math would still be the same ...

Strange
2012-Sep-25, 02:21 PM
Haven't pidgins hitherto been cobbled together by people interacting face to face?

Common underlying linguistic structures are probably important to. Pidgins have some universal features (and share some with "baby talk" or motherese) which may imply that they build on common mental structures. If aliens had totally different ways of thinking then it may be almost impossible to develop a pidgin. It might be necessary to invent an artificial language that can be used by both side - being equally unnatural to both.

Paul Wally
2012-Sep-25, 02:26 PM
The fact that a signal consisted of two alternating values would certainly mean a lot to someone whose education involved Boolean algebra, logic gates etc. But neither Boolean algebra nor logic gates were known to the ancient Greeks.



The Greeks did however have certain binary concepts or dichotomies e.g. true/false, being/not being, atoms/void etc. The Boolean algebra only made explicit what has always been present in our thinking, that's why logic used to be called "the laws of thought".



So what would a signal consisting of two alternating values have meant to them?


A signal of alternating values would mean nothing to them without a key (primer) for decoding it. A one could denote a true statement and zero a false or contradictory statement. The problem is to design the key such that the recipient could find the symbols for true and false. See the movie Contact, the part just after Ellie's meeting with S.R. Hadden:

2 + 3 = 4 = false
**|***|****|()

2 + 3 = 5 = true
**|***|*****|O

So it seems, the ability to recognize patterns and the notions of true and false are required of the receiver of the message.

iquestor
2012-Sep-25, 03:39 PM
Maths in itself may be universal and immutable. But don't cultures differ in how much they know about various aspects of maths, and in how they express what they know?

Does our culture now know all there is to know? Or is it possible that another culture on another world would know things about maths that we don't know? Things that might seem as basic to them as the zero numeral seems to us?

Yes cultures differ in their knowledge. My point is that in order to receive the message, the culture would have to had achieved Radio Astronomy, and that achievement would almost certainly taught them the Maths needed to have a common discourse with the senders. In other words, because they have the technology to receive the message may guarantee they have enough skill to at least recognize the message is based on math, and go through it like a primer to decode it, even if they have to learn something new.




Don't you?

In Attic numerals,
I means one
II means two
III means three
IIII means four

In the binary system
1 means one
10 means two
11 means three
100 means four

How would you understand that without understanding what is meant by "0"?

what I meant was that much can be gleaned by recognizing that a signal has two states. 0 is just what we call OFF, FALSE, or DOWN. The Greeks may not have had the concept of 0 but I assume they would recognize TRUE/FALSE or ON/ OFF or DEAD/ALIVE from their own experiences. they would understand something having two states and then should be Able to grasp at least the concept of Binary.

edit: Binary states are different than a binary number system. I would add that if they have enough basics the message itself could teach them. but if they know enough to build a radio telescope, my bet is they understand binary, because its the most efficient way and (I think) likely path to technology. the same reason bee's honeycombs are hexagons. its the most efficient way to build their homes with the least amount of labor intensive wax.

Colin Robinson
2012-Sep-25, 09:58 PM
Common underlying linguistic structures are probably important to. Pidgins have some universal features (and share some with "baby talk" or motherese) which may imply that they build on common mental structures. If aliens had totally different ways of thinking then it may be almost impossible to develop a pidgin. It might be necessary to invent an artificial language that can be used by both side - being equally unnatural to both.

I think there are 3 possibilities to consider here.

1.The possibility that the humans and the aliens could develop a shared language by exchange of radio signals between solar systems.
2.The possibility that the aliens' ways of thinking are so different from ours, that it will not be possible to develop a shared language at all.
3.The possibility that a shared language will indeed be developed, but not until one side sends a space mission to the solar system of the other side.

Perhaps a radio message, in itself, would be like a puzzle with too few clues. But if humans and aliens could observe each other directly from a comparatively short distance, they would have many more clues to work with.

Colin Robinson
2012-Sep-25, 10:23 PM
The Greeks did however have certain binary concepts or dichotomies e.g. true/false, being/not being, atoms/void etc. The Boolean algebra only made explicit what has always been present in our thinking, that's why logic used to be called "the laws of thought".

Yes, I agree. Modern symbolic logic is clearly indebted to Aristotle's logic. But does that mean Aristotle could have understood a message consisting of two alternating symbols only, e.g. the Arecibo message expressed as a string of ones and zeros?


A signal of alternating values would mean nothing to them without a key (primer) for decoding it.

If the primer is within the signal, how could they use it unless they had some idea of the coding system in the first place?



A one could denote a true statement and zero a false or contradictory statement. The problem is to design the key such that the recipient could find the symbols for true and false. See the movie Contact, the part just after Ellie's meeting with S.R. Hadden:

2 + 3 = 4 = false
**|***|****|()

2 + 3 = 5 = true
**|***|*****|O

So it seems, the ability to recognize patterns and the notions of true and false are required of the receiver of the message.

That would have been based on Hans Freudenthal's proposal "Lincos" (http://en.wikipedia.org/wiki/Lincos_(language))...

Jens
2012-Sep-26, 05:18 AM
I find it hard to imagine how communication could be initiated. It would be possible to send a sort of 0-1-0-1 signal, for example, and math concepts might be transmissible, but how could you possibly initiate the conversation that you really wanted, like how to ask a question? Between humans, it's easy because you can start by things like pointing to yourself, saying your name, then pointing to the other person and being silent. I don't see how you can indicate to the other what you are trying to do.

Jens
2012-Sep-26, 05:21 AM
Could cultural distance make interstellar messaging unworkable?


So in other words, I wonder if the distance itself wouldn't be a problem. If there happened to be an identical me on a solar system several light years away, so we could exchange messages every couple of years, I really wonder if I'd be able to communicate with myself, in the absence of any predecided code. I probably could get away with it by sending pulses that are like - for A, -- for B, but that presupposes a common language and alphabet.

Colin Robinson
2012-Sep-26, 06:26 AM
So in other words, I wonder if the distance itself wouldn't be a problem. If there happened to be an identical me on a solar system several light years away, so we could exchange messages every couple of years, I really wonder if I'd be able to communicate with myself, in the absence of any predecided code. I probably could get away with it by sending pulses that are like - for A, -- for B, but that presupposes a common language and alphabet.

Methods used in the Arecibo message, the Pioneer plaque, and Lincos don't rely on a common alphabet or language, they rely on mathematical and scientific principles, and on line drawings.

They would probably work very well for communicating with the mathematicians and scientists of an identical human species at an identical stage of intellectual history.

The question is whether they would work for a non-identical species at a different stage of its history?

Jens
2012-Sep-26, 06:43 AM
Methods used in the Arecibo message, the Pioneer plaque, and Lincos don't rely on a common alphabet or language, they rely on mathematical and scientific principles, and on line drawings.

But the OP was talking about interstellar messages, so I assume no space ship and no line drawings. Just some kind of pulsed signal.

Colin Robinson
2012-Sep-26, 06:59 AM
But the OP was talking about interstellar messages, so I assume no space ship and no line drawings. Just some kind of pulsed signal.

The Arecibo message used a pulsed signal to generate line drawings.

The signal consisted of 1679 bits. The number 1679 has only 2 prime factors, 23 and 73. The idea was that a mathematically-minded recipient would try arranging the bits in a rectangle of 73 rows and 23 columns. Once that is done, the line drawings can be seen...

See the Wikipedia page "Arecibo Message" (http://en.wikipedia.org/wiki/Arecibo_message).

mike alexander
2012-Sep-26, 08:36 PM
Could be funky if you default to polar coordinates.

Gomar
2012-Sep-27, 01:44 AM
The whole point is not if you do understand 1+1=2, but rather that humans did receive an alien
signal. That's the proof we need of alien existence; not in understanding what the message says.

The message itself is irrelevant to the fact that someone in space sent it. If to us specifically great,
if out into space and we caught it also fine. Is it really important to read the message? nope.
For it might be the cure for cancer, or blue prints for an space ship(Contact), or it might be a recipe
to cook man(Twilight Zone).

Ifcourse, we cant or wont respond, and given vast distances those aliens might be extinct anyway.

Colin Robinson
2012-Sep-27, 08:15 AM
The whole point is not if you do understand 1+1=2, but rather that humans did receive an alien
signal. That's the proof we need of alien existence; not in understanding what the message says.

The message itself is irrelevant to the fact that someone in space sent it. If to us specifically great,
if out into space and we caught it also fine. Is it really important to read the message? nope.
For it might be the cure for cancer, or blue prints for an space ship(Contact), or it might be a recipe
to cook man(Twilight Zone).

Or it might be a serious warning of some sort, like the message of the Llorn in the final chapter of Edmond Hamilton's "The Haunted Stars".


