OK, Say You're an Extraterrestrial ...

[NW-Bound]

Quote:

Originally Posted by M Paquette Contact, Carl Sagan (1985) A message from a star system 25 light years away is received. The message includes a basic communications primer, and ends with plans to construct a very large machine.

I am not into SciFi, so have not read the book but did see the movie starring Jodie Foster.

[growing_older]

Quote:

Why would have a prime number width or height make it easier to guess--I haven't figured that out.

Suppose you are using a video frame 1024 x 768. That means there are 786,432 elements in each frame. We know they are arranged in 768 rows of 1024 pixels each, but it could have been 1024 rows of 768 pixels or 512 rows of 1536 pixels or 2048 rows of 384 pixels, and so on. Many many possible combinations.

Now of course this isn't necessarily an insurmountable problem and some combinations are much more likely than others. We are unlikely to use superpanaromic choices like 24 rows of 32,768 pixels even if the math makes it possible. Likewise, your suggestion that we send square frames makes is easy to guess any number is the square. If it's a square frame, the prime number of pixels reinforces that it MUST be a square because a 1009 x 1009 frame of 1,018,081 pixels cannot be divided any other way, but even if it were simply 1000 x 1000 the resulting 1,000,000 pixels are easy to see as a square and the most likely choice, even if other possibilities (500 x 2000) do exist.

[Totoro]

Brace yourself for a long post

Are you going for 'hard scifi' as in that you need to work within current known science? In that case forget about FTL communication, as it means essentially you are allowing time traveling and break causality ..

So think about how you want the FTL communication setup. What rules does it adhere to? Or do you want to sidestep the issue and not explain it? As a sci-fi reader i prefer stories working within current physics. I don't mind some liberties taken though (e.g. teleportation, FTL, mind reading) as long as you set the rules and remain self-consistent.

The other item you are talking about is the difficulty of establishing a common language. There you have first the issue of the signal carrier (radio waves, quarks, neutrinos, particles?) and then how to encode the language within the signal carrier (frequency modulation, phase-shift keying, amplitude modulation, ..).

After that, you need somehow to convey the rules (grammar) and vocabulary of the language. This issue is well known in formal mathematics. Basically, in order to describe a language you need a language to describe it with. Humans solve this by using the "pointing language" (point at object and name object) to start.

Carl Sagan was mentioned before, his solution in Contact is to use mathematics within a radio signal. This on the assumption that radio is simple and universal enough for multiple species and mathematics (numbers) is a universal construct that all species need to develop. Neither is a given though, but a reasonable assumption.

If I were to design a message I'd start with the carrier using simple on/off signaling using the full spectrum of light that a typical sun uses. This because any mobile species likely has vision, thus will detect this object. I'm disregarding any power constraints here for sending this signal.

Next, how to start interaction. What you want is a response from the listener that shows he understands what you are sending. Prime numbers can be used, the fibonacci sequence too. Any number sequence actually. What might work is leaving out a number in the sequence and listen for the missing number.

As soon as you receive the missing number, you shift to another sequence with another missing number to double check. You might narrow the frequencies as time goes on too.

Now you have a common carrier and (finally) a way to exchange numbers!

How to go from there to actual language I haven't figured out yet.

I do believe simply sending a bitmap is not as easy as you make it to be. How will you know any sent signal is a bitmap? How is it encoded (binary? why?) How many bits per pixel? What color does every bit indicate?

[heeyy_joe]

OK, I'll play along.

"I'm an Extraterrestrial".

Now: Call me a taxi.

[omysteve]

Haven't read the entire thread. But if you're looking for what appears (from watching episode 1) to be shaping up as a really good sci-fi series check this one out - Extant http://en.wikipedia.org/wiki/Extant_(TV_series)

[Animorph]

Quote:

Originally Posted by TromboneAl That's my plan at this point. A nice high-res B&W movie, say 1024 by 1024 pixels. It starts with an image of the probe, showing it next to a planet. The planet shows lights, suggesting a civilization. Then the image zooms out to show the rest of the galaxy, and zooms into other planets that have similar lights. Next, back to an image of the probe and a planet, showing slow (light-speed) signals between the two. Then it zooms out again, and should faster signals. But here's a question: Why do the pixel width and height have to be prime numbers? I know Sagan did that, but I'm not sure it's necessary. If the first frame is a square of rectangles along the outer borders, I think that might clue in the receiving civilization. How would it help if the image were 1009 x 1009?

