IOT POLY ENGINEERING 2-3 COMMUNICATION TECHNOLOGY October 21, 2010 "In the deepest sense the search for extraterrestrial intelligence is a search for ourselves."

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POLY ENGINEERING2-3

COMMUNICATION TECHNOLOGY October 21, 2010

"In the deepest sense the search for extraterrestrial intelligence is a search for ourselves." - Carl Sagan

Are you smarter than an extraterrestrial space alien?

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POLY ENGINEERING2-3

As we go through this lesson, you should letter your answers to these questions.

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"In the deepest sense the search for extraterrestrial intelligence is a search for ourselves." - Carl Sagan

This is the radio telescope located at Arecibo, Puerto Rico. The facility is a part of the NSF operated by Cornell University.

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The Arecibo message was composed by Professors Frank Drake and Carl Sagan of Cornell University. The message was beamed into space a single time via frequency modulated (FM) radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope on 16 November 1974. It was aimed at the star cluster M13 about 25,000 light years away. M13 is a large collection of stars that was available in the sky at the time and place of the ceremony. The message was transmitted at a frequency of 2380 MHz and modulated by shifting the frequency by 10 Hz, with a power of 1000 kW. The "ones" and "zeroes" were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes.

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POLY ENGINEERING2-2

Reminder from last week’s lessons:Radio:

Pulse Modulation: turn the voltage (sine wave) on/off (Morse Code)

Amplitude Modulation: vary the amplitude (peak-to-peak) voltage

Frequency Modulation: vary the frequency (speed)

PM

AM

FM

Encoder: Devices that convert sound and information into a modulated sine wave

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00000010101010000000000001010000010100000001001000100010001001011001010101010101010100100100000000000000000000000000000000000001100000000000000000001101000000000000000000011010000000000000000001010100000000000000000011111000000000000000000000000000000001100001110001100001100010000000000000110010000110100011000110000110101111101111101111101111100000000000000000000000000100000000000000000100000000000000000000000000001000000000000000001111110000000000000111110000000000000000000000011000011000011100011000100000001000000000100001101000011000111001101011111011111011111011111000000000000000000000000001000000110000000001000000000001100000000000000010000011000000000011111100000110000001111100000000001100000000000001000000001000000001000001000000110000000100000001100001100000010000000000110001000011000000000000000110011000000000000011000100001100000000011000011000000100000001000000100000000100000100000001100000000100010000000011000000001000100000000010000000100000100000001000000010000000100000000000011000000000110000000011000000000100011101011000000000001000000010000000000000010000011111000000000000100001011101001011011000000100111001001111111011100001110000011011100000000010100000111011001000000101000001111110010000001010000011000000100000110110000000000000000000000000000000000011100000100000000000000111010100010101010101001110000000001010101000000000000000010100000000000000111110000000000000000111111111000000000000111000000011100000000011000000000001100000001101000000000101100000110011000000011001100001000101000001010001000010001001000100100010000000010001010001000000000000100001000010000000000001000000000100000000000000100101000000000001111001111101001111000

This is the binary code sent from Arecibo observatory on 16 November 1974.

?

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Cryptography (or cryptology; from Greek κρυπτός, kryptos, "hidden, secret"; and γράφω, gráphō, "I write", or -λογία, -logia, respectively) is the practice and study of hiding information. Modern cryptography intersects the disciplines of mathematics, computer science, and engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce.

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As a clue to decoding the message, count the number of “ones” and the total number of binary digits, “ones” and “zeros”. Also count the number of rows and columns.

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The binary digits form a pattern of 41 columns by 41 rows, .. less two binary digits at the end.

There are a total of (41)(41) =1681 less 2 , or 1679 binary digits.

Of the 1679 binary digits, there are 397 ‘ones’ and 1282 ‘zeros’.

1679 is the product of two prime numbers: 23 and 73.

397 is a prime number.

There are two ways to arrange the 1679 binary digits as a pattern of rows and column using prime numbers: a pattern of 23 rows deep by 73 columns wide, or a pattern of 73 rows deep by 23 columns wide.

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POLY ENGINEERING2-3

There are two ways to arrange the 1679 binary digits as a pattern of rows and column using prime numbers: a pattern of 23 rows deep by 73 columns wide, or a pattern of 73 rows deep by 23 columns wide.

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POLY ENGINEERING2-3

There are two ways to arrange the 1679 binary digits as a pattern of rows and column using prime numbers: a pattern of 23 rows deep by 73 columns wide, or a pattern of 73 rows deep by 23 columns wide.

You may now begin to decode the message here in class, and complete it at home for homework.

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POLY ENGINEERING2-3

There are two ways to arrange the 1679 binary digits as a pattern of rows and column using prime numbers: a pattern of 23 rows deep by 73 columns wide, or a pattern of 73 rows deep by 23 columns wide.

The next slide shows the decoded message.

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POLY ENGINEERING2-3

There are two ways to arrange the 1679 binary digits as a pattern of rows and column using prime numbers: a pattern of 23 rows deep by 73 columns wide, or a pattern of 73 rows deep by 23 columns wide.

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"Here is how we count from one to ten. Here are five atoms that we think are interesting or important: hydrogen, carbon, nitrogen, oxygen and phosphorus. Here are some ways to put these atoms together that we think interesting or important - the molecules thymine, adenine, guanine and cytosine, and a chain composed of alternating sugars and phosphates. These molecular building blocks are put together to form a long molecule of DNA comprising about four billion links in the chain. The molecule is a double helix. In some way this molecule is important for the clumsy looking creature at the center of the message. That creature is 14 radio wavelengths or 5 feet 9.5 inches tall. There are about four billion of these creatures on the third plant from our star. There are nine planets altogether, four big ones toward the outside and one little one at the extremity. This message is brought to you courtesy of a radio telescope 2,430 wavelengths or 1,004 feet in diameter. Yours truly."