The document discusses past and proposed methods for communicating with extraterrestrial intelligence (CETI), including searching for signals (SETI), sending messages into space, and developing artificial languages for cosmic communication. It describes the Lincos language designed by Hans Freudenthal in 1960 to introduce logical and mathematical concepts, and proposes an algorithmic language called CosmicOS inspired by Lincos but focused on programming rather than conversation. The document concludes by noting potential studies of understandability for these languages and their use in machine learning.

1. Communication with
Extra Terrestrial Intelligence
(CETI)
Un-Distinguished Lecture Series
Immad Naseer
May 11th, 2007

2. SETI
• Searching for and analyzing signals that
could have been sent by aliens.
• Proactively sending out signals into space in
the hope that they will be picked up by an
intelligent life form.

3. Received signals
• In spite a lot of searching, SETI hasn’t met with any
real success thus far.
• The only exception was a strong narrowband radio
signal detected by the Big Ear telescope of Ohio
State university on August 15, 1977
• The signal lasted for 72 seconds, and wasn’t
detected again in spite of a lot of searching

4. The WOW! signal
The circled code 6EQUJ5 describes the intensity variation
of the signal

5. Why haven’t we been contacted?
• There might be no “intelligent” life out there.
• They are still trying to contact us, waiting for their
signals to be picked by us.
• They may be way more advanced than us, and
waiting for us to “grow up” before we join the
cosmic society.

6. Sent messages
• Arecibo message
• Pioneer plaque
• Voyager record
• Encounter 2001 message
• Encounter 2003 message

7. Arecibo message
• A radio message beamed towards the globular star
cluster M13 (distance: 25,000 light years) in 1974,
from the Arecibo radio telescope
• Created by Dr. Frank Drake and Carl Sagan
• The message consisted of 1679 binary digits.
1679 = 73 * 23 (a semi prime)

8. Pioneer plaque
• A pair of aluminums plaques placed on the Pioneer 10 &
11 spacecraft, feature a pictorial message from humanity.
• The pioneer spacecrafts were the first human-built objects
to leave the solar system.
• The mean time for the spacecraft to come within 30
astronomical units of a star is longer than the current age of
our galaxy.

10. Voyager golden record
• A phonograph record included in the two
Voyager spacecrafts launched in 1977
containing sounds and images of earth.
• The cover of the record contained symbolic
instructions on how to play the record.

11. “Communicating” with ET
• Communicating anything “non-trivial” will
require some sort of language.
• Since they will probably not share a
language with us, we will have to invent a
new language for communicating with them.

12. Lincos – Lingua Cosmica
• An artificial language for cosmic
communication designed by Dr. Hans
Freudanthal in 1960.
• It was designed to be capable of
encapsulating the whole bulk of our
language. Part II of the book was promised
in Part I, but never came out.

13. Lincos
The book is divided into four sections.
Mathematics
Time
Behavior
Space, mass and motion
The book follows the policy of introduction by
description rather than definition.

14. Lincos – Mathematics
> | < | = | + | - | <> | <= | => | . | . . | . . . | .
. . . . . . | 1 | 10 | 11 | 111 | a | b | c | ->
| ? | / | / | <->
Lincos words are presented without any
context, to stress their individuality.

15. Lincos – Mathematics
.....>...
...<.....
....=....
....+..=......
Illustrating basic mathematical operations
through ostensive numerals.

16. Lincos – Mathematics
.=1
. . = 10
. . . = 11
. . . . = 100
Ostensive numerals replaced by
algorithmic
ones.

17. Lincos – Mathematics
100 > 10
100 + 11 > 10 + 11
100 + 1 > 10 + 1
100 + 110 > 10 + 110
100 + a > 10 + a
Introduction to a variable.

18. Lincos – Mathematics
a > 100 => a > 10 (punctuation removed)
a < 111 => a< 1110
a + b = c => a = c – b
a + b = c => b = c – a
a = c – b => a + b = c

19. Lincos – Mathematics
?x . x + 10 = 111
x + 10 = 111 => x = 101
?x . a< b ^ x + a = b
a < b ^ x + a = b => x = b – a
Questions and answers are introduced.