Ifcourse, we cant or wont respond, and given vast distances those aliens might be extinct anyway.

With due respect to Stephen Hawkings, I would think we should respond, at least if the message demonstrates that they already know we are here.

E.g. The scenario in Contact (it's the novel I'm familiar with, but I assume the film was the same), where the first thing that we notice is that the aliens have received an Earth TV signal and broadcast it back to us.

If there was something like that, even if we couldn't understand anything else in the message, at least we wouldn't have to worry that sending a reply would reveal our location to them, because they would already have our location.

In that case, would we wish to offend a highly advanced civilization by saying nothing in reply?

I'd suggest that at least we would want to say something like: "Dear Advanced Civilization, We have received your message, and are trying to understand it, but so far without success. Would you care to repeat what you've said in a different form?"

Jens
2012-Sep-28, 04:28 AM
I'd suggest that at least we would want to say something like: "Dear Advanced Civilization, We have received your message, and are trying to understand it, but so far without success. Would you care to repeat what you've said in a different form?"

Thanks for the info about the Arecibo message, and I understand that some information might be transmitted. But what do you use to convey a concept like "dear" or "advanced"? Those things like fairly abstract, and I can't really think of a way to transmit. Would you use a picture? And how would you convey you are trying to understand it?

Colin Robinson
2012-Sep-28, 09:38 AM
Thanks for the info about the Arecibo message, and I understand that some information might be transmitted. But what do you use to convey a concept like "dear" or "advanced"? Those things like fairly abstract, and I can't really think of a way to transmit. Would you use a picture? And how would you convey you are trying to understand it?

Look, I agree that sending any sort of comprehensible message would be difficult, and perhaps impossible. That is exactly the point I raised in the opening post of this thread.

Hans Freudenthal's Lincos is quite a detailed proposed method of conveying all sorts of ideas by starting with very basic mathematical concepts like counting, adding, subtracting. These concepts are presented in the form of a series of examples, expressed as sequences of beeps. In a later stage of the transmission, there are simple dialogues, where one speaker asks a mathematic question and the other answers it, and the first speaker makes a comment like "true", "false", "good answer", "not so good answer" etc. If the recipient understands the maths, the idea is they will understand the comments and so steadily learn more terminology.

There is a page about Lincos in Wikipedia (http://en.wikipedia.org/wiki/Lincos_(artificial_language)).

You could attempt to use a method like that to define terms such as "advanced", by using more advanced forms of mathematics as an example.

Whether it would work in practice, I don't know... No-one has actually tried out Lincos on an extraterrestrial audience...

If we did received an incomprehensible message, and decided to acknowledge it, then any signal which quoted back part or all of the original message should at least tell them we had received their transmission...

And if we added further content of our own, even if incomprehensible to them, it might persuade them that we at least understood the concept of dialogue and were willing to take part in a dialogue if we could.

swampyankee
2012-Sep-28, 10:09 AM
I think that communications about math, science, and technology are the easy bits, as these will all develop from physical principles that are universal, e.g., that any species that develops radio will figure out relativity, quantum mechanics, and -- almost certainly -- digital computing.

Paul Wally
2012-Sep-28, 02:27 PM
Communication doesn't have to be in the form of a language. It can also take the form of images or even music. We could send images of the Earth and life on Earth then hope whoever receives it will send back some images of their home planet, i.e. we should expect reciprocal behaviour. Maybe the best way to ask for something is to give something and then to expect a similar response.

Noclevername
2012-Sep-28, 02:30 PM
Communication doesn't have to be in the form of a language. It can also take the form of images or even music. We could send images of the Earth and life on Earth then hope whoever receives it will send back some images of their home planet, i.e. we should expect reciprocal behaviour. Maybe the best way to ask for something is to give something and then to expect a similar response.

Figuring out our TV rastering system might not be as easy as recognizing prime numbers or the like.

Noclevername
2012-Sep-28, 02:35 PM
I think that communications about math, science, and technology are the easy bits, as these will all develop from physical principles that are universal, e.g., that any species that develops radio will figure out relativity, quantum mechanics, and -- almost certainly -- digital computing.

Unless they have biological radio and just bred a related species into amplifiers. (playing devil's advocate here, I think interstellar transmission won't work that way, it's too energy-intensive for biology-- unless it's a continent sized colony organism with a high-efficiency selenium-based photosynthesis. :evil:)

Paul Wally
2012-Sep-28, 03:45 PM
Figuring out our TV rastering system might not be as easy as recognizing prime numbers or the like.

Maybe there's a way to do it differently; some way to send intrinsically two-dimensional information. Mike's polar coordinates seem like a more natural system, no left-right and top-bottom conventions.

Grey
2012-Sep-28, 04:37 PM
Maybe there's a way to do it differently; some way to send intrinsically two-dimensional information. Mike's polar coordinates seem like a more natural system, no left-right and top-bottom conventions.Actually, I think that the Arecibo message trick is a pretty good one. If you send a number of bits equal to a product of two primes (or better yet, the square of a prime, so they can't try to split it up in the wrong direction) seems likely to encourage someone to arrange the bits in an n x n array. If I wanted to add an extra clue, I'd take a page from Contact and simultaneously send a sequence of prime numbers (on a nearby channel), stopping at the one I used.

"Why do they keep broadcasting a list of prime numbers up to 97?"

"I don't know. Maybe they like prime numbers?"

"Hey, the signal on the other channel has 9,409 pulses in it. That's 97 times 97! That can't be just a coincidence."

Colin Robinson
2012-Sep-29, 05:48 AM
Actually, I think that the Arecibo message trick is a pretty good one. If you send a number of bits equal to a product of two primes (or better yet, the square of a prime, so they can't try to split it up in the wrong direction) seems likely to encourage someone to arrange the bits in an n x n array. If I wanted to add an extra clue, I'd take a page from Contact and simultaneously send a sequence of prime numbers (on a nearby channel), stopping at the one I used.

"Why do they keep broadcasting a list of prime numbers up to 97?"

"I don't know. Maybe they like prime numbers?"

"Hey, the signal on the other channel has 9,409 pulses in it. That's 97 times 97! That can't be just a coincidence."

So far, so good...

But a structure of 97 times 97 pulses would be just as consistent with a polar coordinate system of 97 concentric circles and 97 radial divisions, as with the sort of system used for the Arecibo message...

Strange
2012-Sep-29, 09:26 AM
So far, so good...

But a structure of 97 times 97 pulses would be just as consistent with a polar coordinate system of 97 concentric circles and 97 radial divisions, as with the sort of system used for the Arecibo message...

So you would try both. And any others you could think of...

Colin Robinson
2012-Sep-29, 11:22 AM
So you would try both. And any others you could think of...

The question is whether two different civilizations, who not only have different histories but different bodies and different senses, would think of the same range of ways of try...

Jens
2012-Sep-29, 11:58 AM
Figuring out our TV rastering system might not be as easy as recognizing prime numbers or the like.

But I think the point of the Arecibo message is that you send it in digital form in a prime x prime grid, so that the person on the other hand might figure that out. I don't know if it would work, but it's not TV rastering.

Paul Wally
2012-Sep-29, 12:42 PM
So far, so good...

But a structure of 97 times 97 pulses would be just as consistent with a polar coordinate system of 97 concentric circles and 97 radial divisions, as with the sort of system used for the Arecibo message...

What I had in mind is to use intrinsic properties of the physical medium to coordinate the information. For example if a higher frequency signal could vary together with some other lower frequency oscillation. I'm thinking of slowly rotating the polarity of the EM wave or perhaps making use of harmonics. Now that I thought a little more about this, I think this should actually be cylindrical coordinates and not polar coordinates. Such a signal would produce a cylinder or helix of information, which is two-dimensional when rolled open.

I think the general idea, with the prime numbers and so on, is to put the information in the form of mathematical structure, i.e. the mathematical structure of the message is the message. So, either they "see" the mathematical structure or they don't, but it's not a matter of interpretation or sense organs.

ravens_cry
2012-Sep-29, 12:44 PM
I think that communications about math, science, and technology are the easy bits, as these will all develop from physical principles that are universal, e.g., that any species that develops radio will figure out relativity, quantum mechanics, and -- almost certainly -- digital computing.
Well, we did, but we did all that AFTER discovering and inventing radio. Plus, it is my (limited)the discoveries that lead to their the theories creation had little to do with radio. It is also not inconceivable that they could have equivalent theories that explain the phenomena they have observed, but don't match the specific explanations our present theories do.
Imagine, for example, if you thought of darkness as the active component and light was the absence.

Jens
2012-Sep-29, 01:46 PM
I think the general idea, with the prime numbers and so on, is to put the information in the form of mathematical structure, i.e. the mathematical structure of the message is the message. So, either they "see" the mathematical structure or they don't, but it's not a matter of interpretation or sense organs.