If it was something like 1024 x 1024 we would have to try lots of possible combinations to decode it. 512 x 2048, 256 x 4096, etc., though not too hard these days. The prime numbers allow only one solution. Still have to figure out which side is up though.

[freebird5825]

Quote:

Originally Posted by brewer12345 How did I know that a thread about extraterrestrials would include lots about a probe?

Skip forward to 2:17 in this clip

ID4 end air battle - YouTube

I couldn't find the diner scene where he talked about his alien abduction experience. It was a classic!

[Keim]

Quote:

Originally Posted by heeyy_joe OK, I'll play along. "I'm an Extraterrestrial". Now: Call me a taxi.

Okay. You're a taxi. Feel better?

[yakers]

We had gathered on the second moon of Anzor, a challenging development. A new, the 11th, type of sentient species had been identified, they called themselves ‘humans’. We had to decide did we want to study them more or initiate direct contact. An unusual species, so far they had remarkable achievements both positive and negative. Their technology had led them to the lowest level of interstellar species but we know from observing them and from our own species experience that they may have a discontinuous development and we needed to be prepared to initiate contact or deal with their eventual emergence.

Initially we would monitor them, XST (X-space/time) which would provide a virtually impossible barrier for them to grasp until they eventually did……

[heeyy_joe]

Quote:

Originally Posted by Keim Okay. You're a taxi. Feel better?

https://www.youtube.com/watch?v=XY_w...:laugh::laugh:

[dallas27]

Otherways to make contact.... Holographic portray the aliens on the planet surface, would be immediate culture shock. Also, telepathy of course.

Then there are always crop circles.

I alway thought projecting a movie onto the stratosphere would be cool. Aurora-like.


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[ls99]

'been accused of being extraterrestial on and off sice around age ten. This in spite of lacking a cone head..

No need for all the fancy technical stuff. Thought transfer is instanenous. Twins often have it. Not sure other civilaztions have the same herding instinct as air breathing earthlings, or have any interest in what could be considered a miserably failed social experiment of earthlings..

At one time during a discussion of aliens visiting earth, Edwart Teller supposed said: we are already here.

[TromboneAl]

Quote:

Originally Posted by growing_older If it's a square frame, the prime number of pixels reinforces that it MUST be a square because a 1009 x 1009 frame of 1,018,081 pixels cannot be divided any other way, but even if it were simply 1000 x 1000 the resulting 1,000,000 pixels are easy to see as a square and the most likely choice, even if other possibilities (500 x 2000) do exist.

Ah, good, that explains it, thanks.

[TromboneAl]

Quote:

Originally Posted by M Paquette There have been a number of SF stories that used contact with an interstellar communications network as a significant element. Here are a few of the better known ones. The Ophiuchi Hotline, John Varley (1977) One plot element involves a 'contact' mechanism that uses a sort of observation post, and a laser communications line which just misses the inner solar system, so space travel by the locals is required to receive the messages. Router, Charles Stross, Asimov's Science Fiction (Sept 2002), also as Accelerando, Chapter 5 (2005) An automated system has installed a local router with faster-than-light connectivity elsewhere. Humanity eventually notices the router and contacts it. Hilarity ensues, including a 419 scam from outer space. Singularity Sky, Charles Stross, 2003 An automated system designed to open (or re-open) communications with civilizations enters a solar system. Since communications implies exchange of information, potentially profitable, a variety of other commerce-oriented systems, researchers of a sort, and other hangers-on follow in the immediate wake of the telephone repairman to take advantage of new opportunities. Hilarity, and an economic singularity, ensues... Contact, Carl Sagan (1985) A message from a star system 25 light years away is received. The message includes a basic communications primer, and ends with plans to construct a very large machine.

Thanks, I'll take a look at those. I've read Contact before and am reading it again right now.

This free PDF book is interesting. It talks about an analogy for understanding signals from an alien civilization: The decryption of dead languages for which we have no information.

It also mentions the Voynich Manuscript, which has never been deciphered.



You can check out some other books I'm reading on this topic here.

[sengsational]

I like the way most SF shows with alians just ignore the whole language thing...they just make everyone speak english (i.e. Star Trek). Except for Darmok, which I thought was a cool episode. But presuming the alians speak english might not be too far from reality since we are not that far from a "universal translator" right now, you have got to expect that a civilization that figured out FTL transmissions will also just be able to tune into our radio and TV and in five minutes, have languages broadcast there figured out. Sort of like what I can do when I encounter a wifi signal "encrypted" with WEP.