20. Lincos – Mathematics
1/11 = 0,01010101 Etc.
1/101 =0,0011001100110011 Etc.
a0 = 1
a1 = aa0 = a
a10 = aa1 = aa
a11 = aa10 = aaa
Etc.
Introduction to “etc”

21. Lincos – Mathematics
The book goes on to introduce propositional
logic, set theory, and first-order logic.

22. Lincos – Time
Similar to the introduction of numbers, time-
signals are introduced as ostensive,
ideophonetic signs.
Dur ------ = Sec A

23. Lincos – Time
Ecc ___ -----
V x.y. Fre x = A ^ Fre y = B ^ x Ant y
x Ant y  y Pst x
The concept of ‘before’ and ‘after’

24. Lincos – Time
After some time, a clock is installed on a
particular frequency. It ticks per second
through all Lincos programs onwards.
The receiver is instructed on how to read the
clock.

25. Lincos – Time
Arbitrary “events” are introduced by a wild
complex of radio signals.
P t2 . (event)
t1
T1 Usq T2 Fit P (report on event)

26. Lincos – Behavior
• Behavior requires the presence of actors.
Actors Ha, Hb and Hc are introduced, and
the distinctness of each actor is stressed.
• Since mathematics is the only subject we
know till now, the actors start conversing
about mathematics.

27. Lincos – Behavior
Ha Inq Hb ?x. 10x = 101
Hb Inq Ha 101/10
Ha Inq Hb Ben (good)
Conversations require the concept of good
(Ben) and bad (Mal), in addition to true (Ver)
and false (Fal)

28. Lincos – Behavior
Ha Inq Hb ?x 100x = 1010
Hb Inq Ha 1010/100
Ha Inq Hb Mal
Hb Inq Ha 1/10
Ha Inq Hb Mal
Hb Inq Ha 101/10
Ha Inq Hb Ben

29. Lincos – Behavior
Ha Inq Hb ?x. x10 = 11001
Hb Inq Ha 101x101 = 11001
Ha Inq Hb Mal
Hb Inq Ha 101x101 = 11001 ∈Ver
Ha Inq Hb Ver Tan Mal . x10 = 11001 => x=101
Hb Inq Ha 101 ∨ -101
Ha Inq Ha Ben
True but Bad

30. Lincos – Behavior
Ha Inq Hb ?x 10x10 = x
Hb Inq Ha 10x10=10
Ha Inq Hb Mal
Ha Inq Hc ?x 10x10 = x
Hc Inq Ha 10x10 = 100
Ha Inq Hc Ben
Hc >IQ Hb Hc has greater IQ than Hb

31. Lincos – Behavior
• The book goes on to give more complex
examples of behavior such as
– Honest quoting
– Animals cannot speak
– Understanding as recognizing what another
person said.
– Polite speech
– Games. Minimax principle etc.

32. Lincos – Space, motion and mass
• So far, the actors Ha, Hb and Hc were
ghosts.
• Distance of place recognized by delay of
signals.
• Three dimensional space, volume
introduced.
• Movement.
• Kepler’s laws of motion. Relativity etc.

33. Encounter 2001 & 2003
messages
• Among other information, contained messages
inspired from the Lincos language.
• In addition to words, contains crude pictures of the
solar system, mountains, male and female humans,
DNA, continents etc.
• Physics, chemistry and astronomy are described, but
complicated human behavior is not shown.

34. Algorithmic languages
• An algorithm can speak a thousand words!
• Instead of introducing game-centric behavior
of humans, why not build a game for them
that they can play themselves?

35. CosmicOS
• Inspired by Lincos, but instead of a language for
conversation, introduces a programming language
based on lambda calculus.
• After the introduction of the basics, introduces the
semantics of the Java bytecodes.
• Finally, a game is described using Java’s bytecodes.
The game’s logic is fully described though it is not
rendered anywhere.

36. CosmicOS
The message as a single image

37. Conclusion
• Perhaps there should be some “understandability”
studies for some of these languages.
• Apart from ET, they can also be used as input for
some machine learning algorithms, particularly
CosmicOS.
• For those interested, there are several artificially
constructed messages available on the internet to
decode.

38. References
• Interstellar communication, http://www.matessa.org/~mike/inter-comm.html
• Arecibo message, http://en.wikipedia.org/wiki/Arecibo_message
• Pioneer plaques, http://en.wikipedia.org/wiki/Pioneer_plaque
• Voyager record, http://en.wikipedia.org/wiki/Voyager_Golden_Record
• Encounter 2001 message, http://www.matessa.org/~mike/2001.html
• Encounter 2003 message,
http://web.archive.org/web/20030705140835/teamencounter.com/missions/message.asp
• LINCOS: Design of a Language for Cosmic Intercourse. Hans Freudenthal. North-Holland
Publishing Company, Amsterdam, 1960.
• Lincos, http://www.matessa.org/~mike/lincos.html
• CosmicOS, http://cosmicos.sourceforge.net/