Fine, you can use this idea to convey some information. But the question I have, and I think many others have, is, how do you transform this into an actual conversation? It seems like a very tricky problem, because you're not really sure whether the other side is answering a question or whether they're asking a question of their own or just conveying information.

Grey
2012-Sep-29, 07:19 PM
Fine, you can use this idea to convey some information. But the question I have, and I think many others have, is, how do you transform this into an actual conversation? It seems like a very tricky problem, because you're not really sure whether the other side is answering a question or whether they're asking a question of their own or just conveying information.It is a hard problem. But let's say that you've been sending images using the technique I suggested. You can send pictures of people, or buildings, or scientific diagrams, or maybe images of galaxies or nebulae that you know they can see, too. I could imagine a response being for them to take an image that they received, and send it back, but with some simple modification. Assuming you get to that point, you know that they understand your image format, so you could increase the size to allow showing more detail, and start passing images back and forth to try to establish common ground, and introduce terminology. It would be an astonishingly slow way of doing things. But considering that the real bottleneck is not bandwidth, but the long delay before there's a response, there's no reason not to send thousands of images to try to communicate even a simple idea.

Paul Wally
2012-Sep-29, 07:34 PM
Fine, you can use this idea to convey some information. But the question I have, and I think many others have, is, how do you transform this into an actual conversation? It seems like a very tricky problem, because you're not really sure whether the other side is answering a question or whether they're asking a question of their own or just conveying information.

I think the problem that you are referring to is on a different level; higher-level semantic/ natural language level. I would agree that it's quite a complex problem, but there will have to be some consensus on the lower level communications, i.e. the physical medium, the mathematical etc. I think Colin's concern is whether mathematics itself is relative to culture, which would make even the lower level communications difficult. I think it comes down to the Constructivist (mental construct/ invention) vs Platonic (discovered) view of mathematics.

If we assume the Platonic view that mathematical truths are universal truths discoverable by any sufficiently intelligent being in the universe, then I guess we will have to find ways to express concepts like "question" mathematically . Perhaps a question can take the form of incomplete information; a "fill in the gaps" type of thing, i.e. one way to ask a question is to explicitly show our ignorance of something and then hope that they're kind enough to fill in the blanks for us. Another idea, is to send something like a mathematical algorithm or function that simulates the communication protocol and contains the notion of "asking a question".

cjameshuff
2012-Oct-05, 10:30 PM
I find it hard to imagine how communication could be initiated. It would be possible to send a sort of 0-1-0-1 signal, for example, and math concepts might be transmissible, but how could you possibly initiate the conversation that you really wanted, like how to ask a question? Between humans, it's easy because you can start by things like pointing to yourself, saying your name, then pointing to the other person and being silent. I don't see how you can indicate to the other what you are trying to do.

Once you have basic mathematics down (and I really think anyone who can receive an interstellar transmission will be sophisticated and flexible enough to find a mapping between a reasonably well-designed message and their own preferred mathematical systems...they're certainly not going to get hung up on binary or zero), you can start describing physical phenomena, and start naming substances and objects described by their physical characteristics and describing the rules of grammar. From there it's just a matter of slowly working your way to more abstract ideas from context, analogy, and repeated patterns, much the way we learn language ourselves.

Certainly not a simple or fast process, but there's no fundamental reason it wouldn't work. And even if they never figure out grammar, just a limited vocabulary of concrete concepts derived from mathematical descriptions of nature would be enough to, for instance, describe the current situation and a hypothetical one in order to propose a trade.

ravens_cry
2012-Oct-06, 12:15 AM
If we are unlucky, maybe they don't have the concept of trade, perhaps everything is taken by force from conquered subordinates.
They still could have a civilisation; a massive pyramid, most conquering likely been largely ritualistic, but still with a very defined, but potentially mobile, pecking order.

cjameshuff
2012-Oct-06, 12:23 AM
If we are unlucky, maybe they don't have the concept of trade, perhaps everything is taken by force from conquered subordinates.
They still could have a civilisation; a massive pyramid, most conquering likely been largely ritualistic, but still with a very defined, but potentially mobile, pecking order.

Conquering's going to be kind of difficult to accomplish over a radio/optical comms link.

Noclevername
2012-Oct-06, 12:26 AM
Shipping tribute across interstellar distances, besides being extremely not cost effective, means they need to give us or let us develop starship technology-- which means we now have a potential relativistic kinetic weapon aimed at their homeworld.

If they come here for pickup, we'll know they're coming and be able to develop defenses-- like dropping rocks in their path. A relativistic vehicle is kind of hard to steer.

ravens_cry
2012-Oct-06, 12:32 AM
Conquering's going to be kind of difficult to accomplish over a radio/optical comms link.
No doubt, but if they don't have trade even as a concept, they aren't going to want to trade with us, no?

cjameshuff
2012-Oct-06, 01:22 AM
No doubt, but if they don't have trade even as a concept, they aren't going to want to trade with us, no?

They're not even going to try talking to us if they can't even conceive of trading information, so what does it matter?

ravens_cry
2012-Oct-06, 01:45 AM
They're not even going to try talking to us if they can't even conceive of trading information, so what does it matter?

They mighg still size up ones opponent, find out information one can, and above all else, try to establish a hierarchy, whether through force or bluster.

Gomar
2012-Oct-14, 02:50 PM
we now have a potential relativistic kinetic weapon aimed at their homeworld.
If they come here for pickup, we'll know they're coming and be able to develop defenses-- like dropping rocks in their path. A relativistic vehicle is kind of hard to steer.

Right. ok. Do you really think humans could defeat or stop an alien invading force that could travel
from their planet to ours within say months? Any force that has that type of tech wont be stopped
by anything. It's like saying the Aztecs or Incas or Mayas who had huge armies could stop
the Europeans from conquering them.
Who knows, maybe humans will be scared by some alien-animal combo who will be thought
of as a god; or the aliens who have been watching humans for hundreds of years will simply send
a false messiah and humans will just submit to alien will.
Best way to dupe humans is to make them believe whatever it is they wish to believe.

cjameshuff
2012-Oct-14, 03:46 PM
Right. ok. Do you really think humans could defeat or stop an alien invading force that could travel
from their planet to ours within say months?

There's nowhere that they could get here from in that time period. And you don't need the ability to travel between stars to mount an effective defense against an interstellar invasion. There's many ways we could make things extremely hazardous for a ship attempting to decelerate into the system, and effectively defending an interstellar craft would be extremely costly, let alone moving enough materiel to take and maintain control of the system.

MaDeR
2012-Oct-14, 07:20 PM
There's nowhere that they could get here from in that time period. And you don't need the ability to travel between stars to mount an effective defense against an interstellar invasion. There's many ways we could make things extremely hazardous for a ship attempting to decelerate into the system, and effectively defending an interstellar craft would be extremely costly, let alone moving enough materiel to take and maintain control of the system.
You watch too much movies where evil aliens are regularly somehow defeated. Taking aside fact there will be never "alien invasion" as depicted in popular culture, tech difference makes, well, DIFFERENCE. You may as well believe sharpened stones and clubs winning against tactical nuclear bomber.

Noclevername
2012-Oct-14, 11:57 PM
You watch too much movies where evil aliens are regularly somehow defeated. Taking aside fact there will be never "alien invasion" as depicted in popular culture, tech difference makes, well, DIFFERENCE. You may as well believe sharpened stones and clubs winning against tactical nuclear bomber.

Or maybe he just reads history, as "primitives" have defeated more "advanced" militiaries throughout human existence.

swampyankee
2012-Oct-15, 02:01 AM
Or maybe he just reads history, as "primitives" have defeated more "advanced" militiaries throughout human existence.

The "primitives" have also been exterminated, like the indigenous Tasmanians, or nearly wiped out, like the Northeastern Indians in the US. I think it was Kipling who said "We have the Maxim gun, and they have not."

cjameshuff
2012-Oct-15, 02:58 AM
We also have a vast advantage in numbers, resources, response time, and position...it's a lot easier to put a vast amount of kinetic weaponry in the way of an incoming starship than it is to send a starship on an interstellar invasion. It's actually possible to achieve some degree of stealth for the defending weapon systems, it's not remotely possible for the starship. The planets are easy targets if you're not concerned with making any use of them, but other infrastructure can be anywhere, and could even be to the point where the off-planet civilization is growing faster than a few warships can destroy bits of it. Once the defending system has any significant presence in space, the energy and mass requirements vastly favor the defender.

Jeff Root
2012-Oct-15, 03:19 AM
If the native Americans had smallpox while the Europeans had
not, then the Europeans probably would not have been able to
survive in the Americas despite their superior technology.

-- Jeff, in Minneapolis

Jeff Root
2012-Oct-15, 03:56 AM
My opinion on this thread's question is that anyone who is
able to receive a halfway-decently-crafted message from
us will be able to correctly interpret it almost immediately.
And any message we receive will be correctly interpreted
almost immediately, once we get the start of the message.

Unlike what happens in the movie 'Contact', the first signals
we notice will not be the beginning of their message, but
somewhere in the middle. None of it will make any sense
until the beginning is repeated. Then any high school kid
will be able to figure out what that beginning section means.

To me, the idea that we would have a hard time establishing
a common language is silly. They will be at least as intelligent
as us and will definitely have more experience in making contact.
At a minimum, they will have experience with being contacted,
and will have been instructed by others who have experience
in making contact.

Movies will be absolutely essential to establishing a common
language. Without movies, communication will be very limited.
With movies there will hardly be any limits. The first signals
we detect from extraterrestrial civilization will probably be
movies, since they will occupy the majority of the bandwidth.

-- Jeff, in Minneapolis

swampyankee
2012-Oct-15, 11:10 AM
If the native Americans had smallpox while the Europeans had
not, then the Europeans probably would not have been able to
survive in the Americas despite their superior technology.

-- Jeff, in Minneapolis

Don't forget malaria.

In most of British North America, the Europeans needed active assistance of the Native Americans to survive. Also, the Native Americans were neither homogeneous nor living in an Rousseauvian paradise; there were significant, even very violent, conflicts between different Native American nations. Some nations allied with the Europeans against others -- just read any of the histories of the wars between settlers and Native Americans, like King Phillip's War in New England. Similarly, the European imperialists in India and Africa took advantage of divisions between indigenous groups.

I can easily imagine various countries and groups allying with invading aliens to settle scores and improve their relative position. Of course, this would require the aliens to be sufficiently close to us to understand how to take advantage of these divisions. Those hive minds couldn't do it ;)

MaDeR
2012-Oct-15, 01:37 PM
It's actually possible to achieve some degree of stealth for the defending weapon systems, it's not remotely possible for the starship.
Why starship would have to hide? I do not see any way to defend/defeat with current tech someone capable to travel between stars and sending warships with malicious intent. Just do carpet nuclear (aliens do not even need antimatter or other fancy-schmancy weapons) bombing of every larger city from orbit and be done with humanity. Or terawat lasers, if you are concerned with little details like state of Earth biosphere after[1].


defending weapon systems,
What "defense"? Please tell me more about those mysterious "defense weapon system" that we supposedly have against alien warships.

[1] Assumption: they invade for evilulz or they are insane (reasons for invasion are irrational, for example religious cursade against rest or universe or something equally loony). I do not see any sane (economical, physical, ethical etc) reason to do invasion as depicted in SF.

Strange
2012-Oct-15, 01:44 PM
To me, the idea that we would have a hard time establishing
a common language is silly.

I think you underestimate the extent to which human languages are based on the underlying mental structures. It may be that much of that would be common among other advanced species. An advanced civilization probably couldn't develop without long-term memory of some sort, for example. But there may be other significant difference like that make communication non-trivial.


Movies will be absolutely essential to establishing a common language.

What if they don't have a visual system? Would we be able to make sense of a "movie" made by a species that relied on echo-location or the sensing of electric fields or just touch to explore their surroundings?

Noclevername
2012-Oct-15, 03:04 PM
Why starship would have to hide? I do not see any way to defend/defeat with current tech someone capable to travel between stars and sending warships with malicious intent. Just do carpet nuclear (aliens do not even need antimatter or other fancy-schmancy weapons) bombing of every larger city from orbit and be done with humanity. Or terawat lasers, if you are concerned with little details like state of Earth biosphere after[1].


The U.S. have had nuclear bombs during our last several wars, but have not used them in combat since 1945. There are other considerations besides technology involved in warfare.

Besides, if the ET's just wanted to wipe us out and didn't care about the state of Earth afterwards, they wouldn't bother to come in person or use nukes, just send a relativistic kinetic weapon and blast the whole planet at once.

If they come here in starships they will have to decelerate, which means we will see them coming years away and have time to develop defenses-- a relativistic ship is very vulnerable.

Jeff Root
2012-Oct-15, 04:49 PM
I think you underestimate the extent to which human languages
are based on the underlying mental structures. It may be that
much of that would be common among other advanced species.
An advanced civilization probably couldn't develop without
long-term memory of some sort, for example. But there may be
other significant difference like that make communication
non-trivial.
No, I'm saying exactly that the idea that language in general
depends on specific brain organization is what is silly. I'm
asserting that minds which function in completely different
ways can communicate with each other via language. Not that
understanding one another would be trivial, but that it would
be much less difficult than the original post of this thread
asserts it might be.

Ideas such as "orange" or "bitter" will take some effort to
communicate, and might never be communicated perfectly, but
I say that an enormous range of ideas can be communicated
quite readily via language even if pictures and movies are
the primary means of establishing that language.



What if they don't have a visual system?
Then they wouldn't contact us. They need to be able to see in
order to make things like radio transmitters and star charts.

-- Jeff, in Minneapolis

cjameshuff
2012-Oct-15, 10:29 PM
Why starship would have to hide? I do not see any way to defend/defeat with current tech someone capable to travel between stars and sending warships with malicious intent.

That's your own fault, read more completely next time. Once again, decelerating starships would be extremely vulnerable to kinetic defenses. Relative velocities are such that collisions with objects that are virtually at a standstill relative to the target system have yields close to or exceeding those of nuclear weapons. Any significant loss of propellant or drive function means they aren't going to be able to stop in the target system. The physics of the situation vastly favors an even moderately prepared defender.



What "defense"? Please tell me more about those mysterious "defense weapon system" that we supposedly have against alien warships.

Leading up to the scenario, we have construction of interstellar communication equipment (itself likely a substantial orbital installation with significant development time), some decades of lightspeed lag just to get both sides talking, some centuries as warships travel to our system (after a launch we stand a good chance of spotting via remote observations), and some more decades of watching them decelerate in. In this time period, which starts out with the knowledge that there is intelligent extraterrestrial life and an attempt being made at contact, you don't think we'll be able to make any efforts at defense?

Noclevername
2012-Oct-15, 10:35 PM
Then they wouldn't contact us. They need to be able to see in
order to make things like radio transmitters and star charts.

Not a given. What connection is there between eyes and inventing radio transmitters?

If they have radio technology developed without sight, they would become aware of stars as radio sources, and so would develop star charts anyway.

cjameshuff
2012-Oct-15, 11:27 PM
Their sense of vision might also be substantially different. It needn't be something that maps well onto a sequence of static 2D image planes of tristimulus values. Plus, video requires rather huge amounts of data.

A better approach would probably be to describe a scenario at a basic level (shapes, materials, and motion), and let them convert it into whatever they find convenient.

MaDeR
2012-Oct-16, 03:16 PM
If they come here in starships they will have to decelerate, which means we will see them coming years away and have time to develop defenses-- a relativistic ship is very vulnerable.
Few years is too short time. Below is answer to guy that thinks we will have few centuries of lead time.


Leading up to the scenario, we have construction of interstellar communication equipment (itself likely a substantial orbital installation with significant development time), some decades of lightspeed lag just to get both sides talking, some centuries as warships travel to our system (after a launch we stand a good chance of spotting via remote observations), and some more decades of watching them decelerate in. In this time period, which starts out with the knowledge that there is intelligent extraterrestrial life and an attempt being made at contact, you don't think we'll be able to make any efforts at defense?
A lot of assumptions here. Sure, if they will play fair and nice by your rules, then yes, we stand theoretical chance, as your aliens are seemingly sufficiently stupid to not think that deccelerating relativistic ship is "sitting duck".
I do not buy it.

Noclevername
2012-Oct-16, 04:52 PM
Few years is too short time. Below is answer to guy that thinks we will have few centuries of lead time.


A lot of assumptions here. Sure, if they will play fair and nice by your rules, then yes, we stand theoretical chance, as your aliens are seemingly sufficiently stupid to not think that deccelerating relativistic ship is "sitting duck".
I do not buy it.

And what could they do about it? Change the laws of physics?

headrush
2012-Oct-16, 04:56 PM
Maybe some-one could help me here.

I'm assuming a relativistic weapon is a device that just has to sit there, big and massive while the enemy smashes into it at a much higher relative speed. But no-one's mentioned any speeds for the incoming vessels yet. There has been mention of starships.

How far away could we see an incoming ship if it was travelling at 0.5 c ?
How would we see it at all ? Presumably it wouldn't be putting on a light show if it was hostile, and we couldn't have seen it launch, we can barely make out planets at those distances.

How far away would it have to decelerate and how long does it take light to travel from "there"?

Sure we'd need defenses, but would we actually have time ?

Noclevername
2012-Oct-16, 05:03 PM
Maybe some-one could help me here.

I'm assuming a relativistic weapon is a device that just has to sit there, big and massive while the enemy smashes into it at a much higher relative speed. But no-one's mentioned any speeds for the incoming vessels yet. There has been mention of starships.

How far away could we see an incoming ship if it was travelling at 0.5 c ?
How would we see it at all ? Presumably it wouldn't be putting on a light show if it was hostile, and we couldn't have seen it launch, we can barely make out planets at those distances.

How far away would it have to decelerate and how long does it take light to travel from "there"?

Sure we'd need defenses, but would we actually have time ?

It depends on a lot of variables, mainly acceleration rates and delta-V, which in turn may be determined by (unpredictable) technology level and by the aliens' biology, if they come in person.

A relativistic weapon would be constantly accelerating until impact, and with no one onboard to limit its acceleration. So it would probably be going so close to lightspeed that its visible image would arrive only a very short time prior to impact. Again, the exact details will vary by how advasnced the propulsion is.

cjameshuff
2012-Oct-16, 05:13 PM
I only assume the defenders aren't totally incompetent, an assumption supported by the fact that they made contact. Yes, an incoming starship can attempt to defend itself, but that can't change the fact that the basic physics of the situation gives an enormous advantage to the defender.

The invading starship's defenses have to be launched across interstellar distances along with propulsion capability for bringing everything to a halt and equipment for making war on arrival. The defenses don't have to accelerate to anything like the starship's maximum velocity, and don't ever need to decelerate, they need only get in the way of the invader.

cjameshuff
2012-Oct-16, 05:47 PM
How far away could we see an incoming ship if it was travelling at 0.5 c ?
How would we see it at all ? Presumably it wouldn't be putting on a light show if it was hostile, and we couldn't have seen it launch, we can barely make out planets at those distances.

If they're not planning on spending tens or hundreds of thousands of years in flight, there's a good chance would see it launch. They might not like the light show they're putting on, but they have little choice in the matter. The energy requirements of interstellar travel are enormous, and if we're to the point that we're trying to communicate with them, we'll have a variety of large and capable radio and optical telescopes observing the system. Deceleration is less energy intensive, as the craft will be far less massive after acceleration, but it will be far closer and directing its drive right at us...impossible to miss for a civilization that has established interstellar communications with the system of origin.

There's too many variables to say exactly how much warning we'd have in terms of observations indicating that an unannounced starship is inbound, but a century is certainly not overly optimistic. And that's ignoring the development in space infrastructure and defense we'd be working on from the time we realize there's another civilization out there.

headrush
2012-Oct-16, 05:49 PM
I only assume the defenders aren't totally incompetent, an assumption supported by the fact that they made contact. Yes, an incoming starship can attempt to defend itself, but that can't change the fact that the basic physics of the situation gives an enormous advantage to the defender.

The invading starship's defenses have to be launched across interstellar distances along with propulsion capability for bringing everything to a halt and equipment for making war on arrival. The defenses don't have to accelerate to anything like the starship's maximum velocity, and don't ever need to decelerate, they need only get in the way of the invader.

This where I'm getting confused. You mention defenses a lot at both ends of the argument. Maybe you could distinguish between them and us more clearly. I'm of the opinion that we wouldn't know they were out there/coming until they were nearly upon us. Hence we would have little time to prepare our defenses. Their defenses are irrelevant until we are in a position to know ...
a) that they're there at all
b) where they are
c) where they're going to be and (d) when.

Because without those pieces of information, we have no need for any defenses.

Have they already said they're coming ? Just dragging the thread back to interstellar messaging.

I've read the whole thread but I didn't see any mention of a situation whereby the aliens would tell us that they were invading, some 5000(*) years before they arrive.

* pick a number.

cjameshuff
2012-Oct-16, 06:54 PM
This where I'm getting confused. You mention defenses a lot at both ends of the argument. Maybe you could distinguish between them and us more clearly.

Come on, there's nothing tricky or subtle here. Starship defenses have to be shipped across interstellar distances and brake into the target system along with the starship, their mass is extremely costly and cuts directly into the payload capacity. System defenses have vastly lower propulsion requirements, they don't have to accelerate nearly as much and don't have to brake at all, and don't need to carry any payload.



I'm of the opinion that we wouldn't know they were out there/coming until they were nearly upon us. Hence we would have little time to prepare our defenses.

If we're trying to talk with them, we know exactly where they are, and they are rather limited in their possible approaches for attack. At that point, we know everything we need to start planning defenses, without even having sent a signal. We'd be putting up instruments to see whatever we can coming from that system, simply because it's another civilization, one close enough to attempt communications with. How would we fail to notice an incoming starship?



I've read the whole thread but I didn't see any mention of a situation whereby the aliens would tell us that they were invading, some 5000(*) years before they arrive.

They don't need to say they're coming (though they'd be far better off doing so, dressing it up as a peaceful mission rather than pretending the ship they launched at our system doesn't exist). If we're trying to talk with them at all, we're looking hard in their direction.

Noclevername
2012-Oct-16, 06:54 PM
This where I'm getting confused. You mention defenses a lot at both ends of the argument. Maybe you could distinguish between them and us more clearly. I'm of the opinion that we wouldn't know they were out there/coming until they were nearly upon us. Hence we would have little time to prepare our defenses. Their defenses are irrelevant until we are in a position to know ...
a) that they're there at all
b) where they are
c) where they're going to be and (d) when.

Because without those pieces of information, we have no need for any defenses.

Have they already said they're coming ? Just dragging the thread back to interstellar messaging.

I've read the whole thread but I didn't see any mention of a situation whereby the aliens would tell us that they were invading, some 5000(*) years before they arrive.

* pick a number.

If we know where they are sending messages from or where we're sending messages to, we know where they would launch from, and no doubt every telescope we have would be pointed towards the source of an alien message or the recipient of one of ours. Any vessel with interstellar capacity would be visible a long way off-- thermodynamics means everything that could propel them that distance fast enough to matter would give off a lot of energy. To get to us from there they'd have to be moving along predictable, mathematically determinable paths.

headrush
2012-Oct-16, 07:32 PM
Come on, there's nothing tricky or subtle here. Starship defenses have to be shipped across interstellar distances and brake into the target system along with the starship, their mass is extremely costly and cuts directly into the payload capacity. System defenses have vastly lower propulsion requirements, they don't have to accelerate nearly as much and don't have to brake at all, and don't need to carry any payload.

I realise this. That is not the issue I was highlighting.


I only assume the defenders aren't totally incompetent ...


Yes, an incoming starship can attempt to defend itself...


but that can't change the fact that the basic physics of the situation gives an enormous advantage to the defender.


The invading starship's defenses have to be launched...

The defenses don't have to accelerate to...

they need only get in the way of the invader

The first quote doesn't make it clear which "defenders" we are discussing.
The 2nd and 3rd quotes appear to be referring to the same "defender".
the 4th refers to the the invaders defenses, but the 5th appears to refer to them too, which jars when you reach the 6th quote.

I can infer to a certain extent, but that was hard to parse.
No matter, you've explained it more clearly, and I am obviously on a different wavelength.
:)

swampyankee
2012-Oct-16, 11:25 PM
And that's ignoring the development in space infrastructure and defense we'd be working on from the time we realize there's another civilization out there.

Optimistic, aren't you? There are a number of countries who would welcome allies who may be willing to help them cut an enemy's throat. For your idea to work, we'd need a great deal of fence-mending to get rid of those sorts of feelings.

cjameshuff
2012-Oct-17, 01:33 AM
Optimistic, aren't you? There are a number of countries who would welcome allies who may be willing to help them cut an enemy's throat. For your idea to work, we'd need a great deal of fence-mending to get rid of those sorts of feelings.

This makes no sense.

What are you thinking, that every little country with a grudge will establish their own independent interstellar communications platform and offer a portion of their enemies' lands in exchange for support? And that interest in space and interstellar defense will then immediately cease due to international ill-will, while everyone and everyone's enemies are talking to the aliens and spying on each others conversations? Or that someone will decide to sell out to the aliens and somehow protect them from the vast field of defensive weaponry they're about to plow into, built and operated by other nations? What are they going to do, shoot all the kinetic weapons down from behind?

swampyankee
2012-Oct-17, 08:01 PM
This makes no sense.

What are you thinking, that every little country with a grudge will establish their own independent interstellar communications platform and offer a portion of their enemies' lands in exchange for support? And that interest in space and interstellar defense will then immediately cease due to international ill-will, while everyone and everyone's enemies are talking to the aliens and spying on each others conversations? Or that someone will decide to sell out to the aliens and somehow protect them from the vast field of defensive weaponry they're about to plow into, built and operated by other nations? What are they going to do, shoot all the kinetic weapons down from behind?