[Totoro]

Quote:

Originally Posted by sengsational you have got to expect that a civilization that figured out FTL transmissions will also just be able to tune into our radio and TV and in five minutes, have languages broadcast there figured out.

Given that we still cannot talk to whales and dolphins in a meaningful way and barely understand dogs, horses to train them, I think that's wildly optimistic

[TromboneAl]

Quote:

Originally Posted by Totoro So think about how you want the FTL communication setup. What rules does it adhere to? Or do you want to sidestep the issue and not explain it?

Yes, sidestep it. That puts me somewhere between everything obeys all the laws we know, and REWahoo's "It's science FICTION."

Perhaps I'm being human-centric, but I'd expect that most civilizations of our level, when getting successive 1009 bursts of 1009 bytes (that is 8072 bits) of data would figure out that this might be a bitmap.

In any case, if something like that happens in my book, I think the readers will accept it.

Here's a mockup of a 1009x1009, 8 bits per pixel image:



In reading Contact again, I've concluded that the alien message transmission scheme was much more complicated than necessary just so the suspense of figuring it out could be drawn out.

[M Paquette]

Quote:

Originally Posted by TromboneAl Yes, sidestep it. That puts me somewhere between everything obeys all the laws we know, and REWahoo's "It's science FICTION."

That's your best bet. We don't know how, or if such a thing would work, and if it's not important to your characters or world building, trying to explain it away runs the risk of leaving a lump of exposition that gets invalidated next year, or worse, breaks up your story with an indigestible lump of StarTrekese.

Quote:

In reading Contact again, I've concluded that the alien message transmission scheme was much more complicated than necessary just so the suspense of figuring it out could be drawn out.

You've got it. Sagan's world-building was in service to the larger story, and he used it to pace the middle stretch of the story. It also served to hint at the complexity and multiple layers that his aliens thought in.




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[growing_older]

Quote:

Here's a mockup of a 1009x1009, 8 bits per pixel image

The 8 bits per pixel is a bit of a wildcard here. YOU know 8 bits per pixel and know now to decode them, but the fact that it's eight bits and not half as many 16 bits or twice as many 4 bit pixels is not obvious from the raw data. Likewise, are your 8 bits directly encoding a gray level? If so, which bit is most significant? Or are they some kind of lookup table for color information and more total levels of light/dark/color crammed into groupings. Not to mention more exotic encodings like a few bits for brightness and different bits for hue. All these (and many more) have actually been used in various human systems. It's not necessarily obvious what system we are using, let alone what aliens might think of ours, or try to send us.

A square frame of simply black and white (on/off) pixels might make a logical step as a primer to bridge to whatever n-bit color or greyscale you want to use for more nuanced communication.

[TromboneAl]

Quote:

Originally Posted by growing_older The 8 bits per pixel is a bit of a wildcard here. YOU know 8 bits per pixel and know now to decode them, but the fact that it's eight bits and not half as many 16 bits or twice as many 4 bit pixels is not obvious from the raw data. Likewise, are your 8 bits directly encoding a gray level? If so, which bit is most significant? Or are they some kind of lookup table for color information and more total levels of light/dark/color crammed into groupings. Not to mention more exotic encodings like a few bits for brightness and different bits for hue. All these (and many more) have actually been used in various human systems. It's not necessarily obvious what system we are using, let alone what aliens might think of ours, or try to send us. A square frame of simply black and white (on/off) pixels might make a logical step as a primer to bridge to whatever n-bit color or greyscale you want to use for more nuanced communication.

Yes, I agree. My assumption is that the sending party assumes that the receiver will think "Hey this may be an image," and experiment with the different combinations of bits per pixel, LSB, MSB, color, gray level, etc. As soon as the right combination is hit, the receiver will know immediately.

Here's the current scheme:

1. A burst of 1,018,081 bits of data, a brief pause
2. A burst of 1,018,081 bits of data, a brief pause
3. This continues for a total of 1009 repetitions

The bits in the first and last bursts are all 1s.
All the intervening bursts start with 11111111 and end with 11111111, with all zeroes in between.

That might get the receiver into the right frame of mind.

Also, after that first black with white frame image is sent the next image could look like this, since the probe could take a photo of earth, and use it as part of the movie: