The Following is a Simulation Only!

On Monday, March 26th, 2007 at 6:24:28 a.m. Universal Time the first page of a seven-page interstellar message was received by radio telescopes on the earth.  Scientists have concluded that the radio message could only be the work of an extraterrestrial intelligence.  The radio message came from the star 47 Ursae Majoris in the constellation Ursa Major (i.e., the Big Dipper).  There are two known planets orbiting the star 47 Ursae Majoris.  One A.U. (astronomical unit) is the average distance of the earth from the sun (i.e., 149.6 million kilometers = 93 million miles).  The following table contains a description of the star itself:

47 Ursae Majoris

The following table contains a description of the known planets of the star:

Planets of 47 Ursae Majoris

The following table contains a basic description of the radio signal.  A jansky is a unit which measures the power flux received at the receiver per unit of bandwidth.  One jansky equals 1.0E-26 watts per square meter per hertz.

Radio Signal

If we assume that the radio transmitter is a parabolic dish with a diameter of 100 meters then a received signal strength of 5.0 janskies translates into a power of 31.7 megawatts emitted by the transmitter.  The following table gives some signal strengths of various natural radio sources in the sky at a frequency of 1420 MHz:

Natural Radio Sources

The radio signal from 47 Ursae Majoris is divided into pulses.  Each pulse lasts 0.38 seconds followed by a delay of 0.38 seconds before the next pulse.  Each pulse is rectangular in shape.  Pages are delimited by extended delays lasting 24.32 seconds (64 times the duration of a single pulse).  Each page is repeated 1,024 times before being replaced by the next page.  There are seven pages in total.  Each pulse is frequency shifted relative to the carrier frequency by one of the following 13 values.  We denote each specific frequency shift by a unique letter starting at A.

Frequency Shifts relative to Carrier Frequency

Each frequency shift is 1.189 (i.e., the 4th root of 2.0) times the previous frequency shift.  We can convert the frequency shifts into sound pulses for the purposes of this web site.  This allows us to listen to each page as a piece of interstellar music.

Click on each of the following links to go to the specific page of the interstellar message.  Each page has both a symbol representation and a sound representation plus notes on how to translate the message into English.