They'll certainly try to establish independent communications, especially if a conquering alien horde is on the way. Say the original message was discovered and decrypted by China. Do you really think that the US, Russia, Japan, France, Germany, etc won't try to establish independent communications? Do you really think any one of them would not try to make a deal for their specific advantage, even (or especially) to the detriment of anybody else?

So, yes, I do think that every country with a grudge will try to do just that. There are certainly historical precedents for very similar actions between terrestrial actors. Not many countries would immediately fall in line and obey when somebody says "we're being attacked by BEM; you have to follow us so we can fight them off." They'll need proof, and part of that proof is likely to include sufficient information to establish an independent communications capability. Everybody knows that the government of <country name redacted> is run by a bunch of arrogant prigs who think they're the best thing since sliced bread, and who lie like rugs.

Noclevername
2012-Oct-18, 12:02 AM
It could be that some Earth cultures have an easier time communicating with the aliens than others. The same might be true of the aliens, assuming they are multicultural.

cjameshuff
2012-Oct-18, 01:09 AM
They'll certainly try to establish independent communications, especially if a conquering alien horde is on the way. Say the original message was discovered and decrypted by China. Do you really think that the US, Russia, Japan, France, Germany, etc won't try to establish independent communications? Do you really think any one of them would not try to make a deal for their specific advantage, even (or especially) to the detriment of anybody else?

So, your position is that they'll all rush to establish their own communications platform in a bid to get extraterrestrial assistance in a strike against their enemies, but none will move a finger to establish any sort of defense from an extraterrestrial power moving to aid their enemies. Is that accurate?



So, yes, I do think that every country with a grudge will try to do just that. There are certainly historical precedents for very similar actions between terrestrial actors. Not many countries would immediately fall in line and obey when somebody says "we're being attacked by BEM; you have to follow us so we can fight them off." They'll need proof, and part of that proof is likely to include sufficient information to establish an independent communications capability. Everybody knows that the government of <country name redacted> is run by a bunch of arrogant prigs who think they're the best thing since sliced bread, and who lie like rugs.

Who needs to prove anything, and why? Are the enemies of the first nation to make contact going to ignore the possibility that their enemies might actually be talking to an extraterrestrial civilization? Are they going to idly sit around as their enemies start rapidly expanding their off-planet capabilities? Are they going to stop kinetic weapons in their tracks through sheer stubborn stupidity? Your argument makes no sense at all.

How, exactly, is the presence of an unfriendly nation on Earth going to keep an incoming starship from smashing to bits in a near-relativistic collision with a kinetic weapon?

lpetrich
2012-Oct-18, 01:18 PM
It seems to me that one may have to send a palimpsest message. A narrow-band announcement signal with broader-band information signals. The info signals would use mathematics and physical science in a language tutorial, because mathematics and physical science are what the senders will share with likely receivers. Thus, one may find counterparts of "Hydrogen is the lightest chemical element" and "Carbon atoms can bond to 1, 2, 3, or 4 atoms. These atoms may also be carbon atoms." in the message.

MaDeR
2012-Oct-18, 02:29 PM
And what could they do about it? Change the laws of physics?
If we really want to have crewed invasion[1], then yeah, I do not see it. They will not invade (as described in SF) in first place. I said at beginning that I doubt there will be any realistic scenario. My discussion was more like "if they still invade us, they would have to be SURE it can be done", somehow avoiding pointed out issues. If they manage to be here in solar system unharmed, we are screwed, period. Sorry if this point was not clear.

[1] As someone else mentioned, uncrewed invasion aka Rods from (Alien) God cannot be defeated with current tech. Try to stop, destroy or change course of relativistic kinetic sabot directed at Earth with sufficient mass to wipe out entire surface biosphere.

Noclevername
2012-Oct-18, 02:38 PM
If they manage to be here in solar system unharmed, we are screwed, period.

Depends on how they get here and what they bring with them, how much warning we get, how good they are at using what they have under combat conditions, whether they come to conquer/enslave/convert or do something else and what methods they use to do so, how unified or dedicated they are in their cause, and a whole host of other factors. Technical advancement alone does not guarantee victory.

cjameshuff
2012-Oct-18, 03:47 PM
If we really want to have crewed invasion[1], then yeah, I do not see it. They will not invade (as described in SF) in first place. I said at beginning that I doubt there will be any realistic scenario. My discussion was more like "if they still invade us, they would have to be SURE it can be done", somehow avoiding pointed out issues. If they manage to be here in solar system unharmed, we are screwed, period. Sorry if this point was not clear.

[1] As someone else mentioned, uncrewed invasion aka Rods from (Alien) God cannot be defeated with current tech. Try to stop, destroy or change course of relativistic kinetic sabot directed at Earth with sufficient mass to wipe out entire surface biosphere.

If they do get into the system intact, things are a lot harder for the locals. Still, if the local civilization has spread substantially off-world (and we are talking about a civilization that has known of at least one other for quite some time, almost certainly several centuries), there will be an extreme disparity in available numbers and resources, enough to compensate for quite a large technological advantage on the part of the invaders.

And yes, there's little that can be done to protect planets from relativistic attacks. However, such attacks are very risky...again, if the local civilization is no longer restricted to the planet by the time the attack reaches them, wrecking the planet won't kill them all but will invite retaliation. Which, again, can't reasonably be defended against. And there's little to gain from such attacks, as there's plenty of other systems around where you don't have to clear out natives and risk getting your own planets bombarded.

caveman1917
2012-Oct-18, 05:30 PM
If we're trying to talk with them, we know exactly where they are, and they are rather limited in their possible approaches for attack. At that point, we know everything we need to start planning defenses, without even having sent a signal. We'd be putting up instruments to see whatever we can coming from that system, simply because it's another civilization, one close enough to attempt communications with. How would we fail to notice an incoming starship?

On the other hand, if we're talking about an alien civilization that has interstellar warships lying around to be launched at us to conquer our planet, we can safely assume that they have also been colonizing the neighbourhood a little. This means that they might come from some completely different place.

cjameshuff
2012-Oct-18, 07:04 PM
On the other hand, if we're talking about an alien civilization that has interstellar warships lying around to be launched at us to conquer our planet, we can safely assume that they have also been colonizing the neighbourhood a little. This means that they might come from some completely different place.

That would help achieve some measure of surprise. However, unless that other system is notably closer, that gives an even longer time for the target to develop space capabilities. In the meantime, having found one extrasolar civilization, we might just think of looking at more stars in the vicinity (more likely, we were doing so before successfully making the first contact). If such things really caught our interest (which is rather implied by us successfully making contact in the first place), it wouldn't be hard to get all of the candidate stars under regular if not continuous observation.

Also, it requires that the inhabitants of one system take on the considerable risk and expense of the attack on behalf of the other. Given the lightspeed lag and expense of interstellar transport, systems A and B are going to be highly independent and likely mainly involved in information trade. A contacts us, has a similar opportunity for information trade with us that B lacks, and then requests that B invest the resources and take on the risk in attacking us, while A gets the full advantage from trading with us. They're not human, they might have some overwhelming motivation that would make them do this, but it doesn't seem terribly likely.

caveman1917
2012-Oct-18, 08:43 PM
That would help achieve some measure of surprise. However, unless that other system is notably closer, that gives an even longer time for the target to develop space capabilities. In the meantime, having found one extrasolar civilization, we might just think of looking at more stars in the vicinity (more likely, we were doing so before successfully making the first contact). If such things really caught our interest (which is rather implied by us successfully making contact in the first place), it wouldn't be hard to get all of the candidate stars under regular if not continuous observation.

Also, it requires that the inhabitants of one system take on the considerable risk and expense of the attack on behalf of the other. Given the lightspeed lag and expense of interstellar transport, systems A and B are going to be highly independent and likely mainly involved in information trade. A contacts us, has a similar opportunity for information trade with us that B lacks, and then requests that B invest the resources and take on the risk in attacking us, while A gets the full advantage from trading with us. They're not human, they might have some overwhelming motivation that would make them do this, but it doesn't seem terribly likely.

There is the other possibility that rather than having the spacefaring civilization be mainly planet-bound with small interstellar traffic that it takes the route of true self-contained space habitats which could for advanced enough species have surface areas rivalling a planet, or at least fleets of them combined adding up to that potential. This would probably be a more realistic scenario anyway. They would not move at relativistic speeds, which would make the delay greater, but it would mean two things. First that while we may have more time to advance, so would they while they are en route, and given any development curve faster than linear would make the technological gap even greater over time. Second that when they arrive they will not be that far behind in resources either, at least in terms of population, and other stuff too given that they could camp out a while at the kuiper belt first.

On the other hand that means that planets per se don't really have value to them, so if we somehow get them to want to declare war on us they'd probably just use a big kinetic impact to blast our planet back to the Hadean age and be done with it. Yet on the other other hand (we're assuming three-armed aliens here) by that time we would probably also have moved into space habitats so maybe they would need to come fight it out after all.

Gomar
2012-Oct-19, 12:06 AM
I do not see any sane (economical, physical, ethical etc) reason to do invasion as depicted in SF.

So I guess the Europeans invaded North&South America, Australia, etc. because they were
insane?! ok, surely forcing the natives to convert to worship their god, speak Spanish, English,
French, taking thousands as slaves, killing the natives and taking their land... well, that does
qualify as insanity.

Who knows what motives the aliens have for flying all over the galaxy. Could be to wipe out
any species that refuses to worship a 50foot green alien god with a 5' tail, 2 heads, 16 eyes,
4 hands, who (according to the Zorkonians) created the universe.

Van Rijn
2012-Oct-19, 01:15 AM
So I guess the Europeans invaded North&South America, Australia, etc. because they were
insane?!


Europeans certainly had an economic motive for invasion (one of the motives listed in the bit you quoted).

cjameshuff
2012-Oct-19, 01:23 AM
The thing is, the requirements of interstellar travel enforce some degree of sanity. At 0.1c, 1 kg has kinetic energy equivalent to 5 grams. That is, with acceleration from an external source (avoiding the rocket equation) at perfect efficiency, you have to annihilate 5 grams of matter per kilogram of ship mass to get your ship up to speed. That's a 110 kt nuclear device per kilogram of starship, just for 0.1c. Say you use a antimatter rocket with an effective exhaust velocity of 100000 km/s. For a total delta-v of 0.2c, almost half your starting mass is consumed for propellant, and half of that is antimatter! Crazy people don't get to the point where they can throw around kiloton to megaton quantities (actual mass, not TNT equivalent) of antimatter. For lesser propulsion technologies, the mass ratios quickly become enormous. Either way, the cost in energy and other resources is huge.

The rest of the mass has to be automation that can be relied on to carry out a conquest, or habitats and life support to maintain a crew for centuries to millennia. Then there's the equipment for actually conducting the war. And if the target puts up a fight, any given starship has a very good chance of getting crippled before it brakes into the target system, so add more mass for ship defenses, and then multiply the total requirements and send multiple independent ships, because you really don't want to fail. In all, you're expending enough effort to start multiple colonies just to have a fair shot at conquest...while also putting your more-advanced technology where a newly made and freshly antagonized enemy can capture it. (That's if you're actually sure your technology is more advanced, and that it still is more advanced when you arrive.)

I'm not claiming advanced civilizations will have outgrown war or anything. The difficulty, cost to benefit ratios, and risks involved in conducting interstellar warfare are simply such that I can't see a civilization prone to such irrational actions actually being functional enough to carry them out.

swampyankee
2012-Oct-19, 02:28 AM
While I disagree with CJamesHuff about the reactions of terrestrial governments to a putative alien horde descending on the planet -- history is rife with groups joining the invaders to attack a third party -- for example King Phillip's War and the Pequod War, I must agree with his/her statement that interstellar war, at least within currently known physics, is almost certainly completely impractical.

IsaacKuo
2012-Oct-19, 06:20 AM
I have thought of various ways to engage in practical interstellar war--including "invasions", of sorts, but I don't feel like engaging in the sort of lengthy go-nowhere discussion that would result here. The big thing to get around is the idea that you have to bring everything with you over interstellar distances. If the target system has something like an Oort cloud, attackers could use them in various ways to level the resource playing field. Also, established interstellar aliens can very easily have overwhelming advantages in the energy and power playing fields.

It's actually comparatively easy to stop a relativistic impactor, compared to a low velocity impactor. If you intercept a relativistic impactor, its own incredible kinetic energy is used against itself. But alien attackers could instead use relativistic impactors and/or interstellar lasers indirectly to nudge Oort cloud objects into low velocity impactors (less than 1000km/s). These would be a lot tougher to defend against.

In addition, attackers could land low mass "seed" robots onto Oort cloud objects to mass produce munitions/missiles/drones/etc from those resources. They can take advantage of relativistic impactors and/or interstellar lasers for power and propulsion, to get around the lack of solar power and limitations of atomic power.

The point is, you do NOT have to bring everything with you. You can take advantage of resources nearby the target, for raw mass. Energy can be sent across interstellar distances with decent efficiency, and the energy/power available to established interstellar aliens dwarfs the energy/power available to a nascent single system civilization.

MaDeR
2012-Oct-19, 11:48 AM
Depends
Of course everything depends on details. While you are right tech difference alone is not everything, it certainly skews chances very much in aliens favor.


So I guess the Europeans invaded North&South America, Australia, etc. because they were
insane?!
Analogy fails IMO. Main reason was resources. In space there are a lot of resources. I think we can safely assume that life, especially inteligent life, originated only on very small fraction of all solar systems in galaxy. Rest just wait for harvest - without any pesky natives. While I think natives are screwed if anyone gets here unharmed, why go for costly trouble?


Who knows what motives the aliens have for flying all over the galaxy. Could be to wipe out any species that refuses to worship a 50foot green alien god with a 5' tail, 2 heads, 16 eyes, 4 hands, who (according to the Zorkonians) created the universe.
Insane reasons, as I said. One can only hope such irrationality will wipe out civilizations like these before they are capable of reaching stars.


I'm not claiming advanced civilizations will have outgrown war or anything. The difficulty, cost to benefit ratios, and risks involved in conducting interstellar warfare are simply such that I can't see a civilization prone to such irrational actions actually being functional enough to carry them out.
It is doubtful for me too, but thinking up possible ways to do it is fun.

Going back to possible conflict scenarios... what else is possible? We are leaving alien invasion as depicted in SF, because it is no fun (and make very, very short movie) to show inevitable doom. Already mentioned relativistic sabots are only one possibility. What about gray goo? That stuff would be truly nasty and basically impossible to fight by civilization that cannot make thier own nano (to create counter-goo). Payload size would be small (nano grows from local resources, after all) and with very high chance of avoid detection. No big starships with fragile crew needed.

caveman1917
2012-Oct-19, 12:24 PM
The thing is, the requirements of interstellar travel enforce some degree of sanity.

Only if you're looking to diminish the travel time. If you're going in large slow-moving space habitats it doesn't matter if it takes you thousands of years to get somewhere, it's not like you're leaving your home behind in the meantime, more like taking it with you so to speak.


The difficulty, cost to benefit ratios, and risks involved in conducting interstellar warfare are simply such that I can't see a civilization prone to such irrational actions actually being functional enough to carry them out.

Cost to benefit ratios are inherently based on value judgements and I wouldn't immediately presume their values are akin to ours.

For example suppose it takes the loss of a thousand humans to kill one alien. We would say the cost to benefit ratio precludes such strategy but that relies on us assigning relative values to those outcomes, or on our utility functions so to speak. If they assign a utility to killing one human as higher than the inverse utility of losing a thousand of their own, they will use that strategy even when they are completely rational and using cost to benefit analysis. Cost to benefit ratios are meaningless on their own, they require subjective utility functions to work with.

cjameshuff
2012-Oct-19, 02:38 PM
Only if you're looking to diminish the travel time. If you're going in large slow-moving space habitats it doesn't matter if it takes you thousands of years to get somewhere, it's not like you're leaving your home behind in the meantime, more like taking it with you so to speak.

Successfully making such trips, in closed systems with no outside source of energy or material, will require careful avoidance of any unnecessary waste. If they're prone to such extravagantly wasteful actions as interstellar war, they either won't successfully launch, or their long-derelict vessels will pass through our system, only causing harm if they hit something.

Noclevername
2012-Oct-19, 03:01 PM
If they have some form of suspended animation or cryosleep technology, travel time becomes irrelevant-- they wake just as belligerent as when they went to sleep.

JCoyote
2012-Oct-21, 03:57 AM
If they have some form of suspended animation or cryosleep technology, travel time becomes irrelevant-- they wake just as belligerent as when they went to sleep.

Also don't discount biological differences. WE as mammals may be ill-suited to cryogenic freezing, but other species aren't so hobbled. Species could be longer lived, naturally hibernatory, any number of factors, that could make them better suited to long voyages than us... and all biologically feasible.

Colin Robinson
2012-Oct-21, 04:19 AM
Also don't discount biological differences. WE as mammals may be ill-suited to cryogenic freezing, but other species aren't so hobbled. Species could be longer lived, naturally hibernatory, any number of factors, that could make them better suited to long voyages than us... and all biologically feasible.

One of the major reason being frozen doesn't suit us earthlings, is that water expands when it turns into ice. When it does that, it breaks up the structures in our cells. A species whose cytoplasm contained a solvent other than water (ammonia for instance) would not have this problem.

The conclusion may be drawn that while an H2O-based cytoplasm could quite viable for simple organisms like bacteria, jellyfish and human beings, you definitely wouldn't expect water to be present in the cells of those truly advanced life-forms who explore and conquer galaxies.:)

headrush
2012-Oct-21, 08:59 AM
There are other methods than total freezing though. Being very cold but not actually frozen can be used to reduce oxygen requirements and just let the body tick over at a reduced rate, basically hibernation. Then there is the possibility of anti-freeze based blood, which I seem to remember they found a gene for in a deep sea creature. Also, Clarence Birdseye discovered the principles behind flash freezing so that the ice crystals don't get time to grow. This might be expanded upon and adapted for use in space travel.

caveman1917
2012-Oct-21, 05:35 PM
Successfully making such trips, in closed systems with no outside source of energy or material, will require careful avoidance of any unnecessary waste. If they're prone to such extravagantly wasteful actions as interstellar war, they either won't successfully launch, or their long-derelict vessels will pass through our system, only causing harm if they hit something.

I was assuming that they have been spacefaring for quite a while already, so they would already have plenty of experience with space habitats and the related issues. Perhaps most of their population could already be living in habitats floating around their solar system or on long exploratory voyages.

Gomar
2012-Nov-05, 03:21 AM
interstellar war, at least within currently known physics, is almost certainly completely impractical.

Why should there be a war with aliens at all? As I had stated previously, aliens could just send
a being who will pretend to be, or will be revealed as, the messiah. Then humans will just
simply surrender to him/her/it believing that God (or his son) has arrived.
Ifcourse which religion will claim the messiah as theirs is a toss up.

Also, how humans can fight an alien force that has managed to fly across the galaxy
is unknown to me. Why cant aliens just fire a missile into the north pole, and blow up and
melt the ice caps, flooding the planet?

Jens
2012-Nov-05, 03:59 AM
Why should there be a war with aliens at all? As I had stated previously, aliens could just send
a being who will pretend to be, or will be revealed as, the messiah. Then humans will just
simply surrender to him/her/it believing that God (or his son) has arrived.
Ifcourse which religion will claim the messiah as theirs is a toss up.


Then we must have surrendered a lot, because there is a long list of people who have pretended to be the messiah. Look here (http://en.wikipedia.org/wiki/List_of_messiah_claimants). The alien guy would end up being another name in the Wikipedia list. If claiming that you were the messiah gave you the surrender of humanity, I can guarantee you A LOT of people would be doing it.

Jens
2012-Nov-05, 04:01 AM
Also, how humans can fight an alien force that has managed to fly across the galaxy
is unknown to me. Why cant aliens just fire a missile into the north pole, and blow up and
melt the ice caps, flooding the planet?

I think that if they launched a missile with enough energy to melt the ice caps, the melting ice caps would probably be the least of our worries at that time.

swampyankee
2012-Nov-08, 02:31 PM
Why should there be a war with aliens at all? As I had stated previously, aliens could just send
a being who will pretend to be, or will be revealed as, the messiah. Then humans will just
simply surrender to him/her/it believing that God (or his son) has arrived.
Ifcourse which religion will claim the messiah as theirs is a toss up.

Also, how humans can fight an alien force that has managed to fly across the galaxy
is unknown to me. Why cant aliens just fire a missile into the north pole, and blow up and
melt the ice caps, flooding the planet?

Well, melting the ice caps in the Arctic won't significantly raise sea level, although the amount of energy required to do so would tend to be less than healthful.

As to the first? While there are lots of people who have poorer critical facilities than Bullwinkle T Moose, there are also a lot who have somewhat better ones. Recent messianic cults (Jim Jones, Heaven's Gate, Branch Davidians) have simply not have enough followers to force a surrender. I won't rule out a major world leader falling for something like this, but most of them are either well-schooled in ** detection or are so egocentric as to consider themselves as the new messiah.

Gomar
2012-Nov-09, 03:59 PM
Then we must have surrendered a lot, because there is a long list
of people who have pretended to be the messiah.

True. However, only one took hold in society, a man referred to as Jesus. Whether or not he
was an alien is debatable. I have read books and web sites that claim Jesus was, and
Adam&Eve were alien settlers.


Look here (http://en.wikipedia.org/wiki/List_of_messiah_claimants).
The alien guy would end up being another name in the Wikipedia list.

Perhaps next time the messiah will be female. Or, for all I know, the Greeks were right
and Gods are human-animal hybrids; so a horse with a human head will walk around preaching
the gospel.


If claiming that you were the messiah gave you the surrender of humanity, I can
guarantee you A LOT of people would be doing it.

ok, but if they can perform miracles, such as curing the sick, the lepers, the blind, the deaf,
curing AIDS, cancer, etc. then yes humanity will surrender ASAP.

headrush
2012-Nov-09, 04:19 PM
True. However, only one took hold in society, a man referred to as Jesus.
Which society ?
There are messianic cultures other than western ones.

swampyankee
2012-Nov-10, 02:23 AM
True. However, only one took hold in society, a man referred to as Jesus. Whether or not he
was an alien is debatable. I have read books and web sites that claim Jesus was, and
Adam&Eve were alien settlers.



Perhaps next time the messiah will be female. Or, for all I know, the Greeks were right
and Gods are human-animal hybrids; so a horse with a human head will walk around preaching
the gospel.



ok, but if they can perform miracles, such as curing the sick, the lepers, the blind, the deaf,
curing AIDS, cancer, etc. then yes humanity will surrender ASAP.

Leprosy is treatable. For the others? We already heal the sick. Indeed, we can prevent sickness by a well-proven technology called vaccines. For the others? Given the likely biological differences, the chances that an alien posing as a messiah would be able to miraculously cure that after we figure out how without its help.

In any case, modern medicine can do all of those things, and physicians and surgeons have not been given control of the world ;)

Paul Wally
2012-Nov-10, 10:58 AM
In any case, modern medicine can do all of those things, and physicians and surgeons have not been given control of the world ;)

Yeah but send those same physicians and surgeons back in time a couple of thousand years, then it's a different story.

swampyankee
2012-Nov-10, 02:02 PM
Yeah but send those same physicians and surgeons back in time a couple of thousand years, then it's a different story.

Until they run out of the supplies they'd need. Or get burned as witches.

publiusr
2012-Nov-10, 07:12 PM
I'm reminded of Asimov's story My Son the Physicist: http://en.wikipedia.org/wiki/My_Son,_the_Physicist
Just keep talking

Noclevername
2012-Nov-10, 08:57 PM
If they understand humans well enough to know that we sometimes worship messiahs, then they'd also be able to manuipulate us in other ways, including some that don't require physical travel. They'd bombard us with subliminal signals from their homeworld until we just give up and submit voluntarily.

Spam IN SPACE!

Gomar
2012-Nov-11, 04:19 PM
the chances that an alien posing as a messiah would be
able to miraculously cure

I am sure any aliens who can travel from their planet to Earth, or across the galaxy as easily as
I can fly from NYC to Vegas, will be able to cure cancer and other diseases eventhough their
biology is different from ours. Humans do treat dogs, dolphins, chimps, etc.

Why does the alien messiah have to look human at all? Why cant it be a 15 foot reptile with
a 5' tail, scales, and a jaw of an aligator? As long as it cures AIDS, cancer, the economy,
and restores power to NJ etc.

cjameshuff
2012-Nov-11, 05:19 PM
I am sure any aliens who can travel from their planet to Earth, or across the galaxy as easily as
I can fly from NYC to Vegas, will be able to cure cancer and other diseases eventhough their
biology is different from ours. Humans do treat dogs, dolphins, chimps, etc.

Those all have practically identical biochemistry to ours. No matter how advanced an extraterrestrial species' own medicine is (and advanced medicine is not implied by advanced technology in other areas), they'd be starting over from scratch with us.

Paul Wally
2012-Nov-11, 11:38 PM
I am sure any aliens who can travel from their planet to Earth, or across the galaxy as easily as
I can fly from NYC to Vegas ...

That's if the life-expectancy of the aliens is 17.5 Billion years in the frame of the galaxy, and if they travel at the speed of light.

Gomar
2012-Nov-13, 02:19 AM
That's if the life-expectancy of the aliens is 17.5 Billion years in the frame of the galaxy, and if they travel at the speed of light.

Did you mean >M<illion not >B<illion? I dont see how any species could be older than the univers.

Noclevername
2012-Nov-14, 06:56 PM
If they travel at the speed of light, no time will pass for them and their lifespan won't matter.